0896-62732632000JunNeuronGRASP-1: a neuronal RasGEF associated with the AMPA receptor/GRIP complex.603617603-17The PDZ domain-containing proteins, such as PSD-95 and GRIP, have been suggested to be involved in the targeting of glutamate receptors, a process that plays a critical role in the efficiency of synaptic transmission and plasticity. To address the molecular mechanisms underlying AMPA receptor synaptic localization, we have identified several GRIP-associated proteins (GRASPs) that bind to distinct PDZ domains within GRIP. GRASP-1 is a neuronal rasGEF associated with GRIP and AMPA receptors in vivo. Overexpression of GRASP-1 in cultured neurons specifically reduced the synaptic targeting of AMPA receptors. In addition, the subcellular distribution of both AMPA receptors and GRASP-1 was rapidly regulated by the activation of NMDA receptors. These results suggest that GRASP-1 may regulate neuronal ras signaling and contribute to the regulation of AMPA receptor distribution by NMDA receptor activity.YeBBHoward Hughes Medical Institute, Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.LiaoDDZhangXXZhangPPDongHHHuganirR LRLengGENBANKAF040944AF274057Journal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.