title: Architecture and dynamic remodelling of the septin cytoskeleton during the cell cycle.
abstract: Septins perform diverse functions through the formation of filaments and higher-order structures. However, the exact architecture of septin structures remains unclear. In the budding yeast Saccharomyces cerevisiae, septins form an 'hourglass' at the mother-bud neck before cytokinesis, which is converted into a 'double ring' during cytokinesis. Here, using platinum-replica electron microscopy, we find that the early hourglass consists of septin double filaments oriented along the mother-bud axis. In the late hourglass, these double filaments are connected by periodic circumferential single filaments on the membrane-proximal side and are associated with centrally located, circumferential, myosin-II thick filaments on the membrane-distal side. The double ring consists of exclusively circumferential septin filaments. Live-cell imaging studies indicate that the hourglass-to-double ring transition is accompanied by loss of septin subunits from the hourglass and reorganization of the remaining subunits into the double ring. This work provides an unparalleled view of septin structures within cells and defines their remodelling dynamics during the cell cycle.
authors.affiliation: Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, 421 Curie Boulevard, Room 1156, BRB II/III, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Katy
authors.initials: K
authors.lastname: Ong
authors.affiliation: 1] Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, 421 Curie Boulevard, Room 1156, BRB II/III, Philadelphia, Pennsylvania 19104, USA [2] Institut für Biologie, Freie Universität Berlin, 14195 Berlin, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Wloka
authors.affiliation: Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, 421 Curie Boulevard, Room 1156, BRB II/III, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okada
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Svitkina
authors.affiliation: Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, 421 Curie Boulevard, Room 1156, BRB II/III, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Erfei
authors.initials: E
authors.lastname: Bi
mesh_terms: D002453:Cell Cycle; D002455:Cell Division; D003599:Cytoskeleton / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D058112:Septins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D058112:Septins