Csk:p-PAG Interaction of Csk with PAG Authored: Rudd, C.E., de Bono, B, Garapati, P V, 2008-01-24 15:53:10 Csk is a tyrosine kinase that phosphorylates the negative regulatory C-terminal tyrosine residue Y505 of Lck to maintain Lck in an inactive state. In resting T cells, Csk is targeted to lipid rafts through engagement of its SH2 domain with phosphotyrosine residue pY317 of PAG. PAG is expressed as a tyrosine phosphorylated protein in nonstimulated T-cells. This interaction of Csk and PAG allows activation of Csk and inhibition of Lck. Given that PAG-1 T cell knock out show a weak phenotype, some other protein may substitute in activating Csk. Pubmed10790433 Pubmed11827988 Pubmed12938237 Reactome Database ID Release 43203774 Reactome, http://www.reactome.org ReactomeREACT_12603 Reviewed: Trowsdale, J, 2008-02-26 12:02:59