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Liu T, Cao L, Mladenov M, Jegou A, Way M, Moores CA. Cortactin stabilizes actin branches by bridging activated Arp2/3 to its nucleated actin filament. Nat Struct Mol Biol 2024; 31:801-809. [PMID: 38267598 PMCID: PMC11102864 DOI: 10.1038/s41594-023-01205-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024]
Abstract
Regulation of the assembly and turnover of branched actin filament networks nucleated by the Arp2/3 complex is essential during many cellular processes, including cell migration and membrane trafficking. Cortactin is important for actin branch stabilization, but the mechanism by which this occurs is unclear. Given this, we determined the structure of vertebrate cortactin-stabilized Arp2/3 actin branches using cryogenic electron microscopy. We find that cortactin interacts with the new daughter filament nucleated by the Arp2/3 complex at the branch site, rather than the initial mother actin filament. Cortactin preferentially binds activated Arp3. It also stabilizes the F-actin-like interface of activated Arp3 with the first actin subunit of the new filament, and its central repeats extend along successive daughter-filament subunits. The preference of cortactin for activated Arp3 explains its retention at the actin branch and accounts for its synergy with other nucleation-promoting factors in regulating branched actin network dynamics.
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Affiliation(s)
- Tianyang Liu
- Institute of Structural and Molecular Biology, Birkbeck College, London, UK
| | - Luyan Cao
- The Francis Crick Institute, London, UK
| | | | - Antoine Jegou
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Michael Way
- The Francis Crick Institute, London, UK.
- Department of Infectious Disease, Imperial College, London, UK.
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck College, London, UK.
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2
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Narvaez-Ortiz HY, Lynch MJ, Liu SL, Fries A, Nolen BJ. Both Las17-binding sites on Arp2/3 complex are important for branching nucleation and assembly of functional endocytic actin networks in S. cerevisiae. J Biol Chem 2024; 300:105766. [PMID: 38367669 PMCID: PMC10944109 DOI: 10.1016/j.jbc.2024.105766] [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: 09/27/2023] [Revised: 02/07/2024] [Accepted: 02/12/2024] [Indexed: 02/19/2024] Open
Abstract
Arp2/3 complex nucleates branched actin filaments that drive membrane invagination during endocytosis and leading-edge protrusion in lamellipodia. Arp2/3 complex is maximally activated in vitro by binding of a WASP family protein to two sites-one on the Arp3 subunit and one spanning Arp2 and ARPC1-but the importance of each site in the regulation of force-producing actin networks is unclear. Here, we identify mutations in budding yeast Arp2/3 complex that decrease or block engagement of Las17, the budding yeast WASP, at each site. As in the mammalian system, both sites are required for maximal activation in vitro. Dimerization of Las17 partially restores activity of mutations at both CA-binding sites. Arp2/3 complexes defective at either site assemble force-producing actin networks in a bead motility assay, but their reduced activity hinders motility by decreasing actin assembly near the bead surface and by failing to suppress actin filament bundling within the networks. While even the most defective Las17-binding site mutants assembled actin filaments at endocytic sites, they showed significant internalization defects, potentially because they lack the proper architecture to drive plasma membrane remodeling. Together, our data indicate that both Las17-binding sites are important to assemble functional endocytic actin networks in budding yeast, but Arp2/3 complex retains some activity in vitro and in vivo even with a severe defect at either Las17-binding site.
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Affiliation(s)
- Heidy Y Narvaez-Ortiz
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Michael J Lynch
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Su-Ling Liu
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Adam Fries
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
| | - Brad J Nolen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA.
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3
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Graham K, Chandrasekaran A, Wang L, Yang N, Lafer EM, Rangamani P, Stachowiak JC. Liquid-like condensates mediate competition between actin branching and bundling. Proc Natl Acad Sci U S A 2024; 121:e2309152121. [PMID: 38207079 PMCID: PMC10801869 DOI: 10.1073/pnas.2309152121] [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: 05/31/2023] [Accepted: 11/21/2023] [Indexed: 01/13/2024] Open
Abstract
Cellular remodeling of actin networks underlies cell motility during key morphological events, from embryogenesis to metastasis. In these transformations, there is an inherent competition between actin branching and bundling, because steric clashes among branches create a mechanical barrier to bundling. Recently, liquid-like condensates consisting purely of proteins involved in either branching or bundling of the cytoskeleton have been found to catalyze their respective functions. Yet in the cell, proteins that drive branching and bundling are present simultaneously. In this complex environment, which factors determine whether a condensate drives filaments to branch or become bundled? To answer this question, we added the branched actin nucleator, Arp2/3, to condensates composed of VASP, an actin bundling protein. At low actin to VASP ratios, branching activity, mediated by Arp2/3, robustly inhibited VASP-mediated bundling of filaments, in agreement with agent-based simulations. In contrast, as the actin to VASP ratio increased, addition of Arp2/3 led to formation of aster-shaped structures, in which bundled filaments emerged from a branched actin core, analogous to filopodia emerging from a branched lamellipodial network. These results demonstrate that multi-component, liquid-like condensates can modulate the inherent competition between bundled and branched actin morphologies, leading to organized, higher-order structures, similar to those found in motile cells.
