SU 6656 is a selective inhibitor of Src kinases, Including Src, Yes, Lyn, and Fyn (IC50 = 280, 20, 130, 170 nM, respectively). By comparing PDGF-stimulated
tyrosine phosphorylation events in untreated and SU6656-treated cells, we found that some substrates (for example, c-Cbl, and protein kinase C delta) were Src family substrates whereas others (for
example, phospholipase C-gamma) were not.