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Magliozzi JO, Rands TJ, Shrestha S, Simke WC, Hase NE, Juanes MA, Kelley JB, Goode BL. The roles of yeast formins and their regulators Bud6 and Bil2 in the pheromone response. Mol Biol Cell 2024; 35:ar85. [PMID: 38656798 PMCID: PMC11238086 DOI: 10.1091/mbc.e23-11-0459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/09/2024] [Accepted: 04/17/2024] [Indexed: 04/26/2024] Open
Abstract
In response to pheromone Saccharomyces cerevisiae extend a mating projection. This process depends on the formation of polarized actin cables which direct secretion to the mating tip and translocate the nucleus for karyogamy. Here, we demonstrate that proper mating projection formation requires the formin Bni1, as well as the actin nucleation promoting activities of Bud6, but not the formin Bnr1. Further, Bni1 is required for pheromone gradient tracking. Our work also reveals unexpected new functions for Bil2 in the pheromone response. Previously we identified Bil2 as a direct inhibitor of Bnr1 during vegetative cell growth. Here, we show that Bil2 has Bnr1-independent functions in spatially focusing Bni1-GFP at mating projection tips, and in vitro Bil2 and its binding partner Bud6 organize Bni1 into clusters that nucleate actin assembly. bil2∆ cells also display entangled Bni1-generated actin cable arrays and defects in secretory vesicle transport and nuclear positioning. At low pheromone concentrations, bil2∆ cells are delayed in establishing a polarity axis, and at high concentrations they prematurely form a second and a third mating projection. Together, these results suggest that Bil2 promotes the proper formation and timing of mating projections by organizing Bni1 and maintaining a persistent axis of polarized growth.
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Affiliation(s)
| | - Thomas J. Rands
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Sudati Shrestha
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - William C Simke
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Niklas E. Hase
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - M. Angeles Juanes
- Department of Biology, Brandeis University, Waltham, MA 02454
- Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Joshua B. Kelley
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Bruce L. Goode
- Department of Biology, Brandeis University, Waltham, MA 02454
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Varela Salgado M, Adriaans IE, Touati SA, Ibanes S, Lai-Kee-Him J, Ancelin A, Cipelletti L, Picas L, Piatti S. Phosphorylation of the F-BAR protein Hof1 drives septin ring splitting in budding yeast. Nat Commun 2024; 15:3383. [PMID: 38649354 PMCID: PMC11035697 DOI: 10.1038/s41467-024-47709-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/09/2024] [Indexed: 04/25/2024] Open
Abstract
A double septin ring accompanies cytokinesis in yeasts and mammalian cells. In budding yeast, reorganisation of the septin collar at the bud neck into a dynamic double ring is essential for actomyosin ring constriction and cytokinesis. Septin reorganisation requires the Mitotic Exit Network (MEN), a kinase cascade essential for cytokinesis. However, the effectors of MEN in this process are unknown. Here we identify the F-BAR protein Hof1 as a critical target of MEN in septin remodelling. Phospho-mimicking HOF1 mutant alleles overcome the inability of MEN mutants to undergo septin reorganisation by decreasing Hof1 binding to septins and facilitating its translocation to the actomyosin ring. Hof1-mediated septin rearrangement requires its F-BAR domain, suggesting that it may involve a local membrane remodelling that leads to septin reorganisation. In vitro Hof1 can induce the formation of intertwined septin bundles, while a phosphomimetic Hof1 protein has impaired septin-bundling activity. Altogether, our data indicate that Hof1 modulates septin architecture in distinct ways depending on its phosphorylation status.
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Affiliation(s)
- Maritzaida Varela Salgado
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Ingrid E Adriaans
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Sandra A Touati
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013, Paris, France
| | - Sandy Ibanes
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Joséphine Lai-Kee-Him
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 34090, Montpellier, France
| | - Aurélie Ancelin
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 34090, Montpellier, France
| | - Luca Cipelletti
- L2C (Laboratoire Charles Coulomb), University of Montpellier, CNRS 34095, Montpellier, France
- IUF (Institut Universitaire de France, 75231, Paris, France
| | - Laura Picas
- IRIM (Institut de Recherche en Infectiologie de Montpellier), University of Montpellier, CNRS UMR 9004, 34293, Montpellier, France
| | - Simonetta Piatti
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France.