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Affiliation(s)
- Kristin Graham
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX78712
| | - Aravind Chandrasekaran
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA92093
| | - Liping Wang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX78229
| | - Noel Yang
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX78712
| | - Eileen M. Lafer
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX78229
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA92093
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX78712
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX78712
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4
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Basant A, Way M. The amount of Nck rather than N-WASP correlates with the rate of actin-based motility of Vaccinia virus. Microbiol Spectr 2023; 11:e0152923. [PMID: 37855608 PMCID: PMC10883800 DOI: 10.1128/spectrum.01529-23] [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: 04/11/2023] [Accepted: 09/03/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Vaccinia virus is a large double-stranded DNA virus and a close relative of Mpox and Variola virus, the causative agent of smallpox. During infection, Vaccinia hijacks its host's transport systems and promotes its spread into neighboring cells by recruiting a signaling network that stimulates actin polymerization. Over the years, Vaccinia has provided a powerful model to understand how signaling networks regulate actin polymerization. Nevertheless, we still lack important quantitative information about the system, including the precise number of viral and host molecules required to induce actin polymerization. Using quantitative fluorescence microscopy techniques, we have determined the number of viral and host signaling proteins accumulating on virions during their egress. Our analysis has uncovered two unexpected new aspects of this process: the number of viral proteins in the virion is not fixed and the velocity of virus movement depends on the level of a single adaptor within the signaling network.
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Affiliation(s)
- Angika Basant
- Cellular Signalling and Cytoskeletal Function Laboratory, The Francis Crick Institute , London, United Kingdom
| | - Michael Way
- Cellular Signalling and Cytoskeletal Function Laboratory, The Francis Crick Institute , London, United Kingdom
- Department of Infectious Disease, Imperial College , London, United Kingdom
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5
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Fregoso FE, Boczkowska M, Rebowski G, Carman PJ, van Eeuwen T, Dominguez R. Mechanism of synergistic activation of Arp2/3 complex by cortactin and WASP-family proteins. Nat Commun 2023; 14:6894. [PMID: 37898612 PMCID: PMC10613254 DOI: 10.1038/s41467-023-42229-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/29/2023] [Indexed: 10/30/2023] Open
Abstract
Cortactin coactivates Arp2/3 complex synergistically with WASP-family nucleation-promoting factors (NPFs) and stabilizes branched networks by linking Arp2/3 complex to F-actin. It is poorly understood how cortactin performs these functions. We describe the 2.89 Å resolution cryo-EM structure of cortactin's N-terminal domain (Cort1-76) bound to Arp2/3 complex. Cortactin binds Arp2/3 complex through an inverted Acidic domain (D20-V29), which targets the same site on Arp3 as the Acidic domain of NPFs but with opposite polarity. Sequences N- and C-terminal to cortactin's Acidic domain do not increase its affinity for Arp2/3 complex but contribute toward coactivation with NPFs. Coactivation further increases with NPF dimerization and for longer cortactin constructs with stronger binding to F-actin. The results suggest that cortactin contributes to Arp2/3 complex coactivation with NPFs in two ways, by helping recruit the complex to F-actin and by stabilizing the short-pitch (active) conformation, which are both byproducts of cortactin's core function in branch stabilization.
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Affiliation(s)
- Fred E Fregoso
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Grzegorz Rebowski
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter J Carman
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Trevor van Eeuwen
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, 10065, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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6
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Štepihar D, Florke Gee RR, Hoyos Sanchez MC, Fon Tacer K. Cell-specific secretory granule sorting mechanisms: the role of MAGEL2 and retromer in hypothalamic regulated secretion. Front Cell Dev Biol 2023; 11:1243038. [PMID: 37799273 PMCID: PMC10548473 DOI: 10.3389/fcell.2023.1243038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/31/2023] [Indexed: 10/07/2023] Open
Abstract
Intracellular protein trafficking and sorting are extremely arduous in endocrine and neuroendocrine cells, which synthesize and secrete on-demand substantial quantities of proteins. To ensure that neuroendocrine secretion operates correctly, each step in the secretion pathways is tightly regulated and coordinated both spatially and temporally. At the trans-Golgi network (TGN), intrinsic structural features of proteins and several sorting mechanisms and distinct signals direct newly synthesized proteins into proper membrane vesicles that enter either constitutive or regulated secretion pathways. Furthermore, this anterograde transport is counterbalanced by retrograde transport, which not only maintains membrane homeostasis but also recycles various proteins that function in the sorting of secretory cargo, formation of transport intermediates, or retrieval of resident proteins of secretory organelles. The retromer complex recycles proteins from the endocytic pathway back to the plasma membrane or TGN and was recently identified as a critical player in regulated secretion in the hypothalamus. Furthermore, melanoma antigen protein L2 (MAGEL2) was discovered to act as a tissue-specific regulator of the retromer-dependent endosomal protein recycling pathway and, by doing so, ensures proper secretory granule formation and maturation. MAGEL2 is a mammalian-specific and maternally imprinted gene implicated in Prader-Willi and Schaaf-Yang neurodevelopmental syndromes. In this review, we will briefly discuss the current understanding of the regulated secretion pathway, encompassing anterograde and retrograde traffic. Although our understanding of the retrograde trafficking and sorting in regulated secretion is not yet complete, we will review recent insights into the molecular role of MAGEL2 in hypothalamic neuroendocrine secretion and how its dysregulation contributes to the symptoms of Prader-Willi and Schaaf-Yang patients. Given that the activation of many secreted proteins occurs after they enter secretory granules, modulation of the sorting efficiency in a tissue-specific manner may represent an evolutionary adaptation to environmental cues.
