1
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Brokatzky D, Gomes MC, Robertin S, Albino C, Miles SL, Mostowy S. Septins promote macrophage pyroptosis by regulating gasdermin D cleavage and ninjurin-1-mediated plasma membrane rupture. Cell Chem Biol 2024:S2451-9456(24)00305-2. [PMID: 39106869 DOI: 10.1016/j.chembiol.2024.07.003] [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: 12/13/2023] [Revised: 05/20/2024] [Accepted: 07/11/2024] [Indexed: 08/09/2024]
Abstract
The septin cytoskeleton is primarily known for roles in cell division and host defense against bacterial infection. Despite recent insights, the full breadth of roles for septins in host defense is poorly understood. In macrophages, Shigella induces pyroptosis, a pro-inflammatory form of cell death dependent upon gasdermin D (GSDMD) pores at the plasma membrane and cell surface protein ninjurin-1 (NINJ1) for membrane rupture. Here, we discover that septins promote macrophage pyroptosis induced by lipopolysaccharide (LPS)/nigericin and Shigella infection, but do not affect cytokine expression or release. We observe that septin filaments assemble at the plasma membrane, and cleavage of GSDMD is impaired in septin-depleted cells. We found that septins regulate mitochondrial dynamics and the expression of NINJ1. Using a Shigella-zebrafish infection model, we show that septin-mediated pyroptosis is an in vivo mechanism of infection control. The discovery of septins as a mediator of pyroptosis may inspire innovative anti-bacterial and anti-inflammatory treatments.
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Affiliation(s)
- Dominik Brokatzky
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, Keppel Street, London WC1E 7HT, UK.
| | - Margarida C Gomes
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, Keppel Street, London WC1E 7HT, UK
| | - Stevens Robertin
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, Keppel Street, London WC1E 7HT, UK
| | - Carolina Albino
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, Keppel Street, London WC1E 7HT, UK
| | - Sydney L Miles
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, Keppel Street, London WC1E 7HT, UK
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, Keppel Street, London WC1E 7HT, UK.
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2
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Prislusky MI, Lam JGT, Contreras VR, Ng M, Chamberlain M, Pathak-Sharma S, Fields M, Zhang X, Amer AO, Seveau S. The septin cytoskeleton is required for plasma membrane repair. EMBO Rep 2024:10.1038/s44319-024-00195-6. [PMID: 38969946 DOI: 10.1038/s44319-024-00195-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/30/2024] [Accepted: 06/07/2024] [Indexed: 07/07/2024] Open
Abstract
Plasma membrane repair is a fundamental homeostatic process of eukaryotic cells. Here, we report a new function for the conserved cytoskeletal proteins known as septins in the repair of cells perforated by pore-forming toxins or mechanical disruption. Using a silencing RNA screen, we identified known repair factors (e.g. annexin A2, ANXA2) and novel factors such as septin 7 (SEPT7) that is essential for septin assembly. Upon plasma membrane injury, the septin cytoskeleton is extensively redistributed to form submembranous domains arranged as knob and loop structures containing F-actin, myosin IIA, S100A11, and ANXA2. Formation of these domains is Ca2+-dependent and correlates with plasma membrane repair efficiency. Super-resolution microscopy revealed that septins and F-actin form intertwined filaments associated with ANXA2. Depletion of SEPT7 prevented ANXA2 recruitment and formation of submembranous actomyosin domains. However, ANXA2 depletion had no effect on domain formation. Collectively, our data support a novel septin-based mechanism for resealing damaged cells, in which the septin cytoskeleton plays a key structural role in remodeling the plasma membrane by promoting the formation of SEPT/F-actin/myosin IIA/ANXA2/S100A11 repair domains.
