CD28 bound to B7 ligands phospho CD28:B7-1/B7-2 Phosphorylation of CD28 Authored: Garapati, P V, 2008-12-16 11:12:19 EC Number: 2.7.10 Edited: Garapati, P V, 2008-12-16 11:12:19 Pubmed8946678 Pubmed9973466 Reactome Database ID Release 43388831 Reactome, http://www.reactome.org ReactomeREACT_19264 Reviewed: Bluestone, JA, Esensten, J, 2009-06-01 18:47:33 The interaction of CD28 with its ligands, B7-1 (CD80) and B7-2 (CD86) on antigen-presenting cells enhances a number of TCR-mediated responses like production of interleukins. CD28 mediated costimulation is dependent upon phosphorylation of tyrosine residue 191 of the CD28 cytoplasmic tail, present in a 'YMNM' motif. p56Lck and p59Fyn phosphorylate CD28 and the phosphorylated residue allows the recruitment of PI3K, growth factor receptor-bound protein 2 (GRB2) and Grb2-related adaptor downstream of SHC (GADS) via their src-homology region 2 (SH2) domains. has a Stoichiometric coefficient of 2 Lck/Fyn