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Reactome User's Guide

Introduction

This document is an overview of the Reactome database of biological pathways and processes and its web site. This is not a comprehensive guide, but should provide you with enough information to browse the database and use its principal tools for data analysis. Please read through it and contact us with any comments or questions.

To explain some of the terms used in this User Guide, we have created a Glossary.

What is Reactome?

Reactome is a curated database of pathways and reactions (pathway steps) in human biology. The Reactome definition of a 'reaction' includes many events in biology that are changes in state, such as binding, activation, translocation and degradation, in addition to classical biochemical reactions. Information in the database is authored by expert biologist researchers, maintained by Reactome editorial staff, and extensively cross-referenced to other resources e.g. NCBI, Ensembl, UniProt, UCSC Genome Browser, HapMap, KEGG (Gene and Compound), ChEBI, PubMed and GO. Inferred orthologous reactions are available for over 20 non-human species including mouse, rat, chicken, puffer fish, worm, fly, yeast, rice, Arabidopsis and E.coli.

The Reactome Front Page

This is the normal entry point for most users of Reactome. To view this page, type: http://www.reactome.org into the URL slot on your browser.

Reactome Home Page


This page is divided into six parts:

  • The Banner contains a Reactome icon in the banner, which is interactive and when clicked from elsewhere within the website will bring the user back to the homepage.
  • The Navigation Bar just below the banner has drop down menus giving access to data and functionality available on the Reactome website.
  • Six Tool Buttons on the left-hand side of the page provides shortcut buttons to the most popular analysis tools and downloadable Reactome datasets.
  • The Main Text section includes a description of Reactome, the participating research institutions and our funding sources.
  • The Twitter feed box on the right-hand side provides up-to the minute Reactome news and a user feedback system.
  • The Homepage footer that lists all the webpages accessible throughout the Reactome website.

The Navigation Bar

Most Navigation Bar items are drop down menus. It is found on many pages of the Reactome website. Links from the Navigation Bar include:

  • About. Background information such as a description of Reactome and the people involved.
  • Content. An overview of the Reactome database, the areas of biology we cover, our plans for content expansion, the structure of our data, and statistics about the current content.
  • Documentation. Includes this User Guide, plus technical aspects of Reactome's functionality and data.
  • Tools. Tools in addition to those linked as shortcut buttons on the Sidebar. Some of these tools are covered in more detail in the Reactome Tools section.
  • Community. Details of Reactome training, publications and representation at conferences and workshops.
  • Download. Links to a page where Reactome data and code is available in various formats. See below for more details.
  • Contact Us. Opens a form page, which allow you to send your questions or comments to the Reactome helpdesk.
  • Search. Type in text (words) or identifiers to locate them in Reactome. For details see Searching Reactome section. Search Examples are listed within the Search text box.

The Six Tool Buttons

The Six Tools Buttons provides easy access to tools, the lower has shortcuts to popular Downloads, Featured tools, and Help. From top to bottom, the features are:

  • Browse Pathways ; Directly access the Reactome Pathway Browser; see The Pathway Browser and Tools
  • Analyze Data . Directly access the most popular Reactome tools; see Reactome Tools for detailed descriptions.
  • Reactome FI network. Link to a page describing how to install and use the Reactome Functional Interaction (FI) Network plugin; more details can be found at FI Network Tool
  • User Guide. Access this User Guide.
  • Downloads. Popular Reactome data downloads.
  • Contact Us. Send feedback to Reactome or ask us a question.

The Main Text

This is the text area under the Six Tool Buttons, to the right of the Twitter feed. This area contains the following:

  • About Reactome. A one paragraph statement linked to more detailed information.
  • Participating Research Institutions. Reactome is a collaboration amongst OICR, NYUMC, CSHL and EBI.
  • Funding Agencies. Acknowledging the different funding agencies that support the Reactome project.

The Pathway Browser and Tools

The Pathway Browser is the primary means of viewing and interacting with specific pathways. It includes a search tool, interactive pathway viewer and set of tools for several types of analysis including:

  • Comparison of a pathway with its equivalent in another species
  • The overlay of user-supplied expression data onto a pathway
  • The overlay of protein-protein or protein-compound data from external databases or user-supplied data onto a pathway.
  • The display of context-sensitive information from other resources in a separate panel, using widgets provided by the external resources.

The Tool bar on Reactome's Homepage gives access to extended versions of these tools that query across all Reactome pathways (see Reactome Tools).

The Pathway Browser

The Pathway Browser is launched by clicking the top button on the Tool bar. The Pathway Browser has 4 panels:

Pathway Browser
  • Features bar. On the far left is a Home button that returns you to the homepage. It also includes a key to the most common pathway objects, and a link to a full Diagram Key (far right-hand side). At the top is a species selector, with drop-down list of species. The default is Homo sapiens. Change to another species and the pathway displayed will be computationally inferred from the curated human pathway. N.B. Reactome data is human-centric, data for other species is inferred from human pathways - pathway steps may be missing for other organisms if they are not identified by the inference process (described here). Currently, infectious disease pathways involving pathogen proteins are only listed under the species "Homo sapiens". This include the HIV, Influenza, and botulinum neurotoxicity pathways. Buttons for showing/hiding the hierarchy tree, details panel and the diagram key (and one for expanding the pathway diagram)
  • Pathway Hierarchy Panel. The hierarchy of Reactome pathways is listed in the panel on the left side. Similar to the Windows File Manager, sub-pathways can be revealed by clicking on the + symbol to the left of the pathway name. Click on and drag the grey line, separating the Hierarchy panel from the Pathway Diagram Panel, will adjust the width of the Pathway Hierarchy Panel.
  • Pathway Diagram Panel. This is where pathway diagrams are displayed, when selected in the Pathway Hierarchy Panel. The Pathway Diagram panel will display a brief guide to the pathway browser until you select a pathway. Top-left of this panel is a navigate/zoom tool. Click on the arrows to move across the diagram. The ‘double arrow” button resizes the pathway diagram to fit the available space. Click on the ‘+’ or ‘-‘ buttons to zoom in and out, respectively. The mouse wheel also zooms.
  • Tabbed Details Panel. It gives details of the selected pathway, reaction, complex, set or proteins, when they are selected in the pathway diagram or Pathway Hierarchy panel. This panel can be revealed/hidden using the small yellow triangle on the border with the Pathway Diagram panel. Selecting a location in the pathway diagram with your cursor, and scrolling the wheel will zoom in/out wherever the cursor is located.

The Pathway Hierarchy Panel

This contains a list of Reactome pathway topics, sorted alphabetically. Some topics, such as apoptosis, are too large to represent as a single pathway. Instead they are divided into sub-pathways, which may be further divided into sub-pathways. Most Reactome pathway topics are divided into smaller sub-pathways. Individual steps in a pathway are known as reactions. The organisation of pathways, sub-pathways and reactions is represented on the Pathway Hierarchy panel as a pathway hierarchy. This view functions in a similar manner to the Windows File Manager; sub-pathways are revealed by clicking on the + symbol to the left of the pathway name, and hidden by clicking on the – symbol. The ‘U’, ‘N’ and ‘+’ icons to the left of the pathway name identify whether a pathway is Updated, New or associated with Disease.

