1
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Bandyopadhyay S, Zhang X, Ascura A, Edelblum KL, Bonder EM, Gao N. Salmonella engages CDC42 effector protein 1 for intracellular invasion. J Cell Physiol 2024; 239:36-50. [PMID: 37877586 DOI: 10.1002/jcp.31142] [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: 03/01/2023] [Revised: 08/25/2023] [Accepted: 10/03/2023] [Indexed: 10/26/2023]
Abstract
Human enterocytes are primary targets of infection by invasive bacterium Salmonella Typhimurium, and studies using nonintestinal epithelial cells established that S. Typhimurium activates Rho family GTPases, primarily CDC42, to modulate the actin cytoskeletal network for invasion. The host intracellular protein network that engages CDC42 and influences the pathogen's invasive capacity are relatively unclear. Here, proteomic analyses of canonical and variant CDC42 interactomes identified a poorly characterized CDC42 interacting protein, CDC42EP1, whose intracellular localization is rapidly redistributed and aggregated around the invading bacteria. CDC42EP1 associates with SEPTIN-7 and Villin, and its relocalization and bacterial engagement depend on host CDC42 and S. Typhimurium's capability of activating CDC42. Unlike CDC42, CDC42EP1 is not required for S. Typhimurium's initial cellular entry but is found to associate with Salmonella-containing vacuoles after long-term infections, indicating a contribution to the pathogen's intracellular growth and replication. These results uncover a new host regulator of enteric Salmonella infections, which may be targeted to restrict bacterial load at the primary site of infection to prevent systemic spread.
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Affiliation(s)
| | - Xiao Zhang
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Andrea Ascura
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Karen L Edelblum
- Department of Pathology, Immunology, and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Edward M Bonder
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
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2
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Zhang Y, Qu H, Li C, Li L, He L. The S-Nitrosylation of Septin2 (SNO-Septin2) axis: A novel potential therapeutic target for treating aneurysms and dissection. Drug Discov Ther 2024; 18:207-209. [PMID: 38987209 DOI: 10.5582/ddt.2024.01047] [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: 07/12/2024]
Abstract
Aortic aneurysm and aortic dissection (AAD) are severe life-threatening cardiovascular disorders for which no approved pharmaceutical therapies are currently available. Protein S-nitrosylation (SNO) is a typical redox-dependent posttranslational modification whose role in AAD has yet to be described. Recently, Zhang et al. revealed for the first time that SNO modification of macrophage cytoskeletal protein septin2 promotes vascular inflammation and extracellular matrix degradation in aortic aneurysm. Mechanically, the TIAM1-RAC1(T lymphoma invasion and metastasis-inducing protein 1-Ras-related C3 botulinum toxin substrate 1) axis participates in the progression of AAD induced with S-nitrosylated septin2. More importantly, developing R-ketorolac and NSC23766 compounds that specifically target the TIAM1-RAC1 pathway may be new a potential strategy for alleviating AAD.
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Affiliation(s)
- Ying Zhang
- Department of Neurosurgery, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China
| | - Hongtao Qu
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China
| | - Chuanhua Li
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China
| | - Lanfang Li
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China
| | - Lu He
- Department of Neurosurgery, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China
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3
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Liu H, Yan P, Wu C, Rao M, Zhu J, Lv L, Li W, Liang Y, Qi S, Lu K, Kong E. Palmitoylated Sept8-204 modulates learning and anxiety by regulating filopodia arborization and actin dynamics. Sci Signal 2023; 16:eadi8645. [PMID: 38051778 DOI: 10.1126/scisignal.adi8645] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 11/02/2023] [Indexed: 12/07/2023]
Abstract
Septin proteins are involved in diverse physiological functions, including the formation of specialized cytoskeletal structures. Septin 8 (Sept8) is implicated in spine morphogenesis and dendritic branching through palmitoylation. We explored the role and regulation of a Sept8 variant in human neural-like cells and in the mouse brain. We identified Sept8-204 as a brain-specific variant of Sept8 that was abundant in neurons and modified by palmitoylation, specifically at Cys469, Cys470, and Cys472. Sept8-204 palmitoylation was mediated by the palmitoyltransferase ZDHHC7 and was removed by the depalmitoylase PPT1. Palmitoylation of Sept8-204 bound to F-actin and induced cytoskeletal dynamics to promote the outgrowth of filopodia in N2a cells and the arborization of neurites in hippocampal neurons. In contrast, a Sept8-204 variant that could not be palmitoylated because of mutation of all three Cys residues (Sept8-204-3CA) lost its ability to bind F-actin, and expression of this mutant did not promote morphological changes. Genetic deletion of Sept8, Sept8-204, or Zdhhc7 caused deficits in learning and memory and promoted anxiety-like behaviors in mice. Our findings provide greater insight into the regulation of Sept8-204 by palmitoylation and its role in neuronal morphology and function in relation to cognition.