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Affiliation(s)
- Denis Štepihar
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Rebecca R. Florke Gee
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Maria Camila Hoyos Sanchez
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
| | - Klementina Fon Tacer
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX, United States
- Texas Center for Comparative Cancer Research (TC3R), Amarillo, TX, United States
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7
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van Eeuwen T, Boczkowska M, Rebowski G, Carman PJ, Fregoso FE, Dominguez R. Transition State of Arp2/3 Complex Activation by Actin-Bound Dimeric Nucleation-Promoting Factor. Proc Natl Acad Sci U S A 2023; 120:e2306165120. [PMID: 37549294 PMCID: PMC10434305 DOI: 10.1073/pnas.2306165120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/03/2023] [Indexed: 08/09/2023] Open
Abstract
Arp2/3 complex generates branched actin networks that drive fundamental processes such as cell motility and cytokinesis. The complex comprises seven proteins, including actin-related proteins (Arps) 2 and 3 and five scaffolding proteins (ArpC1-ArpC5) that mediate interactions with a pre-existing (mother) actin filament at the branch junction. Arp2/3 complex exists in two main conformations, inactive with the Arps interacting end-to-end and active with the Arps interacting side-by-side like subunits of the short-pitch helix of the actin filament. Several cofactors drive the transition toward the active state, including ATP binding to the Arps, WASP-family nucleation-promoting factors (NPFs), actin monomers, and binding of Arp2/3 complex to the mother filament. The precise contribution of each cofactor to activation is poorly understood. We report the 3.32-Å resolution cryo-electron microscopy structure of a transition state of Arp2/3 complex activation with bound constitutively dimeric NPF. Arp2/3 complex-binding region of the NPF N-WASP was fused C-terminally to the α and β subunits of the CapZ heterodimer. One arm of the NPF dimer binds Arp2 and the other binds actin and Arp3. The conformation of the complex is intermediate between those of inactive and active Arp2/3 complex. Arp2, Arp3, and actin also adopt intermediate conformations between monomeric (G-actin) and filamentous (F-actin) states, but only actin hydrolyzes ATP. In solution, the transition complex is kinetically shifted toward the short-pitch conformation and has higher affinity for F-actin than inactive Arp2/3 complex. The results reveal how all the activating cofactors contribute in a coordinated manner toward Arp2/3 complex activation.
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Affiliation(s)
- Trevor van Eeuwen
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Grzegorz Rebowski
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Peter J. Carman
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Fred E. Fregoso
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Roberto Dominguez
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
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8
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Scanlon KR, Keb G, Wolf K, Jewett TJ, Fields KA. Chlamydia trachomatis TmeB antagonizes actin polymerization via direct interference with Arp2/3 activity. Front Cell Infect Microbiol 2023; 13:1232391. [PMID: 37483386 PMCID: PMC10360934 DOI: 10.3389/fcimb.2023.1232391] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/26/2023] [Indexed: 07/25/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that actively promotes invasion of epithelial cells. A virulence-associated type III secretion system contributes to chlamydial entry and at least four effectors have been described that are deployed during this time. Two of these invasion-related effectors, the translocated membrane-associated effectors A and B (TmeA and TmeB), are encoded in a bi-cistronic operon. TmeA directly activates host N-WASP to stimulate Arp2/3-dependent actin polymerization. According to current working models, TmeA-mediated N-WASP activation contributes to invasion. TmeB has not been functionally characterized. Unlike a tmeA null strain, loss of tmeB does not impact invasion efficiency of C. trachomatis. Using strains deficient for multiple genes, we provide evidence that TmeA is dispensable for invasion in the absence of TmeB. Our data indicate that overabundance of TmeB interferes with invasion and that this activity requires active Arp2/3 complex. We further show that TmeB is capable of interfering with Arp2/3-mediated actin polymerization. In aggregate, these data point to opposing functions for TmeA and TmeB that manifest during the invasion process. These studies raise intriguing questions regarding the dynamic interplay between TmeA, TmeB, and branched actin polymerization during chlamydial entry.
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Affiliation(s)
- Kaylyn R. Scanlon
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Gabrielle Keb
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Katerina Wolf
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Travis J. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Kenneth A. Fields
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
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9
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Han X, Hu Z, Surya W, Ma Q, Zhou F, Nordenskiöld L, Torres J, Lu L, Miao Y. The intrinsically disordered region of coronins fine-tunes oligomerization and actin polymerization. Cell Rep 2023; 42:112594. [PMID: 37269287 DOI: 10.1016/j.celrep.2023.112594] [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: 10/18/2022] [Revised: 04/21/2023] [Accepted: 05/16/2023] [Indexed: 06/05/2023] Open
Abstract
Coronins play critical roles in actin network formation. The diverse functions of coronins are regulated by the structured N-terminal β propeller and the C-terminal coiled coil (CC). However, less is known about a middle "unique region" (UR), which is an intrinsically disordered region (IDR). The UR/IDR is an evolutionarily conserved signature in the coronin family. By integrating biochemical and cell biology experiments, coarse-grained simulations, and protein engineering, we find that the IDR optimizes the biochemical activities of coronins in vivo and in vitro. The budding yeast coronin IDR plays essential roles in regulating Crn1 activity by fine-tuning CC oligomerization and maintaining Crn1 as a tetramer. The IDR-guided optimization of Crn1 oligomerization is critical for F-actin cross-linking and regulation of Arp2/3-mediated actin polymerization. The final oligomerization status and homogeneity of Crn1 are contributed by three examined factors: helix packing, the energy landscape of the CC, and the length and molecular grammar of the IDR.
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Affiliation(s)
- Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Zixin Hu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Qianqian Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Feng Zhou
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Institute for Digital Molecular Analytics and Science, Nanyang Technological University, Singapore 636921, Singapore.
