Stable Pom1 clusters form a glucose-modulated concentration gradient that regulates mitotic entry

Allard, Corey A.H.; Opalko, Hannah E.; Moseley, James B.

doi:10.1101/547224

Cited by 9 publications

(11 citation statements)

References 70 publications

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“…Therefore, the density of nodes in the broad band increased modestly with the cellular Pom1 concentration as the broad band occupied a smaller fraction of the cell length (Figure 5G). The ratio of the broad band width to the cell length decreased with the total cellular Pom1, indicating that Pom1 controls the width of the broad band (Figure 5H) as expected from previous work (Allard et al, 2019).…”

Section: Resultssupporting

confidence: 85%

The number of cytokinesis nodes in mitotic fission yeast scales with cell size

Sayyad

2021

Preprint

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Cytokinesis nodes are assemblies of stoichiometric ratios of proteins associated with the plasma membrane, which serve as precursors for the contractile ring during cytokinesis by fission yeast. The total number of nodes is uncertain, because of the limitations of the methods used previously. Here we used the ~140 nm resolution of Airyscan confocal microscopy to resolve a large population of dim, unitary cytokinesis nodes in 3D reconstructions of whole fission yeast cells. Wild-type fission yeast cells make about 200 unitary cytokinesis nodes. Most, but not all of these nodes condense into a contractile ring. The number of cytokinesis nodes scales with cell size in four strains tested, although wide rga4Δ mutant cells form somewhat fewer cytokinesis nodes than expected from the overall trend. The surface density of Pom1 kinase on the plasma membrane around the equators of cells is similar with a wide range of node numbers, so Pom1 does not control cytokinesis node number. However, varying protein concentrations with the nmt1 promoter showed that the numbers of nodes increase above a baseline of about 200 with the total cellular concentration of either Pom1 or the kinase Cdr2.

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Section: Resultssupporting

confidence: 85%

The number of cytokinesis nodes in mitotic fission yeast scales with cell size

Sayyad

2021

Preprint

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“…At the plasma membrane, Pom1 auto-phosphorylates to promote its return to the cytosol. It also forms cortical clusters that support its graded distribution from cell poles to mid-cell (Allard et al, 2019;Gerganova et al, 2019). These clusters, together with autophosphorylation-mediated detachment, promote robustness of the gradient (Hersch et al, 2015;Saunders et al, 2012).…”

Section: Introductionmentioning

confidence: 98%

“…The pathway is also sensitive to changes in nutritional status. Specifically, Pom1 graded localization is altered when cells encounter low-glucose environment (Allard et al, 2019;Kelkar and Martin, 2015).…”

Section: Introductionmentioning

confidence: 99%

Direct and indirect regulation of Pom1 cell size pathway by the protein phosphatase 2C Ptc1

Gerganova

Bhatia

Martin

2020

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The fission yeast cells Schizosaccharomyces pombe divide at constant cell size regulated by environmental stimuli. An important pathway of cell size control involves the membrane-associated DYRK-family kinase Pom1, which forms decreasing concentration gradients from cell poles and inhibits mitotic inducers at mid-cell. Here, we identify the phosphatase 2C Ptc1 as negative regulator of Pom1. Ptc1 localizes to cell poles in a manner dependent on polarity and cell-wall integrity factors. We show that Ptc1 directly binds Pom1 and can dephosphorylate it in vitro but modulates Pom1 localization indirectly upon growth in low glucose conditions by influencing microtubule stability. Thus, Ptc1 phosphatase plays both direct and indirect roles in the Pom1 cell size control pathway.

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“…However, the functional role of this region within kinase domains suggests that other kinases with insertions at the GHI subdomain may be regulated by mechanisms similar to the one we describe here. Phosphorylation of these residues in Wee1 explains the cell size defects of cdr1∆ mutants, and likely represent the functional output of the well-studied Pom1-Cdr2-Cdr1-Wee1 pathway (Martin and Berthelot-Grosjean, 2009;Moseley et al, 2009;Pan et al, 2014;Allard et al, 2018Allard et al, , 2019Gerganova et al, 2019). Efficient signaling in this pathway requires organization within oligomeric clustered structures at the cell cortex.…”

Section: Spatial Control Of Cdr1-wee1 Signaling In Cellsmentioning

confidence: 99%

A mechanism for how Cdr1/Nim1 kinase promotes mitotic entry by inhibiting Wee1

Opalko

Nasa

Kettenbach

et al. 2019

Preprint

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To enter into mitosis, cells must shut off the cell cycle inhibitor Wee1. SAD family protein kinases regulate Wee1 signaling in yeast and humans. In S. pombe, two SAD kinases (Cdr1/Nim1 and Cdr2) act as upstream inhibitors of Wee1. Previous studies found that S. pombe Cdr1/Nim1 directly phosphorylates and inhibits Wee1 in vitro, but different results were obtained for budding yeast and human SAD kinases. Without a full understanding of Cdr1 action on Wee1, it has been difficult to assess the in vivo relevance and conservation of this mechanism.Here, we show that both Cdr1 and Cdr2 promote Wee1 phosphorylation in cells, but only Cdr1 inhibits Wee1 kinase activity. Inhibition occurs when Cdr1 phosphorylates a cluster of serine residues linking a-helices G and H of the Wee1 kinase domain. This region is highly divergent among different Wee1 proteins, consistent with distinct regulatory mechanisms. A wee(4A) mutant that impairs phosphorylation by Cdr1 delays mitotic entry and causes elongated cells. By disrupting and re-targeting Cdr1 localization, we show that Cdr1 inhibition of Wee1 occurs in cells at cortical nodes formed by Cdr2. Based on our results, we propose a two-step model for inhibition of Wee1 by Cdr1 and Cdr2 at nodes.

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Stable Pom1 clusters form a glucose-modulated concentration gradient that regulates mitotic entry

Cited by 9 publications

References 70 publications

The number of cytokinesis nodes in mitotic fission yeast scales with cell size

The number of cytokinesis nodes in mitotic fission yeast scales with cell size

Direct and indirect regulation of Pom1 cell size pathway by the protein phosphatase 2C Ptc1

A mechanism for how Cdr1/Nim1 kinase promotes mitotic entry by inhibiting Wee1

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