Figure 3

G _q , but not G _s or G _i signaling is linked to stimulatory phosphorylation of PKD in HEK293 cells. HEK293 cells were stably transfected with BK₂R (A), β₂AR (B) or fMLPR, in the absence (C) or presence of Gα₁₆ (D). Transfectants were serum starved for 4 h prior to treatment with 100 nM bradykinin (BK), 10 μM isoproterenol (ISO) or 300 nM N-formyl-methionyl-leucyl-phenylalanine (fMLP) for the indicated durations. Cell lysates were resolved in SDS-PAGE, and the presence of ERK, PKD and CREB phosphorylation was detected by their respective anti-phospho or anti-total antisera. Activation of PKD was observed only for BK₂R and fMLPR/Gα₁₆ stable cells. CREB activation served as a positive control for β₂AR stable cells.