scholarly journals Fission yeast Cyk3p is a transglutaminase-like protein that participates in cytokinesis and cell morphogenesis

2012 ◽  
Vol 23 (13) ◽  
pp. 2433-2444 ◽  
Author(s):  
Luther W. Pollard ◽  
Masayuki Onishi ◽  
John R. Pringle ◽  
Matthew Lord
Keyword(s):  
Fission Yeast ◽  
Primary Role ◽  
Cell Integrity ◽  
Cell Morphogenesis ◽  
Contractile Ring ◽  
Physiological Importance ◽  
Complex Process ◽  
Catalytic Active Site ◽  
Thiol Proteases ◽  
Ring Constriction

Cell morphogenesis is a complex process that relies on a diverse array of proteins and pathways. We have identified a transglutaminase-like protein (Cyk3p) that functions in fission yeast morphogenesis. The phenotype of a cyk3 knockout strain indicates a primary role for Cyk3p in cytokinesis. Correspondingly, Cyk3p localizes both to the actomyosin contractile ring and the division septum, promoting ring constriction, septation, and subsequent cell separation following ring disassembly. In addition, Cyk3p localizes to polarized growth sites and plays a role in cell shape determination, and it also appears to contribute to cell integrity during stationary phase, given its accumulation as dynamic puncta at the cortex of such cells. Our results and the conservation of Cyk3p across fungi point to a role in cell wall synthesis and remodeling. Cyk3p possesses a transglutaminase domain that is essential for function, even though it lacks the catalytic active site. In a wider sense, our work illustrates the physiological importance of inactive members of the transglutaminase family, which are found throughout eukaryotes. We suggest that the proposed evolution of animal transglutaminase cross-linking activity from ancestral bacterial thiol proteases was accompanied by the emergence of a subclass whose function does not depend on enzymatic activity.

scholarly journals Calcium spikes accompany cleavage furrow ingression and cell separation during fission yeast cytokinesis

2021 ◽  
Vol 32 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Abhishek Poddar ◽  
Oumou Sidibe ◽  
Aniruddha Ray ◽  
Qian Chen
Keyword(s):  
Fission Yeast ◽  
Cell Separation ◽  
Cleavage Furrow ◽  
Cell Integrity ◽  
Embryonic Cells ◽  
Contractile Ring ◽  
Calcium Spikes ◽  
Division Plane ◽  
Ring Constriction ◽  
And Function

Calcium rises transiently at the division plane during cytokinesis of embryonic cells, but the conservation and function of such calcium transients remain unclear. We discovered similar calcium spikes during fission yeast cytokinesis, and demonstrated that calcium promotes contractile ring constriction and daughter cell integrity.

scholarly journals Contractile ring constriction and septation in fission yeast are integrated mutually stabilizing processes

2021 ◽  
Author(s):  
Sathish Thiyagarajan ◽  
Zachary A McDargh ◽  
Shuyuan Wang ◽  
Ben O'Shaughnessy
Keyword(s):  
Cell Wall ◽  
Fission Yeast ◽  
Growth Ring ◽  
Integrated System ◽  
Animal Cells ◽  
Contractile Ring ◽  
Cell Wall Growth ◽  
Ring Constriction ◽  
Wall Growth ◽  
In Cells

