title: p190RhoGAP has cellular RacGAP activity regulated by a polybasic region.
abstract: p190RhoGAP is a GTPase-activating protein (GAP) known to regulate actin cytoskeleton dynamics by decreasing RhoGTP levels through activation of the intrinsic GTPase activity of Rho. Although the GAP domain of p190RhoGAP stimulates the intrinsic' GTPase activity of several Rho family members (Rho, Rac, Cdc42) under in vitro conditions, p190RhoGAP is generally regarded as a GAP for RhoA in the cell. The cellular RacGAP activity of the protein has not been proven directly. We have previously shown that the in vitro RacGAP and RhoGAP activity of p190RhoGAP was inversely regulated through a polybasic region of the protein. Here we provide evidence that p190RhoGAP shows remarkable GAP activity toward Rac also in the cell. The cellular RacGAP activity of p190RhoGAP requires an intact polybasic region adjacent to the GAP domain whereas the RhoGAP activity is inhibited by the same domain. Our data indicate that through its alternating RacGAP and RhoGAP activity, p190RhoGAP plays a more complex role in the Rac-Rho antagonism than it was realized earlier.
authors.affiliation: Department of Physiology, Semmelweis University, Budapest, Hungary.
authors.forename: Magdolna
authors.initials: M
authors.lastname: Lévay
authors.forename: Balázs
authors.initials: B
authors.lastname: Bartos
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Ligeti
mesh_terms: D008841:Actin Cytoskeleton; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000378:metabolism
chemical_list: C513041:Arhgap35 protein, mouse; D020690:GTPase-Activating Proteins; D012097:Repressor Proteins; C085379:rho GTPase-activating protein; D020744:rac GTP-Binding Proteins