title: Phosphorylation-dependent regulation of septin dynamics during the cell cycle.
abstract: Septins are GTPases involved in cytokinesis. In yeast, they form a ring at the cleavage site. Using FRAP, we show that septins are mobile within the ring at bud emergence and telophase and are immobile during S, G2, and M phases. Immobilization of the septins is dependent on both Cla4, a PAK-like kinase, and Gin4, a septin-dependent kinase that can phosphorylate the septin Shs1/Sep7. Induction of septin ring dynamics in telophase is triggered by the translocation of Rts1, a kinetochore-associated regulatory subunit of PP2A phosphatase, to the bud neck and correlates with Rts1-dependent dephosphorylation of Shs1. In rts1-Delta cells, the actomyosin ring contracts properly but cytokinesis fails. Together our results implicate septins in a late step of cytokinesis and indicate that proper regulation of septin dynamics, possibly through the control of their phosphorylation state, is required for the completion of cytokinesis.
authors.affiliation: Institute of Biochemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093, Zürich, Switzerland.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Dobbelaere
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Gentry
authors.forename: Richard L
authors.initials: RL
authors.lastname: Hallberg
authors.forename: Yves
authors.initials: Y
authors.lastname: Barral
mesh_terms: D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology*; D002478:Cells, Cultured; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000235:genetics / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D051304:Profilins; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C099504:CDC12 protein, S cerevisiae; C086662:CDC3 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D051304:Profilins; D021122:Protein Subunits; C115656:SHS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C095212:CLA4 protein, S cerevisiae; C107283:GIN4 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D018844:Cyclin-Dependent Kinases; D004262:DNA Restriction Enzymes; C024369:endodeoxyribonuclease Rts1; D010749:Phosphoprotein Phosphatases