title: Analysis of S. pombe SIN protein association to the SPB reveals two genetically separable states of the SIN.
abstract: The Schizosaccharomyces pombe septation initiation network (SIN) regulates cytokinesis, and asymmetric association of SIN proteins with the mitotic spindle pole bodies (SPBs) is important for its regulation. Here, we have used semi-automated image analysis to study SIN proteins in large numbers of wild-type and mutant cells. Our principal conclusions are: first, that the association of Cdc7p with the SPBs in early mitosis is frequently asymmetric, with a bias in favour of the new SPB; second, that the early association of Cdc7p-GFP to the SPB depends on Plo1p but not Spg1p, and is unaffected by mutations that influence its asymmetry in anaphase; third, that Cdc7p asymmetry in anaphase B is delayed by Pom1p and by activation of the spindle assembly checkpoint, and is promoted by Rad24p; and fourth, that the length of the spindle, expressed as a fraction of the length of the cell, at which Cdc7p becomes asymmetric is similar in cells dividing at different sizes. These data reveal that multiple regulatory mechanisms control the SIN in mitosis and lead us to propose a two-state model to describe the SIN.
authors.affiliation: Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland.
authors.forename: Paulina
authors.initials: P
authors.lastname: Wachowicz
authors.affiliation: Swiss-Prot. Group and Vital-IT Group, Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Chasapi
authors.affiliation: Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Krapp
authors.affiliation: Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland.
authors.forename: Elena
authors.initials: E
authors.lastname: Cano Del Rosario
authors.affiliation: Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schmitter
authors.affiliation: Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sage
authors.affiliation: Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Unser
authors.affiliation: Swiss-Prot. Group and Vital-IT Group, Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Xenarios
authors.affiliation: Bioinformatics and Biostatistics Core Facility, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Jacques
authors.initials: J
authors.lastname: Rougemont
authors.affiliation: Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland viesturs.simanis@epfl.ch.
authors.forename: Viesturs
authors.initials: V
authors.lastname: Simanis
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics; D048749:Cytokinesis / Q000235:genetics; D020558:GTP Phosphohydrolases / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D007091:Image Processing, Computer-Assisted; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D059566:M Phase Cell Cycle Checkpoints / Q000235:genetics*; D008938:Mitosis / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics*; D008941:Spindle Apparatus / Q000235:genetics* / Q000502:physiology; D064048:Spindle Pole Bodies / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; C544863:Etd1 protein, S pombe; D047908:Intracellular Signaling Peptides and Proteins; D029702:Schizosaccharomyces pombe Proteins; C501114:rad24 protein, S pombe; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; C112212:Pom1 protein, S pombe; C489406:cdc7 protein, S pombe; C501407:Plo1 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D020558:GTP Phosphohydrolases; C510604:Spg1 protein, S pombe
keywords: Cytokinesis; S. pombe; SIN