Pathways and reactions can be differentiated by a representative symbol to the left of the name, see the image Pathway Hierarchy Symbols below. You may also see a symbol representing 'black-box' reactions, where complete details have been omitted as unnecessary or are not completely determined.

Within a pathway, the order of reactions in the hierarchy from top to bottom usually follows their order in the pathway, so that preceding reactions are above the subsequent reaction, but note that this is not always the case. Reactome has a more formal way of identifying connected reactions called Preceding and Following Events, visible in the Reaction Details (see Details Panel below).


Pathway Hierarchy
Pathway Hierarchy Symbols

Pathway Diagrams

Pathway diagrams represent the steps of a pathway as a series of interconnected pathway steps, known in Reactome as 'reactions'. Reactions are the core unit of Reactome's data model. They encapsulate 'changes of state' in biology, such as the familiar biochemical reaction where substrates are converted into products by the action of a catalyst, but also include processes such as transport of molecules from one cellular compartment to another, binding, dissociation, phosphorylation, degradation and others.

A "pop out" diagram key is found in the upper right corner of the webpage.

Prediagramkey2.png

The diagram key provides a descriptions of the icons used in the diagrams:

Diagram Key

Objects on the diagram represent reaction inputs and outputs, and the catalyst if relevant (see A below).

  • Inputs, outputs and catalysts are represented as boxes or ovals.
  • Green ovals are small molecules or sets of small molecules.
  • Green boxes with rounded off corners are individual proteins or sets of proteins or mixed sets.
  • Green boxes with square corners are proteins that have no Uniprot accession (or did not at the time the reaction was created).
  • Blue boxes are complexes, i.e. proteins and/or small molecules that are bound to each other.
  • Green boxes with white inner boxes are sub-pathways.
  • Input and output molecules are joined by lines to a central 'reaction node' (surrounded by a green box in Reaction Objects A, below). Clicking this node selects the reaction.
  • The outputs of a reaction have an arrowhead on the line connecting them to the reaction node.
  • Numbered boxes on the line between an input/output and the reaction node indicate the number of units of this input/output in the reaction (when n >1).
  • Reaction input/output molecules are often connected by arrows to molecules that take part in preceding or subsequent reactions (i.e. the preceding/subsequent steps in the pathway).
  • Catalysts are connected to the reaction node by a line ending in an open circle.
  • Molecules that regulate a reaction are connected to the reaction node by a line ending in an open triangle for positive regulation or a 'T'-shaped head for negative regulation (see B below).


Reaction Objects A
Reaction Objects B

Reactions are superimposed onto pink boxes that represent cellular compartments - a typical diagram has a box representing the cytoplasm, bounded by a double-line representing the plasma membrane. The white background beyond this represents the extracellular space. Other organelles are represented as additional labeled boxes within the cytoplasm. Reaction objects are placed in the physiologically correct cellular compartment, or span the boundary of a compartment to indicate they are in the corresponding membrane, e.g. the boundary of the cytosol is the plasma membrane.

The reaction node has 5 subtypes, indicating subclasses of reaction (see Reaction Objects C, below):

  • Open squares represent a 'transition'
  • Filled circles represent 'association', i.e. binding
  • Double-circles represent 'dissociation'
  • Squares with two slashes represent 'omitted process'. This is used to denote a reaction where the full details have been deliberately omitted. This is most commonly used for events that include specific members of a protein family to illustrate the general behaviour of the larger group. It is used for reactions that occur with no fixed order or stoichiometry, and for degradation where the output is a random set of peptide fragments.
  • Squares containing a question mark represent 'uncertain process', where some details of the reaction are known, but the process is thought to be more complex than it is represented. Explanatory details are typically included in the Description.


Reaction Objects C

Navigating Pathway Diagrams

Clicking on a pathway or reaction name in the Pathway Hierarchy panel causes it to be highlighted in green, opens the corresponding pathway diagram in the Pathway Diagram panel and populates the Details panel.

When a pathway diagram is visible in the Pathway Diagram panel, moving the mouse pointer over the name of one of it's sub-pathways or reactions on the Pathway Hierarchy panel will highlight the reaction node(s) for that sub-pathway/reaction in green on the diagram. If the sub-pathway or reaction name is selected (clicked) on the Pathway Hierarchy panel, it is highlighted in green, it's parent pathway or pathways are highlighted in yellow-green, and the reaction node(s) corresponding to the sub-pathway or reaction are surrounded by a green box in the pathway diagram. In addition, the Details panel will update to show details of the sub-pathway or reaction selected. If the selected sub-pathway or reaction is not currently visible in the pathway diagram, it will re-centre on the selected object(s).

Selecting a reaction in the Pathway Diagram will cause it's name and the name of parent pathway(s) in the hierarchy to be highlighted on the Pathway Hierarchy panel.

Highlighted reactions are also visible in the thumbnail diagram and can be used to navigate quickly to the region of interest in the diagram using the thumbnail window, bottom left of the Pathway Diagram. The blue box outline represents the current view. Click and drag blue box will reposition the pathway diagram. To centre the diagram at the point, click outside the blue outline. Moving the cursor out of thumbnail box while dragging will stops the pathway repositioning.

Hovering over a protein, complex or small molecule node shows a tooltip with node's name and type. An information icon to the top left of the node is displayed. Clicking the ‘info’ icon will display a context sensitive menu, providing access to more information about the pathway node.

There is a navigation tool top-left of the Pathway Diagram. With this you can navigate left, right up or down and zoom in or out of the diagram. You can also zoom using the mouse wheel, and click and drag the diagram.

Located at the top right of the Pathway diagram is the Pathway Options button, will display the pathway diagram settings, allowing the user to configure different aspects viewing the pathway diagram and to download the pathway diagram.


Pathway Browser showing a selected sub-pathway highlighted in green and parent pathways highlighted in yellow-green, reaction nodes for all reactions in the sub-pathway are surrounded by green squares in the Pathway Diagram


Sub-pathway Diagrams

Large topics such as apoptosis contain too much information to be displayed as a single pathway or diagram. Where this is the case, the topic is divided into sub-pathways in the pathway hierarchy, and sub-pathway diagrams in the Pathway Diagram Panel. If you select a pathway in the Pathway Hierarchy panel that only has sub-pathways diagrams, the Pathway Diagram displays an overview diagram, containing boxes with green borders, the symbol for a sub-pathway diagram. This symbol indicates that a detailed diagram is available but is not part of the currently displayed Pathway Diagram. The sub-pathway diagram symbol can also be used within a pathway diagram if the details of a sub-pathway are too complicated for inclusion, to indicate that the sub-pathway has it's own, separate diagram.

There are two ways to access a sub-pathway diagram. The simplest is to right-click on the sub-pathway diagram symbol. This produces a menu, select the option 'Go To Pathway'. Alternatively, left-click to select the sub-pathway diagram symbol - the corresponding sub-pathway name will be highlighted on the Pathway Hierarchy panel. In the example shown below, the sub-pathway diagram symbol for 'Intrinsic Pathway for Apoptosis' is selected (boxed in green) causing the corresponding sub-pathway and it's parent pathway to be highlighted green on the Pathway tab. The sub-pathway name has not been clicked. Clicking on the sub-pathway name in the hierarchy causes the corresponding pathway diagram to open in the Pathway Diagram panel.

