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Willet AH, Wos M, Igarashi MG, Ren L, Turner LA, Gould KL. Elevated levels of sphingolipid MIPC in the plasma membrane disrupt the coordination of cell growth with cell wall formation in fission yeast. PLoS Genet 2023; 19:e1010987. [PMID: 37792890 PMCID: PMC10578601 DOI: 10.1371/journal.pgen.1010987] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/16/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023] Open
Abstract
Coupling cell wall expansion with cell growth is a universal challenge faced by walled organisms. Mutations in Schizosaccharomyces pombe css1, which encodes a PM inositol phosphosphingolipid phospholipase C, prevent cell wall expansion but not synthesis of cell wall material. To probe how Css1 modulates cell wall formation we used classical and chemical genetics coupled with quantitative mass spectrometry. We found that elevated levels of the sphingolipid biosynthetic pathway's final product, mannosylinositol phosphorylceramide (MIPC), specifically correlated with the css1-3 phenotype. We also found that an apparent indicator of sphingolipids and a sterol biosensor accumulated at the cytosolic face of the PM at cell tips and the division site of css1-3 cells and, in accord, the PM in css1-3 was less dynamic than in wildtype cells. Interestingly, disrupting the protein glycosylation machinery recapitulated the css1-3 phenotype and led us to investigate Ghs2, a glycosylated PM protein predicted to modify cell wall material. Disrupting Ghs2 function led to aberrant cell wall material accumulation suggesting Ghs2 is dysfunctional in css1-3. We conclude that preventing an excess of MIPC in the S. pombe PM is critical to the function of key PM-localized proteins necessary for coupling growth with cell wall formation.
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Affiliation(s)
- Alaina H. Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Marcin Wos
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Maya G. Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Lesley A. Turner
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States of America
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2
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Bhattacharjee R, Hall AR, Mangione MC, Igarashi MG, Roberts-Galbraith RH, Chen JS, Vavylonis D, Gould KL. Multiple polarity kinases inhibit phase separation of F-BAR protein Cdc15 and antagonize cytokinetic ring assembly in fission yeast. eLife 2023; 12:83062. [PMID: 36749320 PMCID: PMC9904764 DOI: 10.7554/elife.83062] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 12/16/2022] [Indexed: 02/08/2023] Open
Abstract
The F-BAR protein Cdc15 is essential for cytokinesis in Schizosaccharomyces pombe and plays a key role in attaching the cytokinetic ring (CR) to the plasma membrane (PM). Cdc15's abilities to bind to the membrane and oligomerize via its F-BAR domain are inhibited by phosphorylation of its intrinsically disordered region (IDR). Multiple cell polarity kinases regulate Cdc15 IDR phosphostate, and of these the DYRK kinase Pom1 phosphorylation sites on Cdc15 have been shown in vivo to prevent CR formation at cell tips. Here, we compared the ability of Pom1 to control Cdc15 phosphostate and cortical localization to that of other Cdc15 kinases: Kin1, Pck1, and Shk1. We identified distinct but overlapping cohorts of Cdc15 phosphorylation sites targeted by each kinase, and the number of sites correlated with each kinases' abilities to influence Cdc15 PM localization. Coarse-grained simulations predicted that cumulative IDR phosphorylation moves the IDRs of a dimer apart and toward the F-BAR tips. Further, simulations indicated that the overall negative charge of phosphorylation masks positively charged amino acids necessary for F-BAR oligomerization and membrane interaction. Finally, simulations suggested that dephosphorylated Cdc15 undergoes phase separation driven by IDR interactions. Indeed, dephosphorylated but not phosphorylated Cdc15 undergoes liquid-liquid phase separation to form droplets in vitro that recruit Cdc15 binding partners. In cells, Cdc15 phosphomutants also formed PM-bound condensates that recruit other CR components. Together, we propose that a threshold of Cdc15 phosphorylation by assorted kinases prevents Cdc15 condensation on the PM and antagonizes CR assembly.
