1
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Kumari R, Ven K, Chastney M, Kokate SB, Peränen J, Aaron J, Kogan K, Almeida-Souza L, Kremneva E, Poincloux R, Chew TL, Gunning PW, Ivaska J, Lappalainen P. Focal adhesions contain three specialized actin nanoscale layers. Nat Commun 2024; 15:2547. [PMID: 38514695 PMCID: PMC10957975 DOI: 10.1038/s41467-024-46868-7] [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: 01/25/2024] [Accepted: 03/13/2024] [Indexed: 03/23/2024] Open
Abstract
Focal adhesions (FAs) connect inner workings of cell to the extracellular matrix to control cell adhesion, migration and mechanosensing. Previous studies demonstrated that FAs contain three vertical layers, which connect extracellular matrix to the cytoskeleton. By using super-resolution iPALM microscopy, we identify two additional nanoscale layers within FAs, specified by actin filaments bound to tropomyosin isoforms Tpm1.6 and Tpm3.2. The Tpm1.6-actin filaments, beneath the previously identified α-actinin cross-linked actin filaments, appear critical for adhesion maturation and controlled cell motility, whereas the adjacent Tpm3.2-actin filament layer beneath seems to facilitate adhesion disassembly. Mechanistically, Tpm3.2 stabilizes ACF-7/MACF1 and KANK-family proteins at adhesions, and hence targets microtubule plus-ends to FAs to catalyse their disassembly. Tpm3.2 depletion leads to disorganized microtubule network, abnormally stable FAs, and defects in tail retraction during migration. Thus, FAs are composed of distinct actin filament layers, and each may have specific roles in coupling adhesions to the cytoskeleton, or in controlling adhesion dynamics.
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Affiliation(s)
- Reena Kumari
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Katharina Ven
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Megan Chastney
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, FI-20520, Turku, Finland
| | - Shrikant B Kokate
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Johan Peränen
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Jesse Aaron
- Advanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Konstantin Kogan
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Leonardo Almeida-Souza
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Elena Kremneva
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Renaud Poincloux
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Teng-Leong Chew
- Advanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Peter W Gunning
- School of Biomedical Sciences, UNSW Sydney, Wallace Wurth Building, Sydney, NSW 2052, Australia
| | - Johanna Ivaska
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, FI-20520, Turku, Finland
- Department of Life Technologies, University of Turku, FI-20520, Turku, Finland
- InFLAMES Research Flagship Center, University of Turku, Turku, Finland
- Foundation for the Finnish Cancer Institute, Tukholmankatu 8, FI-00014, Helsinki, Finland
| | - Pekka Lappalainen
- HiLIFE Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland.
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
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2
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Henderson JM, Ljubojevic N, Belian S, Chaze T, Castaneda D, Battistella A, Giai Gianetto Q, Matondo M, Descroix S, Bassereau P, Zurzolo C. Tunnelling nanotube formation is driven by Eps8/IRSp53-dependent linear actin polymerization. EMBO J 2023; 42:e113761. [PMID: 38009333 PMCID: PMC10711657 DOI: 10.15252/embj.2023113761] [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: 02/13/2023] [Revised: 10/27/2023] [Accepted: 11/02/2023] [Indexed: 11/28/2023] Open
Abstract
Tunnelling nanotubes (TNTs) connect distant cells and mediate cargo transfer for intercellular communication in physiological and pathological contexts. How cells generate these actin-mediated protrusions to span lengths beyond those attainable by canonical filopodia remains unknown. Through a combination of micropatterning, microscopy, and optical tweezer-based approaches, we demonstrate that TNTs formed through the outward extension of actin achieve distances greater than the mean length of filopodia and that branched Arp2/3-dependent pathways attenuate the extent to which actin polymerizes in nanotubes, thus limiting their occurrence. Proteomic analysis using epidermal growth factor receptor kinase substrate 8 (Eps8) as a positive effector of TNTs showed that, upon Arp2/3 inhibition, proteins enhancing filament turnover and depolymerization were reduced and Eps8 instead exhibited heightened interactions with the inverted Bin/Amphiphysin/Rvs (I-BAR) domain protein IRSp53 that provides a direct connection with linear actin polymerases. Our data reveals how common protrusion players (Eps8 and IRSp53) form tunnelling nanotubes, and that when competing pathways overutilizing such proteins and monomeric actin in Arp2/3 networks are inhibited, processes promoting linear actin growth dominate to favour tunnelling nanotube formation.