Pathway Browser showing a selected sub-pathway diagram symbol surrounded by green square, corresponding sub-pathway and parent pathway are highlighted in green on the Pathway Hierarchy panel.

Details Panel

The Details Panel is at the bottom of the Pathway Browser. It gives details of the selected pathway, reaction, complex, set or proteins, when they are selected in the Pathway Diagram or Pathway Hierarchy panel. The height of the Details panel can be adjusted by clicking on and dragging the grey line, separating the Details Panel from the Pathway Diagram, to the intended depth.

The different tabs within the “Details" panel, provides alternative displays of graphical and textual information depending on whether a pathway, reaction, or physical entity node is selected:

  • Overview. Displays summary information relating to the selected pathway, reaction or entity.
  • Molecules. Displays external annotations and links outs to other bioinformatics resources describing the selected molecule. Molecule information can be downloaded as a csv, tsv, xml or excel file.
  • Structures. Displays 3D structural data and citations from PDB.
  • Expression. Feeds condition-specific gene expression data from the Gene Expression Atlas.
  • Processes. Displays the associated Reactome pathways and reactions associated with the selected pathway node or events.
  • Download. Allows users to download a variety of compatible with third-party tools

Pathway Details Panel

The Overview tab of the Pathway Details Panel typically includes, the pathway name, the species, a stable identifier, a description of the pathway (summation), the GO biological process term for the pathway, the GO cellular compartment term (if applicable), and references linked to PubMed providing background information relevant to the pathway.

If the pathway is not supported directly by human experimental data but has been inferred from another species, this is indicated by the phrase 'This event is deduced on the basis of event(s)' and a link to that pathway. The ‘Computationally inferred to' drop down menu lists species that have been computationally predicted to have the same pathway. There is also information that reflects the authors and reviewers that have contributed to the curation of this pathway.

Clicking a ‘+’ or ‘-‘ icon associated with the different displayed fields within the Overview tab will show or hide more information about the pathway overview.

The molecules that participate in a pathway can be displayed and/or downloaded by clicking on the ‘Molecules’ tab of the Pathways Details Panel. The user can select the type(s) of molecules to download, the type of information desired for each molecule type, and the format of the download file.

The 'Expression' tab displays gene expression data derived from transcription profiling of individual and mixture of 16 human tissues RNA (Illumina Body Map). The heat map employs a two-dimensional matrix where rows correspond to genes (encoding pathway components) and columns correspond to 16 human tissues, such as adipose, brain, colon, etc. Filled boxes indicate genes expressed. Click 'Display levels' to show expression. A human anatomogram provides a graphical display of the gene expression data as a user clicks on the different tissues or gene expression data presented in the table. Clicking the gender symbols denoting male and female will update the anatomogram with sex-specific gene expression data.

The user can select to display the other Reactome pathways for the selected sub-pathway by clicking the Process tab. Clicking a ‘+’ or ‘-‘ icon next to ‘Involved in pathways’ within the Process tab will show or hide more information about the associated pathway and literature citations.

The Download tab provides options for the user to download different files types for the selected pathways. These files include:

  • [SBML]. An exchange format used by systems biologists for their models.
  • [SBGN]. An exchange format used to represent pathway and network diagrams.
  • [BioPAX2]. An exchange format used by systems biologists for their models.
  • [BioPAX3]. An exchange format used by systems biologists for their models.
  • [PDF]. Text dump of the pathway, organized to look like a research report.
  • [Word]. A document format compatible with Microsoft and other word processor software.
  • [Protege]. A format used for ontology exchange.

SBML, SBGN and BioPAX are exchange formats of interest to bioinformaticians. Word and PDF are familiar document formats, providing you with a convenient "document" of the pathway. Protégé is an extensible, platform-independent environment for creating and editing ontologies and knowledge bases, this download is likely to be of interest to those wishing to extend Reactome functionality.

The complete Reactome textbook of biological processes in PDF or RTF format, the complete set of human reactions in Reactome (in SBML or BioPAX level 2 or 3 format), and a list of human protein-protein interaction pairs are available to download from the Download page, linked to the Menu Bar on the Reactome homepage.

To find out about how Reactome generates SBML, see SBML At Reactome.

For general information about SBML, click here. For more information about BioPAX click here.

Reaction Details Panel

Included in the Overview tab of the Reactions Details Panel is a reaction name, a stable identifier, and a summary of the reaction. Reactions must contain literature references that contain experimental data verifying the reaction, or an 'Inferred From' link if the reaction has been manually inferred from experimental data from model organisms. For pathway details see the previous section.

Other details within the Overview section include:

  • Input/Output. Identifies the input/output molecules, sets or complexes for this reaction. Icons to the right of these named items link to further information in Reactome.
  • Authors. The expert biologists that contributed materials that allowed this reaction to be created in Reactome.
  • Reviewers. The expert biologists that verified the content for this pathway.
  • Preceding event(s). A list of events that occur immediately before the event being viewed.
  • Following event(s). A list of events that occur immediately after the event being viewed.
  • Catalyst (when relevant). The protein or complex that catalyzes the reaction. The Gene Ontology molecular function term that represents the activity of a catalyst or transporter within the reaction will be listed. If the catalyst is a complex, the component, or domain in a simple catalyst, that enables the reaction to occur will be listed.
  • Inferred from another species (when relevant). This indicates that event has not been experimentally demonstrated in humans, but has been inferred on the basis of data acquired for another species. The link points to a web page containing the experimental data for the reaction in that species.
  • Positively (or Negatively) regulated by. The protein or complex that regulates the reactions.
  • References. The research publications that describe the evidence supporting the reaction, each hyperlinked to its PubMed abstract (when applicable).
  • Taxon. The species in which the event occurs.
  • Computationally inferred to. Links to descriptions of the events in other species that are either confirmed to occur in a very similar way in both species, or have been electronically inferred .

The molecules that participate in a reaction can be displayed and/or downloaded by clicking on the ‘Molecules’ tab of the Reaction Details Panel. The user can select the type(s) of molecules to download, the type of information desired for each molecule type, and the format of the download file.

The 'Expression' tab displays gene expression data derived from the Illumina Body Map for the proteins associated with the selected reaction.

The user can display the other Reactome pathways for the selected reaction by clicking the Process tab. Clicking a ‘+’ or ‘-‘ icon next to ‘Involved in pathways’ within the Process tab will show or hide more information about the associated events and literature citations.

The Download tab provides reaction in one of the formats:SBML, SBGN, BioPAX2, BioPAX3, PDF, Word and Protege {Need to Check this is correct}.

Protein, Small Molecule, Complex and Set Details

The details of any protein, small molecule, complex or set represented in the pathway diagrams can be displayed in the Details panel by selecting the object within the diagram. These views are all very similar, an example of protein details is represented below. Clicking a ‘+’ or ‘-‘ icon associated with the different displayed fields within the Detail panel tabs will show or hide more information about the protein, small molecule, complex and set.