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Affiliation(s)
- Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
| | - Aaron R Hall
- Department of Physics, Lehigh UniversityBethlehemUnited States
| | - MariaSanta C Mangione
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
| | - Maya G Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh UniversityBethlehemUnited States,Center for Computational Biology, Flatiron InstituteNew YorkUnited States
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
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3
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Lipid Polarization during Cytokinesis. Cells 2022; 11:cells11243977. [PMID: 36552741 PMCID: PMC9776629 DOI: 10.3390/cells11243977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
The plasma membrane of eukaryotic cells is composed of a large number of lipid species that are laterally segregated into functional domains as well as asymmetrically distributed between the outer and inner leaflets. Additionally, the spatial distribution and organization of these lipids dramatically change in response to various cellular states, such as cell division, differentiation, and apoptosis. Division of one cell into two daughter cells is one of the most fundamental requirements for the sustenance of growth in all living organisms. The successful completion of cytokinesis, the final stage of cell division, is critically dependent on the spatial distribution and organization of specific lipids. In this review, we discuss the properties of various lipid species associated with cytokinesis and the mechanisms involved in their polarization, including forward trafficking, endocytic recycling, local synthesis, and cortical flow models. The differences in lipid species requirements and distribution in mitotic vs. male meiotic cells will be discussed. We will concentrate on sphingolipids and phosphatidylinositols because their transbilayer organization and movement may be linked via the cytoskeleton and thus critically regulate various steps of cytokinesis.
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4
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Bellingham-Johnstun K, Commer B, Levesque B, Tyree ZL, Laplante C. Imp2p forms actin-dependent clusters and imparts stiffness to the contractile ring. Mol Biol Cell 2022; 33:ar145. [PMID: 36287824 PMCID: PMC9727792 DOI: 10.1091/mbc.e22-06-0221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The contractile ring must anchor to the plasma membrane and cell wall to transmit its tension. F-BAR domain containing proteins including Imp2p and Cdc15p in fission yeast are likely candidate anchoring proteins based on their mutant phenotypes. Cdc15p is a node component, links the actin bundle to the plasma membrane, recruits Bgs1p to the division plane, prevents contractile ring sliding, and contributes to the stiffness of the contractile ring. Less is known about Imp2p. We found that similarly to Cdc15p, Imp2p contributes to the stiffness of the contractile ring and assembles into protein clusters. Imp2p clusters contain approximately eight Imp2p dimers and depend on the actin network for their stability at the division plane. Importantly, Imp2p and Cdc15p reciprocally affect the amount of each other in the contractile ring, indicating that the two proteins influence each other during cytokinesis, which may partially explain their similar phenotypes.
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Affiliation(s)
| | - Blake Commer
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
| | - Brié Levesque
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
| | - Zoe L Tyree
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
| | - Caroline Laplante
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
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5
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Snider CE, Bhattacharjee R, Igarashi MG, Gould KL. Fission yeast paxillin contains two Cdc15 binding motifs for robust recruitment to the cytokinetic ring. Mol Biol Cell 2022; 33:br4. [PMID: 35108037 PMCID: PMC9250355 DOI: 10.1091/mbc.e21-11-0560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The F-BAR protein Cdc15 mediates attachment of the cytokinetic ring (CR) to the plasma membrane and is essential for cytokinesis in Schizosaccharomyces pombe. While its N-terminal F-BAR domain is responsible for oligomerization and membrane binding, its C-terminal SH3 domain binds other partners at a distance from the membrane. We previously demonstrated that the essential cytokinetic formin Cdc12, through an N-terminal motif, directly binds the cytosolic face of the F-BAR domain. Here, we show that paxillin-like Pxl1, which is important for CR stability, contains a motif highly related to that in formin Cdc12, and also binds the Cdc15 F-BAR domain directly. Interestingly, Pxl1 has a second site for binding the Cdc15 SH3 domain. To understand the importance of these two Pxl1-Cdc15 interactions, we mapped and disrupted both. Disrupting the Pxl1-Cdc15 F-BAR domain interaction reduced Pxl1 levels in the CR, whereas disrupting Pxl1’s interaction with the Cdc15 SH3 domain, did not. Unexpectedly, abolishing Pxl1-Cdc15 interaction greatly reduced but did not eliminate CR Pxl1 and did not significantly affect cytokinesis. These data point to another mechanism of Pxl1 CR recruitment and show that very little CR Pxl1 is sufficient for its cytokinetic function.
