[annotation] annotation of ion channel subunits

[Doug howe]

For the Ref. Genomes we are annotating the gene p2rx3, a subunit of an 
ATP activated cation channel.
A paper I have shows that adding this gene to hek293 cells results in 
the generation of an inward current in the presence of ATP.

We know (not from this paper) that p2x receptors are a complex of 
subunits.  Should this be annotated as 'contributes_to' ATP-gated cation 
channel activity by IDA because it is thought to be part of an ion 
channel complex, or is it not 'contributes_to' because you get the 
current by introduction of just the single gene product (even if it is 
forming a homomeric channel complex)??

Introduction of both zebrafish p2rx3 and rat p2rx5 produces a channel 
with novel properties....what can be done with that? 
'protein heterooligomerization' with the rat p2rx5 by IGI?


-Doug