The Overview tab will display the following information depending whether the selected node is a :

  • Links to corresponding entries in other databases. Cross-reference to identifiers used for this molecule in external reference databases, with hyperlinks to the record.
  • Cellular compartment. The cellular compartment that contains this molecule, with hyperlink to the corresponding GO term.
  • Computationally inferred orthologues. Lists equivalent molecules in other species if these have been inferred to exist. A description of the inference process can be found here.
  • Components. If this molecule is part of any complexes, they are listed here
  • Produced by. If this molecule is 'created', e.g. becomes incorporated into a complex or degraded, the appropriate reactions are listed.
  • Consumed by events. If this molecule is 'consumed', e.g. becomes incorporated into a complex or degraded, the appropriate reactions are listed.
  • Post-translational modification. If this molecule exists within Reactome in an alternate, post-translationally modified form, the appropriate molecules are listed.

The ‘Molecules’ tab will show more information and link outs to external bioinformatics resources. The user can select the type(s) of molecules to download, the type of information desired for each molecule type, and the format of the download file.

The ‘Structures’ tab will displays 3D structural data and citations from PDB. The most relevant (best) crystal structure for the selected node will be shown. Clicking the "All structures..." will display other associated crystal structure. Users can also explore additional crystal structure infromation at PDB by clicking the different icons:

  • Book. A paper describing the PDB entry.
  • Person/Multi-Cladogram. The taxon or source of the biomolecule.
  • Circular plasmid/Multi. The expermental technique used to create the crystal.
  • NMR/X-RAY. The technique that was used to determine the 3D structure.
  • Protein Domain. The protein sequence and domain information associated with protein.
  • DNA helix. Nucleic acids (DNA, RNA) are associated (green-highlighted) or not associated (grey-highlighted) with the crystal structure.
  • Benzene ring. Ligand is associated (green-highlighted) or not associated (grey-highlighted) with the crystal structure.

The 'Expression' tab displays gene expression data derived from transcription profiling of individual and mixture of 16 human tissues RNA (Illumina Body Map). The heat map employs a two-dimensional matrix where rows correspond to genes (encoding pathway components) and columns correspond to 16 human tissues, such as adipose, brain, colon, etc. Filled boxes indicate genes expressed. Click 'Display levels' to show expression. A human anatomogram provides a graphical display of the gene expression data as a user clicks on the different tissues or gene expression data presented in the table. Clicking the gender symbols denoting male and female will update the anatomogram with sex-specific gene expression data.

The ‘Process’ tab shows the Reactome events associated with the selected node. Clicking a ‘+’ or ‘-‘ icon next to ‘Involved in pathways’ will show or hide more information about the associated events and literature citations. "Is present in sets" displays information about the Reactome sets that the selected node participates in.

Context Sensitive Menus in Pathway Diagrams

Within pathway diagrams, hovering on a node will display an information icon, which when clicked will display a context sensitive menu. Alternatively, right-clicking on the box representing a molecule, complex, set or reaction presents the user with a menu or list of features dependent on the nature of the item selected. Note that unavailable options do not appear, so very few items will have the full range of options.

A context sensitive menu is engaged when a user clicks on the the pathway diagram background (space between nodes and reactions). This menu allows the user to explore additional features of the pathway diagram. Some of these features from this menu are also accessible from the Pathway option tool button that is accessible from the top-right corner of the pathway diagram.

Right-click Menu Items associated with Pathway Nodes

Other Pathways
Lists other pathways that include the selected item as a participant. Clicking on any of the pathway names will display that pathway in the Pathway Diagram Panel.


Popup menu with Other Pathways highlighted


Display Interactors
Surrounds the selected diagram item with a set of boxes representing protein-protein or protein-small molecule interactors. For more information see Molecular Interaction Overlay. N.B. Interactors can only be displayed for individual proteins, not for complexes or molecule sets.
Hide Interactors
Removes interactors from the selected diagram item, unless it is an interactor of another item in the display. For more information see Molecular Interaction Overlay
Popup menu with Display Interactors highlighted
Export Interactors
Exports all interactors of the selected diagram item from the pre-selected source interaction database and displays them in a new browser tab/window. Interaction data is displayed in PSI-MITAB format. For more information see Molecular Interaction Overlay
Participating Molecules
Lists the component molecules for the selected item, e.g. lists the proteins that make up a complex. Clicking on any molecule in that list will open a new window with details.
Participating Molecules highlighted on the popup menu
Display Participating Molecules
This popup menu item is displayed following Species Comparison or Expression Analysis. It causes the display of a grid of cells that represent the components of the set or complex. See the relevant sections of the User Guide for more details.
Go To Pathway
Associated with symbol for sub-pathway diagrams, selecting this from the popup menu causes the sub-pathway diagram to be displayed. See Sub-pathway Diagrams

Right-click Menu Items associated with Pathway Diagram

This menu is engaged when a user clicks on the the pathway diagram background (space between nodes and reactions). This menu allows the user to explore additional features of the pathway diagram.

Search Diagram (ctrl-f)
A user can search for a word or phrase within the nodes and reactions of the pathway diagram. The search tab appears with by pressing the 'ctrl-f' key combination. See Search Pathway Diagram
Snapshot Current View
Permits the user to download the current pathway diagram view, including overlays, as a PNG image file that is opened in a new tab.
Download Diagram
Allows the user to download the entire pathway diagram, including overlays, as a PNG image file that is opened in a new tab.
Interaction Overlay Options...
Opens a pop-up box for configuration of the interaction overlay. For more information see Molecular Interaction Overlay
Zoom In
Zoom in within the pathway diagram.
Zoom Out
Zoom out within the pathway diagram.
Center Diagram Here
In combination with the functions of the mouse scroll wheel, the user can zoom in/out within the pathway diagram, relative to the position of the mouse cursor.

Pathway Options Menu

This button, located on the top-right of the Pathway diagram, opens a control panel that has several functions:

Search Diagram (ctrl-f).
Search the diagram nodes and reactions for a word or phrase. The search tab appears with by pressing the 'ctrl-f' key combination. See Search Pathway Diagram for more information.
Snapshot Current View.
Take a screenshot of the current pathway diagram view, which will be opened in a new window.
Download Diagram.
Will open the entire pathway diagram in a new window, ready for download.
Interaction Overlay Options…
Allows configuration of Molecular Interactions onto the pathway diagram.

Navigating Disease Pathway Diagrams

Biological processes are captured in Reactome by identifying the molecules (DNA, RNA, protein, small molecules) involved in them and describing the details of their interactions. From this molecular viewpoint, human disease pathways have three mechanistic causes:

  • the inclusion of microbially-expressed proteins
  • altered functions of human proteins
  • changed expression levels of otherwise functionally normal human proteins

For some Reactome disease pathways, such as "Signaling by EGFR in cancer" it is helpful to describe the effects of disease related reactions and entities on the normal human pathway. In this case, disease related events and normal events are grouped together in the pathway hierarchy and the disease events (reactions and associated molecular entities) are overlaid on top of the diagram of the normal human pathway that they affect. This “merged" diagram can be viewed by clicking on the "parent" disease pathway. Disease related entities and reactions are outlined in red whereas the normal events and entities are “greyed out”. In the event hierarchy, the parent pathway contains both the normal pathway (Signaling by EGFR) and a pathway containing uniquely the disease associated reactions (Signaling by constitutively active EGFR).

Parent Disease pathway

Clicking on the “normal" subpathway hides the diseased entities and reactions entirely from the diagram allowing the user to browse just the normal events.