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Affiliation(s)
- J Michael Henderson
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and InfectionCNRS UMR 3691, Université de Paris, Institut PasteurParisFrance
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 168, Laboratoire Physico‐Chimie CurieParisFrance
- Present address:
Department of ChemistryBowdoin CollegeBrunswickMEUSA
| | - Nina Ljubojevic
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and InfectionCNRS UMR 3691, Université de Paris, Institut PasteurParisFrance
- Sorbonne UniversitéParisFrance
| | - Sevan Belian
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and InfectionCNRS UMR 3691, Université de Paris, Institut PasteurParisFrance
- Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Thibault Chaze
- Proteomics Platform, Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut PasteurParisFrance
| | - Daryl Castaneda
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and InfectionCNRS UMR 3691, Université de Paris, Institut PasteurParisFrance
- Keele UniversityKeeleUK
| | - Aude Battistella
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 168, Laboratoire Physico‐Chimie CurieParisFrance
| | - Quentin Giai Gianetto
- Proteomics Platform, Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut PasteurParisFrance
- Bioinformatics and Biostatistics Hub, Computational Biology DepartmentCNRS USR 3756, Institut PasteurParisFrance
| | - Mariette Matondo
- Proteomics Platform, Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut PasteurParisFrance
| | - Stéphanie Descroix
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 168, Laboratoire Physico‐Chimie CurieParisFrance
- Institut Pierre‐Gilles de GennesParisFrance
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 168, Laboratoire Physico‐Chimie CurieParisFrance
| | - Chiara Zurzolo
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and InfectionCNRS UMR 3691, Université de Paris, Institut PasteurParisFrance
- Department of Molecular Medicine and Medical BiotechnologyUniversity of Naples Federico IINaplesItaly
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3
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Dai F, Guo M, Shao Y, Li C. Novel secreted STPKLRR from Vibrio splendidus AJ01 promotes pathogen internalization via mediating tropomodulin phosphorylation dependent cytoskeleton rearrangement. PLoS Pathog 2023; 19:e1011419. [PMID: 37216400 DOI: 10.1371/journal.ppat.1011419] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/11/2023] [Indexed: 05/24/2023] Open
Abstract
We previously demonstrated that the flagellin of intracellular Vibrio splendidus AJ01 could be specifically identified by tropomodulin (Tmod) and further mediate p53-dependent coelomocyte apoptosis in the sea cucumber Apostichopus japonicus. In higher animals, Tmod serves as a regulator in stabilizing the actin cytoskeleton. However, the mechanism on how AJ01 breaks the AjTmod-stabilized cytoskeleton for internalization remains unclear. Here, we identified a novel AJ01 Type III secretion system (T3SS) effector of leucine-rich repeat-containing serine/threonine-protein kinase (STPKLRR) with five LRR domains and a serine/threonine kinase (STYKc) domain, which could specifically interact with tropomodulin domain of AjTmod. Furthermore, we found that STPKLRR directly phosphorylated AjTmod at serine 52 (S52) to reduce the binding stability between AjTmod and actin. After AjTmod dissociated from actin, the F-actin/G-actin ratio decreased to induce cytoskeletal rearrangement, which in turn promoted the internalization of AJ01. The STPKLRR knocked out strain could not phosphorylated AjTmod and displayed lower internalization capacity and pathogenic effect compared to AJ01. Overall, we demonstrated for the first time that the T3SS effector STPKLRR with kinase activity was a novel virulence factor in Vibrio and mediated self-internalization by targeting host AjTmod phosphorylation dependent cytoskeleton rearrangement, which provided a candidate target to control AJ01 infection in practice.
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Affiliation(s)
- Fa Dai
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, PR China
| | - Ming Guo
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, PR China
| | - Yina Shao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, PR China
| | - Chenghua Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, PR China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, PR China
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4
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Zapater I Morales C, Carman PJ, Soffar DB, Windner SE, Dominguez R, Baylies MK. Drosophila Tropomodulin is required for multiple actin-dependent processes within developing myofibers. Development 2023; 150:dev201194. [PMID: 36806912 PMCID: PMC10112908 DOI: 10.1242/dev.201194] [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: 08/09/2022] [Accepted: 02/09/2023] [Indexed: 02/22/2023]
Abstract
Proper muscle contraction requires the assembly and maintenance of sarcomeres and myofibrils. Although the protein components of myofibrils are generally known, less is known about the mechanisms by which they individually function and together synergize for myofibril assembly and maintenance. For example, it is unclear how the disruption of actin filament (F-actin) regulatory proteins leads to the muscle weakness observed in myopathies. Here, we show that knockdown of Drosophila Tropomodulin (Tmod), results in several myopathy-related phenotypes, including reduction of muscle cell (myofiber) size, increased sarcomere length, disorganization and misorientation of myofibrils, ectopic F-actin accumulation, loss of tension-mediating proteins at the myotendinous junction, and misshaped and internalized nuclei. Our findings support and extend the tension-driven self-organizing myofibrillogenesis model. We show that, like its mammalian counterpart, Drosophila Tmod caps F-actin pointed-ends, and we propose that this activity is crucial for cellular processes in different locations within the myofiber that directly and indirectly contribute to the maintenance of muscle function. Our findings provide significant insights to the role of Tmod in muscle development, maintenance and disease.
