The emerging functions of septins in metazoans

Saarikangas, Juha; Barral, Yves

doi:10.1038/embor.2011.193

Cited by 120 publications

(116 citation statements)

References 102 publications

(154 reference statements)

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“…N-terminal polybasic motif is critical for membrane recruitment of septins Septin structures are tightly apposed to the PM and have been implicated in membrane reorganization, curvature, and even vesicular trafficking (Byers and Goetsch 1976;TanakaTakiguchi et al 2009;Saarikangas and Barral 2011;Mostowy and Cossart 2012). Work both in vitro (Bertin et al 2010) and in vivo (Bridges et al 2014) supports the notion that the presence of membranes promotes filament assembly and the formation of higher-order septin structures.…”

Section: Evidence For Heterotypic Octamer-octamer Interaction In Vivosupporting

confidence: 55%

“…After it was shown that Shs1 could occupy the same terminal position as Cdc11 in yeast septin hetero-octamers and confer different properties on the resulting complexes , it became apparent that, for mammalian septin complexes, placement of alternative subunits at different positions within hetero-octamers would likely provide a mechanism to impart differential features or functions appropriate to the septin structures in particular cell types or at particular stages in development (Saarikangas and Barral 2011;Mostowy and Cossart 2012;Sellin et al 2012;Fung et al 2014;Sellin et al 2014). Therefore, understanding how paralogous subunits, like Cdc11 and Shs1, have coevolved within the same complex and in the same cell type is of significant interest.…”

Section: Evidence For Heterotypic Octamer-octamer Interaction In Vivomentioning

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: Evidence For Heterotypic Octamer-octamer Interaction In Vivosupporting

confidence: 55%

Section: Evidence For Heterotypic Octamer-octamer Interaction In Vivomentioning

confidence: 99%

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

et al. 2015

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“…Биологическая функция септинов связана с их способностью образовывать друг с другом гетероолиго-мерные комплексы, которые в свою очередь формируют длинные полимеры (филаменты) (Sirajuddin et al, 2007;McMurray et al, 2011). Септины участвуют в цитокинезе, установлении и поддержании внутриклеточной поляр-ности, функционировании микротрубочкового и акти-нового цитоскелета, клеточном движении, везикулярном транспорте, экзоцитозе, нейрогенезе и других процессах (Saarikangas, Barral, 2011;Mostowy, Cossart, 2012). Для септинов характерно наличие консервативного ГТФазного домена, который, как показывают последние исследова-ния, играет важную роль в динамике септиновых структур внутри клетки (Sirajuddin et al, 2009;Zent, Wittinghofer, 2014;.…”

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The role of Pnut and its functional domains in Drosophila spermatogenesis

Akhmetova¹,

Dorogova²,

Болоболова³

et al. 2016

Vestn. VOGiS

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Drosophila Pnut protein belongs to the family of septins, conservative GTPases participating in cytokinesis and many more other fundamental cellular processes. Because of their filame tous appearance, membrane association and functions, septins are considered as the fourth component of the cytoskeleton, along with actin, microtubules and intermediate filame ts. However, septins are much less studied than the other cytoskeleton elements. We had previously demonstrated that deletion of the peanut (pnut) gene leads to mitotic abnormalities in somatic cells. The goal of this work was to study the role of pnut in Drosophila spermatogenesis. We designed a construct for pnut RNA interference allowing pnut expression to be suppressed ectopically. We analyzed the effect of pnut RNA interference on Drosophila spermatogenesis. The most sensitive to Pnut depletion were germ line cells at the earliest stages of spermatogenesis: the suppression of pnut expression at these stages leads to male sterility as a result of immotile sperm. Testes of those sterile males did not show any significa t meiotic defects; axonemes and mitochondria were normal. We also analyzed the effect of mutations in Pnut conservative domains on Drosophila spermatogenesis. Mutations in the GTPase domain resulted in cyst elongation defects. Deletions of the C-terminal domain led to abnormal testis morphology. Both GTPase domain and C-terminal domain mutant males were sterile and produced immotile sperm. To summarize, we showed that Pnut participates in spermiogenesis, that is, late stages of spermatogenesis, when major morphological changes in spermatocytes occur.Key words: Drosophila; RNA interference; spermatogenesis; septin; peanut; Pnut.Белок Pnut дрозофилы принадлежит к семейству септинов -консервативных ГТФаз, участвующих в цитокинезе и других фундаментальных клеточных процессах. В связи с их способностью формировать комплексы, которые могут затем полимеризоваться в филаменты, а также на основе их взаимодействия с клеточной мембраной и выполняемыми функциями септины стали рас-смат ри вать как четвертую составляющую цитоскелета наряду с актином, микротрубочками и промежуточными филаментами. Однако в отличие от других цитоскелетных компонентов септины изучены гораздо слабее. Ранее нами было показано, что удаление септина, кодируемого геном peanut (pnut), в соматических тканях приводит к аномалиям митоза. Задачей данной работы было выяснение роли pnut в сперматогенезе дрозофилы. Нами была получена плазмидная конструкция для РНК-интерференции pnut, позволяющая эктопически подавлять экспрессию данного гена. Был исследован сперматогенез при подавлении экспрессии гена pnut при помощи РНК-интерференции. Установлено, что чувствительными к РНК-интерференции гена pnut являются генеративные клетки на самых ранних этапах сперматогенеза: снижение уровня экспрессии данного гена в генеративных клетках семенников на этих стадиях приводило к стерильности самцов, причиной которой является неподвижность спермиев. При этом в семенниках таких стерильных самцов не обнаруж...

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“…Septins are guanosine triphosphate (GTP)-binding proteins that assemble into hetero-oligomeric complexes and form nonpolar filaments that associate with cellular membranes and the cytoskeleton (Mostowy and Cossart, 2012;Saarikangas and Barral, 2011).…”

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confidence: 99%