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Affiliation(s)
- Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Maya G Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
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6
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Mangione MC, Chen JS, Gould KL. Cdk1 phosphorylation of fission yeast paxillin inhibits its cytokinetic ring localization. Mol Biol Cell 2021; 32:1534-1544. [PMID: 34133210 PMCID: PMC8351747 DOI: 10.1091/mbc.e20-12-0807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/02/2021] [Accepted: 06/11/2021] [Indexed: 11/11/2022] Open
Abstract
Divisions of the genetic material and cytoplasm are coordinated spatially and temporally to ensure genome integrity. This coordination is mediated in part by the major cell cycle regulator cyclin-dependent kinase (Cdk1). Cdk1 activity peaks during mitosis, but during mitotic exit/cytokinesis Cdk1 activity is reduced, and phosphorylation of its substrates is reversed by various phosphatases including Cdc14, PP1, PP2A, and PP2B. Cdk1 is known to phosphorylate several components of the actin- and myosin-based cytokinetic ring (CR) that mediates division of yeast and animal cells. Here we show that Cdk1 also phosphorylates the Schizosaccharomyces pombe CR component paxillin Pxl1. We determined that both the Cdc14 phosphatase Clp1 and the PP1 phosphatase Dis2 contribute to Pxl1 dephosphorylation at mitotic exit, but PP2B/calcineurin does not. Preventing Pxl1 phosphorylation by Cdk1 results in increased Pxl1 levels, precocious Pxl1 recruitment to the division site, and increased duration of CR constriction. In vitro Cdk1-mediated phosphorylation of Pxl1 inhibits its interaction with the F-BAR domain of the cytokinetic scaffold Cdc15, thereby disrupting a major mechanism of Pxl1 recruitment. Thus, Pxl1 is a novel substrate through which S. pombe Cdk1 and opposing phosphatases coordinate mitosis and cytokinesis.
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Affiliation(s)
- MariaSanta C. Mangione
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240
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7
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Willet AH, Igarashi MG, Chen JS, Bhattacharjee R, Ren L, Cullati SN, Elmore ZC, Roberts-Galbraith RH, Johnson AE, Beckley JR, Gould KL. Phosphorylation in the intrinsically disordered region of F-BAR protein Imp2 regulates its contractile ring recruitment. J Cell Sci 2021; 134:271847. [PMID: 34279633 DOI: 10.1242/jcs.258645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/12/2021] [Indexed: 11/20/2022] Open
Abstract
The F-BAR protein Imp2 is an important contributor to cytokinesis in the fission yeast, Schizosaccharomyces pombe. Because cell cycle regulated phosphorylation of the central intrinsically disordered region (IDR) of the Imp2 paralog, Cdc15, controls Cdc15 oligomerization state, localization, and ability to bind protein partners, we investigated whether Imp2 is similarly phosphoregulated. We found that Imp2 is endogenously phosphorylated on 28 sites within its IDR with the bulk of phosphorylation being constitutive. In vitro, casein kinase 1 (CK1) Hhp1 and Hhp2 can phosphorylate 17 sites and Cdk1 the remaining 11 sites. Mutations that prevent Cdk1 phosphorylation result in precocious Imp2 recruitment to the cell division site, and mutations designed to mimic these phosphorylation events delay Imp2 CR accumulation. Mutations that eliminated CK1 phosphorylation sites allowed CR sliding, and phosphomimetic substitutions at these sites reduced Imp2 protein levels and slowed CR constriction. Thus, like Cdc15, the Imp2 IDR is phosphorylated at many sites by multiple kinases. In contrast to Cdc15, for which phosphorylation plays a major cell cycle regulatory role, Imp2 phosphorylation is primarily constitutive with milder effects on localization and function.