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Affiliation(s)
- Huicong Liu
- Second Affiliated Hospital of Xinxiang Medical University, Xinxiang 453003, China
- Institute of Psychiatry and Neuroscience, Xinxiang Key Laboratory of Protein Palmitoylation and Major Human Diseases, Xinxiang Medical University, Xinxiang 453003, China
| | - Peipei Yan
- Second Affiliated Hospital of Xinxiang Medical University, Xinxiang 453003, China
- Institute of Psychiatry and Neuroscience, Xinxiang Key Laboratory of Protein Palmitoylation and Major Human Diseases, Xinxiang Medical University, Xinxiang 453003, China
| | - Can Wu
- Institute of Psychiatry and Neuroscience, Xinxiang Key Laboratory of Protein Palmitoylation and Major Human Diseases, Xinxiang Medical University, Xinxiang 453003, China
| | - Muding Rao
- Institute of Psychiatry and Neuroscience, Xinxiang Key Laboratory of Protein Palmitoylation and Major Human Diseases, Xinxiang Medical University, Xinxiang 453003, China
| | - Jiangli Zhu
- Department of Urology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and National Collaborative Innovation Center, Chengdu 610041, China
| | - Luxian Lv
- Second Affiliated Hospital of Xinxiang Medical University, Xinxiang 453003, China
| | - Wenqiang Li
- Second Affiliated Hospital of Xinxiang Medical University, Xinxiang 453003, China
| | - Yinming Liang
- Institute of Psychiatry and Neuroscience, Xinxiang Key Laboratory of Protein Palmitoylation and Major Human Diseases, Xinxiang Medical University, Xinxiang 453003, China
| | - Shiqian Qi
- Department of Urology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and National Collaborative Innovation Center, Chengdu 610041, China
| | - Kefeng Lu
- Department of Neurology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610065, China
| | - Eryan Kong
- Second Affiliated Hospital of Xinxiang Medical University, Xinxiang 453003, China
- Institute of Psychiatry and Neuroscience, Xinxiang Key Laboratory of Protein Palmitoylation and Major Human Diseases, Xinxiang Medical University, Xinxiang 453003, China
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4
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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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5
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Moradimotlagh A, Chen S, Koohbor S, Moon KM, Foster LJ, Reiner N, Nandan D. Leishmania infection upregulates and engages host macrophage Argonaute 1, and system-wide proteomics reveals Argonaute 1-dependent host response. Front Immunol 2023; 14:1287539. [PMID: 38098491 PMCID: PMC10720368 DOI: 10.3389/fimmu.2023.1287539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/26/2023] [Indexed: 12/17/2023] Open
Abstract
Leishmania donovani, an intracellular protozoan parasite, is the causative agent of visceral leishmaniasis, the most severe form of leishmaniasis in humans. It is becoming increasingly clear that several intracellular pathogens target host cell RNA interference (RNAi) pathways to promote their survival. Complexes of Argonaute proteins with small RNAs are core components of the RNAi. In this study, we investigated the potential role of host macrophage Argonautes in Leishmania pathogenesis. Using Western blot analysis of Leishmania donovani-infected macrophages, we show here that Leishmania infection selectively increased the abundance of host Argonaute 1 (Ago1). This increased abundance of Ago1 in infected cells also resulted in higher levels of Ago1 in active Ago-complexes, suggesting the preferred use of Ago1 in RNAi in Leishmania-infected cells. This analysis used a short trinucleotide repeat containing 6 (TNRC6)/glycine-tryptophan repeat protein (GW182) protein-derived peptide fused to Glutathione S-transferase as an affinity matrix to capture mature Ago-small RNAs complexes from the cytosol of non-infected and Leishmania-infected cells. Furthermore, Ago1 silencing significantly reduced intracellular survival of Leishmania, demonstrating that Ago1 is essential for Leishmania pathogenesis. To investigate the role of host Ago1 in Leishmania pathogenesis, a quantitative whole proteome approach was employed, which showed that expression of several previously reported Leishmania pathogenesis-related proteins was dependent on the level of macrophage Ago1. Together, these findings identify Ago1 as the preferred Argonaute of RNAi machinery in infected cells and a novel and essential virulence factor by proxy that promotes Leishmania survival.