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10
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Graham K, Chandrasekaran A, Wang L, Yang N, Lafer EM, Rangamani P, Stachowiak JC. Liquid-like condensates mediate competition between actin branching and bundling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.23.546267. [PMID: 37425724 PMCID: PMC10327076 DOI: 10.1101/2023.06.23.546267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Cellular remodeling of actin networks underlies cell motility during key morphological events, from embryogenesis to metastasis. In these transformations there is an inherent competition between actin branching and bundling, because steric clashes among branches create a mechanical barrier to bundling. Recently, liquid-like condensates consisting purely of proteins involved in either branching or bundling of the cytoskeleton have been found to catalyze their respective functions. Yet in the cell, proteins that drive branching and bundling are present simultaneously. In this complex environment, which factors determine whether a condensate drives filaments to branch versus becoming bundled? To answer this question, we added the branched actin nucleator, Arp2/3, to condensates composed of VASP, an actin bundling protein. At low actin to VASP ratios, branching activity, mediated by Arp2/3, robustly inhibited VASP-mediated bundling of filaments, in agreement with agent-based simulations. In contrast, as the actin to VASP ratio increased, addition of Arp2/3 led to formation of aster-shaped structures, in which bundled filaments emerged from a branched actin core, analogous to filopodia emerging from a branched lamellipodial network. These results demonstrate that multi-component, liquid-like condensates can modulate the inherent competition between bundled and branched actin morphologies, leading to organized, higher-order structures, similar to those found in motile cells.
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Affiliation(s)
- Kristin Graham
- University of Texas at Austin, Department of Biomedical Engineering
| | | | - Liping Wang
- University of Texas Health Science Center at San Antonio, Department of Biochemistry and Structural Biology
| | - Noel Yang
- University of Texas at Austin, Department of Biomedical Engineering
| | - Eileen M. Lafer
- University of Texas Health Science Center at San Antonio, Department of Biochemistry and Structural Biology
| | - Padmini Rangamani
- University of California San Diego, Department of Mechanical and Aerospace Engineering
| | - Jeanne C. Stachowiak
- University of Texas at Austin, Department of Biomedical Engineering
- University of Texas at Austin, Department of Chemical Engineering
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11
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Spona D, Hanisch PT, Hegemann JH, Mölleken K. A single chlamydial protein reshapes the plasma membrane and serves as recruiting platform for central endocytic effector proteins. Commun Biol 2023; 6:520. [PMID: 37179401 PMCID: PMC10182996 DOI: 10.1038/s42003-023-04913-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Uptake of obligate intracellular bacterial pathogens into mammalian epithelial cells is critically dependent on modulation of the host's endocytic machinery. It is an open question how the invading pathogens generate a membrane-bound vesicle appropriate to their size. This requires extensive deformation of the host plasma membrane itself by pathogen-derived membrane-binding proteins, accompanied by substantial F-actin-based forces to further expand and finally pinch off the vesicle. Here we show that upon adhesion to the host cell, the human pathogenic bacterium Chlamydia pneumoniae secretes the scaffolding effector protein CPn0677, which binds to the inner leaflet of the invaginating host's PM, induces inwardly directed, negative membrane curvature, and forms a recruiting platform for the membrane-deforming BAR-domain containing proteins Pacsin and SNX9. In addition, while bound to the membrane, CPn0677 recruits monomeric G-actin, and its C-terminal region binds and activates N-WASP, which initiates branching actin polymerization via the Arp2/3 complex. Together, these membrane-bound processes enable the developing endocytic vesicle to engulf the infectious elementary body, while the associated actin network generates the forces required to reshape and detach the nascent vesicle from the PM. Thus, Cpn0677 (now renamed SemD) acts as recruiting platform for central components of the endocytic machinery during uptake of chlamydia.
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Affiliation(s)
- Dominik Spona
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Philipp T Hanisch
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Johannes H Hegemann
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Katja Mölleken
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany.
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12
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Cao L, Ghasemi F, Way M, Jégou A, Romet‐Lemonne G. Regulation of branched versus linear Arp2/3-generated actin filaments. EMBO J 2023; 42:e113008. [PMID: 36939020 PMCID: PMC10152144 DOI: 10.15252/embj.2022113008] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/01/2023] [Accepted: 03/01/2023] [Indexed: 03/21/2023] Open
Abstract
Activation of the Arp2/3 complex by VCA-motif-bearing actin nucleation-promoting factors results in the formation of "daughter" actin filaments branching off the sides of pre-existing "mother" filaments. Alternatively, when stimulated by SPIN90, Arp2/3 directly nucleates "linear" actin filaments. Uncovering the similarities and differences between these two mechanisms is fundamental to understanding how actin cytoskeleton dynamics are regulated. Here, analysis of individual filaments reveals that, unexpectedly, the VCA motifs of WASP, N-WASP, and WASH destabilize existing branches, as well as SPIN90-Arp2/3 at linear filament ends. Furthermore, branch stabilizer cortactin and destabilizer GMF each have a similar impact on SPIN90-activated Arp2/3. However, unlike branch junctions, SPIN90-Arp2/3 at the ends of linear filaments is not destabilized by piconewton forces and does not become less stable with time. It thus appears that linear and branched Arp2/3-generated filaments respond similarly to the regulatory proteins we have tested, albeit with some differences, but significantly differ in their responses to aging and mechanical stress. These kinetic differences likely reflect the small conformational differences recently reported between Arp2/3 in branch junctions and linear filaments and suggest that their turnover in cells may be differently regulated.
