Diacylglycerol kinase γ interacts with and activates β2-chimaerin, a Rac-specific GAP, in response to epidermal growth factor

Diacylglycerol kinase (DGK)gamma was shown to act as an upstream suppressor of Rac1. Here we report that, in COS7 cells stimulated with epidermal growth factor (EGF), DGK gamma specifically interacts and co-localizes at the plasma membrane with beta 2-chimaerin, a GTPase-activating protein (GAP) for Rac. Moreover, DGK gamma enhanced EGF-dependent translocation of beta 2-chimaerin to the plasma membrane. Interestingly, DGK gamma markedly augmented EGF-dependent GAP activity of beta 2-chimaerin through its catalytic action. These results indicate that DGK gamma is a novel regulator of beta 2-chimaerin, and thus suggest that beta 2-chimaerin is an effector molecule, linking DGK gamma functionally with Rac1. (c) 2007 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.