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Affiliation(s)
- Carolina Zapater I Morales
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Peter J Carman
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David B Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Stefanie E Windner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Roberto Dominguez
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mary K Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
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5
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Selvaraj M, Kokate SB, Reggiano G, Kogan K, Kotila T, Kremneva E, DiMaio F, Lappalainen P, Huiskonen JT. Structural basis underlying specific biochemical activities of non-muscle tropomyosin isoforms. Cell Rep 2023; 42:111900. [PMID: 36586407 DOI: 10.1016/j.celrep.2022.111900] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 11/03/2022] [Accepted: 12/07/2022] [Indexed: 12/31/2022] Open
Abstract
The actin cytoskeleton is critical for cell migration, morphogenesis, endocytosis, organelle dynamics, and cytokinesis. To support diverse cellular processes, actin filaments form a variety of structures with specific architectures and dynamic properties. Key proteins specifying actin filaments are tropomyosins. Non-muscle cells express several functionally non-redundant tropomyosin isoforms, which differentially control the interactions of other proteins, including myosins and ADF/cofilin, with actin filaments. However, the underlying molecular mechanisms have remained elusive. By determining the cryogenic electron microscopy structures of actin filaments decorated by two functionally distinct non-muscle tropomyosin isoforms, Tpm1.6 and Tpm3.2, we reveal that actin filament conformation remains unaffected upon binding. However, Tpm1.6 and Tpm3.2 follow different paths along the actin filament major groove, providing an explanation for their incapability to co-polymerize on actin filaments. We also elucidate the molecular basis underlying specific roles of Tpm1.6 and Tpm3.2 in myosin II activation and protecting actin filaments from ADF/cofilin-catalyzed severing.
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Affiliation(s)
- Muniyandi Selvaraj
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Shrikant B Kokate
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Gabriella Reggiano
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Konstantin Kogan
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Tommi Kotila
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Elena Kremneva
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
| | - Juha T Huiskonen
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
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6
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Chen B, Wang M, Qiu J, Liao K, Zhang W, Lv Q, Ma C, Qian Z, Shi Z, Liang R, Lin Y, Ye J, Qiu Y, Lin Y. Cleavage of tropomodulin-3 by asparagine endopeptidase promotes cancer malignancy by actin remodeling and SND1/RhoA signaling. J Exp Clin Cancer Res 2022; 41:209. [PMID: 35765111 PMCID: PMC9238189 DOI: 10.1186/s13046-022-02411-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/07/2022] [Indexed: 12/12/2022] Open
Abstract
Abstract
Background
Abnormal proliferation and migration of cells are hallmarks of cancer initiation and malignancy. Asparagine endopeptidase (AEP) has specific substrate cleavage ability and plays a pro-cancer role in a variety of cancers. However, the underlying mechanism of AEP in cancer proliferation and migration still remains unclear.
Methods
Co-immunoprecipitation and following mass spectrometry were used to identify the substrate of AEP. Western blotting was applied to measure the expression of proteins. Single cell/nuclear-sequences were done to detect the heterogeneous expression of Tmod3 in tumor tissues. CCK-8 assay, flow cytometry assays, colony formation assay, Transwell assay and scratch wound-healing assay were performed as cellular functional experiments. Mouse intracranial xenograft tumors were studied in in vivo experiments.
Results
Here we showed that AEP cleaved a ubiquitous cytoskeleton regulatory protein, tropomodulin-3 (Tmod3) at asparagine 157 (N157) and produced two functional truncations (tTmod3-N and tTmod3-C). Truncated Tmod3 was detected in diverse tumors and was found to be associated with poor prognosis of high-grade glioma. Functional studies showed that tTmod3-N and tTmod3-C enhanced cancer cell migration and proliferation, respectively. Animal models further revealed the tumor-promoting effects of AEP truncated Tmod3 in vivo. Mechanistically, tTmod3-N was enriched in the cell cortex and competitively inhibited the pointed-end capping effect of wild-type Tmod3 on filamentous actin (F-actin), leading to actin remodeling. tTmod3-C translocated to the nucleus, where it interacted with Staphylococcal Nuclease And Tudor Domain Containing 1 (SND1), facilitating the transcription of Ras Homolog Family Member A/Cyclin Dependent Kinases (RhoA/CDKs).
Conclusion
The newly identified AEP-Tmod3 protease signaling axis is a novel “dual-regulation” mechanism of tumor cell proliferation and migration. Our work provides new clues to the underlying mechanisms of cancer proliferation and invasive progression and evidence for targeting AEP or Tmod3 for therapy.
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7
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Kokate SB, Ciuba K, Tran VD, Kumari R, Tojkander S, Engel U, Kogan K, Kumar S, Lappalainen P. Caldesmon controls stress fiber force-balance through dynamic cross-linking of myosin II and actin-tropomyosin filaments. Nat Commun 2022; 13:6032. [PMID: 36229430 PMCID: PMC9561149 DOI: 10.1038/s41467-022-33688-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
Contractile actomyosin bundles are key force-producing and mechanosensing elements in muscle and non-muscle tissues. Whereas the organization of muscle myofibrils and mechanism regulating their contractility are relatively well-established, the principles by which myosin-II activity and force-balance are regulated in non-muscle cells have remained elusive. We show that Caldesmon, an important component of smooth muscle and non-muscle cell actomyosin bundles, is an elongated protein that functions as a dynamic cross-linker between myosin-II and tropomyosin-actin filaments. Depletion of Caldesmon results in aberrant lateral movement of myosin-II filaments along actin bundles, leading to irregular myosin distribution within stress fibers. This manifests as defects in stress fiber network organization and contractility, and accompanied problems in cell morphogenesis, migration, invasion, and mechanosensing. These results identify Caldesmon as critical factor that ensures regular myosin-II spacing within non-muscle cell actomyosin bundles, and reveal how stress fiber networks are controlled through dynamic cross-linking of tropomyosin-actin and myosin filaments.