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Affiliation(s)
- Luyan Cao
- Université Paris Cité, CNRS, Institut Jacques MonodParisFrance
- The Francis Crick InstituteLondonUK
| | - Foad Ghasemi
- Université Paris Cité, CNRS, Institut Jacques MonodParisFrance
| | - Michael Way
- The Francis Crick InstituteLondonUK
- Department of Infectious DiseaseImperial CollegeLondonUK
| | - Antoine Jégou
- Université Paris Cité, CNRS, Institut Jacques MonodParisFrance
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13
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Chinnathambi S, Das R, Desale SE. Tau aggregates improve the purinergic receptor P2Y12-associated podosome rearrangements in microglial cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119477. [PMID: 37061007 DOI: 10.1016/j.bbamcr.2023.119477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 03/18/2023] [Accepted: 04/06/2023] [Indexed: 04/17/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is associated with protein misfolding, plaque accumulation, neuronal dysfunction, synaptic loss, and cognitive decline. The pathological cascade of AD includes the intracellular Tau hyperphosphorylation and its subsequent aggregation, extracellular Amyloid-β plaque formation and microglia-mediated neuroinflammation. The extracellular release of aggregated Tau is sensed by surveilling microglia through the involvement of various cell surface receptors. Among all, purinergic P2Y12R signaling is involved in microglial chemotaxis towards the damaged neurons. Microglial migration is highly linked with membrane-associated actin remodeling leading to the phagocytosis of extracellular Tau species. Here, we studied the formation of various actin structures such as podosome, lamellipodia and filopodia, in response to extracellular Tau monomers and aggregates. Microglial podosomes are colocalized with actin nucleator protein WASP, Arp2 and TKS5 adaptor protein during Tau-mediated migration. Moreover, the P2Y12 receptors were associated with F-actin-rich podosome structures, which signify the potential of Tau aggregates in microglial chemotaxis through the involvement of actin remodeling.
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Affiliation(s)
- Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Institute of National Importance, Hosur Road, Bangalore 560029, Karnataka, India.
| | - Rashmi Das
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Smita Eknath Desale
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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14
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Rosenbloom AD, Pollard TD. The proline-rich domain of fission yeast WASp (Wsp1p) interacts with actin filaments and inhibits actin polymerization. FEBS Lett 2023; 597:672-681. [PMID: 36650956 PMCID: PMC10023459 DOI: 10.1002/1873-3468.14571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 01/19/2023]
Abstract
Members of the Wiskott-Aldrich Syndrome protein (WASp) family activate Arp2/3 complex (actin-related proteins 2 and 3 complex) to form actin filament branches. The proline-rich domain (PRD) of WASp contributes to branching nucleation, and the PRD of budding yeast Las17 binds actin filaments [Urbanek AN et al. (2013) Curr Biol 23, 196-203]. Biochemical assays showed the recombinant PRD of fission yeast Schizosaccharomyces pombe Wsp1p binds actin filaments with micromolar affinity. Recombinant PRDs of both Wsp1p and Las17p slowed the elongation of actin filaments by Mg-ATP-actin monomers by half and slowed the spontaneous polymerization of Mg-ATP-actin monomers modestly. The affinity of PRDs of WASp-family proteins for actin filaments is high enough to contribute to the reported stimulation of actin filament branching by Arp2/3 complex.
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Affiliation(s)
- Aaron D. Rosenbloom
- Department of Chemistry, Yale University, PO Box 208107, New Haven, CT 06520-8103 USA
| | - Thomas D. Pollard
- Departments of Molecular Cellular and Developmental Biology, of Molecular Biophysics and Biochemistry and of Cell Biology, Yale University, PO Box 208103, New Haven, CT 06520-8103 USA
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15
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Bieling P, Rottner K. From WRC to Arp2/3: Collective molecular mechanisms of branched actin network assembly. Curr Opin Cell Biol 2023; 80:102156. [PMID: 36868090 DOI: 10.1016/j.ceb.2023.102156] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 03/05/2023]
Abstract
Branched actin networks have emerged as major force-generating structures driving the protrusions in various distinct cell types and processes, ranging from lamellipodia operating in mesenchymal and epithelial cell migration or tails pushing intracellular pathogens and vesicles to developing spine heads on neurons. Many key molecular features are conserved among all those Arp2/3 complex-containing, branched actin networks. Here, we will review recent progress in our molecular understanding of the core biochemical machinery driving branched actin nucleation, from the generation of filament primers to Arp2/3 activator recruitment, regulation and turnover. Due to the wealth of information on distinct, Arp2/3 network-containing structures, we are largely focusing-in an exemplary fashion-on canonical lamellipodia of mesenchymal cells, which are regulated by Rac GTPases, their downstream effector WAVE Regulatory Complex and its target Arp2/3 complex. Novel insight additionally confirms that WAVE and Arp2/3 complexes regulate or are themselves tuned by additional prominent actin regulatory factors, including Ena/VASP family members and heterodimeric capping protein. Finally, we are considering recent insights into effects exerted by mechanical force, both at the branched network and individual actin regulator level.
