cAMP induces subplasmalemmal accumulation of STIM1-YFP. TIRF intensity recordings of subplasmalemmal fluorescence of STIM1-YFP in cells within pancreatic islets. A and B, adenylyl cyclase activator forskolin (5 μm) increases subplasmalemmal fluorescence of STIM1-YFP in epinephrine-identified (Epi, 5 μm) α- and β-cells. C, phosphodiesterase inhibitor IBMX (50 μm) increases subplasmalemmal STIM1-YFP fluorescence, and the adenylyl cyclase inhibitor DDA (100 μm) reverses this effect in an epinephrine-identified (5 μm) β-cells. D, IBMX increases subplasmalemmal STIM1-YFP fluorescence, and DDA reverses this effect in an epinephrine-identified (5 μm) α-cells. E, specific PKA agonist N6-phenyladenosine-3′,5′-cyclic monophosphate (6-Phe-cAMP) (100 μm) increases subplasmalemmal STIM1-YFP fluorescence and forskolin (10 μm) has additional effect in an epinephrine-identified (5 μm) β-cell. F, specific Epac agonist 8-(4-chlorophenylthio)-2′-O-methyladenosine-3′,5′-cyclic monophosphate, acetoxymethyl ester (8-CPT-AM) (1 μm) increases subplasmalemmal STIM1-YFP fluorescence in an epinephrine-identified (5 μm) β-cell. The glucose concentration was 3 mm in all panels.