Normal pathway

Clicking on the “disease" subpathway shows the merged (disease/normal) diagram again. The disease reaction nodes are highlighted with green boxes. Disease related pathways, reactions, and entities may be flagged, in the details section, with the most relevant EBI Human disease ontology term. *Please note that it is not currently possible to link to the Human disease ontology website directly from the disease tagged entity/event, but this feature will appear in the V40 release.

Disease pathway


Some disease pathways in Reactome have not been grouped, in the hierarchy, with a separately annotated "normal" pathway and diagram. These include infectious disease pathways (and the Amyloids pathway) in which the majority of annotated reactions involve pathogen (abnormal) proteins only and/or involve interactions among pathogen (abnormal) and human proteins. These disease pathways have each been placed in a single diagram. Red lines are used to emphasize disease events. Reactions involved in disease or disease progression are highlighted in red as are any entities that are disease-associated or derived from another species (pathogen). Host/human or normal entities are black. Complexes that contain both host and disease associated/pathogen derived entities are colored red.

Disease single ELV1.png

View Equivalent Pathway In Another Species

Reactome is human-centric and aims to represent human biology. Pathway in other species are electronically inferred from curated human pathways - a description of the inference process can be found here .

To view the predicted conservation of the displayed pathway in another species, use the "Switch Species" drop-down menu at the top of the Pathway Browser. Selecting causes the pathway diagram to re-draw (a revolving arrow icon on the Pathway Hierarchy panel indicates the diagram is re-drawing). The layout of the diagram is preserved, but any reactions that were not inferred will be absent. The event hierarchy is also updated to display the events present in the selected species. Note however that when the species Gallus gallus. is selected (this species has both manually curated and electronically inferred pathways in Reactome), it is currently only possible to view the manually curated Gallus pathways. To view the electronically inferred Gallus pathways, you must go to a pathway of interest in human and select the electronically inferred Gallus event in the details section. The inferred Gallus pathway diagram will then be displayed, but the manually curated pathways for Gallus will be listed in the event hierarchy. To navigate within these inferred Gallus pathway diagrams, you can select individual reaction nodes or reaction participants and see their descriptions in the details panel.


A more sophisticated method of comparing pathways between species is available as the Species Comparison tool.


Selection of a species to compare the predicted pathway coverage

Molecular Interaction Overlay

Molecular Interaction (MI) overlay allows protein-protein or protein-compound interactions to be overlaid (superimposed) onto the pathway diagram. The source depends on the currently selected interaction database. The default is IntAct, other sources of interaction data (protein-protein and protein-compound) including a user-supplied list can be selected using the ‘Interactor Overlay Options…’ feature of the Pathway Options button in the top-right corner of the Pathway diagram.

Pathway Options button

A maximum of 10 interactors are displayed as a ring of blue-bordered boxes connected by blue lines to the selected protein. A white box superimposed onto the selected protein displays the number of interactors up to a value of 50, if more than 50 are available 50+ will be displayed.

Several items can be sequentially selected for interactor display. If the same interactor is connected to more than one item it is re-used, i.e. connected to all the selected items in the diagram.

Inteactors displayed for Syk.
  • Hovering the mouse pointer over a protein interactor produces a pop-up containing the name and identifier of the protein.
  • Hovering over a chemical interactor displays the formula and name of the chemical.
  • Clicking on a protein interactor opens the Uniprot entry for that protein in a new window.
  • Clicking on a chemical interactor opens up the ChEBI entry for that chemical in a new window.
  • Clicking on the line that connects the interactor to the pathway item opens a new window containing details of the interaction at the source database (see example below) ** Please note that link to the source database is not currently working for Internet Explorer 8**.


The IntAct entry for the interaction between Syk and CD18


Details of up to 50 interactors for every protein in the pathway diagram can be viewed as a table accessed via the Analyze, Update & Annotate button. An extended version of this table with no limit to the number of interactors per protein can be exported. See Analyze, Update & Annotate button for details.

While interactors are displayed, right clicking on the selected protein produces two new options, Hide Interactors which removes them, and Export Interactors. Interactions are exported in PSI-MITAB format.


The Analyze, Update & Annotate control panel with MI Overlay tab selected
MI Overlay tab

This tab contains the following features:

  • Interaction database - a drop-down list allows selection of the source of interactors. This is automatically populated by querying the PSICQUIC Registry. If a new database is selected while interactors are displayed on the pathway diagram, the proteins represented by those items will be used as queries in the new database and the display will automatically update. If the table of interactions is displayed, it will automatically update to list the interactions found in the new database.
  • Upload a file - allows a user supplied list to be used as the source of interactors. Data must be in PSI-MITAB format though the only columns that need to be filled in are the accession number, gene name and confidence score columns (confidence score is only necessary if you want to use the color interactions feature). If the upload is successful, the label you submit when prompted will appear on the 'Interaction Database' drop down and can be selected as a source of interactions. A data set submitted in this manner will persist for the user session.
Upload dialogue
  • Clear overlay - removes all interactors from the pathway diagram.
  • Submit a New PSICQUIC service - can be used to add a new source interactions database. The URL field should contain the URL of the PSICQUIC service (REST interface). A service added this way will appear on the interaction database drop down for a period of three days, assuming you connect from the same computer.
  • Set Confidence Level Threshold - this allows the user to set a confidence threshold used for colouring interactors. The default threshold is 0.5. Interactions with a confidence level below this threshold will be coloured according to the colur set as the 'Below' colour, interactions with confidence scores equal to or above the threshold will be coloured with the 'Above' colour.
  • Colour button - activates colouring of the pathway diagram - interactions will be coloured only if a confidence score is available at the source database. The colours used can be changed by clicking on the coloured squares for 'Above' and 'Below'. A dialog allows selection of an alternative colour. Click 'Apply' to update the colours displayed.
  • Colouring Off button - removes colouring.
Interactions colored based on confidence scores:interaction with ABL exceeds the threshold and is coloured green, other interactions are below the threshold and are coloured red

The colours used for interaction colouring can be changed by clicking on the coloured squares for 'Above' and 'Below'. A dialog allows selection of an alternative colour, click 'Apply' to update the colours displayed.

Interaction colouring selection
  • Display/Hide Table of all interactors for pathway - this button switches on/off the table of pathway item-interactor pairs.
    • Clicking on the blue 'toggle' squares within this table will cause the pathway diagram to centre on the protein represented in the first column and display its interactors.
    • All entries (rows in the table) for that pathway protein will be shaded a pale blue when interactors are displayed. Clicking the toggle for a particular pathway protein a second time will hide the interactors and its table entries will be coloured white.
    • Clicking on a pathway protein ID (listed in the second column of the table) will re-centre the pathway diagram on that protein.


Table view of interactors. The first column contains a toggle that controls the display of interactors. Blue-shaded rows indicate a protein whose interactors are currently displayed. The second column identifies proteins in the pathway. The third column lists the interactors retrieved from the current interaction database (in this case IntAct) for each protein in the pathway.
  • Export all interactors for pathway - exports a full list of interactors for each protein on the pathway diagram, in PSI-MITAB format, as a new window.
Search Pathway Diagram

The Search Diagram (found in diagram options menu) permits the selection of an entity matching the search term and centers the diagram if it is not visible. The "Select All" feature allows for navigation of all entities matching the search query. "Next" and "Back" allows the user to cycle through the diagram search results.

