title: Role of the Rho GTPase-activating protein RICS in neurite outgrowth.
abstract: The Rho family of small GTPases, including RhoA, Rac1 and Cdc42, are critical regulators of the actin cytoskeleton. In neuronal systems, Rho GTPase-activating proteins (RhoGAPs) and their substrates, Rho GTPases, have been implicated in regulating multiple processes in the morphological development of neurons, including axonal growth and guidance, dendritic elaboration and formation of synapses. RICS is mainly expressed in the brain and functions as a RhoGAP protein for Cdc42 and Rac1 in vitro. To examine the biological function of RICS, we disrupted the RICS gene in mice. RICS knockout mice developed normally and were fertile. However, when cultured in vitro, Cdc42 activity in RICS(-/-) neurons was higher than that in wild-type neurons. Consistent with this finding, hippocampal and cerebellar granule neurons derived from RICS(-/-) mice bore longer neurites than those from wild-type mice. These findings suggest that RICS plays an important role in neurite extension by regulating Cdc42 in vivo.
authors.affiliation: Laboratory of Molecular and Genetic Information, Institute for Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nasu-Nishimura
authors.forename: Tomoatsu
authors.initials: T
authors.lastname: Hayashi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ohishi
authors.forename: Toshio
authors.initials: T
authors.lastname: Okabe
authors.forename: Susumu
authors.initials: S
authors.lastname: Ohwada
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Takao
authors.initials: T
authors.lastname: Senda
authors.forename: Chikashi
authors.initials: C
authors.lastname: Toyoshima
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakamura
authors.forename: Tetsu
authors.initials: T
authors.lastname: Akiyama
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D016501:Neurites / Q000473:pathology / Q000502:physiology*; D009474:Neurons / Q000473:pathology; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020830:rac1 GTP-Binding Protein
chemical_list: C470196:ARHGAP32 protein, human; D020690:GTPase-Activating Proteins; D009479:Neuropeptides; C484602:Rac1 protein, mouse; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein