PI3K alpha ICOS:PI3K PI3K binds ICOS Authored: Garapati, P V, 2008-12-16 11:12:19 Edited: Garapati, P V, 2008-12-16 11:12:19 Pubmed12538664 Reactome Database ID Release 43388830 Reactome, http://www.reactome.org ReactomeREACT_19171 Reviewed: Bluestone, JA, Esensten, J, 2009-06-01 18:47:33 The p85 unit of PI3K is the only signaling molecule identified so far that interacts with ICOS. ICOS contains several conserved motifs also found in CD28, including the YxxM motif in the cytoplasmic tail, which binds the lipid kinase phosphatidylinositol 3-kinase (PI3K) upon tyrosine phosphorylation after complex formation with ICOS. However, ICOS costimulation shows greater PI3K activity than CD28 in T cells.