Skip to main content
. 2009 Apr 17;284(16):10728–10736. doi: 10.1074/jbc.M900166200

FIGURE 3.

FIGURE 3.

Differential Rap1 activation properties of cAMP analogs. A, Western blot analysis demonstrating the weak effect of 8-pCPT-2′-O-Me-cAMP (ESCA, left panel) and the strong effect of 8-pCPT-2′-O-Me-cAMP-AM (ESCA-AM, right panel) to activate Rap1 in lysates prepared from monolayers of INS-1 cells transfected with FLAG-Rap1 and Eapc1. Active Rap1 is labeled as Rap1-GTP and the quantity of active Rap1 was assessed by densitometry. For the left panel, treatment with 3.0 μm 8-pCPT-2′-O-Me-cAMP increased the amount of active Rap1 by 1.41-fold relative to the untreated control value. For the right panel, treatment with 3.0 μm 8-pCPT-2′-O-Me-cAMP-AM increased the amount of active Rap1 by 4.79-fold relative to the untreated control value. B, time course of Rap1 activation by 8-pCPT-2′-O-Me-cAMP-AM (ESCA-AM). The exposure time corresponds to the time in which INS-1 cells were exposed to the test solution. C, contrasting actions of PKA-selective Bt2cAMP-AM (db-cAMP-AM) and Epac-selective 8-pCPT-2′-O-Me-cAMP-AM (ESCA-AM) to activate Rap1 under conditions in which INS-1 cells were or were not pretreated with the PKA inhibitor H-89 (10 μm). For panels A-C, each experiment was repeated 3 times with similar results.