From ReactomeWiki

BlackBoxEvent

Use

Should be used for events such as transactivation, degradation, and others where the evidence does not support a full understanding of the reaction, or it is impossible to fully annotate the reaction. An example of the later is a full description of the production of a protein from its gene. It is possible using our data model to fully annotate this. Using a BlackBoxEvent allows us to simply state that the protein "springs into existence", without using all of the steps required.

NYCCM08 Notes

• Use of BlackBoxEvent as a surrogate for unknown proteins in a complex when some of the subunits are known, but others are not resolved is not a desirable behavior. Instead annotate the known members of a complex, and use the "summation" slot on the complex entity to note that there are other unknown members of the complex. This summation slot is invisible to the user, so for the R user, the same concepts should be noted in the reaction summation.
• Use of BBE when the order of reactions is unknown. Like many things this is somewhat of a grey area, but generally a BBE is probably not required here. This is more of a granularity issue, we are often operating at a level that is somewhat arbitrary, so using a "normal" reaction allows us to capture the unknown order by simply collapsing the three reactions into one larger reaction. You can think of this as a placeholder to go back to or not.
• Use the curator tool to search through gkcentral to see how these reactions are used.