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Affiliation(s)
- Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Maya G Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Sierra N Cullati
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Zachary C Elmore
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Alyssa E Johnson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Janel R Beckley
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
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8
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The state of F-BAR domains as membrane-bound oligomeric platforms. Trends Cell Biol 2021; 31:644-655. [PMID: 33888395 DOI: 10.1016/j.tcb.2021.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/16/2022]
Abstract
Fes/Cip4 homology Bin/amphiphysin/Rvs (F-BAR) domains, like all BAR domains, are dimeric units that oligomerize and bind membranes. F-BAR domains are generally coupled to additional domains that function in protein binding or have enzymatic activity. Because of their crescent shape and ability to oligomerize, F-BAR domains have been traditionally viewed as membrane-deformation modules. However, multiple independent studies have provided no evidence that certain F-BAR domains are able to tubulate membrane. Instead, a growing body of literature featuring structural, biochemical, biophysical, and microscopy-based studies supports the idea that the F-BAR domain family can be unified only by their ability to form oligomeric assemblies on membranes to provide platforms for molecular assembly.
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9
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Snider CE, Chandra M, McDonald NA, Willet AH, Collier SE, Ohi MD, Jackson LP, Gould KL. Opposite Surfaces of the Cdc15 F-BAR Domain Create a Membrane Platform That Coordinates Cytoskeletal and Signaling Components for Cytokinesis. Cell Rep 2020; 33:108526. [PMID: 33357436 PMCID: PMC7775634 DOI: 10.1016/j.celrep.2020.108526] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 11/02/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022] Open
Abstract
Many eukaryotes assemble an actin- and myosin-based cytokinetic ring (CR) on the plasma membrane (PM) for cell division, but how it is anchored there remains unclear. In Schizosaccharomyces pombe, the F-BAR protein Cdc15 links the PM via its F-BAR domain to proteins in the CR’s interior via its SH3 domain. However, Cdc15’s F-BAR domain also directly binds formin Cdc12, suggesting that Cdc15 may polymerize a protein network directly adjacent to the membrane. Here, we determine that the F-BAR domain binds Cdc12 using residues on the face opposite its membrane-binding surface. These residues also bind paxillin-like Pxl1, promoting its recruitment with calcineurin to the CR. Mutation of these F-BAR domain residues results in a shallower CR, with components localizing ~35% closer to the PM than in wild type, and aberrant CR constriction. Thus, F-BAR domains serve as oligomeric membrane-bound platforms that can modulate the architecture of an entire actin structure. Multiple F-BAR domains link actin structures to membrane. Snider et al. show that the flat Cdc15 F-BAR domain utilizes opposite surfaces to bind the plasma membrane and cytokinetic ring proteins simultaneously. Disrupting Cdc15 F-BAR domain’s interaction with proteins results in an overall compression of the entire cytokinetic ring architecture.
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Affiliation(s)
- Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Scott E Collier
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Melanie D Ohi
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
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10
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Su M, Zhuang Y, Miao X, Zeng Y, Gao W, Zhao W, Wu M. Comparative Study of Curvature Sensing Mediated by F-BAR and an Intrinsically Disordered Region of FBP17. iScience 2020; 23:101712. [PMID: 33205024 PMCID: PMC7649350 DOI: 10.1016/j.isci.2020.101712] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/11/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
Membrane curvature has emerged as an intriguing physical principle underlying biological signaling and membrane trafficking. The CIP4/FBP17/Toca-1 F-BAR subfamily is unique in the BAR family because its structurally folded F-BAR domain does not contain any hydrophobic motifs that insert into membrane. Although widely assumed so, whether the banana-shaped F-BAR domain alone can sense curvature has never been experimentally demonstrated. Using a nanobar-supported lipid bilayer system, we found that the F-BAR domain of FBP17 displayed minimal curvature sensing in vitro. In comparison, an alternatively spliced intrinsically disordered region (IDR) adjacent to the F-BAR domain has the membrane curvature-sensing ability greatly exceeding that of F-BAR domain alone. In living cells, the presence of the IDR delayed the recruitment of FBP17 in curvature-coupled cortical waves. Collectively, we propose that contrary to the common belief, FBP17's curvature-sensing capability largely originates from IDR, and not the F-BAR domain alone.