In common with other cellular machineries, the actomyosin contractile ring that divides cells during cytokinesis does not operate in isolation. Contractile rings in animal cells interact with contiguous actomyosin cortex, while ring constriction in many cell-walled organisms couples tightly to cell wall growth. In fission yeast, a septum grows in the wake of the constricting ring, ensuring cytokinesis leaves two daughter cells fully enclosed by cell wall. Here we mathematical modeled the integrated constriction-septation system in fission yeast, with a kinetic growth model evolving the 3D septum shape coupled to a molecularly explicit simulation of the contractile ring highly constrained by experimental data. Simulations revealed influences in both directions, stabilizing the ring-septum system as a whole. By providing a smooth circular anchoring surface for the ring, the inner septum leading edge stabilized ring organization and tension production; by mechanically regulating septum circularity and in-plane growth, ring tension stabilized septum growth and shape. Genetic or pharmacological perturbation of either subsystem destabilized this delicate balance, precipitating uncontrolled positive feedback with disastrous morphological and functional consequences. Thus, high curvature septum irregularities triggered bridging instabilities, in which contractile ring segments became unanchored. Bridging abolished the local tension-mediated septum shape regulation, exacerbating the irregularity in a mutually destabilizing runaway process. Our model explains a number of previously mysterious experimental observations, including unanchoring of ring segments observed in cells with mutations in the septum-growing β-glucan synthases, and irregular septa in cells with mutations in the contractile ring myosin-II Myo2. Thus, the contractile ring and cell wall growth cellular machineries operate as a single integrated system, whose stability relies on mutual regulation by the two subsystems.

scholarly journals Profilin-mediated Competition between Capping Protein and Formin Cdc12p during Cytokinesis in Fission Yeast

2005 ◽  
Vol 16 (5) ◽  
pp. 2313-2324 ◽  
Author(s):  
David R. Kovar ◽  
Jian-Qiu Wu ◽  
Thomas D. Pollard
Keyword(s):  
Fission Yeast ◽  
Actin Filament ◽  
Actin Filaments ◽  
Cell Separation ◽  
The Other ◽  
Temperature Sensitive ◽  
Contractile Ring ◽  
Capping Protein ◽  
Division Site ◽  
Ring Constriction

Fission yeast capping protein SpCP is a heterodimer of two subunits (Acp1p and Acp2p) that binds actin filament barbed ends. Neither acp1 nor acp2 is required for viability, but cells lacking either or both subunits have cytokinesis defects under stressful conditions, including elevated temperature, osmotic stress, or in combination with numerous mild mutations in genes important for cytokinesis. Defects arise as the contractile ring constricts and disassembles, resulting in delays in cell separation. Genetic and biochemical interactions show that the cytokinesis formin Cdc12p competes with capping protein for actin filament barbed ends in cells. Deletion of acp2 partly suppresses cytokinesis defects in temperature-sensitive cdc12-112 cells and mild overexpression of capping protein kills cdc12-112 cells. Biochemically, profilin has opposite effects on filaments capped with Cdc12p and capping protein. Profilin depolymerizes actin filaments capped by capping protein but allows filaments capped by Cdc12p to grow at their barbed ends. Once associated with a barbed end, either Cdc12p or capping protein prevents the other from influencing polymerization at that end. Given that capping protein arrives at the division site 20 min later than Cdc12p, capping protein may slowly replace Cdc12p on filament barbed ends in preparation for filament disassembly during ring constriction.

scholarly journals Characterization of the roles of Blt1p in fission yeast cytokinesis

2014 ◽  
Vol 25 (13) ◽  
pp. 1946-1957 ◽  
Author(s):  
John W. Goss ◽  
Sunhee Kim ◽  
Hannah Bledsoe ◽  
Thomas D. Pollard
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Cell Separation ◽  
Analytical Ultracentrifugation ◽  
Contractile Ring ◽  
Glucan Synthase ◽  
Temporal Regulation ◽  
Septation Initiation Network ◽  
Ring Constriction

