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PP2A-Cdc55 phosphatase regulates actomyosin ring contraction and septum formation during cytokinesis.

ABSTRACT: Eukaryotic cells divide and separate all their components after chromosome segregation by a process called cytokinesis to complete cell division. Cytokinesis is highly regulated by the recruitment of the components to the division site and through post-translational modifications such as phosphorylations. The budding yeast mitotic kinases Cdc28-Clb2, Cdc5, and Dbf2-Mob1 phosphorylate several cytokinetic proteins contributing to the regulation of cytokinesis. The PP2A-Cdc55 phosphatase regulates mitosis counteracting Cdk1- and Cdc5-dependent phosphorylation. This prompted us to propose that PP2A-Cdc55 could also be counteracting the mitotic kinases during cytokinesis. Here we show that in the absence of Cdc55, AMR contraction and the primary septum formation occur asymmetrically to one side of the bud neck supporting a role for PP2A-Cdc55 in cytokinesis regulation. In addition, by in vivo and in vitro assays, we show that PP2A-Cdc55 dephosphorylates the chitin synthase II (Chs2 in budding yeast) a component of the Ingression Progression Complexes (IPCs) involved in cytokinesis. Interestingly, the non-phosphorylable version of Chs2 rescues the asymmetric AMR contraction and the defective septa formation observed in cdc55∆ mutant cells. Therefore, timely dephosphorylation of the Chs2 by PP2A-Cdc55 is crucial for proper actomyosin ring contraction. These findings reveal a new mechanism of cytokinesis regulation by the PP2A-Cdc55 phosphatase and extend our knowledge of the involvement of multiple phosphatases during cytokinesis.

SUBMITTER: Moyano-Rodriguez Y

PROVIDER: S-EPMC8888506 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:The yeast PP2A-Cdc55 Serine/Threonine phosphatase regulates transcription under certain conditions. It is required for full activation of the environmental stress response mediated by the transcription factors Msn2 and Msn4. PP2A-Cdc55 contributes to sustained nuclear accumulation of Msn2 and Msn4 and extended chromatin recruitment under stress conditions such as hyperosmolarity stress. Transcript profiles of Msn2 and Msn4 double mutants are similar to cdc55 and the corresponding triple mutants. This argues for a Msn2/4 specific function of PP2A-Cdc55. Time course of 10 20 and 30 minutes hyperosmolarity treated yeast cells of wild type (W303), msn2msn4, cdc55, msn2msn5cdc55 genetic background.

2012-06-07 | E-GEOD-38565 | biostudies-arrayexpress

The yeast PP2A-CDC55 phosphatase regulates the transcriptional response to hyperosmolarity stress by regulating Msn2 and Msn4

Project description:This SuperSeries is composed of the following subset Series: GSE38565: The yeast PP2A-CDC55 phosphatase regulates the transcriptional response to hyperosmolarity stress by regulating Msn2 and Msn4 [Time course 1] GSE42033: The yeast PP2A-CDC55 phosphatase regulates the transcriptional response to hyperosmolarity stress by regulating Msn2 and Msn4 [Time course 2] Refer to individual Series

2012-11-06 | E-GEOD-42034 | biostudies-arrayexpress

The yeast PP2A-CDC55 phosphatase regulates the transcriptional response to hyperosmolarity stress by regulating Msn2 and Msn4

Project description:This SuperSeries is composed of the SubSeries listed below.

2012-11-06 | GSE42034 | GEO

Stabilization of the actomyosin ring enables spermatocyte cytokinesis in Drosophila.

Project description:The scaffolding protein anillin is required for completion of cytokinesis. Anillin binds filamentous (F) actin, nonmuscle myosin II, and septins and in cell culture models has been shown to restrict actomyosin contractility to the cleavage furrow. Whether anillin also serves this function during the incomplete cytokinesis that occurs in developing germ cells has remained unclear. Here, we show that anillin is required for cytokinesis in dividing Drosophila melanogaster spermatocytes and that anillin, septins, and myosin II stably associate with the cleavage furrow in wild-type cells. Anillin is necessary for recruitment of septins to the cleavage furrow and for maintenance of F-actin and myosin II at the equator in late stages of cytokinesis. Remarkably, expression of DE-cadherin suppresses the cytokinesis defect of anillin-depleted spermatocytes. DE-cadherin recruits beta-catenin (armadillo) and alpha-catenin to the cleavage furrow and stabilizes F-actin at the equator. Similarly, E-cadherin expression suppresses the cytokinesis defect caused by anillin knockdown in mouse L-fibroblast cells. Our results show that the anillin-septin and cadherin-catenin complexes can serve as alternative cassettes to promote tight physical coupling of F-actin and myosin II to the cleavage furrow and successful completion of cytokinesis.

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Involvement of an actomyosin contractile ring in Saccharomyces cerevisiae cytokinesis.

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Curvature-induced expulsion of actomyosin bundles during cytokinetic ring contraction.

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