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Affiliation(s)
- Atieh Moradimotlagh
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Stella Chen
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Sara Koohbor
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Leonard J. Foster
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Neil Reiner
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Devki Nandan
- Division of Infectious Diseases, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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6
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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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7
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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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8
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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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9
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Benoit B, Poüs C, Baillet A. Septins as membrane influencers: direct play or in association with other cytoskeleton partners. Front Cell Dev Biol 2023; 11:1112319. [PMID: 36875762 PMCID: PMC9982393 DOI: 10.3389/fcell.2023.1112319] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/23/2023] [Indexed: 02/19/2023] Open
Abstract
The cytoskeleton comprises three polymerizing structures that have been studied for a long time, actin microfilaments, microtubules and intermediate filaments, plus more recently investigated dynamic assemblies like septins or the endocytic-sorting complex required for transport (ESCRT) complex. These filament-forming proteins control several cell functions through crosstalks with each other and with membranes. In this review, we report recent works that address how septins bind to membranes, and influence their shaping, organization, properties and functions, either by binding to them directly or indirectly through other cytoskeleton elements.
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Affiliation(s)
- Béatrice Benoit
- INSERM UMR-S 1193, UFR de Pharmacie, University Paris-Saclay, Orsay, France
| | - Christian Poüs
- INSERM UMR-S 1193, UFR de Pharmacie, University Paris-Saclay, Orsay, France.,Laboratoire de Biochimie-Hormonologie, Hôpital Antoine Béclère, AP-HP, Hôpitaux Universitaires Paris-Saclay, Clamart, France
| | - Anita Baillet
- INSERM UMR-S 1193, UFR de Pharmacie, University Paris-Saclay, Orsay, France
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10
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Romero MD, Carabeo RA. Distinct roles of the Chlamydia trachomatis effectors TarP and TmeA in the regulation of formin and Arp2/3 during entry. J Cell Sci 2022; 135:jcs260185. [PMID: 36093837 PMCID: PMC9659389 DOI: 10.1242/jcs.260185] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/05/2022] [Indexed: 12/13/2022] Open
Abstract
The obligate intracellular pathogen Chlamydia trachomatis manipulates the host actin cytoskeleton to assemble actin-rich structures that drive pathogen entry. The recent discovery of TmeA, which, like TarP, is an invasion-associated type III effector implicated in actin remodeling, raised questions regarding the nature of their functional interaction. Quantitative live-cell imaging of actin remodeling at invasion sites revealed differences in recruitment and turnover kinetics associated with the TarP and TmeA pathways, with the former accounting for most of the robust actin dynamics at invasion sites. TarP-mediated recruitment of actin nucleators, i.e. formins and the Arp2/3 complex, was crucial for rapid actin kinetics, generating a collaborative positive feedback loop that enhanced their respective actin-nucleating activities within invasion sites. In contrast, the formin Fmn1 was not recruited to invasion sites and did not collaborate with Arp2/3 within the context of TmeA-associated actin recruitment. Although the TarP-Fmn1-Arp2/3 signaling axis is responsible for the majority of actin dynamics, its inhibition had similar effects as the deletion of TmeA on invasion efficiency, consistent with the proposed model that TarP and TmeA act on different stages of the same invasion pathway.