Searching Reactome

A number of options are available for searching Reactome, depending on your requirements. Most users, most of the time, will probably find the "simple search" quite sufficient. This is available from the Reactome home page. If you need to make more complex, logical, queries, then you will need to use the Advanced search.

Simple searches

The simple text search tool is located top left of the homepage. Type the term of interest, and then click on the "Search" button. You will be presented with a results page similar to this:

Text search.png

Results have an associated type: Reaction; Pathway; Protein or Other (includes literature). Type is indicated by an icon and a type name preceding the title of the result. Click on the title to go to the corresponding Reactome web page. Most results will have descriptive text details. Your search terms will be highlighted if they appear within the title or descriptive text.

At the top of the results page is a set of tick boxes, the Type Selector Bar. This includes a count by type (pathways, reactions, proteins, other) for the displayed results, and allows you to limit results by type. Uncheck boxes for type categories that you don't want to see, e.g. if you only want results of type Proteins, uncheck Pathways, Reactions and Others, then click the Show button.


Ten hits are displayed per page. At the bottom of the page is a navigation tool to see additional hits. You can also display all the results in a single page by clicking 'Show all results'.

Each results returned is clickable and will take you to the appropriate Reactome pathway diagram when selected.


Advanced Search

The Advanced Search form can be accessed under Tools on the Reactome homepage Menu Bar, visible from all pages except the Pathway Browser. This search method allows the combination of query terms for exact phrases, any of a list of words, all of a list of words (but in any order), regular expressions, the NOT logical operator, any value or no value. Query terms are joined by 'AND'. This can generate powerful and highly specific searches that make use of fields in the Reactome database schema. To make full use of the Advanced Search we recommended that you read the document Data Model (avialable under Documents from the Menu Bar on the Reactome homepage) and refer to the Database Schema (linked to the Data Model document and under Contents from the Menu Bar).

Advanced Search form. This example would identify Reactome items (pathway events or molecules) with names that include the words serotonin or dopamine where the cellular compartment matches the exact phrase 'Plasma membrane' and the database has no value for 'inferredFrom' (therefore any reactions or pathways in the results will be based on human experimental data, not inferred from a model organism)


Small Molecule Search Tool

This is accessed via the Menu bar on the Reactome homepage, select Tools, Small molecule search. This will open the Small molecule search page where you can specify the small molecule by name or by structure. Structures can be hand-drawn, or pasted as a SMILES string. Options include search for molecules that contain this structure or those that resemble this structure. Click on the Search button to start the search. The tool will search the ChEBI database. A list of matching compounds is returned, with links to the appropriate Reactome pathways.

Reactome Tools

Pathway Analysis

The Pathway Analysis Portal combines a number of analysis and visualization tools to permit the interpretation of user-supplied experimental data sets. This portal is launched by pressing the "Analyze Data" button on the homepage, or the "Analyze Data" link from the "Tools' drop-down menu. The portal opens as a data entry page ("Submit your data" tab), a box for pasting your list of protein identifiers (one per line). Alternatively use the Browse/Choose File button to locate a file. Valid identifiers include UniProt accession numbers and IDs, GenBank/EMBL/DDBJ, RefPep, RefSeq, EntrezGene, MIM and InterPro IDs, Affymetrix and Agilent probe IDs, Ensembl protein, transcript and gene identifiers. Lists with mixed identifier types can be used. Mixed species lists can be used, but only identifiers from the most frequent species are submitted for analysis. A practice data set is available, by clicking "Loading example data", to test the Pathway Analysis Portal. The initial outputs from the analysis is dependant on the dataset uploaded, i.e. a gene list or an expression dataset.

Gene list Dataset

If the dataset is an user-supplied set of human gene or protein identifiers, the analysis portal performs an enrichment test to determine whether any Reactome pathways are enriched in the submitted data, i.e. it answers the question 'does the list represent the proteins within a specific pathway more than would be expected if the set were random?'. A one-tailed Fisher's exact test is used to calculate the probability. The p-values are corrected for multiple testing that arises from evaluating the submitted list of identifiers against every pathway.

The initial results of the enrichment analysis are displayed as a table in the "Analysis results" tab; the columns represent:

  • The Pathway name. Clicking a pathway name opens the Pathway Browser (in a new window) and displays the appropriate pathway diagram. The protein corresponding to the ID in the pathway analysis results table will be highlighted in the pathway diagram. See Pathway Diagrams and Navigating Pathway Diagrams to learn how to interpret and navigate these diagrams.
  • Species. The taxon source of the dataset.
  • IDs in pathway (%). A graphic representing the ratio of proteins in the pathway represented in the submitted and the total number of proteins in the pathway.
  • Enrichment (oval). The p-values associated with the enrichment test.
  • Hochberg FDR. False Discovery Rate.

The columns can be sorted by clicking on the title of the column at the top of the table. A small white arrow appears next to the title, indicating the direction in which the column's contents have been sorted. Clicking the title a second time causes the column to be sorted in the opposite direction.



If the dataset is derived from a model organism data set, the initial table of results of the enrichment analysis are displayed as:

  • The Pathway name. Clicking a pathway name opens the Pathway Browser (in a new window) and displays the appropriate pathway diagram. The protein corresponding to the ID in the pathway analysis results table will be highlighted in the pathway diagram. See Pathway Diagrams and Navigating Pathway Diagrams to learn how to interpret and navigate these diagrams.
  • Species. The taxon source of the dataset.
  • IDs in pathway (%). A graphic representing the ratio of proteins in the pathway represented in the submitted and the total number of proteins in the pathway.

The columns can be sorted by clicking on the title of the column at the top of the table. A small white arrow appears next to the title, indicating the direction in which the column's contents have been sorted. Clicking the title a second time causes the column to be sorted in the opposite direction.
 The "Identifier results tab" displays the Reactome pathways, which the user-submitted data match. Typically, you will end up with a table like this.

The table represents every protein identified from the submitted list. If the ID was not recognized, it is displayed in the first column but all other columns will be blank. The columns can be sorted. Click once on the title of the column. After a while, a small white arrow appears next to the column title, indicating the direction of the sort. Click the title a second time to sort in the opposite direction. N.B. Large datasets may take a couple of minutes to sort – please be patient! The columns represent:

  • ID. The identifiers you supplied.
  • Protein ID The corresponding UniProt identifier.
  • Pathway. List of names of pathways in which this gene or protein is found.

The table of results from both the "Analysis results" and "Identifier results" tabs can be exported in several formats (csv, tsv, JSON and Excel) using the Download button at the top of the table.

Expression Dataset

The analysis portal will analyze a gene or protein list with numerical values, such as gene expression data, and superimposed these results onto Reactome pathways. The first data column of data must identify the protein, ideally with UniProt IDs. Subsequent columns should be numeric, representing expression levels. The results may take some minutes to appear and are displayed as a table in the "Analysis results" tab; the columns represent:

  • The Pathway name. Clicking a pathway name opens the Pathway Browser (in a new window) and displays the appropriate pathway diagram. The protein corresponding to the ID in the pathway analysis results table will be highlighted in the pathway diagram. See Pathway Diagrams and Navigating Pathway Diagrams to learn how to interpret and navigate these diagrams.
  • Species. The taxon source of the dataset.
  • IDs in pathway (%). A graphic representing the ratio of proteins in the pathway represented in the submitted and the total number of proteins in the pathway.
  • Coloured Columns of Numerical Data. Depending on the The yellow-highlighted boxes

The columns can be sorted by clicking on the title of the column at the top of the table. A small white arrow appears next to the title, indicating the direction in which the column's contents have been sorted. Clicking the title a second time causes the column to be sorted in the opposite direction.
 The table of results from both the "Analysis results" and "Identifier results" tab can be exported in several formats (cdv, tsv, JSON and Excel) using the Download button at the top of the table.

