Polar opposites: Fine‐tuning cytokinesis through SIN asymmetry

Johnson, Alyssa E.; McCollum, Dannel; Gould, Kathleen L.

doi:10.1002/cm.21044

Cited by 72 publications

(97 citation statements)

References 140 publications

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“…The SIN regulates key steps of cytokinesis, which in S. pombe comprises the formation and constriction of an actomyosin ring, septation and cell division, and asymmetry between the two SPBs has been implicated in the fine-tuning of these processes [54,55]. Central to the SIN are the GTPase Spg1, the three protein kinases Cdc7, Sid1, Sid2, as well as the inhibitory GAP complex Byr4 -Cdc16.…”

Section: (B) Exit From Mitosismentioning

confidence: 99%

“…Central to the SIN are the GTPase Spg1, the three protein kinases Cdc7, Sid1, Sid2, as well as the inhibitory GAP complex Byr4 -Cdc16. Importantly, the scaffolding protein complex Sid4-Cdc11 anchors the entire SIN cascade to SPBs [54]. This Sid4-Cdc11 scaffold is a stable integral part of SPBs and as such is thought to serve as a hub to assemble the various signalling components and regulators of the SIN [56].…”

Section: (B) Exit From Mitosismentioning

confidence: 99%

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Centrosomes as signalling centres

Arquint

Gabryjonczyk

Nigg

2014

Phil. Trans. R. Soc. B

134

114

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Centrosomes—as well as the related spindle pole bodies (SPBs) of yeast—have been extensively studied from the perspective of their microtubule-organizing roles. Moreover, the biogenesis and duplication of these organelles have been the subject of much attention, and the importance of centrosomes and the centriole–ciliary apparatus for human disease is well recognized. Much less developed is our understanding of another facet of centrosomes and SPBs, namely their possible role as signalling centres. Yet, many signalling components, including kinases and phosphatases, have been associated with centrosomes and spindle poles, giving rise to the hypothesis that these organelles might serve as hubs for the integration and coordination of signalling pathways. In this review, we discuss a number of selected studies that bear on this notion. We cover different processes (cell cycle control, development, DNA damage response) and organisms (yeast, invertebrates and vertebrates), but have made no attempt to be comprehensive. This field is still young and although the concept of centrosomes and SPBs as signalling centres is attractive, it remains primarily a concept—in need of further scrutiny. We hope that this review will stimulate thought and experimentation.

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Section: (B) Exit From Mitosismentioning

confidence: 99%

Section: (B) Exit From Mitosismentioning

confidence: 99%

Centrosomes as signalling centres

Arquint

Gabryjonczyk

Nigg

2014

Phil. Trans. R. Soc. B

134

114

View full text Add to dashboard Cite

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“…The SIN plays multiple roles during cytokinesis (reviewed by Goyal et al, 2011;Johnson et al, 2012;Roberts-Galbraith and Gould, 2008) and mitotic commitment (Grallert et al, 2012). The spindle pole body (SPB) serves as a microtubule-organising centre, and coordination point for cell cycle regulators (Grallert et al, 2012;Grallert et al, 2013;Hagan, 2008).…”

Section: Introductionmentioning

confidence: 99%

Analysis ofS. pombeSIN protein SPB-association reveals two genetically separable states of the SIN

Wachowicz

Chasapi

Krapp

et al. 2014

Journal of Cell Science

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The Schizosaccharomyces pombe septation initiation network (SIN) regulates cytokinesis, and asymmetric association of SIN proteins with the mitotic spindle pole bodies (SPBs) is important for its regulation. Here, we have used semi-automated image analysis to study SIN proteins in large numbers of wild-type and mutant cells. Our principal conclusions are: first, that the association of Cdc7p with the SPBs in early mitosis is frequently asymmetric, with a bias in favour of the new SPB; second, that the early association of Cdc7p-GFP to the SPB depends on Plo1p but not Spg1p, and is unaffected by mutations that influence its asymmetry in anaphase; third, that Cdc7p asymmetry in anaphase B is delayed by Pom1p and by activation of the spindle assembly checkpoint, and is promoted by Rad24p; and fourth, that the length of the spindle, expressed as a fraction of the length of the cell, at which Cdc7p becomes asymmetric is similar in cells dividing at different sizes. These data reveal that multiple regulatory mechanisms control the SIN in mitosis and lead us to propose a two-state model to describe the SIN.

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“…A signaling cascade called the septation initiation network (SIN) originates from spindle pole bodies (SPBs) and regulates the onset of cytokinesis and septation (Johnson et al, 2012;Sparks et al, 1999). A GTPase-activating protein (GAP) composed of Byr4p and Cdc16p negatively regulates the GTPase Spg1p at the top of the SIN.…”

Section: Introductionmentioning

confidence: 99%

“…As a cell enters mitosis, cell cycle kinases Cdk1p and Plo1p phosphorylate Byr4p, inhibiting the GAP activity and activating the SIN (Rachfall et al, 2014). Activating Spg1p on one SPB during mitosis turns on a cascade of three kinases -Cdc7p, Sid1p and Sid2p (Fankhauser and Simanis, 1994;Guertin et al, 2002;Johnson et al, 2012;Krapp and Simanis, 2008;Sohrmann et al, 1998). Low Cdk1p activity during anaphase allows Sid1p to accumulate on the SPB (Guertin et al, 2000) and to activate Sid2p, which moves with its binding partner Mob1p to the contractile ring to initiate constriction (Hou et al, 2004;Sparks et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

The septation initiation network controls the assembly of nodes containing Cdr2p for cytokinesis in fission yeast

Akamatsu

Pollard

2014

Journal of Cell Science

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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.

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Polar opposites: Fine‐tuning cytokinesis through SIN asymmetry

Cited by 72 publications

References 140 publications

Centrosomes as signalling centres

Centrosomes as signalling centres

Analysis ofS. pombeSIN protein SPB-association reveals two genetically separable states of the SIN

The septation initiation network controls the assembly of nodes containing Cdr2p for cytokinesis in fission yeast

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