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Affiliation(s)
- Maohan Su
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8002, USA.,Centre for BioImaging Sciences, Mechanobiology Institute, Department of Biological Sciences, National University of Singapore, Singapore, 117411
| | - Yinyin Zhuang
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8002, USA.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637457
| | - Xinwen Miao
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637457
| | - Yongpeng Zeng
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637457
| | - Weibo Gao
- School of Physics and Mathematical Science, Nanyang Technological University, Singapore, 637371
| | - Wenting Zhao
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637457
| | - Min Wu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8002, USA.,Centre for BioImaging Sciences, Mechanobiology Institute, Department of Biological Sciences, National University of Singapore, Singapore, 117411
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11
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Garabedian MV, Wirshing A, Vakhrusheva A, Turegun B, Sokolova OS, Goode BL. A septin-Hof1 scaffold at the yeast bud neck binds and organizes actin cables. Mol Biol Cell 2020; 31:1988-2001. [PMID: 32579428 PMCID: PMC7543067 DOI: 10.1091/mbc.e19-12-0693] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cellular actin arrays are often highly organized, with characteristic patterns critical to their in vivo functions, yet the mechanisms for establishing these higher order geometries remain poorly understood. In Saccharomyces cerevisiae, formin-polymerized actin cables are spatially organized and aligned along the mother–bud axis to facilitate polarized vesicle traffic. Here, we show that the bud neck–associated F-BAR protein Hof1, independent of its functions in regulating the formin Bnr1, binds to actin filaments and organizes actin cables in vivo. Hof1 bundles actin filaments and links them to septins in vitro. F-actin binding is mediated by the “linker” domain of Hof1, and its deletion leads to cable organization defects in vivo. Using superresolution imaging, we show that Hof1 and septins are patterned at the bud neck into evenly spaced axial pillars (∼200 nm apart), from which actin cables emerge and grow into the mother cell. These results suggest that Hof1, while bound to septins at the bud neck, not only regulates Bnr1 activity, but also binds to actin cables and aligns them along the mother–bud axis. More broadly, these findings provide a strong example of how an actin regulatory protein can be spatially patterned at the cell cortex to govern actin network geometry.
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Affiliation(s)
- Mikael V Garabedian
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
| | - Alison Wirshing
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
| | - Anna Vakhrusheva
- Department of Bioengineering, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Bengi Turegun
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
| | - Olga S Sokolova
- Department of Bioengineering, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
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12
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Bhattacharjee R, Mangione MC, Wos M, Chen JS, Snider CE, Roberts-Galbraith RH, McDonald NA, Presti LL, Martin SG, Gould KL. DYRK kinase Pom1 drives F-BAR protein Cdc15 from the membrane to promote medial division. Mol Biol Cell 2020; 31:917-929. [PMID: 32101481 PMCID: PMC7185970 DOI: 10.1091/mbc.e20-01-0026] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In many organisms, positive and negative signals cooperate to position the division site for cytokinesis. In the rod-shaped fission yeast Schizosaccharomyces pombe, symmetric division is achieved through anillin/Mid1-dependent positive cues released from the central nucleus and negative signals from the DYRK-family polarity kinase Pom1 at cell tips. Here we establish that Pom1's kinase activity prevents septation at cell tips even if Mid1 is absent or mislocalized. We also find that Pom1 phosphorylation of F-BAR protein Cdc15, a major scaffold of the division apparatus, disrupts Cdc15's ability to bind membranes and paxillin, Pxl1, thereby inhibiting Cdc15's function in cytokinesis. A Cdc15 mutant carrying phosphomimetic versions of Pom1 sites or deletion of Cdc15 binding partners suppresses division at cell tips in cells lacking both Mid1 and Pom1 signals. Thus, inhibition of Cdc15-scaffolded septum formation at cell poles is a key Pom1 mechanism that ensures medial division.
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Affiliation(s)
- Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - MariaSanta C Mangione
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Marcin Wos
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Libera Lo Presti
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
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