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Affiliation(s)
- M Isabella Prislusky
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Jonathan G T Lam
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Viviana Ruiz Contreras
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
- Grupo Investigaciones Biomédicas, Universidad de Sucre, Sincelejo, Sucre, Colombia
| | - Marilynn Ng
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Madeline Chamberlain
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Sarika Pathak-Sharma
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Madalyn Fields
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Xiaoli Zhang
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH, USA
| | - Amal O Amer
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Stephanie Seveau
- Department of Microbial Infection & Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, USA.
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3
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Hecht M, Alber N, Marhoffer P, Johnsson N, Gronemeyer T. The concerted action of SEPT9 and EPLIN modulates the adhesion and migration of human fibroblasts. Life Sci Alliance 2024; 7:e202201686. [PMID: 38719752 PMCID: PMC11077590 DOI: 10.26508/lsa.202201686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/12/2024] Open
Abstract
Septins are cytoskeletal proteins that participate in cell adhesion, migration, and polarity establishment. The septin subunit SEPT9 directly interacts with the single LIM domain of epithelial protein lost in neoplasm (EPLIN), an actin-bundling protein. Using a human SEPT9 KO fibroblast cell line, we show that cell adhesion and migration are regulated by the interplay between both proteins. The low motility of SEPT9-depleted cells could be partly rescued by increased levels of EPLIN. The normal organization of actin-related filopodia and stress fibers was directly dependent on the expression level of SEPT9 and EPLIN. Increased levels of SEPT9 and EPLIN enhanced the size of focal adhesions in cell protrusions, correlating with stabilization of actin bundles. Conversely, decreased levels had the opposite effect. Our work thus establishes the interaction between SEPT9 and EPLIN as an important link between the septin and the actin cytoskeleton, influencing cell adhesion, motility, and migration.
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Affiliation(s)
- Matthias Hecht
- https://ror.org/032000t02 Institute of Molecular Genetics and Cell Biology, James Franck Ring N27, Ulm University, Ulm, Germany
| | - Nane Alber
- https://ror.org/032000t02 Institute of Molecular Genetics and Cell Biology, James Franck Ring N27, Ulm University, Ulm, Germany
| | - Pia Marhoffer
- https://ror.org/032000t02 Institute of Molecular Genetics and Cell Biology, James Franck Ring N27, Ulm University, Ulm, Germany
| | - Nils Johnsson
- https://ror.org/032000t02 Institute of Molecular Genetics and Cell Biology, James Franck Ring N27, Ulm University, Ulm, Germany
| | - Thomas Gronemeyer
- https://ror.org/032000t02 Institute of Molecular Genetics and Cell Biology, James Franck Ring N27, Ulm University, Ulm, Germany
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4
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Sanovec O, Frolikova M, Kraus V, Vondrakova J, Qasemi M, Spevakova D, Simonik O, Moritz L, Caswell DL, Liska F, Ded L, Cerny J, Avidor-Reiss T, Hammoud SS, Schorle H, Postlerova P, Steger K, Komrskova K. Protamine 2 Deficiency Results In Septin 12 Abnormalities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596175. [PMID: 38854089 PMCID: PMC11160614 DOI: 10.1101/2024.05.28.596175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
There is a well-established link between abnormal sperm chromatin states and poor motility, however, how these two processes are interdependent is unknown. Here, we identified a possible mechanistic insight by showing that Protamine 2, a nuclear DNA packaging protein in sperm, directly interacts with cytoskeletal protein Septin 12, which is associated with sperm motility. Septin 12 has several isoforms, and we show, that in the Prm2 -/- sperm, the short one (Mw 36 kDa) is mislocalized, while two long isoforms (Mw 40 and 41 kDa) are unexpectedly lost in Prm2 -/- sperm chromatin-bound protein fractions. Septin 12 co-immunoprecipitated with Protamine 2 in the testicular cell lysate of WT mice and with Lamin B1/B2/B3 in co-transfected HEK cells despite we did not observe changes in Lamin B2/B3 protein or SUN4 expression in Prm2 -/- testes. Furthermore, the Prm2 -/- sperm have on average a smaller sperm nucleus and aberrant acrosome biogenesis. In humans, patients with low sperm motility (asthenozoospermia) have imbalanced histone- protamine 1/2 ratio and modified levels of cytoskeletal proteins. We detected retained Septin 12 isoforms (Mw 40 and 41 kDa) in the sperm membrane, chromatin-bound and tubulin/mitochondria protein fractions, which was not true for healthy normozoospermic men. In conclusion, our findings expand the current knowledge regarding the connection between Protamine 2 and Septin 12 expression and localization, resulting in low sperm motility and morphological abnormalities.
