scholarly journals Fission yeast Pak1 phosphorylates anillin-like Mid1 for spatial control of cytokinesis

2020 ◽  
Vol 219 (8) ◽  
Author(s):  
Joseph O. Magliozzi ◽  
Jack Sears ◽  
Lauren Cressey ◽  
Marielle Brady ◽  
Hannah E. Opalko ◽  
...  
Keyword(s):  
Cell Division ◽  
Protein Kinases ◽  
Cell Polarity ◽  
Genetic Interactions ◽  
Polarized Growth ◽  
Signaling Mechanism ◽  
Spatial Control ◽  
Division Site ◽  
N Terminus ◽  
A Cell

Protein kinases direct polarized growth by regulating the cytoskeleton in time and space and could play similar roles in cell division. We found that the Cdc42-activated polarity kinase Pak1 colocalizes with the assembling contractile actomyosin ring (CAR) and remains at the division site during septation. Mutations in pak1 led to defects in CAR assembly and genetic interactions with cytokinesis mutants. Through a phosphoproteomic screen, we identified novel Pak1 substrates that function in polarized growth and cytokinesis. For cytokinesis, we found that Pak1 regulates the localization of its substrates Mid1 and Cdc15 to the CAR. Mechanistically, Pak1 phosphorylates the Mid1 N-terminus to promote its association with cortical nodes that act as CAR precursors. Defects in Pak1-Mid1 signaling lead to misplaced and defective division planes, but these phenotypes can be rescued by synthetic tethering of Mid1 to cortical nodes. Our work defines a new signaling mechanism driven by a cell polarity kinase that promotes CAR assembly in the correct time and place.

scholarly journals Fission yeast Pak1 phosphorylates anillin-like Mid1 for spatial control of cytokinesis

2019 ◽  
Author(s):  
Joseph O. Magliozzi ◽  
Jack Sears ◽  
Lauren Cressey ◽  
Marielle Brady ◽  
Hannah E. Opalko ◽  
...  
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Cell Polarity ◽  
Genetic Interactions ◽  
Polarized Growth ◽  
Signaling Mechanism ◽  
Spatial Control ◽  
Division Site ◽  
N Terminus ◽  
A Cell

AbstractProtein kinases direct polarized growth by regulating the cytoskeleton in time and space, and could play similar roles in cell division. We found that the Cdc42-activated polarity kinase Pak1 colocalizes with the assembling contractile actomyosin ring (CAR) and remains at the division site during septation. Mutations in pak1 led to defects in CAR assembly and genetic interactions with cytokinesis mutants. Through a phosphoproteomic screen, we identified novel Pak1 substrates that function in polarized growth and cytokinesis. For cytokinesis, we found that Pak1 regulates the localization of its substrates Mid1 and Cdc15 to the CAR. Mechanistically, Pak1 phosphorylates the Mid1 N-terminus to promote its association with cortical nodes that act as CAR precursors. Defects in Pak1-Mid1 signaling lead to misplaced and defective division planes, but these phenotypes can be rescued by synthetic tethering of Mid1 to cortical nodes. Our work defines a new signaling mechanism driven by a cell polarity kinase that promotes CAR assembly in the correct time and place.SummaryMagliozzi et al. show that fission yeast cell polarity kinase Pak1 regulates cytokinesis. Through a phosphoproteomic screen and subsequent mutant analysis, their work uncovers direct targets and mechanisms for Pak1 activity during cell division.

scholarly journals A Role for Cell Polarity in Lifespan and Mitochondrial Quality Control in the Budding Yeast Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Emily J. Yang ◽  
Wolfgang M Pernice ◽  
Liza A. Pon
Keyword(s):  
Cell Cycle ◽  
Quality Control ◽  
Cell Division ◽  
Yeast Cell ◽  
Cell Polarity ◽  
Yeast Saccharomyces Cerevisiae ◽  
A Cell ◽  
Mitochondrial Distribution ◽  
Mother Cells ◽  
F Box Protein

SummaryBabies are born young, largely independent of the age of their mothers. Mother-daughter age asymmetry in yeast is achieved, in part, by inheritance of higher-functioning mitochondria by daughter cells and retention of some high-functioning mitochondria in mother cells. The mitochondrial F-box protein, Mfb1p, tethers mitochondria at both poles in a cell cycle-regulated manner: it localizes to and anchors mitochondria to the mother cell tip throughout the cell cycle, and to the bud tip prior to cytokinesis. Here, we report that cell polarity and polarized localization of Mfb1p decline with age in S. cerevisiae. Moreover, deletion of BUD1/RSR1, a Ras protein required for cytoskeletal polarization during asymmetric yeast cell division, results in depolarized Mfb1p localization, defects in mitochondrial distribution and quality control, and reduced replicative lifespan. Our results demonstrate a role for the polarity machinery in lifespan through modulating Mfb1 function in asymmetric inheritance of mitochondria during yeast cell division.

scholarly journals The septin-associated kinase Gin4 recruits Gps1 to the site of cell division

2017 ◽  
Vol 28 (7) ◽  
pp. 883-889 ◽  
Author(s):  
Franz Meitinger ◽  
Gislene Pereira
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Polarity ◽  
Rho Gtpases ◽  
G1 Phase ◽  
Division Site ◽  
Bud Neck ◽  
Unicellular Organisms ◽  
Cycle Dependent ◽  
Spatiotemporal Control