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Affiliation(s)
- Shrikant B Kokate
- HiLIFE Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Katarzyna Ciuba
- HiLIFE Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.,Nencki Institute of Experimental Biology PAS, 3 Pasteur Street, 02-093, Warszawa, Poland
| | - Vivien D Tran
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Reena Kumari
- HiLIFE Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Sari Tojkander
- Faculty of Medicine and Health Technology, Tampere University, Kauppi Campus, Arvo Building, E318, Arvo Ylpön katu 34, 33520, Tampere, Finland
| | - Ulrike Engel
- Nikon Imaging Center at Heidelberg University and Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld 267, Heidelberg, 69120, Germany
| | - Konstantin Kogan
- HiLIFE Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Sanjay Kumar
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Pekka Lappalainen
- HiLIFE Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland.
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8
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Dai F, Guo M, Shao Y, Li C. Vibrio splendidus flagellin C binds tropomodulin to induce p38 MAPK-mediated p53-dependent coelomocyte apoptosis in Echinodermata. J Biol Chem 2022; 298:102091. [PMID: 35654141 PMCID: PMC9249833 DOI: 10.1016/j.jbc.2022.102091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 12/27/2022] Open
Abstract
As a typical pathogen-associated molecular pattern, bacterial flagellin can bind Toll-like receptor 5 and the intracellular NAIP5 receptor component of the NLRC4 inflammasome to induce immune responses in mammals. However, these flagellin receptors are generally poorly understood in lower animal species. In this study, we found that the isolated flagellum of Vibrio splendidus AJ01 destroyed the integrity of the tissue structure of coelomocytes and promoted apoptosis in the sea cucumber Apostichopus japonicus. To further investigate the molecular mechanism, the novel intracellular LRR domain-containing protein tropomodulin (AjTmod) was identified as a protein that interacts with flagellin C (FliC) with a dissociation constant (Kd) of 0.0086 ± 0.33 μM by microscale thermophoresis assay. We show that knockdown of AjTmod also depressed FliC-induced apoptosis of coelomocytes. Further functional analysis with different inhibitor treatments revealed that the interaction between AjTmod and FliC could specifically activate p38 MAPK, but not JNK or ERK MAP kinases. We demonstrate that the transcription factor p38 is then translocated into the nucleus, where it mediates the expression of p53 to induce coelomocyte apoptosis. Our findings provide the first evidence that intracellular AjTmod serves as a novel receptor of FliC and mediates p53-dependent coelomocyte apoptosis by activating the p38 MAPK signaling pathway in Echinodermata.
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Affiliation(s)
- Fa Dai
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, China; State-Province Joint Laboratory of Marine Biotechnology and Engineering, Ningbo University, Ningbo, China
| | - Ming Guo
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, China; State-Province Joint Laboratory of Marine Biotechnology and Engineering, Ningbo University, Ningbo, China
| | - Yina Shao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, China; State-Province Joint Laboratory of Marine Biotechnology and Engineering, Ningbo University, Ningbo, China
| | - Chenghua Li
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, China; State-Province Joint Laboratory of Marine Biotechnology and Engineering, Ningbo University, Ningbo, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, PR China.
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9
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Wang M, Chen B, Zhang W, Zhang F, Qiu Y, Lin Y, Yang S. Dematin inhibits glioblastoma malignancy through RhoA-mediated CDKs downregulation and cytoskeleton remodeling. Exp Cell Res 2022; 417:113196. [PMID: 35561787 DOI: 10.1016/j.yexcr.2022.113196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/06/2022] [Accepted: 05/05/2022] [Indexed: 12/24/2022]
Abstract
Glioblastoma multiforme (GBM) is well known as a highly aggressive brain tumor subtype. Here, we show that overexpression (OE) of dematin actin-binding protein (DMTN) inhibits GBM proliferation and invasion by affecting cell cycle regulation and actin remodeling, respectively. RT-qPCR, western blotting, and immunohistochemical (IHC) staining demonstrated a significant reduction in DMTN expression in gliomas, especially in high-grade gliomas (HGG) compared with normal brains, which correlates with worse survival in HGG patients. Functional studies revealed inhibitory effects of DMTN on tumor proliferation and migratory capacities. The attenuation in tumor proliferative ability upon DMTN OE was accompanied by RhoA suppression and CDK1, CDK2, CDK4, and cyclin D1 downregulation, while RhoA rescue restored the proliferative phenotype. Meanwhile, overexpression of DMTN produced profoundly disorganized stress fibers, which led to impaired tumor invasion. Furthermore, DMTN overexpression produced substantial suppression of tumor growth upon subcutaneous and intracranial implantation in mice, and this was accompanied by significantly reduced vinculin expression and Ki67 positivity. Taken together, these findings demonstrate the role of DMTN in regulating GBM cell proliferation, actin cytoskeleton, and cell morphology and identify DMTN as a vital tumor suppressor in GBM progression.