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Affiliation(s)
- Peter Bieling
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany; Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
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16
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Zhang S, Vavylonis D. Steps of actin filament branch formation by Arp2/3 complex investigated with coarse-grained molecular dynamics. Front Cell Dev Biol 2023; 11:1071977. [PMID: 36733458 PMCID: PMC9887124 DOI: 10.3389/fcell.2023.1071977] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/04/2023] [Indexed: 01/18/2023] Open
Abstract
The nucleation of actin filament branches by the Arp2/3 complex involves activation through nucleation promotion factors (NPFs), recruitment of actin monomers, and binding of the complex to the side of actin filaments. Because of the large system size and processes that involve flexible regions and diffuse components, simulations of branch formation using all-atom molecular dynamics are challenging. We applied a coarse-grained model that retains amino-acid level information and allows molecular dynamics simulations in implicit solvent, with globular domains represented as rigid bodies and flexible regions allowed to fluctuate. We used recent electron microscopy structures of the inactive Arp2/3 complex bound to NPF domains and to mother actin filament for the activated Arp2/3 complex. We studied interactions of Arp2/3 complex with the activating VCA domain of the NPF Wiskott-Aldrich syndrome protein, actin monomers, and actin filament. We found stable configurations with one or two actin monomers bound along the branch filament direction and with CA domain of VCA associated to the strong and weak binding sites of the Arp2/3 complex, supporting prior structural studies and validating our approach. We reproduced delivery of actin monomers and CA to the Arp2/3 complex under different conditions, providing insight into mechanisms proposed in previous studies. Simulations of active Arp2/3 complex bound to a mother actin filament indicate the contribution of each subunit to the binding. Addition of the C-terminal tail of Arp2/3 complex subunit ArpC2, which is missing in the cryo-EM structure, increased binding affinity, indicating a possible stabilizing role of this tail.
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Affiliation(s)
- Shuting Zhang
- Department of Physics, Lehigh University, Bethlehem, PA, United States
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA, United States,Center for Computational Biology, Flatiron Institute, New York, NY, United States,*Correspondence: Dimitrios Vavylonis ,
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17
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Miah MM, Tabassum N, Afroj Zinnia M, Islam ABMMK. Drug and Anti-Viral Peptide Design to Inhibit the Monkeypox Virus by Restricting A36R Protein. Bioinform Biol Insights 2022; 16:11779322221141164. [PMID: 36570327 PMCID: PMC9772960 DOI: 10.1177/11779322221141164] [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: 07/20/2022] [Accepted: 11/06/2022] [Indexed: 12/24/2022] Open
Abstract
Most recently, monkeypox virus (MPXV) has emanated as a global public health threat. Unavailability of effective medicament against MPXV escalates demand for new therapeutic agent. In this study, in silico strategies were conducted to identify novel drug against the A36R protein of MPXV. The A36R protein of MPXV is responsible for the viral migration, adhesion, and vesicle trafficking to the host cell. To block the A36R protein, 4893 potential antiviral peptides (AVPs) were retrieved from DRAMP and SATPdb databases. Finally, 57 sequences were screened based on peptide filtering criteria, which were then modeled. Likewise, 31 monkeypox virus A36R protein sequences were collected from NCBI protein database to find consensus sequence and to predict 3D protein model. The refined and validated models of the A36R protein and AVP peptides were used to predict receptor-ligand interactions using DINC 2 server. Three peptides that showed best interactions were SATPdb10193, SATPdb21850, and SATPdb26811 with binding energies -6.10, -6.10, and -6.30 kcal/mol, respectively. Small molecules from drug databases were also used to perform virtual screening against the A36R protein. Among databases, Enamine-HTSC showed strong affinity with docking scores ranging from -8.8 to 9.8 kcal/mol. Interaction of target protein A36R with the top 3 peptides and the most probable drug (Z55287118) examined by molecular dynamic (MD) simulation. Trajectory analyses (RMSD, RMSF, SASA, and Rg) confirmed the stable nature of protein-ligand and protein-peptide complexes. This work suggests that identified top AVPs and small molecules might interfere with the function of the A36R protein of MPXV.
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Affiliation(s)
| | - Nuzhat Tabassum
- Department of Pharmacy, East West University, Dhaka, Bangladesh
| | | | - Abul Bashar Mir Md. Khademul Islam
- Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka, Bangladesh,Abul Bashar Mir Md. Khademul Islam, Department of Genetic Engineering and Biotechnology, University of Dhaka, Nilkhet Rd, Dhaka 1000, Bangladesh.
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18
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Lappalainen P, Kotila T, Jégou A, Romet-Lemonne G. Biochemical and mechanical regulation of actin dynamics. Nat Rev Mol Cell Biol 2022; 23:836-852. [PMID: 35918536 DOI: 10.1038/s41580-022-00508-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 12/30/2022]
Abstract
Polymerization of actin filaments against membranes produces force for numerous cellular processes, such as migration, morphogenesis, endocytosis, phagocytosis and organelle dynamics. Consequently, aberrant actin cytoskeleton dynamics are linked to various diseases, including cancer, as well as immunological and neurological disorders. Understanding how actin filaments generate forces in cells, how force production is regulated by the interplay between actin-binding proteins and how the actin-regulatory machinery responds to mechanical load are at the heart of many cellular, developmental and pathological processes. During the past few years, our understanding of the mechanisms controlling actin filament assembly and disassembly has evolved substantially. It has also become evident that the activities of key actin-binding proteins are not regulated solely by biochemical signalling pathways, as mechanical regulation is critical for these proteins. Indeed, the architecture and dynamics of the actin cytoskeleton are directly tuned by mechanical load. Here we discuss the general mechanisms by which key actin regulators, often in synergy with each other, control actin filament assembly, disassembly, and monomer recycling. By using an updated view of actin dynamics as a framework, we discuss how the mechanics and geometry of actin networks control actin-binding proteins, and how this translates into force production in endocytosis and mesenchymal cell migration.