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5
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Stjepić V, Nakamura M, Hui J, Parkhurst SM. Two Septin complexes mediate actin dynamics during cell wound repair. Cell Rep 2024; 43:114215. [PMID: 38728140 PMCID: PMC11203717 DOI: 10.1016/j.celrep.2024.114215] [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: 11/16/2023] [Revised: 03/18/2024] [Accepted: 04/24/2024] [Indexed: 05/12/2024] Open
Abstract
Cells have robust wound repair systems to prevent further damage or infection and to quickly restore cell cortex integrity when exposed to mechanical and chemical stress. Actomyosin ring formation and contraction at the wound edge are major events during closure of the plasma membrane and underlying cytoskeleton during cell wound repair. Here, we show that all five Drosophila Septins are required for efficient cell wound repair. Based on their different recruitment patterns and knockdown/mutant phenotypes, two distinct Septin complexes, Sep1/Sep2/Pnut and Sep4/Sep5/Pnut, are assembled to regulate actin ring assembly, contraction, and remodeling during the repair process. Intriguingly, we find that these two Septin complexes have different F-actin bending activities. In addition, we find that Anillin regulates the recruitment of only one of two Septin complexes upon wounding. Our results demonstrate that two functionally distinct Septin complexes work side by side to discretely regulate actomyosin ring dynamics during cell wound repair.
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Affiliation(s)
- Viktor Stjepić
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Mitsutoshi Nakamura
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Justin Hui
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Susan M Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA.
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6
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López-Jiménez AT, Özbaykal Güler G, Mostowy S. The great escape: a Shigella effector unlocks the septin cage. Nat Commun 2024; 15:4104. [PMID: 38750009 PMCID: PMC11096336 DOI: 10.1038/s41467-024-48208-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 04/19/2024] [Indexed: 05/18/2024] Open
Affiliation(s)
- Ana T López-Jiménez
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Gizem Özbaykal Güler
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK.
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7
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Becker IC, Wilkie AR, Unger BA, Sciaudone AR, Fatima F, Tsai IT, Xu K, Machlus KR, Italiano JE. Dynamic actin/septin network in megakaryocytes coordinates proplatelet elaboration. Haematologica 2024; 109:915-928. [PMID: 37675512 PMCID: PMC10905084 DOI: 10.3324/haematol.2023.283369] [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: 04/19/2023] [Accepted: 08/18/2023] [Indexed: 09/08/2023] Open
Abstract
Megakaryocytes (MK) undergo extensive cytoskeletal rearrangements as they give rise to platelets. While cortical microtubule sliding has been implicated in proplatelet formation, the role of the actin cytoskeleton in proplatelet elongation is less understood. It is assumed that actin filament reorganization is important for platelet generation given that mouse models with mutations in actin-associated proteins exhibit thrombocytopenia. However, due to the essential role of the actin network during MK development, a differential understanding of the contribution of the actin cytoskeleton on proplatelet release is lacking. Here, we reveal that inhibition of actin polymerization impairs the formation of elaborate proplatelets by hampering proplatelet extension and bead formation along the proplatelet shaft, which was mostly independent of changes in cortical microtubule sliding. We identify Cdc42 and its downstream effectors, septins, as critical regulators of intracellular actin dynamics in MK, inhibition of which, similarly to inhibition of actin polymerization, impairs proplatelet movement and beading. Super-resolution microscopy revealed a differential association of distinctive septins with the actin and microtubule cytoskeleton, respectively, which was disrupted upon septin inhibition and diminished intracellular filamentous actin dynamics. In vivo, septins, similarly to F-actin, were subject to changes in expression upon enforcing proplatelet formation through prior platelet depletion. In summary, we demonstrate that a Cdc42/septin axis is not only important for MK maturation and polarization, but is further required for intracellular actin dynamics during proplatelet formation.
