title: FilGAP, a Rho-ROCK-regulated GAP for Rac, controls adherens junctions in MDCK cells.
abstract: Rho family small GTPases are essential for the formation of adherens junctions in epithelial cells. Here, we found that FilGAP (also known as ARHGAP24), a Rac-specific Rho GTPase-activating protein, promoted the formation of adherens junctions in Madin-Darby canine kidney (MDCK) cells. Knockdown of FilGAP by siRNA stimulated the disassembly and migration of MDCK cells induced by hepatocyte growth factor (HGF). By contrast, forced expression of FilGAP induced accumulation of E-cadherin at adherens junctions. Endogenous FilGAP colocalized with E-cadherin at adherens junctions, and depletion of FilGAP reduced the amount of E-cadherin expressed at the surface. The Rac GAP domain of FilGAP was necessary for the suppression of cell scattering induced by HGF. In agreement with this, siRNA-mediated knockdown of both Rac1 and FilGAP suppressed cell scattering induced by HGF. Forced expression of Rho kinase (ROCK, of which there are two isoforms ROCK1 and ROCK2) induced the accumulation of E-cadherin at the adherens junction, and depletion of FilGAP prevented the accumulation of E-cadherin. Moreover, wild-type FilGAP but not a non-phosphorylatable FilGAP mutant rescued the accumulation of E-cadherin at adherens junctions. These results suggest that FilGAP might regulate cell-cell adhesion through inactivation of Rac downstream of Rho-ROCK-signaling in MDCK cells.
authors.affiliation: Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Nakahara
authors.affiliation: Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Tsutsumi
authors.affiliation: Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Zuinen
authors.affiliation: Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan yohta@kitasato-u.ac.jp.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Ohta
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism*; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D002460:Cell Line; D004285:Dogs; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D012234:Rho Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D054460:rho-Associated Kinases / Q000378:metabolism*
chemical_list: D015820:Cadherins; D020690:GTPase-Activating Proteins; D012234:Rho Factor; C085379:rho GTPase-activating protein; D017228:Hepatocyte Growth Factor; D054460:rho-Associated Kinases; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins
keywords: Adherens junctions; E-cadherin; EMT; Rac; Rho