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Affiliation(s)
- Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland.
| | - Tommi Kotila
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland
| | - Antoine Jégou
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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19
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Zhang S, Liao X, Chen S, Qian W, Li M, Xu Y, Yang M, Li X, Mo S, Tang M, Wu X, Hu Y, Li Z, Yu R, Abudourousuli A, Song L, Li J. Large Oncosome-Loaded VAPA Promotes Bone-Tropic Metastasis of Hepatocellular Carcinoma Via Formation of Osteoclastic Pre-Metastatic Niche. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201974. [PMID: 36169100 PMCID: PMC9631052 DOI: 10.1002/advs.202201974] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 08/23/2022] [Indexed: 05/31/2023]
Abstract
Tumor-derived extracellular vesicles (EVs) function as critical mediators in selective modulation of the microenvironment of distant organs to generate a pre-metastatic niche that facilitates organotropic metastasis. Identifying the organ-specific molecular determinants of EVs can develop potential anti-metastatic therapeutic targets. In the current study, large oncosomes (LOs), atypically large cancer-derived EVs, are found to play a crucial role in facilitating bone-tropic metastasis of hepatocellular carcinoma (HCC) cells by engineering an osteoclastic pre-metastatic niche and establishing a vicious cycle between the osteoclasts and HCC cells. Transmembrane protein, VAMP-associated protein A (VAPA), is significantly enriched on LOs surface via direct interaction with LOs marker αV-integrin. VAPA-enriched LOs-induced pre-metastatic education transforms the bone into a fertile milieu, which supports the growth of metastatic HCC cells. Mechanically, LOs-delivered VAPA integrates to plasma membrane of osteoclasts and directly interacts with and activates neural Wiskott-Aldrich syndrome protein (N-WASP) via dual mechanisms, consequently resulting in ARP2/3 complex-mediated reorganization of actin cytoskeleton in osteoclasts and osteoclastogenesis. Importantly, treatment with N-WASP inhibitor 187-1-packaged LOs (LOs/187-1) dramatically abolishes the inductive effect of VAPA-enriched LOs on pre-metastatic niche formation and precludes HCC bone metastasis. These findings reveal a plausible mechanism for bone-tropism of HCC and can represent a potential strategy to prevent HCC bone metastasis.
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Affiliation(s)
- Shuxia Zhang
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Xinyi Liao
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Suwen Chen
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Wanying Qian
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Man Li
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Yingru Xu
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Meisongzhu Yang
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Xincheng Li
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Shuang Mo
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Miaoling Tang
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Xingui Wu
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Yameng Hu
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Ziwen Li
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Ruyuan Yu
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Ainiwaerjiang Abudourousuli
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
| | - Libing Song
- State Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhou510080P. R. China
| | - Jun Li
- Program of Cancer ResearchKey Laboratory of Protein Modification and Degradation and Guangzhou Institute of OncologyAffiliated Guangzhou Women and Children's HospitalSchool of Basic Medical SciencesGuangzhou Medical UniversityGuangzhou510623P. R. China
- Department of BiochemistryZhongshan School of MedicineSun Yat‐sen UniversityGuangzhou510080P. R. China
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20
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Chun JI, Kim SM, Jeong NR, Kim SH, Jung C, Kang JH. Tomato ARPC1 regulates trichome morphology and density and terpene biosynthesis. PLANTA 2022; 256:38. [PMID: 35821288 DOI: 10.1007/s00425-022-03955-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Based on transcriptomic analysis of wild-type and mutant tomato plants, ARPC1 was found to be important for trichome formation and development and it plays a key role in terpene synthesis. Trichomes are protruding epidermal cells in plant species. They function as the first defense layer against biotic and abiotic stresses. Despite the essential role of tomato trichomes in defense against herbivores, the understanding of their development is still incomplete. Therefore, the aim of this study was to identify genes involved in trichome formation and morphology and terpene synthesis, using transcriptomic techniques. To achieve this, we examined leaf morphology and compared the expression levels of some putative genes involved in trichome formation between wild-type (WT) and hairless-3 (hl-3) tomato mutant. The hl-3 plants displayed swollen and distorted trichomes and reduced trichome density (type I and IV) and terpene synthesis compared with that of the WT plants. Gene expression analysis showed that Actin-Related Protein Component1 (ARPC1) was expressed more highly in the WT than in the hl-3 mutant, indicating its critical role in trichome morphology and density. Additionally, the expression of MYC1 and several terpene synthase genes (TPS9, 12, 20), which are involved in type VI trichome initiation and terpene synthesis, was lower in the hl-3 mutant than in the WT plants. Moreover, transformation of the hl-3 mutant with WT ARPC1 restored normal trichome structure and density, and terpene synthesis. Structural and amino acid sequence analysis showed that there was a missplicing mutation in the hl-3 mutant, which was responsible for the abnormal trichome structure and density, and impaired terpene synthesis. Overall, the findings of this study demonstrated that ARPC1 is involved in regulating trichome structure and terpene synthesis in tomato.
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Affiliation(s)
- Jae-In Chun
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
| | - Seong-Min Kim
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
| | - Na-Rae Jeong
- Department of International Agricultural Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sang Hee Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Choonkyun Jung
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
- Department of International Agricultural Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
| | - Jin-Ho Kang
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea.
- Department of International Agricultural Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea.
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21
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Vaseghi-Shanjani M, Snow AL, Margolis DJ, Latrous M, Milner JD, Turvey SE, Biggs CM. Atopy as Immune Dysregulation: Offender Genes and Targets. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY. IN PRACTICE 2022; 10:1737-1756. [PMID: 35680527 DOI: 10.1016/j.jaip.2022.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Allergic diseases are a heterogeneous group of disorders resulting from exaggerated type 2 inflammation. Although typically viewed as polygenic multifactorial disorders caused by the interaction of several genes with the environment, we have come to appreciate that allergic diseases can also be caused by monogenic variants affecting the immune system and the skin epithelial barrier. Through a myriad of genetic association studies and high-throughput sequencing tools, many monogenic and polygenic culprits of allergic diseases have been described. Identifying the genetic causes of atopy has shaped our understanding of how these conditions occur and how they may be treated and even prevented. Precision diagnostic tools and therapies that address the specific molecular pathways implicated in allergic inflammation provide exciting opportunities to improve our care for patients across the field of allergy and immunology. Here, we highlight offender genes implicated in polygenic and monogenic allergic diseases and list targeted therapeutic approaches that address these disrupted pathways.