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Affiliation(s)
- Mengying Wang
- Brain Injury Center, Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China; Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China
| | - Binghong Chen
- Brain Injury Center, Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China; Department of Neurosurgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350001, PR China
| | - Wenrui Zhang
- Brain Injury Center, Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China; Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China
| | - Fengchen Zhang
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China
| | - Yongming Qiu
- Brain Injury Center, Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China
| | - Yingying Lin
- Brain Injury Center, Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China; Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China.
| | - Shaofeng Yang
- Brain Injury Center, Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, PR China.
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10
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Ghosh A, Coffin M, West R, Fowler VM. Erythroid differentiation in mouse erythroleukemia cells depends on Tmod3-mediated regulation of actin filament assembly into the erythroblast membrane skeleton. FASEB J 2022; 36:e22220. [PMID: 35195928 DOI: 10.1096/fj.202101011r] [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: 06/16/2021] [Revised: 02/01/2022] [Accepted: 02/10/2022] [Indexed: 11/11/2022]
Abstract
Erythroid differentiation (ED) is a complex cellular process entailing morphologically distinct maturation stages of erythroblasts during terminal differentiation. Studies of actin filament (F-actin) assembly and organization during terminal ED have revealed essential roles for the F-actin pointed-end capping proteins, tropomodulins (Tmod1 and Tmod3). Tmods bind tropomyosins (Tpms), which enhance Tmod capping and F-actin stabilization. Tmods can also nucleate F-actin assembly, independent of Tpms. Tmod1 is present in the red blood cell (RBC) membrane skeleton, and deletion of Tmod1 in mice leads to a mild compensated anemia due to mis-regulated F-actin lengths and membrane instability. Tmod3 is not present in RBCs, and global deletion of Tmod3 leads to embryonic lethality in mice with impaired ED. To further decipher Tmod3's function during ED, we generated a Tmod3 knockout in a mouse erythroleukemia cell line (Mel ds19). Tmod3 knockout cells appeared normal prior to ED, but showed defects during progression of ED, characterized by a marked failure to reduce cell and nuclear size, reduced viability, and increased apoptosis. Tmod3 does not assemble with Tmod1 and Tpms into the Triton X-100 insoluble membrane skeleton during ED, and loss of Tmod3 had no effect on α1,β1-spectrin and protein 4.1R assembly into the membrane skeleton. However, F-actin, Tmod1 and Tpms failed to assemble into the membrane skeleton during ED in absence of Tmod3. We propose that Tmod3 nucleation of F-actin assembly promotes incorporation of Tmod1 and Tpms into membrane skeleton F-actin, and that this is integral to morphological maturation and cell survival during erythroid terminal differentiation.
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Affiliation(s)
- Arit Ghosh
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Megan Coffin
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Richard West
- Delaware Biotechnology Institute, Newark, Delaware, USA
| | - Velia M Fowler
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
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11
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Li H, Zhao S, Chen X, Feng G, Chen Z, Fan S. MiR-145 modulates the radiosensitivity of non-small cell lung cancer cells by suppression of TMOD3. Carcinogenesis 2021; 43:288-296. [PMID: 34888652 DOI: 10.1093/carcin/bgab121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 12/18/2022] Open
Abstract
Radioresistance is a major problem encountered in the treatment of non-small cell lung cancer (NSCLC). Aberrant microRNA (miRNA) expression contributes to multiple cancer‑associated signaling pathways, and profoundly influences effects of radiotherapy (RT) in cancers. MicroRNA-145-5p (miR-145) is recognized as a tumor suppresser in NSCLC. However, the roles of miR-145 during radiotherapy of NSCLC are largely unknown. The present study aimed to investigate the function and underlying mechanism of miR-145 in modulation of radiosensitivity in NSCLC. We generated radioresistant H460 and A549 subclones, named H460R and A549R, respectively, and found that irradiation (IR) could suppress the expression levels of miR-145 in radioresistant NSCLC cells. Furthermore, overexpression of miR-145 could sensitize radioresistant NSCLC cells to IR, while knockdown of miR-145 in NSCLC cells acted the converse manner. Mechanically, miR-145 was able to directly target 3'UTR of tropomodulin 3 (TMOD3) mRNA and decrease the expression of TMOD3 at the levels of mRNA and protein. Additionally, we confirmed that miR-145 could enhance the radiosensitivity of radioresistant NSCLC cells by targeting TMOD3 in vitro and in vivo, and could be used as a target in clinical treatment of NSCLC. Collectively, restoration of miR-145 expression increases the radiosensitivity of radioresistant NSCLC cells by suppression of TMOD3, and miR-145 can act as a new radiosensitizer for NSCLC therapy.
