Figure 2.

Gβγ inhibits Epac-induced Ca ²⁺ elevation. SK-Mel-2 cells were subjected to Ca ²⁺ signal measurements. Arrows indicate addition of 8-pMeOPT (200 μM). a and b) SK-Mel-2 cells were pre-incubated with L9A (20 μM) or mSIRK (20 μM) for 5 min followed by the addition of 8-pMeOPT. mSIRK, but not L9A, inhibited 8-pMeOPT-induced Ca ²⁺ elevation. c) 8-pMeOPT did not increase Ca ²⁺ signal in SK-Mel-2 cells with co-overexpression of Gβ1 and Gγ2. d) 8-pMeOPT increased Ca ²⁺ signal in SK-Mel-2 cells with overexpression βARK-CT even in the presence of mSIRK. e) When SK-Mel-2 cells were pretreated with the combination of mSIRK and GDPβs, 8-pMeOPT increased Ca ²⁺ signal.