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Affiliation(s)
- Isabelle C Becker
- Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA, 02115; Department of Surgery, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115
| | - Adrian R Wilkie
- Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA, 02115; Department of Surgery, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115
| | - Bret A Unger
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720
| | | | - Farheen Fatima
- Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA, 02115; Department of Surgery, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115
| | - I-Ting Tsai
- Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA, 02115; Department of Surgery, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115
| | - Ke Xu
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720
| | - Kellie R Machlus
- Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA, 02115; Department of Surgery, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115
| | - Joseph E Italiano
- Vascular Biology Program, Boston Children's Hospital, 1 Blackfan Circle, Boston, MA, 02115; Department of Surgery, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115.
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8
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Robertin S, Brokatzky D, Lobato-Márquez D, Mostowy S. Regulation of integrin α5β1-mediated Staphylococcus aureus cellular invasion by the septin cytoskeleton. Eur J Cell Biol 2023; 102:151359. [PMID: 37683588 DOI: 10.1016/j.ejcb.2023.151359] [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: 04/05/2023] [Revised: 08/10/2023] [Accepted: 09/01/2023] [Indexed: 09/10/2023] Open
Abstract
Staphylococcus aureus, a Gram-positive bacterial pathogen, is an urgent health threat causing a wide range of clinical infections. Originally viewed as a strict extracellular pathogen, accumulating evidence has revealed S. aureus to be a facultative intracellular pathogen subverting host cell signalling to support invasion. The majority of clinical isolates produce fibronectin-binding proteins A and B (FnBPA and FnBPB) to interact with host integrin α5β1, a key component of focal adhesions. S. aureus binding of integrin α5β1 promotes its clustering on the host cell surface, triggering activation of focal adhesion kinase (FAK) and cytoskeleton rearrangements to promote bacterial invasion into non-phagocytic cells. Here, we discover that septins, a component of the cytoskeleton that assembles on membranes, are recruited as collar-like structures with actin to S. aureus invasion sites engaging integrin α5β1. To investigate septin recruitment to the plasma membrane in a bacteria-free system, we used FnBPA-coated latex beads and showed that septins are recruited upon activation of integrin α5β1. SEPT2 depletion reduced S. aureus invasion, but increased surface expression of integrin α5 and adhesion of S. aureus to host cells. Consistent with this, SEPT2 depletion increased cellular protein levels of integrin α5 and β1 subunits, as well as FAK. Collectively, these results provide insights into regulation of integrin α5β1 and invasion of S. aureus by the septin cytoskeleton.
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Affiliation(s)
- Stevens Robertin
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Dominik Brokatzky
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Damián Lobato-Márquez
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
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9
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Castillo S, Gence R, Pagan D, Koraïchi F, Bouchenot C, Pons BJ, Boëlle B, Olichon A, Lajoie-Mazenc I, Favre G, Pédelacq JD, Cabantous S. Visualizing the subcellular localization of RHOB-GTP and GTPase-Effector complexes using a split-GFP/nanobody labelling assay. Eur J Cell Biol 2023; 102:151355. [PMID: 37639782 DOI: 10.1016/j.ejcb.2023.151355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/04/2023] [Accepted: 08/20/2023] [Indexed: 08/31/2023] Open
Abstract
Small GTPases are highly regulated proteins that control essential signaling pathways through the activity of their effector proteins. Among the RHOA subfamily, RHOB regulates peculiar functions that could be associated with the control of the endocytic trafficking of signaling proteins. Here, we used an optimized assay based on tripartite split-GFP complementation to localize GTPase-effector complexes with high-resolution. The detection of RHOB interaction with the Rhotekin Rho binding domain (RBD) that specifically recognizes the active GTP-bound GTPase, is performed in vitro by the concomitant addition of recombinant GFP1-9 and a GFP nanobody. Analysis of RHOB-RBD complexes localization profiles combined with immunostaining and live cell imaging indicated a serum-dependent reorganization of the endosomal and membrane pool of active RHOB. We further applied this technology to the detection of RHO-effector complexes that highlighted their subcellular localization with high resolution among the different cellular compartments.