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Rezig IM, Yaduma WG, McInerny CJ. Processes Controlling the Contractile Ring during Cytokinesis in Fission Yeast, Including the Role of ESCRT Proteins. J Fungi (Basel) 2024; 10:154. [PMID: 38392827 PMCID: PMC10890238 DOI: 10.3390/jof10020154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
Cytokinesis, as the last stage of the cell division cycle, is a tightly controlled process amongst all eukaryotes, with defective division leading to severe cellular consequences and implicated in serious human diseases and conditions such as cancer. Both mammalian cells and the fission yeast Schizosaccharomyces pombe use binary fission to divide into two equally sized daughter cells. Similar to mammalian cells, in S. pombe, cytokinetic division is driven by the assembly of an actomyosin contractile ring (ACR) at the cell equator between the two cell tips. The ACR is composed of a complex network of membrane scaffold proteins, actin filaments, myosin motors and other cytokinesis regulators. The contraction of the ACR leads to the formation of a cleavage furrow which is severed by the endosomal sorting complex required for transport (ESCRT) proteins, leading to the final cell separation during the last stage of cytokinesis, the abscission. This review describes recent findings defining the two phases of cytokinesis in S. pombe: ACR assembly and constriction, and their coordination with septation. In summary, we provide an overview of the current understanding of the mechanisms regulating ACR-mediated cytokinesis in S. pombe and emphasize a potential role of ESCRT proteins in this process.
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Affiliation(s)
- Imane M Rezig
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK
| | - Wandiahyel G Yaduma
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK
- Department of Chemistry, School of Sciences, Adamawa State College of Education, Hong 640001, Adamawa State, Nigeria
| | - Christopher J McInerny
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK
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Hall AR, Choi YK, Im W, Vavylonis D. Anillin-related Mid1 as an adaptive and multimodal contractile ring anchoring protein: A simulation study. Structure 2024; 32:242-252.e2. [PMID: 38103546 PMCID: PMC10872332 DOI: 10.1016/j.str.2023.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 10/13/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023]
Abstract
Cytokinesis of animal and fungi cells depends crucially on the anillin scaffold proteins. Fission yeast anillin-related Mid1 anchors cytokinetic ring precursor nodes to the membrane. However, it is unclear if both of its Pleckstrin Homology (PH) and C2 C-terminal domains bind to the membrane as monomers or dimers, and if one domain plays a dominant role. We studied Mid1 membrane binding with all-atom molecular dynamics near a membrane with yeast-like lipid composition. In simulations with the full C terminal region started away from the membrane, Mid1 binds through the disordered L3 loop of C2 in a vertical orientation, with the PH away from the membrane. However, a configuration with both C2 and PH initially bound to the membrane remains associated with the membrane. Simulations of C2-PH dimers show extensive asymmetric membrane contacts. These multiple modes of binding may reflect Mid1's multiple interactions with membranes, node proteins, and ability to sustain mechanical forces.
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Affiliation(s)
- Aaron R Hall
- Department of Physics, Lehigh University, Bethlehem, PA 18017, USA
| | - Yeol Kyo Choi
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18017, USA
| | - Wonpil Im
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18017, USA
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA 18017, USA; Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA.
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Igarashi MG, Bhattacharjee R, Willet AH, Gould KL. Polarity kinases that phosphorylate F-BAR protein Cdc15 have unique localization patterns during cytokinesis and contributions to preventing tip septation in Schizosaccharomyces pombe. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000965. [PMID: 37746062 PMCID: PMC10517346 DOI: 10.17912/micropub.biology.000965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/01/2023] [Accepted: 09/07/2023] [Indexed: 09/26/2023]
Abstract
The Schizosaccharomyces pombe F-BAR protein, Cdc15, facilitates the linkage between the cytokinetic ring and the plasma membrane. Cdc15 is phosphorylated on many sites by four polarity kinases and this antagonizes membrane interaction. Dephosphorylation of Cdc15 during mitosis induces its phase separation, allowing oligomerization, membrane association, and protein partner binding. Here, using live cell imaging we examined whether spatial separation of Cdc15 from its four identified kinases potentially explains their diverse effects on tip septation and the mitotic Cdc15 phosphorylation state. We identified a correlation between kinase localization and their ability to antagonize Cdc15 cytokinetic ring and membrane localization.
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Affiliation(s)
- Maya G. Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
- Current address: Biophysical Sciences, University of Chicago, Chicago, IL, US
| | - Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
- Current address: Twist Bioscience, Quincy, MA, US
| | - Alaina H. Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
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