Cell cycle–dependent morphogenesis of unicellular organisms depends on the spatiotemporal control of cell polarity. Rho GTPases are the major players that guide cells through structural reorganizations such as cytokinesis (Rho1 dependent) and polarity establishment (Cdc42 dependent). In budding yeast, the protein Gps1 plays a pivotal role in both processes. Gps1 resides at the bud neck to maintain Rho1 localization and restrict Cdc42 activity during cytokinesis. Here we analyze how Gps1 is recruited to the bud neck during the cell cycle. We show that different regions of Gps1 and the septin-associated kinase Gin4 are involved in maintaining Gps1 at the bud neck from late G1 phase until midanaphase. From midanaphase, the targeting function of Gin4 is taken over by the bud neck–associated protein Nba1. Our data show that Gps1 is targeted to the cell division site in a biphasic manner, via Gin4 and Nba1, to control the spatiotemporal activation of Rho1 and inhibition of Cdc42.

scholarly journals PP1-Dependent Formin Bnr1 Dephosphorylation and Delocalization from a Cell Division Site

PLoS ONE ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. e0146941 ◽  
Author(s):  
Minami Orii ◽  
Keiko Kono ◽  
Hsin-I Wen ◽  
Makoto Nakanishi
Keyword(s):  
Cell Division ◽  
Division Site ◽  
A Cell

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 A Diguanylate Cyclase Acts as a Cell Division Inhibitor in a Two-Step Response to Reductive and Envelope Stresses

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Hyo Kyung Kim ◽  
Rasika M. Harshey
Keyword(s):  
Cell Division ◽  
Step Response ◽  
Diguanylate Cyclase ◽  
Division Site ◽  
Envelope Stress ◽  
Z Ring ◽  
A Cell ◽  
Cell Division Inhibitor ◽  
Signal Transduction Systems

ABSTRACT Cell division arrest is a universal checkpoint in response to environmental assaults that generate cellular stress. In bacteria, the cyclic di-GMP (c-di-GMP) signaling network is one of several signal transduction systems that regulate key processes in response to extra-/intracellular stimuli. Here, we find that the diguanylate cyclase YfiN acts as a bifunctional protein that produces c-di-GMP in response to reductive stress and then dynamically relocates to the division site to arrest cell division in response to envelope stress in Escherichia coli . YfiN localizes to the Z ring by interacting with early division proteins and stalls cell division by preventing the initiation of septal peptidoglycan synthesis. These studies reveal a new role for a diguanylate cyclase in responding to environmental change, as well as a novel mechanism for arresting cell division. IMPORTANCE While the major role of c-di-GMP signaling is to control the decision to move freely or settle in a biofilm, recent studies show a broader range of output functions for c-di-GMP signaling. This work reports an unexpected second role for YfiN, a conserved diguanylate cyclase in Gram-negative bacteria, known to contribute to persistence in the host. We find that YfiN acts as a cell division inhibitor in response to envelope stress. Unlike known cell division inhibitors, the interaction of YfiN with cell division proteins retains the Z ring at the midcell but prevents septal invagination. The new function of YfiN not only emphasizes the versatility of c-di-GMP signaling but describes a novel mechanism for a cell division checkpoint.

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.

scholarly journals Chlamydial MreB Directs Cell Division and Peptidoglycan Synthesis in Escherichia coli in the Absence of FtsZ Activity

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Dev K. Ranjit ◽  
George W. Liechti ◽  
Anthony T. Maurelli
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Morphological Changes ◽  
Content Type ◽  
E Coli ◽  
Obligate Intracellular ◽  
Peptidoglycan Synthesis ◽  
Division Site ◽  
A Cell ◽  
Cell Division Protein

ABSTRACT Cell division is the ultimate process for the propagation of bacteria, and FtsZ is an essential protein used by nearly all bacteria for this function. Chlamydiae belong to a small group of bacteria that lack the universal cell division protein FtsZ but still divide by binary fission. Chlamydial MreB is a member of the shape-determining MreB/Mbl family of proteins responsible for rod shape morphology in Escherichia coli. Chlamydia also encodes a homolog of RodZ, an MreB assembly cytoskeletal protein that links MreB to cell wall synthesis proteins. We hypothesized that MreB directs cell division in Chlamydia and that chlamydial MreB could replace FtsZ function for cell division in E. coli. Overexpression of chlamydial mreB-rodZ in E. coli induced prominent morphological changes with production of large swollen or oval bacteria, eventually resulting in bacterial lysis. Low-level expression of chlamydial mreB-rodZ restored viability of a lethal ΔmreB mutation in E. coli, although the bacteria lost their typical rod shape and grew as rounded cells. When FtsZ activity was inhibited by overexpression of SulA in the ΔmreB mutant of E. coli complemented with chlamydial mreB-rodZ, spherical E. coli grew and divided. Localization studies using a fluorescent fusion chlamydial MreB protein indicated that chlamydial RodZ directs chlamydial MreB to the E. coli division septum. These results demonstrate that chlamydial MreB, in partnership with chlamydial RodZ, acts as a cell division protein. Our findings suggest that an mreB-rodZ-based mechanism allows Chlamydia to divide without the universal division protein FtsZ. IMPORTANCE The study of Chlamydia growth and cell division is complicated by its obligate intracellular nature and biphasic lifestyle. Chlamydia also lacks the universal division protein FtsZ. We employed the cell division system of Escherichia coli as a surrogate to identify chlamydial cell division proteins. We demonstrate that chlamydial MreB, together with chlamydial RodZ, forms a cell division and growth complex that can replace FtsZ activity and support cell division in E. coli. Chlamydial RodZ plays a major role in directing chlamydial MreB localization to the cell division site. It is likely that the evolution of chlamydial MreB and RodZ to form a functional cell division complex allowed Chlamydia to dispense with its FtsZ-based cell division machinery during genome reduction. Thus, MreB-RodZ represents a possible mechanism for cell division in other bacteria lacking FtsZ.

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