Spatial and temporal regulation of cytokinesis is essential for cell division, yet the mechanisms that control the formation and constriction of the contractile ring are incompletely understood. In the fission yeast Schizosaccharomyces pombe proteins that contribute to the cytokinetic contractile ring accumulate during interphase in nodes—precursor structures around the equatorial cortex. During mitosis, additional proteins join these nodes, which condense to form the contractile ring. The cytokinesis protein Blt1p is unique in being present continuously in nodes from early interphase through to the contractile ring until cell separation. Blt1p was shown to stabilize interphase nodes, but its functions later in mitosis were unclear. We use analytical ultracentrifugation to show that purified Blt1p is a tetramer. We find that Blt1p interacts physically with Sid2p and Mob1p, a protein kinase complex of the septation initiation network, and confirm known interactions with F-BAR protein Cdc15p. Contractile rings assemble normally in blt1∆ cells, but the initiation of ring constriction and completion of cell division are delayed. We find three defects that likely contribute to this delay. Without Blt1p, contractile rings recruited and retained less Sid2p/Mob1p and Clp1p phosphatase, and β-glucan synthase Bgs1p accumulated slowly at the cleavage site.

scholarly journals Calcium spikes accompany the cleavage furrow ingression and cell separation during fission yeast cytokinesis

2020 ◽  
Author(s):  
Abhishek Poddar ◽  
Oumou Sidibe ◽  
Aniruddha Ray ◽  
Qian Chen
Keyword(s):  
Fission Yeast ◽  
Embryonic Cell ◽  
Calcium Transients ◽  
Cleavage Furrow ◽  
Cell Integrity ◽  
Calcium Spikes ◽  
Division Plane ◽  
Calcium Indicator ◽  
Intracellular Calcium Level ◽  
Ring Constriction

AbstractThe role of calcium signaling during cytokinesis has long remained ambiguous. The studies of embryonic cell division discovered that calcium concentration increases transiently at the division plane just before the cleavage furrow ingression, leading to the hypothesis that these calcium transients trigger the contractile ring constriction. However, such calcium transients have only been found in animal embryos and their function remains controversial. Here we explored cytokinetic calcium transients in the model organism fission yeast. We adopted GCaMP, a genetically encoded calcium indicator, to determine the intracellular calcium level. We validated GCaMP as a highly sensitive calcium indicator which allowed us to capture the calcium transients stimulated by osmotic shocks. To identify calcium transients during cytokinesis, we first identified a correlation between the intracellular calcium level and cell division. Next, we discovered calcium spikes at the start of the cleavage furrow ingression and the end of the cell separation using time-lapse microscopy to. Inhibition of these calcium spikes slowed down the furrow ingression and led to frequent lysis of the daughter cells. We conclude that like the larger animal embryos fission yeast triggers cytokinetic calcium transients which promote the ring constriction and daughter cell integrity (194).Highlight summary for TOCCalcium rises transiently at the division plane during embryonic cell cytokinesis, but the conservation and function of such calcium transients remain unclear. We identified similar calcium spikes during fission yeast cytokinesis and demonstrated that these spikes promote the contractile ring constriction and the daughter cell integrity (257).

scholarly journals Schizosaccharomyces pombe Pxl1 Is a Paxillin Homologue That Modulates Rho1 Activity and Participates in Cytokinesis

2008 ◽  
Vol 19 (4) ◽  
pp. 1727-1738 ◽  
Author(s):  
Mario Pinar ◽  
Pedro M. Coll ◽  
Sergio A. Rincón ◽  
Pilar Pérez
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Rho Gtpases ◽  
Actin Polymerization ◽  
Cell Integrity ◽  
Contractile Ring ◽  
Cytoskeleton Organization ◽  
Lim Domains ◽  
Actin Cytoskeleton Organization ◽  
Septation Initiation Network

