title: The septation initiation network controls the assembly of nodes   containing Cdr2p for cytokinesis in fission yeast.
abstract: In the fission yeast Schizosaccharomyces pombe, cortical protein structures called interphase nodes help to prepare the cell for cytokinesis by positioning precursors of the cytokinetic contractile ring, and the septation initiation network (SIN) regulates the onset of cytokinesis and septum formation. Previous work has noted that one type of interphase node disappears during mitosis providing SIN activity is high. Here, we used time-lapse fluorescence microscopy to provide evidence that SIN activity is necessary and sufficient to disperse the type 1 node proteins Cdr2p and Mid1p into the cytoplasm, so these nodes assemble only during interphase through early mitosis when SIN activity is low. Activating the SIN in interphase cells dispersed Cdr2p and anillin Mid1p from type 1 nodes a few min after the SIN kinase Cdc7p–GFP accumulated at spindle pole bodies. If the SIN was then turned off in interphase cells, Cdr2p and Mid1p reappeared in nodes in parallel with the decline in SIN activity. Hyperactivating SIN during mitosis dispersed type 1 nodes earlier than normal, and prolonged SIN activation prevented nodes from reforming at the end of mitosis.
authors.forename: Kai-Ming
authors.initials: KM
authors.lastname: Pu
authors.forename: Matthew
authors.initials: M
authors.lastname: Akamatsu
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Pollard
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D003285:Contractile Proteins / Q000378:metabolism; D048749:Cytokinesis / Q000235:genetics / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism; D007399:Interphase / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D000072380:NIMA-Related Kinase 1; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D064048:Spindle Pole Bodies / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D003285:Contractile Proteins; C489694:Mid1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; C095886:anillin; D011494:Protein Kinases; C113816:Sid2 protein, S pombe; C542567:Cdr2 protein, S pombe; D000072380:NIMA-Related Kinase 1; D017346:Protein Serine-Threonine Kinases; C000606921:fin1 protein, S pombe