scholarly journals Protein phosphatase SppA regulates apical growth and dephosphorylates cell polarity determinant DivIVA in Streptomyces coelicolor

2021 ◽  
Author(s):  
Fanny M. Passot ◽  
Stuart Cantlay ◽  
Klas Flärdh
Keyword(s):  
Cell Polarity ◽  
Protein Phosphatase ◽  
Streptomyces Coelicolor ◽  
Apical Growth

scholarly journals Protein phosphatase SppA regulates apical growth and dephosphorylates cell polarity determinant DivIVA in Streptomyces coelicolor

2021 ◽  
Author(s):  
Fanny Passot ◽  
Stuart Cantlay ◽  
Klas Flardh
Keyword(s):  
Cell Wall ◽  
Cell Polarity ◽  
Protein Phosphatase ◽  
Cell Shape ◽  
Streptomyces Coelicolor ◽  
Polar Growth ◽  
Hyphal Branching ◽  
Tip Extension

Bacteria that exhibit polar growth, i.e. build their peptidoglycan cell walls in restricted zones at cell poles, often show large morphological diversity and plasticity. However, their mechanisms for regulation of cell shape and cell wall assembly are poorly understood. The Gram-positive Streptomyces bacteria, like other Actinobacteria, depend on the essential coiled coil protein DivIVA for establishment of cell polarity and direction of polar growth. Streptomycetes grow as filamentous hyphae that exhibit tip extension. New hyphal tips are generated by lateral branching. Cell shape is largely determined by the control of cell wall growth at these hyphal tips. The Ser/Thr protein kinase AfsK is involved in controlling polar growth and directly phosphorylates DivIVA. Here, we identify a protein phosphatase in Streptomyces coelicolor , SppA, that dephosphorylates DivIVA in vivo and in vitro and affects growth and cell shape. An sppA mutant shows reduced rate of hyphal tip extension, altered hyphal branching patterns, and exhibits frequent spontaneous hyphal growth arrests, all contributing to the unusually dense mycelial structure and slow growth rate that characterize sppA mutants. These phenotypes are largely suppressed in an afsK sppA double mutant, showing that AfsK and SppA partially affect the same regulatory pathway and share target proteins that are involved control of polar growth in S. coelicolor . Strains with a non-phosphorylatable mutant DivIVA were constructed and confirm that the effect of afsK on hyphal branching during normal growth is mediated by DivIVA phosphorylation. However, the phenotypic effects of sppA deletion are independent of DivIVA phosphorylation and must be mediated via other substrates. Altogether, this study identifies a PPP-family protein phosphatase directly involved in the control of polar growth and cell shape determination in S. coelicolor and underscore the importance of eukaryotic-type Ser/Thr phosphorylation in regulation of growth and cell envelope biogenesis in Actinobacteria.

Cell polarity and the control of apical growth in Streptomyces

2010 ◽  
Vol 13 (6) ◽  
pp. 758-765 ◽  
Author(s):  
Klas Flärdh
Keyword(s):  
Cell Polarity ◽  
Apical Growth

scholarly journals The phosphatase inhibitor Sds23 regulates cell division symmetry in fission yeast

2019 ◽  
Author(s):  
Katherine L. Schutt ◽  
James B. Moseley
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Cell Polarity ◽  
Protein Phosphatase ◽  
Yeast Cells ◽  
Spatial Control ◽  
Anchoring Proteins ◽  
Family Protein ◽  
Mutant Cells ◽  
Assembly Site

AbstractAnimal and fungal cells divide through the assembly, anchoring, and constriction of a contractile actomyosin ring (CAR) during cytokinesis. The timing and position of the CAR must be tightly controlled to prevent defects in cell division, but many of the underlying signaling events remain unknown. The conserved heterotrimeric protein phosphatase PP2A controls the timing of events in mitosis, and upstream pathways including Greatwall-Ensa regulate PP2A activity. A role for PP2A in CAR regulation has been less clear, although loss of PP2A in yeast causes defects in cytokinesis. Here, we report that Sds23, an inhibitor of PP2A family protein phosphatases, promotes the symmetric division of fission yeast cells through spatial control of cytokinesis. We found that sds23Δ cells divide asymmetrically due to misplaced CAR assembly, followed by sliding of the CAR away from its assembly site. These mutant cells exhibit delayed recruitment of putative CAR anchoring proteins including the glucan synthase Bgs1. Our observations likely reflect a broader role for regulation of PP2A in cell polarity and cytokinesis because sds23Δ phenotypes were exacerbated when combined with mutations in the fission yeast Ensa homolog, Igo1. These results identify the PP2A regulatory network as a critical component in the signaling pathways coordinating cytokinesis.

scholarly journals The phosphatase inhibitor Sds23 regulates cell division symmetry in fission yeast

2019 ◽  
Vol 30 (23) ◽  
pp. 2880-2889 ◽  
Author(s):  
Katherine L. Schutt ◽  
James B. Moseley
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Cell Polarity ◽  
Protein Phosphatase ◽  
Yeast Cells ◽  
Spatial Control ◽  
Anchoring Proteins ◽  
Family Protein ◽  
Mutant Cells ◽  
Assembly Site

Animal and fungal cells divide through the assembly, anchoring, and constriction of a contractile actomyosin ring (CAR) during cytokinesis. The timing and position of the CAR must be tightly controlled to prevent defects in cell division, but many of the underlying signaling events remain unknown. The conserved heterotrimeric protein phosphatase PP2A controls the timing of events in mitosis, and upstream pathways including Greatwall–Ensa regulate PP2A activity. A role for PP2A in CAR regulation has been less clear, although loss of PP2A in yeast causes defects in cytokinesis. Here, we report that Sds23, an inhibitor of PP2A family protein phosphatases, promotes the symmetric division of fission yeast cells through spatial control of cytokinesis. We found that sds23∆ cells divide asymmetrically due to misplaced CAR assembly, followed by sliding of the CAR away from its assembly site. These mutant cells exhibit delayed recruitment of putative CAR anchoring proteins including the glucan synthase Bgs1. Our observations likely reflect a broader role for regulation of PP2A in cell polarity and cytokinesis because sds23∆ phenotypes were exacerbated when combined with mutations in the fission yeast Ensa homologue, Igo1. These results identify the PP2A regulatory network as a critical component in the signaling pathways coordinating cytokinesis.

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