title: Functional interactions between the VRP1-LAS17 and RHO3-RHO4 genes involved in actin cytoskeleton organization in Saccharomyces cerevisiae.
abstract: The RGD1 gene from Saccharomyces cerevisiae, which encodes a GTPase-activating protein for the Rho3 and Rho4 small G proteins, exhibits synthetic lethality with the VRP1 and LAS17 genes. Their products are proline-rich proteins that interact with both actin and myosins to ensure polarized growth. By testing functional links, we found that the VRP1 and LAS17 genes are potent suppressors of the rho3Delta mutation. In particular, they restore the polarization of actin patches in rho3Delta cells. Moreover, the vrp1Delta and las17Delta mutations were found to display a similar pattern of genetic interactions with specific actin-linked genes. These mutations also increase the sensitivity to activated forms of both Rho3p and Rho4p. These data support our working model, in which the VRP1 and LAS17 genes define a cellular complex that works in concert with the RHO3-RHO4 signaling pathway in yeast polarized growth. In addition, other observations lead us to propose that Rvs167p may act as a linking protein between the two cellular elements.
authors.affiliation: Laboratoire de Biologie Moléculaire et Séquençage, IBGC, UMR Université Victor Segalen Bordeaux 2-CNRS 5095, 146 rue Léo Saignat, BP 64, 33076 Bordeaux, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Roumanie
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Peypouquet
authors.forename: Didier
authors.initials: D
authors.lastname: Thoraval
authors.forename: François
authors.initials: F
authors.lastname: Doignon
authors.forename: Marc
authors.initials: M
authors.lastname: Crouzet
mesh_terms: D000199:Actins; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D019204:GTP-Binding Proteins; D008840:Microfilament Proteins / Q000235:genetics* / Q000502:physiology; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D051316:Wiskott-Aldrich Syndrome Protein; D020741:rho GTP-Binding Proteins / Q000235:genetics* / Q000502:physiology
chemical_list: D000199:Actins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; C480361:LAS17 protein, S cerevisiae; D008840:Microfilament Proteins; D029701:Saccharomyces cerevisiae Proteins; C090350:VRP1 protein, S cerevisiae; D051316:Wiskott-Aldrich Syndrome Protein; D019204:GTP-Binding Proteins; C074647:RHO3 protein, S cerevisiae; C074648:RHO4 protein, S cerevisiae; D020741:rho GTP-Binding Proteins