Fig. 8. db-cAMP stimulates PKA phosphorylation of myr-HA-ß₂AR-C in COS-7 cells. COS-7 cells were transfected with myr-HA-ß₂AR-C (A) or myr-HA-ß₂AR-C/PKA^- (B). The transfected cells were starved for 24 hours in serum-free DMEM and then either left untreated (left panels) or treated with 1.5 mM db-cAMP for 40 minutes (right panels). Cell lysates were prepared and analyzed by 2D electrophoresis and HA immunoblotting. Representative examples from three independent experiments are shown. Circles indicate missing spots. Asterisk indicates position of a nonspecific protein.