G-CSF-induced tyrosine phosphorylation patterns are G-CSFR dependent. IP indicates immunoprecipitation; IB, immunoblot; Ptyr, phosphotyrosine. (A) G-CSF-induced tyrosine phosphorylation of Jak2 after 10 minutes' stimulation. Cell lysates were subjected to immunoprecipitation by anti-Jak2 antibody, followed by transfer onto PVDF, and were then blotted with antiphosphotyrosine mAb 4G10. Membrane was stripped and reprobed for Jak2. (B) Time course for G-CSF-induced tyrosine phosphorylation of Gab2. Cell lysates were subjected to immunoprecipitation by anti-Gab2 antibody, followed by transfer onto PVDF, and were then blotted with antiphosphotyrosine mAb 4G10. Membrane was stripped and reprobed for Gab2. (C) G-CSF-induced tyrosine phosphorylation of Gab2 after 10 minutes' stimulation. (D) G-CSF-induced association of Grb2 with Y764 and association of Grb2 with Gab2.