title: Polarity determinants Tea1p, Tea4p, and Pom1p inhibit division-septum assembly at cell ends in fission yeast.
abstract: Correct positioning of the cell-division plane is crucial for cell function in all organisms. The fission yeast Schizosaccharomyces pombe divides by utilizing an actomyosin-based contractile ring and is an attractive model for the study of cytokinesis. The metazoan anillin-related protein Mid1p stimulates medial assembly of the division septum by recruiting actomyosin-ring components to the medial cortex. Here, we describe an inhibitory mechanism, involving the cell-end-localized polarity determinants Tea1p, Tea4p/Wsh3p, and Pom1p (tip complex), which prevents division-septum assembly at the cell ends. While Mid1p and the tip complex are dispensable for cell viability, their simultaneous loss leads to lethality. The FER/CIP homology protein Cdc15p, which organizes the actomyosin ring and cell membranes during cytokinesis, is a candidate for regulation by the tip complex. Since dual regulation of division-site placement is also seen in nematodes, such regulation might be a general feature of eukaryotic cytokinesis.
authors.affiliation: Cell Division Laboratory, Temasek Life Sciences Laboratory and the Department of Biological Sciences, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Yinyi
authors.initials: Y
authors.lastname: Huang
authors.forename: Ting Gang
authors.initials: TG
authors.lastname: Chew
authors.forename: Wanzhong
authors.initials: W
authors.lastname: Ge
authors.forename: Mohan K
authors.initials: MK
authors.lastname: Balasubramanian
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division; D016764:Cell Polarity; D048749:Cytokinesis; D019204:GTP-Binding Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000254:growth & development / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*
chemical_list: C082279:CDC15 protein; D018797:Cell Cycle Proteins; D006360:Heat-Shock Proteins; D007381:Intermediate Filament Proteins; D008869:Microtubule-Associated Proteins; C489694:Mid1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; C432671:Tea1 protein, S pombe; C501888:Tea4 protein, S pombe; C114142:tip1 protein, S pombe; D000205:Actomyosin; D011494:Protein Kinases; C112212:Pom1 protein, S pombe; D019204:GTP-Binding Proteins