Three-dimensional ultrastructure of the septin filament network in<i>Saccharomyces cerevisiae</i>

Bertin, Aurélie; McMurray, Michael A.; Pierson, Jason; Thai, Luong; McDonald, Kent L.; Zehr, Elena A.; García, Galo; Peters, Peter J.; Thorner, Jeremy; Nogales, Eva

doi:10.1091/mbc.e11-10-0850

Cited by 97 publications

(114 citation statements)

References 62 publications

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“…For example, purified Shs1-capped hetero-octamers form elaborate spirals, rings, and "bird nest" structures in vitro, whereas hetero-octamers capped with Shs1(S259D) form instead a meshwork-like structure with a regularly repeating pattern . Such a gauze-like arrangement of filaments (attributed to septins by antibody decoration) was observed at the bud neck when replicas of fixed yeast spheroplasts were examined after "unroofing" by freeze fraction and deep etching (Rodal et al 2005) and lattices of crisscrossed filaments thought to be septins have been seen in more recent EM analysis of the structures assembled at the bud neck (Bertin et al 2012;Ong et al 2014). However, when present as the sole source of Shs1, neither Shs1(S259A) nor Shs1(S259D) had any effect on the ability of Shs1 to support growth in three different Shs1-dependent strain backgrounds (Figure 1, D-F), and otherwise wild-type cells expressing either Shs1(S259A) or Shs1(S259D) as the sole source of this subunit have a normal morphology (data not shown).…”

Section: Phosphorylation Of Shs1 Within Its Cte Is Not Required For Fmentioning

confidence: 87%

“…Because loss of the function of these proteins prevents cytokinesis and cell septation, and they seemed to be integral components of the filamentous structures erected at the bud neck, they were dubbed septins (Sanders and Field 1994;Pringle 2008). Indeed, subsequent purification of these proteins from yeast (Frazier et al 1998), and their production as recombinant proteins in bacteria Versele and Thorner 2004;Farkasovsky et al 2005), demonstrated that Cdc3, Cdc10, Cdc11, and Cdc12 were necessary and sufficient for the formation of long-paired filaments in vitro (Bertin et al 2008) the bud neck in vivo (Bertin et al 2012;Ong et al 2014). Detailed ultrastructural analysis led to the discovery that the septin complex that is the fundamental building block of the yeast filaments is a linear, hetero-octameric rod, with the order Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11 (Bertin et al 2008), which polymerizes end-on-end via Cdc11-Cdc11 interaction.…”

mentioning

confidence: 99%

“…the bud neck in vivo (Bertin et al 2012;Ong et al 2014). Detailed ultrastructural analysis led to the discovery that the septin complex that is the fundamental building block of the yeast filaments is a linear, hetero-octameric rod, with the order Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11 (Bertin et al 2008), which polymerizes end-on-end via Cdc11-Cdc11 interaction.…”

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confidence: 99%

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Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 inSaccharomyces cerevisiae

et al. 2015

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Septins are a family of GTP-binding proteins considered to be cytoskeletal elements because they self-assemble into filaments and other higher-order structures in vivo. In budding yeast, septins establish a diffusion barrier at the bud neck between a mother and daughter cell, promote membrane curvature there, and serve as a scaffold to recruit other proteins to the site of cytokinesis. However, the mechanism by which any septin engages a partner protein has been unclear. The two most related and recently evolved subunits appear to be Cdc11 and Shs1, and the basic building blocks for assembling septin structures are hetero-octameric rods (Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11 and Shs1-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Shs1). Loss of Cdc11 is not normally tolerated, whereas cells lacking Shs1 do not appear grossly abnormal. We established several different sensitized genetic backgrounds wherein Shs1 is indispensable, which allowed us to carry out the first comprehensive and detailed genetic analysis of Shs1 in vivo. Our analysis revealed several novel insights, including: (i) the sole portion of Shs1 essential for its function is a predicted coiled-coil-forming segment in its C-terminal extension (CTE); (ii) the CTE of Cdc11 shares this function; (iii) this role for the CTEs of Cdc11 and Shs1 is quite distinct from that of the CTEs of Cdc3 and Cdc12; and (iv) heterotypic Cdc11 and Shs1 junctions likely occur in vivo. KEYWORDS yeast; cytoskeleton; complexes; filaments; mutants S EPTINS are GTP-binding proteins conserved across Eukarya (except higher plants) (Pan et al. 2007;Nishihama et al. 2011). This protein family was first identified because the corresponding loci were among the temperature-sensitive (ts) cell division cycle (cdc) mutations isolated in Saccharomyces cerevisiae (Hartwell 1978). At the restrictive temperature, cdc3, cdc10, cdc11, and cdc12 mutants continued to bud, replicate, and segregate their chromosomes, yet failed to execute cell division, resulting in the formation of chains of multinucleate cells (Hartwell 1971). Shifting a ts allele of any of these four homologous gene products to restrictive temperature prevented formation of what appeared to be rings of highly ordered membrane-associated filaments at the bud neck (Byers and Goetsch 1976). Antibody decoration (Haarer and Pringle 1987;Ford and Pringle 1991;Kim et al. 1991) and, later, use of fusions to green fluorescent protein (GFP) (Cid et al. 1998) demonstrated that these four proteins colocalized with and were likely constituents of these filaments. Because loss of the function of these proteins prevents cytokinesis and cell septation, and they seemed to be integral components of the filamentous structures erected at the bud neck, they were dubbed septins (Sanders and Field 1994;Pringle 2008). Indeed, subsequent purification of these proteins from yeast (Frazier et al. 1998), and their production as recombinant proteins in bacteria Versele and Thorner 2004;Farkasovsky et al. 2005), demonstrated that Cdc3, Cdc10, Cdc11...