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Affiliation(s)
- Sebastian Castillo
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | - Rémi Gence
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | - Delphine Pagan
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | - Faten Koraïchi
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | | | - Benoit J Pons
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn TR10 9FE, United Kingdom
| | - Betty Boëlle
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | - Aurélien Olichon
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), 97410 Saint-Pierre, La Réunion, France
| | - Isabelle Lajoie-Mazenc
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | - Gilles Favre
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France
| | - Jean-Denis Pédelacq
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UPS), Toulouse, France
| | - Stéphanie Cabantous
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM, Université de Toulouse, UPS, CNRS, 31037 Toulouse, France.
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10
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Stjepić V, Nakamura M, Hui J, Parkhurst SM. Two Septin Complexes Mediate Actin Dynamics During Cell Wound Repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.567084. [PMID: 38014090 PMCID: PMC10680708 DOI: 10.1101/2023.11.14.567084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Cells have robust wound repair systems to prevent further damage or infection and to quickly restore cell cortex integrity when exposed to mechanical and chemical stress. Actomyosin ring formation and contraction at the wound edge are major events during closure of the plasma membrane and underlying cytoskeleton during cell wound repair. Here, we show that all five Drosophila Septins are required for efficient cell wound repair. Based on their different recruitment patterns and knockdown/mutant phenotypes, two distinct Septin complexes, Sep1-Sep2-Pnut and Sep4-Sep5-Pnut, are assembled to regulate actin ring assembly, contraction, and remodeling during the repair process. Intriguingly, we find that these two Septin complexes have different F-actin bending activities. In addition, we find that Anillin regulates the recruitment of only one of two Septin complexes upon wounding. Our results demonstrate that two functionally distinct Septin complexes work side-by-side to discretely regulate actomyosin ring dynamics during cell wound repair.
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Affiliation(s)
- Viktor Stjepić
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA 98109
| | - Mitsutoshi Nakamura
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA 98109
| | - Justin Hui
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA 98109
| | - Susan M. Parkhurst
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA 98109
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11
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Nakazawa K, Chauvin B, Mangenot S, Bertin A. Reconstituted in vitro systems to reveal the roles and functions of septins. J Cell Sci 2023; 136:jcs259448. [PMID: 37815088 DOI: 10.1242/jcs.259448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023] Open
Abstract
Septins are essential cytoskeletal proteins involved in key cellular processes and have also been implicated in diseases from cancers to neurodegenerative pathologies. However, they have not been as thoroughly studied as other cytoskeletal proteins. In vivo, septins interact with other cytoskeletal proteins and with the inner plasma membrane. Hence, bottom-up in vitro cell-free assays are well suited to dissect the roles and behavior of septins in a controlled environment. Specifically, in vitro studies have been invaluable in describing the self-assembly of septins into a large diversity of ultrastructures. Given that septins interact specifically with membrane, the details of these septin-membrane interactions have been analyzed using reconstituted lipid systems. In particular, at a membrane, septins are often localized at curvatures of micrometer scale. In that context, in vitro assays have been performed with substrates of varying curvatures (spheres, cylinders or undulated substrates) to probe the sensitivity of septins to membrane curvature. This Review will first present the structural properties of septins in solution and describe the interplay of septins with cytoskeletal partners. We will then discuss how septins interact with biomimetic membranes and induce their reshaping. Finally, we will highlight the curvature sensitivity of septins and how they alter the mechanical properties of membranes.