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Affiliation(s)
- Hang Li
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, P.R. China
| | - Shuya Zhao
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, P.R. China
| | - Xin Chen
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Guoxing Feng
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, P.R. China
| | - Zhiyuan Chen
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, P.R. China
| | - Saijun Fan
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, P.R. China
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12
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Stobdan T, Jain PP, Xiong M, Bafna V, Yuan JXJ, Haddad GG. Heterozygous Tropomodulin 3 mice have improved lung vascularization after chronic hypoxia. Hum Mol Genet 2021; 31:1130-1140. [PMID: 34718575 DOI: 10.1093/hmg/ddab291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 09/13/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
The molecular mechanisms leading to high altitude pulmonary hypertension (HAPH) remains poorly understood. We previously analyzed the whole genome sequence of Kyrgyz highland population and identified eight genomic intervals having a potential role in HAPH. Tropomodulin 3 gene (TMOD3) which encodes a protein that binds and caps the pointed ends of actin filaments and inhibits cell migration, was one of the top candidates. Here we systematically sought additional evidence to validate the functional role of TMOD3. In-silico analysis reveals that some of the SNPs in HAPH associated genomic intervals were positioned in a regulatory region that could result in alternative splicing of TMOD3. In order to functionally validate the role of TMOD3 in HAPH, we exposed Tmod3-/+ mice to 4 weeks of constant hypoxia, i.e. 10% O2 and analyzed both functional (hemodynamic measurements) and structural (angiography) parameters related to HAPH. The hemodynamic measurements, such as right ventricular systolic pressure, a surrogate measure for pulmonary arterial systolic pressure, and right ventricular contractility (RV- ± dP/dt), increases with hypoxia did not separate between Tmod3-/+ and control mice. Remarkably, there was a significant increase in the number of lung vascular branches and total length of pulmonary vascular branches (p < 0.001) in Tmod3-/+ after 4 weeks of constant hypoxia as compared to controls. Notably, the Tmod3-/+ endothelial cells migration was also significantly higher than that from the wild-type littermates. Our results indicate that, under chronic hypoxia, lower levels of Tmod3 play an important role in the maintenance or neo-vascularization of pulmonary arteries.
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Affiliation(s)
- Tsering Stobdan
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Pritesh P Jain
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mingmei Xiong
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Vineet Bafna
- Department of Computer Science & Engineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jason X-J Yuan
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gabriel G Haddad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA.,Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA.,Rady Children's Hospital, San Diego, CA 92123, USA
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13
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Kadzik RS, Homa KE, Kovar DR. F-Actin Cytoskeleton Network Self-Organization Through Competition and Cooperation. Annu Rev Cell Dev Biol 2021; 36:35-60. [PMID: 33021819 DOI: 10.1146/annurev-cellbio-032320-094706] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many fundamental cellular processes such as division, polarization, endocytosis, and motility require the assembly, maintenance, and disassembly of filamentous actin (F-actin) networks at specific locations and times within the cell. The particular function of each network is governed by F-actin organization, size, and density as well as by its dynamics. The distinct characteristics of different F-actin networks are determined through the coordinated actions of specific sets of actin-binding proteins (ABPs). Furthermore, a cell typically assembles and uses multiple F-actin networks simultaneously within a common cytoplasm, so these networks must self-organize from a common pool of shared globular actin (G-actin) monomers and overlapping sets of ABPs. Recent advances in multicolor imaging and analysis of ABPs and their associated F-actin networks in cells, as well as the development of sophisticated in vitro reconstitutions of networks with ensembles of ABPs, have allowed the field to start uncovering the underlying principles by which cells self-organize diverse F-actin networks to execute basic cellular functions.
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Affiliation(s)
- Rachel S Kadzik
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; , .,Department of Molecular BioSciences, Northwestern University, Evanston, Illinois 60208, USA;
| | - Kaitlin E Homa
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; ,
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; , .,Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA
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14
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Abstract
Arit Ghosh and Velia Fowler introduce the structural features and functions of tropomodulins - actin-binding proteins that cap the slow-growing (pointed) ends of actin filaments.
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Affiliation(s)
- Arit Ghosh
- Department of Biological Sciences, University of Delaware, 105 The Grn, 118 Wolf Hall, Newark, DE 19716, USA
| | - Velia M Fowler
- Department of Biological Sciences, University of Delaware, 105 The Grn, 118 Wolf Hall, Newark, DE 19716, USA.
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15
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Down-regulated in renal cell carcinoma 1 (DRR1) regulates axon outgrowth during hippocampal neuron development. Biochem Biophys Res Commun 2021; 558:36-43. [PMID: 33895549 DOI: 10.1016/j.bbrc.2021.04.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 11/22/2022]
Abstract
Down-regulated in renal cell carcinoma 1 (DRR1), a unique stress-induced protein, is highly expressed in the nervous system. This study investigated the roles of DRR1 in the brain by examining its expression pattern at different developmental stages of a rat brain and in cultured primary hippocampal neurons. High expression of DRR1 was observed in all developmental stages of a rat brain and cultured primary hippocampal neurons. We then focused on the role of DRR1 in promoting neurite outgrowth during the early stage of hippocampal neuron development. Results showed that down-regulation of DRR1 suppressed axon outgrowth. Mass spectrometry analysis revealed that tropomodulin-2 (Tmod2) is a novel binding partner of DRR1. Our results showed that both DRR1 and Tmod2 mediate axon formation during the early stage of hippocampal neuron development. Suppression of TMOD2 expression rescued the abnormal axon outgrowth induced by DRR1 knockdown during the early stage of hippocampal neuron development.