Clicking on any of the Pathway Names in the "Analysis results" table launches the Pathway Browser in a new browser tab and displays the relevant pathway diagram (see example below). {DIAGRAM INSERT}

Nodes in the pathway diagram are coloured according to the user-submitted numerical values. The yellow-blue colour range is used to distinguish the expression values, employing a linear spectrum from yellow for the highest values to dark blue for the lowest values. The scale automatically adjusts to fit the numerical range represented in the dataset.

  • Protein Nodes - yellow or blue colour depending on expression value. Hovering the mouse pointer over a protein node displays the submitted identifier and the expression value.
  • Pathway Nodes – coloured in horizontal segments (from lowest to highest expression level) with each segment representing a protein in the pathway
  • Complex Nodes - coloured in horizontal segments (from lowest to highest expression level) with each segment representing a component in the complex that is a protein. The value associated with each component of a complex can be viewed; right click on the complex and select 'Display Participating Molecules'. A popup is displayed representing the complex as a table with the component name, expression identifier, and the expression level.
  • White nodes represents proteins or small molecules with no numerical data are coloured white.

Hovering the mouse pointer over a cell displays the name of the protein. Clicking on the cell displays details of the protein in the Details pane. The grid can be closed by clicking the 'x' in the top right corner.

The Experiment Browser toolbar (orange bar with pale blue arrows, at the bottom of the Pathway Diagram) allows you to step through the columns of your data, e.g. time-points or disease progression. Move between them by pressing the arrow buttons. The header of the data column (if present) is displayed between the arrows. The pathway diagram will re-colour to reflect the new values.

Species Comparison

Reactome uses manually-curated human pathways to electronically 'infer' their equivalents in 19 other species. A full description of the inference process can be found here. The Species Comparison tool allows you to compare human pathways with these predicted pathways, to see what is common to both or perhaps missing in the model organism.

Species Comparison is launched using a button on the sidebar, on the left side of the homepage. On the resulting page is a selection tool that reveals a drop-down list of species.


Species comparison2.png

Choose one and click the Apply button. It may take some minutes before the results appear. The results page will look something like this:

Species comparison table2.png

The table contains one row for each Reactome pathway. The columns represent:

  • Pathway name.
  • The species used for comparison with human.
  • Number of proteins in the human pathway.
  • Number of proteins inferred to exist in the comparison species.
  • Graphic representing the ratio of values in column 3 and 4.
  • A View button that launches the Pathway Browser and displays the relevant pathway diagram.

These columns can be sorted by clicking on the title of the column at the top of the table. A small white arrow appears next to the title, indicating the direction in which the column's contents have been sorted. Clicking the title a second time causes the column to be sorted in the opposite direction.

Clicking on a view button launches the Pathway Browser and displays the relevant pathway diagram (see example below).

Species comparison diagram2.png

The nodes are colour coded:

  • Yellow indicates that the protein's orthologue is present in the comparison species.
  • Blue indicates that the protein is only known in human, no orthologue could be found in the comparison species.
  • White indicates that inference was not possible, used for small molecules and genomic objects that have no UniProt entry (or did not at the time the pathway was constructed).
  • The yellow-blue horizontal segments means the entity is a complex. Right click on the complex to reveal a grid representing the proteins in that complex:
Speciescomparison complex2.png

See the Pathway Diagrams and Navigating Pathway Diagrams sections for more information on pathway diagrams.

Reactome BioMart

What is Reactome BioMart?

This section is intended to give some basic ideas how Reactome BioMart helps biologists in searching data of their interests. The Reactome BioMart is a tool that allows fast bulk querying and download of Reactome data and associated data from a number of other databases, including UniProt and ENSEMBL. BioMart can link queries together, so that the results contain information from more than one database. For example, it is possible to find the Affymetrix IDs associated with the genes in selected Reactome pathways by linking a Reactome query to an ENSEMBL query.

To access Reactome BioMart, click on the "BioMart: query, link" item in the Tools menu on the navigation bar.

There are two ways to use Mart. Firstly, the Reactome canned queries that can be accessed at the top of the page and secondly, the Regular BioMart query interface that is below the canned query selector.

Entry Page.jpg

Canned Queries

Reactome provides a small set of canned queries. You can use these without needing to understand the details of the BioMart query interface. The canned query selecter allows you to choose a canned query. Once you have done so, clicking on the button "Go!" takes you to the page where you enter your data.

The following queries are currently available:

  • Find list of pathways for specific species (single data item). You can use this to list all pathways known to Reactome for a species of your choice.
  • Find list of reactions for specific pathways (multiple data items). If you have a list of Reactome stable identifiers for pathways that interest you, you can use this canned query to find all of the reactions involved in the pathways. If you use this query without submitting any data values, all reactions involved in all known pathways will be returned.
  • Find list of proteins for specific pathways (multiple data items). If you have a list of Reactome stable identifiers for pathways that interest you, you can use this canned query to find all of the proteins involved in the pathways. If you use this query without submitting any data values, all proteins involved in all known pathways will be returned. Proteins are characterized by their UniProt IDs.
  • Find list of complexes for specific proteins (multiple data items). If you have a list of protein UniProt IDs, you can use this canned query to find all of the complexes in Reactome involving those proteins. If you use this query without submitting any data values, all complexes and their associated proteins will be returned.
  • Find list of pathways for specific genes (multiple data items). If you have a list of Entrez gene IDs, you can use this canned query to find all of the pathways in Reactome involving those genes. If you use this query without submitting any data values, all pathways and their associated genes will be returned.
  • Find list of genes for specific pathways (multiple data items). This is the converse of the previous query: if you have a list of Reactome stable identifiers for pathways that interest you, you can use this canned query to find all of the genes involved in the pathways. If you use this query without submitting any data values, all genes involved in all known pathways will be returned. Genes are characterized by their Entrez gene IDs.
  • Find list of reactions for specific genes (multiple data items). If you have a list of Entrez gene IDs, you can use this canned query to find all of the reactions in Reactome involving those genes. If you use this query without submitting any data values, all reactions and their associated genes will be returned.
Canned Query.jpg

The data entry page will be different, depending on whether only a single data item is allowed or whether multiple data items are allowed. If only a single item is allowed, then you will be presented with a selecter to choose the item, e.g. species.

Canned Query Pathways.jpg

If multiple data items are allowed, you will get a text area, which you can use to enter the items separated by newlines, e.g. a set of UniProt IDs.

Canned Query Pathway Proteins.jpg

In this case you will also see some extra buttons. Above the text field will be the button "Show example". Pressing this causes example values to be loaded into the text area, which you can use for guidance or testing purposes. Below the text field is the "Browse..." button, which allows you to choose a file from your local computer to upload as data. By default, the contents of this file will not be displayed, but you can examine (and edit) it by clicking on the button "Preview file content".