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Affiliation(s)
- Matthew D. Romero
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Rey A. Carabeo
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
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11
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PIAS1 Regulates Hepatitis C Virus-Induced Lipid Droplet Accumulation by Controlling Septin 9 and Microtubule Filament Assembly. Pathogens 2021; 10:pathogens10101327. [PMID: 34684276 PMCID: PMC8537804 DOI: 10.3390/pathogens10101327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 01/22/2023] Open
Abstract
Chronic hepatitis C virus (HCV) infection often leads to fibrosis and chronic hepatitis, then cirrhosis and ultimately hepatocellular carcinoma (HCC). The processes of the HVC life cycle involve intimate interactions between viral and host cell proteins and lipid metabolism. However, the molecules and mechanisms involved in this tripartite interaction remain poorly understood. Herein, we show that the infection of HCC-derived Huh7.5 cells with HCV promotes upregulation of the protein inhibitor of activated STAT1 (PIAS1). Reciprocally, PIAS1 regulated the expression of HCV core protein and HCV-induced LD accumulation and impaired HCV replication. Furthermore, PIAS1 controlled HCV-promoted septin 9 filament formation and microtubule polymerization. Subsequently, we found that PIAS1 interacted with septin 9 and controlled its assembly on filaments, which thus affected septin 9-induced lipid droplet accumulation. Taken together, these data reveal that PIAS1 regulates the accumulation of lipid droplets and offer a meaningful insight into how HCV interacts with host proteins.
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12
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Abstract
Septins are an integral component of the cytoskeleton, assembling into higher-order oligomers and filamentous polymers that associate with actin filaments, microtubules and membranes. Here, we review septin interactions with actin and microtubules, and septin-mediated regulation of the organization and dynamics of these cytoskeletal networks, which is critical for cellular morphogenesis. We discuss how actomyosin-associated septins function in cytokinesis, cell migration and host defense against pathogens. We highlight newly emerged roles of septins at the interface of microtubules and membranes with molecular motors, which point to a 'septin code' for the regulation of membrane traffic. Additionally, we revisit the functions of microtubule-associated septins in mitosis and meiosis. In sum, septins comprise a unique module of cytoskeletal regulators that are spatially and functionally specialized and have properties of bona fide actin-binding and microtubule-associated proteins. With many questions still outstanding, the study of septins will continue to provide new insights into fundamental problems of cytoskeletal organization and function.
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13
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Robertin S, Mostowy S. The history of septin biology and bacterial infection. Cell Microbiol 2021; 22:e13173. [PMID: 32185906 DOI: 10.1111/cmi.13173] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/29/2022]
Abstract
Investigation of cytoskeleton during bacterial infection has significantly contributed to both cell and infection biology. Bacterial pathogens Listeria monocytogenes and Shigella flexneri are widely recognised as paradigms for investigation of the cytoskeleton during bacterial entry, actin-based motility, and cell-autonomous immunity. At the turn of the century, septins were a poorly understood component of the cytoskeleton mostly studied in the context of yeast cell division and human cancer. In 2002, a screen performed in the laboratory of Pascale Cossart identified septin family member MSF (MLL septin-like fusion, now called SEPT9) associated with L. monocytogenes entry into human epithelial cells. These findings inspired the investigation of septins during L. monocytogenes and S. flexneri infection at the Institut Pasteur, illuminating important roles for septins in host-microbe interactions. In this review, we revisit the history of septin biology and bacterial infection, and discuss how the comparative study of L. monocytogenes and S. flexneri has been instrumental to understand septin roles in cellular homeostasis and host defence.
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Affiliation(s)
- Stevens Robertin
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Serge Mostowy
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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14
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Septins in Infections: Focus on Viruses. Pathogens 2021; 10:pathogens10030278. [PMID: 33801245 PMCID: PMC8001386 DOI: 10.3390/pathogens10030278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/17/2021] [Accepted: 02/25/2021] [Indexed: 11/17/2022] Open
Abstract
Human septins comprise a family of 13 genes that encode conserved GTP-binding proteins. They form nonpolar complexes, which assemble into higher-order structures, such as bundles, scaffolding structures, or rings. Septins are counted among the cytoskeletal elements. They interact with the actin and microtubule networks and can bind to membranes. Many cellular functions with septin participation have been described in the literature, including cytokinesis, motility, forming of scaffolding platforms or lateral diffusion barriers, vesicle transport, exocytosis, and recognition of micron-scale curvature. Septin dysfunction has been implicated in diverse human pathologies, including neurodegeneration and tumorigenesis. Moreover, septins are thought to affect the outcome of host–microbe interactions. Implication of septins has been demonstrated in fungal, bacterial, and viral infections. Knowledge on the precise function of a particular septin in the different steps of the virus infection and replication cycle is still limited. Published data for vaccinia virus (VACV), hepatitis C virus (HCV), influenza A virus (H1N1 and H5N1), human herpesvirus 8 (HHV-8), and Zika virus (ZIKV), all of major concern for public health, will be discussed here.
