Effect of SFKs and Syk kinase inhibitors on integrin-induced tyrosine phosphorylation in MKs. Purified BM-derived mature MKs were preincubated for 15 minutes with PP1 (10μM) or R406 (2μM), plated on fibronectin (FN) or BSA-coated dish for 3 hours. (A) MKs were lysed and whole-cell lysates (WCLs) were analyzed by Western blot with SFK activation loop p-Tyr-418, Src inhibitory site p-Tyr-529, pan Src, and actin antibodies. Blots are representative of 3 independent experiments. (B) Syk and PLCγ2 were immunoprecipitated from equal amounts of WCLs and blotted with an anti-phosphotyrosine antibody. Membranes were subsequently stripped and reblotted with anti-Syk and anti-PLCγ2 antibodies. Blots are representative of 3 independent experiments. (C) MKs were lysed and WCLs were analyzed by Western blot with MLC-P and MLC antibodies. Blots are representative of 3 independent experiments.