Once you have your data, you can click on "Run query" to get the results. Additionally, there is a button "Reset", which clears the page and allows you to start again, if you wish. If you do not enter any data, then the query will be performed over all known data items.

Once the query has been performed, the results are presented in a regular BioMart results page. This allows you to export the results as tab-separated values or as an Excel file, and additionally, to perform more complex queries. See below for more details.

Regular BioMart Query Interface

The regular BioMart query interface is situated directly below the canned query selecter. It is powered by the BioMart engine and you can find full documentation at www.biomart.org .

On the right hand side of the page, you can select database and dataset. In addition to the Reactome database, there are a number of other databases available, currently UniProt, ENSEMBL and PRIDE.

Select Database.jpg

Reactome provides three datasets, "complex", "pathway" and "reaction". The interactions dataset is a test dataset. Choose the one most appropriate to the kind of query you want to make. E.g. if you would like to find all pathways associated with a given GO accession, start by selecting the "pathway" dataset.

Select Dataset.jpg

Filters are also split into categories, but in a different way to the attributes. The first one is labelled "Limit to ... containing these IDs". This allows you to enter a list of IDs that will restrict the results returned by the query. E.g. if you have selected the "complex" dataset, you can supply a list of UniProt IDs. This returns only those complexes containing the proteins corresponding to the UniProt IDs.

Regular Query Filters.jpg

The next filter is labelled simply "Species". If you do not use this filter, then the results will contain information from all species known to Reactome. If you select a species, then the results will be restricted to the (single) chosen species.

For the "pathway" and "reaction" datasets, the next filter will be labelled "GO accession". This allows you to enter a GO biological process accession number, and restrict the results to reactions or pathways containing that accession.

Finally, the "Miscellaneous" filter allows you to restrict either by version number or name. Version number means the stable ID version. This is a number that gets incremented every time something gets changed by a curator. E.g. if you are only interested in things that have never been changed, you could set the contents of this slot to "1". If you want to restrict by name, you should note that you need to enter the full name.

The attributes to be displayed in the results table can be selected on the left hand side of the page. They are split into several different categories, which are pretty much the same for all datasets. The first category contains attributes that are directly taken from the dataset itself. E.g. for "complex", you will find things like the stable ID, but also associated complex name and species name. Subsequent categories may include other Reactome classes you can link to, plus in all cases, DNA, protein and small molecule. This means, for example, that you can show all of the proteins and small molecules associated with the reactions that interest you, assuming you have initially selected the "reaction" dataset.

Regular Query Attributes.jpg

You can use the second "Dataset" link in the left hand panel to choose another dataset to link to. E.g. if you want to find the UniProt Protein existence (type of evidence that supports the existence of the protein) associated with a set of pathways, select "pathway" as your first dataset, then select "UNIPROT (EBI UK)] UNIPROT" as your second dataset. In the second dataset, click on "Attributes" in the leftmost panel, and expand the "Protein attributes" category by clicking the "+" symbol in the right panel. Select the "Protein existence" to include this attribute in the final results display.

Second Dataset.jpg

There is a little pitfall that you will need to be aware of when you link from Reactome to other datasets. Let's take linking pathways from Reactome to ENSEMBL transcripts as an example. On the Reactome side, there is gene and protein information associated with a pathway, and, if you wanted, you could select ENSEMBL gene ID or UniProt ID as Reactome attributes. However, if the database you are linking to also provides these attributes (ENSEMBL does) then you are strongly advised to select these attributes only in the linked-to database (ENSEMBL, in this case).

The reason is, you are making the link from the pathway and not from the gene or protein IDs. So, there will be no correspondence between, say, UniProt IDs coming from Reactome and transcript IDs coming from ENSEMBL.

To run a regular BioMart query, click on the "Results" link.

Once you have run your query and have produced a results page, you have a number of options for viewing the information. By default, the format will be "HTML", and you will be presented with the first 10 lines of the results on the web page.

Regular Query Results.jpg

Using the selecter labeled "Display maximum", you can increase the number of lines displayed by your browser to a maximum of 200. If you would like to see more lines, then you need to dump to a file, by clicking the "Go" button. Make sure you select the right output format before you do this. The default "HTML" might not be what you want. Other options are "TSV" (tab separated value, generates a .txt file with columns separated by tabs) and "XLS" (Excel spreadsheet, generates a .xls file that you can display with Excel - does not necessarily look good in OpenOffice).

If you have used other BioMart sites, you might be wondering why there is no "CSV" (comma-separated value) output format. This is because many of the values that are returned by Reactome, e.g. pathway names, contain commas, which would lead to confusing and unparsable output.


The Reactome Pathfinder

The Pathfinder tool is used to identify or discover pathways that connect a given input and one or more output molecules or events. When multiple output molecules/events are designated, the shortest path is displayed. (See notes on requirements below). A link to the Pathfinder tool can be found in the Tools menu of the main menu bar on each page.

For example, to search for a human pathway between the enzyme G6PD, which catalyzes the first reaction of the pentose phosphate pathway, and xylulose 5-phosphate, one of the intermediate products of the pathway, G6PD is entered as the input and xylulose as the output. Very common molecules are excluded to reduce the number of irrelevant pathways generated. These are listed as "non-connecting compounds". Additional molecules can be excluded by adding their names to the precompiled list. Hitting GO! will search Reactome for the start and end compounds/events entered.

Pathfinder Start.jpg

A drop-down list of hits to the entered names is provided. Here G6PD is selected as the input and several reactions that yield xylulose 5-phosphate are selected as an output. The search is initiated by clicking on GO!

Pathfinder Select.jpg

If a path is found, a list of the events and molecules connecting the input and output molecules is shown at the bottom of the page. The path between the entered input molecules is displayed by highlighting these reactions in the starry sky display of reaction space.

Pathfinder Result.jpg

This graphical display feature uses an old view of Reactome content that will soon be retired. Work is underway to develop a graphical display for Pathfinder output that uses the same pathway diagrams as the rest of the Reactome web site.


FI Network Tool

  1. REDIRECT ReactomeFIViz


Download Reactome

To Download Reactome data and code please go to the Download page, linked to the Menu Bar on the Reactome homepage.

Exporting Data From Reactome

Reactome content can be exported in a number of different formats. For your convenience, export files for the entirety of Reactome are available in the download section, see Download Reactome for details. The details panel for pathway diagrams also provides a way to do exports for individual pathways or even reactions, take a look at Pathway Details. The following export formats are available:

  • SBML. An exchange format used by systems biologists for their models. See SBML At Reactome for comprehensive information about SBML export.
  • BioPAX. An exchange format used by systems biologists for their models.
  • PDF. Text dump of the pathway, organized to look like a research report.
  • Word. Text dump of the pathway, organized to look like a research report. The file generated is of type RTF, and can also be understood by OpenOffice and LibreOffice.
  • Protege. A format used for ontology exchange.
  • PSI-MOD. A tabular format containing protein-protein interactions derived from Reactome's reactions and complexes. Take a look at PSI-MITAB Interactions for details.
  • MySQL. A database dump of all of Reactome's data. To understand the schema properly, please take look at objectrelational-mapping.