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Affiliation(s)
- Koyomi Nakazawa
- Physico Chimie Curie , Institut Curie, CNRS UMR 168, Sorbonne Université, 11 Rue Pierre et Paris Curie, 75005 Paris, France
| | - Brieuc Chauvin
- Physico Chimie Curie , Institut Curie, CNRS UMR 168, Sorbonne Université, 11 Rue Pierre et Paris Curie, 75005 Paris, France
| | - Stéphanie Mangenot
- Laboratoire Matière et Systèmes Complexes , Université de Paris Cité, CNRS UMR 7057, 45 Rue des Saint Pères, 75006 Paris, France
| | - Aurélie Bertin
- Physico Chimie Curie , Institut Curie, CNRS UMR 168, Sorbonne Université, 11 Rue Pierre et Paris Curie, 75005 Paris, France
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12
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Okletey J, Angelis D, Jones TM, Montagna C, Spiliotis ET. An oncogenic isoform of septin 9 promotes the formation of juxtanuclear invadopodia by reducing nuclear deformability. Cell Rep 2023; 42:112893. [PMID: 37516960 PMCID: PMC10530659 DOI: 10.1016/j.celrep.2023.112893] [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: 03/11/2023] [Revised: 06/17/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023] Open
Abstract
Invadopodia are extracellular matrix (ECM) degrading structures, which promote cancer cell invasion. The nucleus is increasingly viewed as a mechanosensory organelle that determines migratory strategies. However, how the nucleus crosstalks with invadopodia is little known. Here, we report that the oncogenic septin 9 isoform 1 (SEPT9_i1) is a component of breast cancer invadopodia. SEPT9_i1 depletion diminishes invadopodium formation and the clustering of the invadopodium precursor components TKS5 and cortactin. This phenotype is characterized by deformed nuclei and nuclear envelopes with folds and grooves. We show that SEPT9_i1 localizes to the nuclear envelope and juxtanuclear invadopodia. Moreover, exogenous lamin A rescues nuclear morphology and juxtanuclear TKS5 clusters. Importantly, SEPT9_i1 is required for the amplification of juxtanuclear invadopodia, which is induced by the epidermal growth factor. We posit that nuclei of low deformability favor the formation of juxtanuclear invadopodia in a SEPT9_i1-dependent manner, which functions as a tunable mechanism for overcoming ECM impenetrability.
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Affiliation(s)
- Joshua Okletey
- Department of Biology, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA
| | - Dimitrios Angelis
- Department of Biology, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA
| | - Tia M Jones
- Department of Biology, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA
| | - Cristina Montagna
- Department of Radiology and Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08901, USA
| | - Elias T Spiliotis
- Department of Biology, Drexel University, 3245 Chestnut Street, Philadelphia, PA 19104, USA.
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Tomasso MR, Padrick SB. BORG family proteins in physiology and human disease. Cytoskeleton (Hoboken) 2023; 80:182-198. [PMID: 37403807 DOI: 10.1002/cm.21768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/06/2023]
Abstract
The binder of rho GTPases (BORG)/Cdc42 effector proteins (Cdc42EP) family is composed of five Rho GTPase binding proteins whose functions and mechanism of actions are of emerging interest. Here, we review recent findings pertaining to the family as a whole and consider how these change our understanding of cellular organization. Recent studies have implicated BORGs in both fundamental physiology and in human diseases, mainly cancers. An emerging pattern suggests that BORG family members cancer-promoting properties are related to their ability to regulate the cytoskeleton, with many impacting the organization of acto-myosin stress fibers. This is consistent with the broader literature indicating that BORG family members are regulators of both the septin and actin cytoskeleton networks. The exact mechanism through which BORGs modify the cytoskeleton is not clear, but we consider here a few data-supported and speculative possibilities. Finally, we delve into how the Rho GTPase Cdc42 modifies BORG function in cells. This remains open-ended as Cdc42's effects on BORGs appear cell type- and cell state-dependent. Collectively, these data point to the importance of the BORG family and suggest broader themes in their function and regulation.