Schizosaccharomyces pombe Rho GTPases regulate actin cytoskeleton organization and cell integrity. We studied the fission yeast gene SPBC4F6.12 based on its ability to suppress the thermosensitivity of cdc42-1625 mutant strain. This gene, named pxl1+, encodes a protein with three LIM domains that is similar to paxillin. Pxl1 does not interact with Cdc42 but it interacts with Rho1, and it negatively regulates this GTPase. Fission yeast Pxl1 forms a contractile ring in the cell division region and deletion of pxl1+ causes a delay in cell–cell separation, suggesting that it has a function in cytokinesis. Pxl1 N-terminal region is required and sufficient for its localization to the medial ring, whereas the LIM domains are necessary for its function. Pxl1 localization requires actin polymerization and the actomyosin ring, but it is independent of the septation initiation network (SIN) function. Moreover, Pxl1 colocalizes and interacts with Myo2, and Cdc15, suggesting that it is part of the actomyosin ring. Here, we show that in cells lacking Pxl1, the myosin ring is not correctly assembled and that actomyosin ring contraction is delayed. Together, these data suggest that Pxl1 modulates Rho1 GTPase signaling and plays a role in the formation and contraction of the actomyosin ring during cytokinesis.

scholarly journals Contractile Ring Constriction and Cell Wall Growth are Regulated by Mechanical Feedback and Destabilized by Mutations in Fission Yeast

2020 ◽  
Vol 118 (3) ◽  
pp. 440a
Author(s):  
Sathish Thiyagarajan ◽  
Zachary A. McDargh ◽  
Shuyuan Wang ◽  
Ben O'Shaughnessy
Keyword(s):  
Cell Wall ◽  
Fission Yeast ◽  
Contractile Ring ◽  
Cell Wall Growth ◽  
Ring Constriction ◽  
Wall Growth ◽  
Mechanical Feedback

scholarly journals Mechanism of Cytokinetic Contractile Ring Constriction in Fission Yeast

2014 ◽  
Vol 29 (5) ◽  
pp. 547-561 ◽  
Author(s):  
Matthew R. Stachowiak ◽  
Caroline Laplante ◽  
Harvey F. Chin ◽  
Boris Guirao ◽  
Erdem Karatekin ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Contractile Ring ◽  
Ring Constriction

scholarly journals A novel checkpoint pathway controls actomyosin ring constriction trigger in fission yeast

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Tomás Edreira ◽  
Rubén Celador ◽  
Elvira Manjón ◽  
Yolanda Sánchez
Keyword(s):  
Cell Wall ◽  
Fission Yeast ◽  
Wall Stress ◽  
Cell Integrity ◽  
Wild Type ◽  
Cell Wall Stress ◽  
Checkpoint Pathway ◽  
In The Wild ◽  
Septation Initiation Network ◽  
Ring Constriction

In fission yeast, the septation initiation network (SIN) ensures temporal coordination between actomyosin ring (CAR) constriction with membrane ingression and septum synthesis. However, questions remain about CAR regulation under stress conditions. We show that Rgf1p (Rho1p GEF), participates in a delay of cytokinesis under cell wall stress (blankophor, BP). BP did not interfere with CAR assembly or the rate of CAR constriction, but did delay the onset of constriction in the wild type cells but not in the rgf1Δ cells. This delay was also abolished in the absence of Pmk1p, the MAPK of the cell integrity pathway (CIP), leading to premature abscission and a multi-septated phenotype. Moreover, cytokinesis delay correlates with maintained SIN signaling and depends on the SIN to be achieved. Thus, we propose that the CIP participates in a checkpoint, capable of triggering a CAR constriction delay through the SIN pathway to ensure that cytokinesis terminates successfully.

scholarly journals Roles of Mso1 and the SM protein Sec1 in efficient vesicle fusion during fission yeast cytokinesis

2020 ◽  
Vol 31 (15) ◽  
pp. 1570-1583
Author(s):  
Kenneth S. Gerien ◽  
Sha Zhang ◽  
Alexandra C. Russell ◽  
Yi-Hua Zhu ◽  
Vedud Purde ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fission Yeast ◽  
Vesicle Fusion ◽  
Contractile Ring ◽  
Division Site ◽  
Ring Constriction ◽  
Sm Protein

Mso1 and the SM protein Sec1 aid in the efficient fusion of vesicles at the division site in fission yeast, which is important for proper contractile-ring constriction and plasma-membrane closure during cytokinesis.

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