Identification of the GAB1-associated proteins. Anti-GAB1 immunoprecipitates were prepared from UT-7 cells stimulated for 10 minutes with 10 U/mL Epo or from control cells and analyzed by Western blot using antiphosphotyrosine (anti-PY) antibodies. The blot was stripped and reprobed with anti-SHIP, anti-SHP2, anti-SHC, anti-GRB2, and anti-GAB1 antibodies, successively.