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Affiliation(s)
- Meagan R Tomasso
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Shae B Padrick
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
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14
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Okletey J, Angelis D, Jones TM, Montagna C, Spiliotis ET. An oncogenic isoform of septin 9 promotes the formation of juxtanuclear invadopodia by reducing nuclear deformability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.18.545473. [PMID: 37398172 PMCID: PMC10312791 DOI: 10.1101/2023.06.18.545473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Invadopodia are extracellular matrix (ECM) degrading structures, which promote cancer cell invasion. The nucleus is increasingly viewed as a mechanosensory organelle that determines migratory strategies. However, how the nucleus crosstalks with invadopodia is little known. Here, we report that the oncogenic septin 9 isoform 1 (SEPT9_i1) is a component of breast cancer invadopodia. SEPT9_i1 depletion diminishes invadopodia formation and the clustering of invadopodia precursor components TKS5 and cortactin. This phenotype is characterized by deformed nuclei, and nuclear envelopes with folds and grooves. We show that SEPT9_i1 localizes to the nuclear envelope and juxtanuclear invadopodia. Moreover, exogenous lamin A rescues nuclear morphology and juxtanuclear TKS5 clusters. Importantly, SEPT9_i1 is required for the amplification of juxtanuclear invadopodia, which is induced by the epidermal growth factor. We posit that nuclei of low deformability favor the formation of juxtanuclear invadopodia in a SEPT9_i1-dependent manner, which functions as a tunable mechanism for overcoming ECM impenetrability. Highlights The oncogenic SEPT9_i1 is enriched in breast cancer invadopodia in 2D and 3D ECMSEPT9_i1 promotes invadopodia precursor clustering and invadopodia elongationSEPT9_i1 localizes to the nuclear envelope and reduces nuclear deformabilitySEPT9_i1 is required for EGF-induced amplification of juxtanuclear invadopodia. eTOC Blurb Invadopodia promote the invasion of metastatic cancers. The nucleus is a mechanosensory organelle that determines migratory strategies, but how it crosstalks with invadopodia is unknown. Okletey et al show that the oncogenic isoform SEPT9_i1 promotes nuclear envelope stability and the formation of invadopodia at juxtanuclear areas of the plasma membrane.
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Lobato-Márquez D, Conesa JJ, López-Jiménez AT, Divine ME, Pruneda JN, Mostowy S. Septins and K63 ubiquitin chains are present in separate bacterial microdomains during autophagy of entrapped Shigella. J Cell Sci 2023; 136:jcs261139. [PMID: 36939083 PMCID: PMC10264824 DOI: 10.1242/jcs.261139] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/21/2023] Open
Abstract
During host cell invasion, Shigella escapes to the cytosol and polymerizes actin for cell-to-cell spread. To restrict cell-to-cell spread, host cells employ cell-autonomous immune responses including antibacterial autophagy and septin cage entrapment. How septins interact with the autophagy process to target Shigella for destruction is poorly understood. Here, we employed a correlative light and cryo-soft X-ray tomography (cryo-SXT) pipeline to study Shigella septin cage entrapment in its near-native state. Quantitative cryo-SXT showed that Shigella fragments mitochondria and enabled visualization of X-ray-dense structures (∼30 nm resolution) surrounding Shigella entrapped in septin cages. Using Airyscan confocal microscopy, we observed lysine 63 (K63)-linked ubiquitin chains decorating septin-cage-entrapped Shigella. Remarkably, septins and K63 chains are present in separate bacterial microdomains, indicating they are recruited separately during antibacterial autophagy. Cryo-SXT and live-cell imaging revealed an interaction between septins and LC3B-positive membranes during autophagy of Shigella. Together, these findings demonstrate how septin-caged Shigella are targeted for autophagy and provide fundamental insights into autophagy-cytoskeleton interactions.