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Novel Functions of the Septin Cytoskeleton: Shaping Up Tissue Inflammation and Fibrosis. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 191:40-51. [PMID: 33039354 DOI: 10.1016/j.ajpath.2020.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/24/2020] [Accepted: 09/16/2020] [Indexed: 12/19/2022]
Abstract
Chronic inflammatory diseases cause profound alterations in tissue homeostasis, including unchecked activation of immune and nonimmune cells leading to disease complications such as aberrant tissue repair and fibrosis. Current anti-inflammatory therapies are often insufficient in preventing or reversing these complications. Remodeling of the intracellular cytoskeleton is critical for cell activation in inflamed and fibrotic tissues; however, the cytoskeleton has not been adequately explored as a therapeutic target in inflammation. Septins are GTP-binding proteins that self-assemble into higher order cytoskeletal structures. The septin cytoskeleton exhibits a number of critical cellular functions, including regulation of cell shape and polarity, cytokinesis, cell migration, vesicle trafficking, and receptor signaling. Surprisingly, little is known about the role of the septin cytoskeleton in inflammation. This article reviews emerging evidence implicating different septins in the regulation of host-pathogen interactions, immune cell functions, and tissue fibrosis. Targeting of the septin cytoskeleton as a potential future therapeutic intervention in human inflammatory and fibrotic diseases is also discussed.
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Abstract
Septins are widely recognized as a component of the cytoskeleton that is essential for cell division, and new work has shown that septins can recognise cell shape by assembling into filaments on membrane regions that display micrometer-scale curvature (e.g. at the cytokinetic furrow). Moreover, infection biology studies have illuminated important roles for septins in mediating the outcome of host-microbe interactions. In this Review, we discuss a selection of mechanistic insights recently gained from studying three infection paradigms: the rice blast fungus Magnaporthe oryzae, the poxvirus family member vaccinia virus and the Gram-negative bacterium Shigella flexneri These studies have respectively discovered that higher-order septin assemblies enable fungal invasion into plant cells, entrap viral particles at the plasma membrane and recognize dividing bacterial cells for delivery to lysosomes. Collectively, these insights illustrate how studying septin biology during microbial infection can provide fundamental advances in both cell and infection biology, and suggest new concepts underlying infection control.
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Affiliation(s)
- Hoan Van Ngo
- Department of Immunology & Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Serge Mostowy
- Department of Immunology & Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
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Boddy KC, Gao AD, Truong D, Kim MS, Froese CD, Trimble WS, Brumell JH. Septin-regulated actin dynamics promote Salmonella invasion of host cells. Cell Microbiol 2018; 20:e12866. [PMID: 29885024 PMCID: PMC6175387 DOI: 10.1111/cmi.12866] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 05/26/2018] [Indexed: 01/08/2023]
Abstract
Actin nucleators and their binding partners play crucial roles during Salmonella invasion, but how these factors are dynamically coordinated remains unclear. Here, we show that septins, a conserved family of GTP binding proteins, play a role during the early stages of Salmonella invasion. We demonstrate that septins are rapidly enriched at sites of bacterial entry and contribute to the morphology of invasion ruffles. We found that SEPTIN2, SEPTIN7, and SEPTIN9 are required for efficient bacterial invasion. Septins contributed to the recruitment of ROCK2 kinase during Salmonella invasion, and the downstream activation of the actin nucleating protein FHOD1. In contrast, activation of the ROCK2 substrate myosin II, which is known to be required for Salmonella enterica serovar Typhimurium invasion, did not require septins. Collectively, our studies provide new insight into the mechanisms involved in Salmonella invasion of host cells.
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Affiliation(s)
- Kirsten C Boddy
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Aggie Duan Gao
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Dorothy Truong
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Moshe S Kim
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada
| | - Carol D Froese
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada
| | - William S Trimble
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - John H Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada.,SickKids IBD Centre, Hospital for Sick Children, Toronto, Canada
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