In isolated rat pancreatic acini, Src, RhoA, P13-K, Vav-2, G alpha(12), and G alpha(13) were detected by immunoblotting. CCK enhanced the levels of these proteins, and the levels of Src and RhoA were reduced by the Src inhibitor herbimycin A and the Rho inhibitor pravastatin. The P13-K inhibitor wortmannin reduced the level of P13-K. These inhibitors also decreased amylase secretion in CCK-treated pancreatic acini Without altering basal secretion. Immuoprecipitation studies indicated that CCK caused Src to associate with Vav-2, RhoA, and P13-K and RhoA and Src to associate with Vav-2. Ras, RasGAP, and SOS did not coimmunoprecipitate with Vav-2, and RasGAP and SOS did not coimmunoprecipitate with Rhok CCK also enhanced Vav-2 and RhoA to coimmunoprecipitate with G(alpha 13). We conclude that CCK Stimulates the recruitment of the Src-RhOA-P13-K signaling pathway by Vav-2 downstream of G(alpha 13) in pancreaticacini. (c) 2005 Elsevier Inc. All rights reserved.