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Affiliation(s)
- Damián Lobato-Márquez
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - José Javier Conesa
- MISTRAL beamline, ALBA Synchrotron Light Source, Cerdanyola del Vallès, 08290 Barcelona, Spain
| | - Ana Teresa López-Jiménez
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Michael E. Divine
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jonathan N. Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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16
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Güler GÖ, Mostowy S. The septin cytoskeleton: Heteromer composition defines filament function. J Cell Biol 2023; 222:e202302010. [PMID: 36821087 PMCID: PMC9998967 DOI: 10.1083/jcb.202302010] [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] [Indexed: 02/24/2023] Open
Abstract
Septins are an evolutionarily conserved protein family whose members form hetero-oligomeric complexes that assemble into filaments and higher-order structures. In this issue, Martins et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202203016) and Cannon et al. (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202204063) report that heteromer composition impacts the physiological role of septin filaments in yeast and human cells.
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Affiliation(s)
- Gizem Özbaykal Güler
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
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17
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Weems AD, Welf ES, Driscoll MK, Zhou FY, Mazloom-Farsibaf H, Chang BJ, Murali VS, Gihana GM, Weiss BG, Chi J, Rajendran D, Dean KM, Fiolka R, Danuser G. Blebs promote cell survival by assembling oncogenic signalling hubs. Nature 2023; 615:517-525. [PMID: 36859545 PMCID: PMC10881276 DOI: 10.1038/s41586-023-05758-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 01/25/2023] [Indexed: 03/03/2023]
Abstract
Most human cells require anchorage for survival. Cell-substrate adhesion activates diverse signalling pathways, without which cells undergo anoikis-a form of programmed cell death1. Acquisition of anoikis resistance is a pivotal step in cancer disease progression, as metastasizing cells often lose firm attachment to surrounding tissue2,3. In these poorly attached states, cells adopt rounded morphologies and form small hemispherical plasma membrane protrusions called blebs4-11. Bleb function has been thoroughly investigated in the context of amoeboid migration, but it has been examined far less in other scenarios12. Here we show by three-dimensional imaging and manipulation of cell morphological states that blebbing triggers the formation of plasma membrane-proximal signalling hubs that confer anoikis resistance. Specifically, in melanoma cells, blebbing generates plasma membrane contours that recruit curvature-sensing septin proteins as scaffolds for constitutively active mutant NRAS and effectors. These signalling hubs activate ERK and PI3K-well-established promoters of pro-survival pathways. Inhibition of blebs or septins has little effect on the survival of well-adhered cells, but in detached cells it causes NRAS mislocalization, reduced MAPK and PI3K activity, and ultimately, death. This unveils a morphological requirement for mutant NRAS to operate as an effective oncoprotein. Furthermore, whereas some BRAF-mutated melanoma cells do not rely on this survival pathway in a basal state, inhibition of BRAF and MEK strongly sensitizes them to both bleb and septin inhibition. Moreover, fibroblasts engineered to sustain blebbing acquire the same anoikis resistance as cancer cells even without harbouring oncogenic mutations. Thus, blebs are potent signalling organelles capable of integrating myriad cellular information flows into concerted cellular responses, in this case granting robust anoikis resistance.
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Affiliation(s)
- Andrew D Weems
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA.
| | - Erik S Welf
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Regeneron Pharmaceuticals, Tarrytown, NY, USA
| | - Meghan K Driscoll
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - Felix Y Zhou
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Bo-Jui Chang
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Vasanth S Murali
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gabriel M Gihana
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Byron G Weiss
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joseph Chi
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Divya Rajendran
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kevin M Dean
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Reto Fiolka
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX, USA.
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