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16
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Shi X, Wen Z, Wang Y, Liu YJ, Shi K, Jiu Y. Feedback-Driven Mechanisms Between Phosphorylated Caveolin-1 and Contractile Actin Assemblies Instruct Persistent Cell Migration. Front Cell Dev Biol 2021; 9:665919. [PMID: 33928090 PMCID: PMC8076160 DOI: 10.3389/fcell.2021.665919] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/22/2021] [Indexed: 12/23/2022] Open
Abstract
The actin cytoskeleton and membrane-associated caveolae contribute to active processes, such as cell morphogenesis and motility. How these two systems interact and control directional cell migration is an outstanding question but remains understudied. Here we identified a negative feedback between contractile actin assemblies and phosphorylated caveolin-1 (CAV-1) in migrating cells. Cytoplasmic CAV-1 vesicles display actin-associated motilities by sliding along actin filaments or/and coupling to do retrograde flow with actomyosin bundles. Inhibition of contractile stress fibers, but not Arp2/3-dependent branched actin filaments, diminished the phosphorylation of CAV-1 on site Tyr14, and resulted in substantially increased size and decreased motility of cytoplasmic CAV-1 vesicles. Reciprocally, both the CAV-1 phospho-deficient mutation on site Tyr14 and CAV-1 knockout resulted in dramatic AMPK phosphorylation, further causing reduced active level of RhoA-myosin II and increased active level of Rac1-PAK1-Cofilin, consequently led to disordered contractile stress fibers and prominent lamellipodia. As a result, cells displayed depolarized morphology and compromised directional migration. Collectively, we propose a model in which feedback-driven regulation between actin and CAV-1 instructs persistent cell migration.
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Affiliation(s)
- Xuemeng Shi
- The Joint Program in Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,The Joint Program in Infection and Immunity, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Zeyu Wen
- Key Laboratory of Molecular Virology and Immunology, The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yajun Wang
- Shanghai Institute of Cardiovascular Diseases, and Institutes of Biomedical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yan-Jun Liu
- Shanghai Institute of Cardiovascular Diseases, and Institutes of Biomedical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Kun Shi
- The Joint Program in Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,The Joint Program in Infection and Immunity, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Yaming Jiu
- The Joint Program in Infection and Immunity, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,The Joint Program in Infection and Immunity, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Molecular Virology and Immunology, The Center for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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17
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Twinfilin uncaps filament barbed ends to promote turnover of lamellipodial actin networks. Nat Cell Biol 2021; 23:147-159. [PMID: 33558729 DOI: 10.1038/s41556-020-00629-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 12/21/2020] [Indexed: 01/18/2023]
Abstract
Coordinated polymerization of actin filaments provides force for cell migration, morphogenesis and endocytosis. Capping protein (CP) is a central regulator of actin dynamics in all eukaryotes. It binds to actin filament (F-actin) barbed ends with high affinity and slow dissociation kinetics to prevent filament polymerization and depolymerization. However, in cells, CP displays remarkably rapid dynamics within F-actin networks, but the underlying mechanism remains unclear. Here, we report that the conserved cytoskeletal regulator twinfilin is responsible for CP's rapid dynamics and specific localization in cells. Depletion of twinfilin led to stable association between CP and cellular F-actin arrays, as well as to its retrograde movement throughout leading-edge lamellipodia. These were accompanied by diminished F-actin turnover rates. In vitro single-filament imaging approaches revealed that twinfilin directly promotes dissociation of CP from filament barbed ends, while enabling subsequent filament depolymerization. These results uncover a bipartite mechanism that controls how actin cytoskeleton-mediated forces are generated in cells.
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18
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Lehtimäki JI, Rajakylä EK, Tojkander S, Lappalainen P. Generation of stress fibers through myosin-driven reorganization of the actin cortex. eLife 2021; 10:60710. [PMID: 33506761 PMCID: PMC7877910 DOI: 10.7554/elife.60710] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
Contractile actomyosin bundles, stress fibers, govern key cellular processes including migration, adhesion, and mechanosensing. Stress fibers are thus critical for developmental morphogenesis. The most prominent actomyosin bundles, ventral stress fibers, are generated through coalescence of pre-existing stress fiber precursors. However, whether stress fibers can assemble through other mechanisms has remained elusive. We report that stress fibers can also form without requirement of pre-existing actomyosin bundles. These structures, which we named cortical stress fibers, are embedded in the cell cortex and assemble preferentially underneath the nucleus. In this process, non-muscle myosin II pulses orchestrate the reorganization of cortical actin meshwork into regular bundles, which promote reinforcement of nascent focal adhesions, and subsequent stabilization of the cortical stress fibers. These results identify a new mechanism by which stress fibers can be generated de novo from the actin cortex and establish role for stochastic myosin pulses in the assembly of functional actomyosin bundles.
