title: Rho4 GTPase is involved in secretion of glucanases during fission yeast cytokinesis.
abstract: Rho GTPases are regulators of signaling pathways that control actin organization and cell polarity processes in all eukaryotic cells. In Schizosaccharomyces pombe, Rho4p is involved in the regulation of septum degradation during cytokinesis. Here we show that Rho4p participates in the secretion of the glucanases Eng1p and Agn1p, which are responsible for the septum degradation. First, eng1+ or agn1+ overexpression suppressed the rho4delta multiseptation phenotype, and simultaneous overproduction of Rho4p and Eng1p or of Rho4p and Agn1p caused a dramatic lysis. Second, Rho4p was not necessary for Eng1p-mediated glucanase activity as measured in cell extracts; however, rho4delta cells have a lower level of (1,3)-beta-D-glucanase activity in the culture medium. Additionally, Eng1- or Agn1-green fluorescent protein did not properly localize to the septum in rho4delta cells grown at 37 degrees C. There was a decreased amount of these enzymes in the cell wall and in the culture medium of rho4delta cells at 37 degrees C. These results provide evidence that Rho4p is involved in the regulation of Eng1p and Agn1p secretion during cytokinesis.
authors.affiliation: Instituto Microbiología-Bioquímica, Departamento de Microbiología-Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Campus Unamuno, 37007 Salamanca, Spain. bsr@usal.es
authors.forename: Beatriz
authors.initials: B
authors.lastname: Santos
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Martín-Cuadrado
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Vázquez de Aldana
authors.forename: Francisco
authors.initials: F
authors.lastname: del Rey
authors.forename: Pilar
authors.initials: P
authors.lastname: Pérez
mesh_terms: D048749:Cytokinesis / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005964:Glucosyltransferases; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006358:Hot Temperature; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology* / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; C506338:RHO4 protein, S pombe; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D006026:Glycoside Hydrolases; D019204:GTP-Binding Proteins