title: Regulation of fission yeast morphogenesis by PP2A activator pta2.
abstract: Cell polarization is key for the function of most eukaryotic cells, and regulates cell shape, migration and tissue architecture. Fission yeast, Schizosaccharomyces pombe cells are cylindrical and polarize cell growth to one or both cell tips dependent on the cell cycle stage. Whereas microtubule cytoskeleton contributes to the positioning of the growth sites by delivering polarity factors to the cell ends, the Cdc42 GTPase polarizes secretion via actin-dependent delivery and tethering of secretory vesicles to plasma membrane. How growth is restricted to cell tips and how re-initiation of tip growth is regulated in the cell cycle remains poorly understood. In this work we investigated the function of protein phosphatase type 2A (PP2A) in S. pombe morphogenesis by deleting the evolutionary conserved PTPA-type regulatory subunit that we named pta2. pta2-deleted cells showed morphological defects and altered growth pattern. Consistent with this, actin patches and active Cdc42 were mislocalized in the pta2 deletion. These defects were additive to the lack of Cdc42-GAP Rga4. pta2Δ cells show upregulated Cdc42 activity and pta2 interacts genetically with polarisome components Tea1, Tea4 and For3 leading to complete loss of cell polarity and rounded morphology. Thus, regulation of polarity by PP2A requires the polarisome and involves Pta2-dependent control of Cdc42 activity.
authors.affiliation: Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Junta de Andalucia, Sevilla, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Bernal
authors.forename: Maria Antonia
authors.initials: MA
authors.lastname: Sanchez-Romero
authors.forename: Silvia
authors.initials: S
authors.lastname: Salas-Pino
authors.forename: Rafael R
authors.initials: RR
authors.lastname: Daga
mesh_terms: D002453:Cell Cycle; D016764:Cell Polarity; D049109:Cell Proliferation; D003080:Cold Temperature; D042541:Intracellular Space / Q000201:enzymology; D009024:Morphogenesis; D010641:Phenotype; D054648:Protein Phosphatase 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D054648:Protein Phosphatase 2; D020764:cdc42 GTP-Binding Protein