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Affiliation(s)
- Jaakko I Lehtimäki
- HiLIFE Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Eeva Kaisa Rajakylä
- Section of Pathology, Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Sari Tojkander
- Section of Pathology, Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Pekka Lappalainen
- HiLIFE Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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19
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Patel S, McKeon D, Sao K, Yang C, Naranjo NM, Svitkina TM, Petrie RJ. Myosin II and Arp2/3 cross-talk governs intracellular hydraulic pressure and lamellipodia formation. Mol Biol Cell 2021; 32:579-589. [PMID: 33502904 PMCID: PMC8101460 DOI: 10.1091/mbc.e20-04-0227] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Human fibroblasts can switch between lamellipodia-dependent and -independent migration mechanisms on two-dimensional surfaces and in three-dimensional (3D) matrices. RhoA GTPase activity governs the switch from low-pressure lamellipodia to high-pressure lobopodia in response to the physical structure of the 3D matrix. Inhibiting actomyosin contractility in these cells reduces intracellular pressure and reverts lobopodia to lamellipodial protrusions via an unknown mechanism. To test the hypothesis that high pressure physically prevents lamellipodia formation, we manipulated pressure by activating RhoA or changing the osmolarity of the extracellular environment and imaged cell protrusions. We find RhoA activity inhibits Rac1-mediated lamellipodia formation through two distinct pathways. First, RhoA boosts intracellular pressure by increasing actomyosin contractility and water influx but acts upstream of Rac1 to inhibit lamellipodia formation. Increasing osmotic pressure revealed a second RhoA pathway, which acts through nonmuscle myosin II (NMII) to disrupt lamellipodia downstream from Rac1 and elevate pressure. Interestingly, Arp2/3 inhibition triggered a NMII-dependent increase in intracellular pressure, along with lamellipodia disruption. Together, these results suggest that actomyosin contractility and water influx are coordinated to increase intracellular pressure, and RhoA signaling can inhibit lamellipodia formation via two distinct pathways in high-pressure cells.
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Affiliation(s)
- Shivani Patel
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Donna McKeon
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Kimheak Sao
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Nicole M Naranjo
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Tatyana M Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Ryan J Petrie
- Department of Biology, Drexel University, Philadelphia, PA 19104
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20
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Liu X, Xia X, Wang X, Zhou J, Sung LA, Long J, Geng X, Zeng Z, Yao W. Tropomodulin1 Expression Increases Upon Maturation in Dendritic Cells and Promotes Their Maturation and Immune Functions. Front Immunol 2021; 11:587441. [PMID: 33552047 PMCID: PMC7856346 DOI: 10.3389/fimmu.2020.587441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 12/03/2020] [Indexed: 12/12/2022] Open
Abstract
Dendritic cells (DCs) are the most potent antigen-presenting cells. Upon maturation, DCs express costimulatory molecules and migrate to the lymph nodes to present antigens to T cells. The actin cytoskeleton plays key roles in multiple aspects of DC functions. However, little is known about the mechanisms and identities of actin-binding proteins that control DC maturation and maturation-associated functional changes. Tropomodulin1 (Tmod1), an actin-capping protein, controls actin depolymerization and nucleation. We found that Tmod1 was expressed in bone marrow-derived immature DCs and was significantly upregulated upon lipopolysaccharide (LPS)-induced DC maturation. By characterizing LPS-induced mature DCs (mDCs) from Tmod1 knockout mice, we found that compared with Tmod1+/+ mDCs, Tmod1-deficient mDCs exhibited lower surface expression of costimulatory molecules and chemokine receptors and reduced secretion of inflammatory cytokines, suggesting that Tmod1 deficiency retarded DC maturation. Tmod1-deficient mDCs also showed impaired random and chemotactic migration, deteriorated T-cell stimulatory ability, and reduced F-actin content and cell stiffness. Furthermore, Tmod1-deficient mDCs secreted high levels of IFN-β and IL-10 and induced immune tolerance in an experimental autoimmune encephalomyelitis (EAE) mouse model. Mechanistically, Tmod1 deficiency affected TLR4 signaling transduction, resulting in the decreased activity of MyD88-dependent NFκB and MAPK pathways but the increased activity of the TRIF/IRF3 pathway. Rescue with exogenous Tmod1 reversed the effect of Tmod1 deficiency on TLR4 signaling. Therefore, Tmod1 is critical in regulating DC maturation and immune functions by regulating TLR4 signaling and the actin cytoskeleton. Tmod1 may be a potential target for modulating DC functions, a strategy that would be beneficial for immunotherapy for several diseases.
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Affiliation(s)
- Xianmei Liu
- School of Basic Medical Sciences, School of Biology and Engineering, Guizhou Medical University, Guiyang, China
- Hemorheology Center, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xue Xia
- School of Basic Medical Sciences, School of Biology and Engineering, Guizhou Medical University, Guiyang, China
- Hemorheology Center, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xifu Wang
- Department of Emergency, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Jing Zhou
- Hemorheology Center, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Lanping Amy Sung
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Jinhua Long
- School of Basic Medical Sciences, School of Biology and Engineering, Guizhou Medical University, Guiyang, China
| | - Xueyu Geng
- Hemorheology Center, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Zhu Zeng
- School of Basic Medical Sciences, School of Biology and Engineering, Guizhou Medical University, Guiyang, China
| | - Weijuan Yao
- Hemorheology Center, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
- Department of Integration of Chinese and Western Medicine, School of Basic Medical Science, Peking University Health Center, Beijing, China
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