RICS, a Novel GTPase-activating Protein for Cdc42 and Rac1, Is Involved in the β-Catenin-N-cadherin andN-Methyl-d-aspartate Receptor Signaling

• Published in: The Journal of biological chemistry 2003-03, Vol.278 (11), p.9920
• Main Authors: Toshio Okabe, Tsutomu Nakamura, Yukiko Nasu Nishimura, Kazuyoshi Kohu, Susumu Ohwada, Yasuo Morishita, Tetsu Akiyama
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M208872200

Cadherin adhesion molecules are believed to be important for synaptic plasticity. β-Catenin, which links cadherins and the actin cytoskeleton, is a modulator of cadherin adhesion and regulates synaptic structure and function. Here we show that β-catenin interacts with a novel GTPase-activating protein, named RICS, that acts on Cdc42 and Rac1. The RICS-β-catenin complex was found to be associated with N-cadherin, N -methyl- d -aspartate receptors, and postsynaptic density-95, and localized to the postsynaptic density. Furthermore, the GTPase-activating protein activity of RICS was inhibited by phosphorylation by Ca 2+ /calmodulin-dependent protein kinase II. These results suggest that RICS is involved in the synaptic adhesion- and N -methyl- d -aspartate-mediated organization of cytoskeletal networks and signal transduction. Thus, RICS may regulate dendritic spine morphology and strength by modulating Rho GTPases.