title: Fission yeast orb6, a ser/thr protein kinase related to mammalian rho kinase and myotonic dystrophy kinase, is required for maintenance of cell polarity and coordinates cell morphogenesis with the cell cycle.
abstract: The molecular mechanisms that coordinate cell morphogenesis with the cell cycle remain largely unknown. We have investigated this process in fission yeast where changes in polarized cell growth are coupled with cell cycle progression. The orb6 gene is required during interphase to maintain cell polarity and encodes a serine/threonine protein kinase, belonging to the myotonic dystrophy kinase/cot1/warts family. A decrease in Orb6 protein levels leads to loss of polarized cell shape and to mitotic advance, whereas an increase in Orb6 levels maintains polarized growth and delays mitosis by affecting the p34(cdc2) mitotic kinase. Thus the Orb6 protein kinase coordinates maintenance of cell polarity during interphase with the onset of mitosis. orb6 interacts genetically with orb2, which encodes the Pak1/Shk1 protein kinase, a component of the Ras1 and Cdc42-dependent signaling pathway. Our results suggest that Orb6 may act downstream of Pak1/Shk1, forming part of a pathway coordinating cell morphogenesis with progression through the cell cycle.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, P.O. Box 016129, Miami, FL, 33101-6129, USA. fverde@chroma.med.miami.edu
authors.forename: F
authors.initials: F
authors.lastname: Verde
authors.forename: D J
authors.initials: DJ
authors.lastname: Wiley
authors.forename: P
authors.initials: P
authors.lastname: Nurse
mesh_terms: D000199:Actins / Q000378:metabolism; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008938:Mitosis; D008969:Molecular Sequence Data; D009223:Myotonic Dystrophy / Q000201:enzymology*; D065636:Myotonin-Protein Kinase; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000166:cytology* / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae; D054462:p21-Activated Kinases; D054460:rho-Associated Kinases
chemical_list: D000199:Actins; D018797:Cell Cycle Proteins; C585517:DMPK protein, human; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C113424:Orb6 protein, S pombe; C094326:PRK1 protein, S cerevisiae; D065636:Myotonin-Protein Kinase; C515903:PAK1 protein, human; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D054460:rho-Associated Kinases; C094341:shk1 protein, S pombe; D016203:CDC2 Protein Kinase; D019204:GTP-Binding Proteins; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae