PI3K Activated TrkA receptor:Phospho-IRS1/2:PI3K(p85:p110) Activated TrkA receptor:Phospho-IRS1/2 Active IRS recruits PI3K to the plasma membrane and activates it Authored: Nasi, S, Annibali, D, 2006-10-10 09:07:07 Reactome Database ID Release 43198315 Reactome, http://www.reactome.org ReactomeREACT_12384 Reviewed: Greene, LA, 2007-11-08 15:39:37 The PI3K regulatory subunit p85 binds to IRS1 or IRS2, tyrosine-phosphorylated at YXXM motifs, through its SH2 domain.<br>As the p85 subunt is constitutively associated with the p110 catalytic subunit, the outcome is that the whole PI3K complex is recruited to the membrane. The interaction at the plasma membrane of the p85 regulatory subunit with the p110 catalytic subunit of PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase) causes a conformational change, resulting in activation of the catalytic subunit.