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Section: Phosphorylation Of Shs1 Within Its Cte Is Not Required For Fmentioning

confidence: 87%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 inSaccharomyces cerevisiae

et al. 2015

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“…The released Cdc14, in turn, promotes mitotic exit by inactivating CDK1 activity and promotes cytokinesis by a mechanism that is not fully understood (see more discussion later). The precise architecture of the septin rings and hourglasses remains unclear, but undoubtedly, the hourglass contains septin filaments both perpendicular and parallel to the mother-daughter axis [Byers and Goetsch, 1976;DeMay et al, 2011;Bertin et al, 2012]. Fluorescence recovery after photobleaching analysis indicates that the nascent septin ring is dynamic, the hourglass is stable, and the double rings are dynamic again [Caviston et al, 2003;Dobbelaere et al, 2003].…”

Section: Septin Structures and Dynamics In Vivomentioning

confidence: 99%

Mechanisms of cytokinesis in budding yeast

Wloka

2012

Cytoskeleton

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Cytokinesis is essential for cell proliferation in all domains of life. Because the core components and mechanisms of cytokinesis are conserved from fungi to humans, the budding yeast Saccharomyces cerevisiae has served as an attractive model for studying this fundamental process. Cytokinesis in budding yeast is driven by two interdependent cellular events: actomyosin ring (AMR) constriction and the formation of a chitinous cell wall structure called the primary septum (PS), the functional equivalent of extracellular matrix remodeling during animal cytokinesis. AMR constriction is thought to drive efficient plasma membrane ingression as well as to guide PS formation, whereas PS formation is thought to stabilize the AMR during its constriction. Following the completion of the PS formation, two secondary septa (SS), consisting of glucans and mannoproteins, are synthesized at both sides of the PS. Degradation of the PS and a part of the SS by a chitinase and glucanases then enables cell separation. In this review, we discuss the mechanics of cytokinesis in budding yeast, highlighting its common and unique features as well as the emerging questions. © 2012 Wiley Periodicals, Inc.

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“…The five mitotic septins of the budding yeast Cdc3p, Cdc10p, Cdc11p, Cdc12p and Shs1p form an octameric septin rod (Pringle, 2008). Septin rods assemble into non-polar filaments and other higher-order structures that appear as rings or collars at the bud neck of the cells (Bertin et al, 2008;Bertin et al, 2012;Byers and Goetsch, 1976;Haarer and Pringle, 1987). Septins mark the site of cell separation at the end of each cell cycle.…”

Section: Introductionmentioning

confidence: 99%

Septin rings act as template for myosin higher-order structures and inhibit redundant polarity establishment

Schneider

Grois

Renz

et al. 2013

Journal of Cell Science

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SummaryThe mechanisms of the coordinated assembly and disassembly of the septin/myosin ring is central for the understanding of polar growth and cytokinesis in yeast and other organisms. The septin-and myosin-binding protein Bni5p provides a dual function during the formation and disassembly of septin/myosin rings. Early in the cell cycle, Bni5p captures Myo1p at the incipient bud site and actively transforms it into higher-order structures. Additionally, Bni5p stabilizes the septin/myosin ring and is released from the septins shortly before the onset of cytokinesis. If this Bni5p dissociation from the septins is artificially prevented, ring disassembly is impaired and the untimely appearance of septin/myosin ring is induced. The prematurely formed septin/myosin rings delay the establishment of a new polarity axis and the progression into a new cell cycle. This observation suggests a negative feedback between septin/myosin ring formation and polarity establishment that might help to guarantee the singular assembly of this structure and the synchronization of its formation with the cell cycle.

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Three-dimensional ultrastructure of the septin filament network inSaccharomyces cerevisiae

Cited by 97 publications

References 62 publications

Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 inSaccharomyces cerevisiae

Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 inSaccharomyces cerevisiae

Mechanisms of cytokinesis in budding yeast

Septin rings act as template for myosin higher-order structures and inhibit redundant polarity establishment

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