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Affiliation(s)
- Maryam Vaseghi-Shanjani
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrew L Snow
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, Md
| | - David J Margolis
- Department of Dermatology and Dermatologic Surgery, University of Pennsylvania Medical Center, Philadelphia, Pa; Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Medical Center, Philadelphia, Pa
| | - Meriem Latrous
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Joshua D Milner
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY
| | - Stuart E Turvey
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Catherine M Biggs
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; St Paul's Hospital, Vancouver, British Columbia, Canada.
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22
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WASp modulates RPA function on single-stranded DNA in response to replication stress and DNA damage. Nat Commun 2022; 13:3743. [PMID: 35768435 PMCID: PMC9243104 DOI: 10.1038/s41467-022-31415-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 06/08/2022] [Indexed: 02/07/2023] Open
Abstract
Perturbation in the replication-stress response (RSR) and DNA-damage response (DDR) causes genomic instability. Genomic instability occurs in Wiskott-Aldrich syndrome (WAS), a primary immunodeficiency disorder, yet the mechanism remains largely uncharacterized. Replication protein A (RPA), a single-strand DNA (ssDNA) binding protein, has key roles in the RSR and DDR. Here we show that human WAS-protein (WASp) modulates RPA functions at perturbed replication forks (RFs). Following genotoxic insult, WASp accumulates at RFs, associates with RPA, and promotes RPA:ssDNA complexation. WASp deficiency in human lymphocytes destabilizes RPA:ssDNA-complexes, impairs accumulation of RPA, ATR, ETAA1, and TOPBP1 at genotoxin-perturbed RFs, decreases CHK1 activation, and provokes global RF dysfunction. las17 (yeast WAS-homolog)-deficient S. cerevisiae also show decreased ScRPA accumulation at perturbed RFs, impaired DNA recombination, and increased frequency of DNA double-strand break (DSB)-induced single-strand annealing (SSA). Consequently, WASp (or Las17)-deficient cells show increased frequency of DSBs upon genotoxic insult. Our study reveals an evolutionarily conserved, essential role of WASp in the DNA stress-resolution pathway, such that WASp deficiency provokes RPA dysfunction-coupled genomic instability. Cancer develops in Wiskott-Aldrich syndrome (WAS). Here the authors identify a role for WAS-protein (WASp) in the DNA stress-resolution pathway by promoting the function of Replication Protein A at replication forks after DNA damage.
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23
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Kramer DA, Piper HK, Chen B. WASP family proteins: Molecular mechanisms and implications in human disease. Eur J Cell Biol 2022; 101:151244. [PMID: 35667337 PMCID: PMC9357188 DOI: 10.1016/j.ejcb.2022.151244] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 02/08/2023] Open
Abstract
Proteins of the Wiskott-Aldrich syndrome protein (WASP) family play a central role in regulating actin cytoskeletal dynamics in a wide range of cellular processes. Genetic mutations or misregulation of these proteins are tightly associated with many diseases. The WASP-family proteins act by transmitting various upstream signals to their conserved WH2-Central-Acidic (WCA) peptide sequence at the C-terminus, which in turn binds to the Arp2/3 complex to stimulate the formation of branched actin networks at membranes. Despite this common feature, the regulatory mechanisms and cellular functions of distinct WASP-family proteins are very different. Here, we summarize and clarify our current understanding of WASP-family proteins and how disruption of their functions is related to human disease.
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Affiliation(s)
- Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Hannah K Piper
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA.
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24
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Sun J, Zhong X, Fu X, Miller H, Lee P, Yu B, Liu C. The Actin Regulators Involved in the Function and Related Diseases of Lymphocytes. Front Immunol 2022; 13:799309. [PMID: 35371070 PMCID: PMC8965893 DOI: 10.3389/fimmu.2022.799309] [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: 10/21/2021] [Accepted: 02/01/2022] [Indexed: 11/21/2022] Open
Abstract
Actin is an important cytoskeletal protein involved in signal transduction, cell structure and motility. Actin regulators include actin-monomer-binding proteins, Wiskott-Aldrich syndrome (WAS) family of proteins, nucleation proteins, actin filament polymerases and severing proteins. This group of proteins regulate the dynamic changes in actin assembly/disassembly, thus playing an important role in cell motility, intracellular transport, cell division and other basic cellular activities. Lymphocytes are important components of the human immune system, consisting of T-lymphocytes (T cells), B-lymphocytes (B cells) and natural killer cells (NK cells). Lymphocytes are indispensable for both innate and adaptive immunity and cannot function normally without various actin regulators. In this review, we first briefly introduce the structure and fundamental functions of a variety of well-known and newly discovered actin regulators, then we highlight the role of actin regulators in T cell, B cell and NK cell, and finally provide a landscape of various diseases associated with them. This review provides new directions in exploring actin regulators and promotes more precise and effective treatments for related diseases.
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Affiliation(s)
- Jianxuan Sun
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department and Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xingyu Zhong
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyu Fu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heather Miller
- Cytek Biosciences, R&D Clinical Reagents, Fremont, CA, United States
| | - Pamela Lee
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Bing Yu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chaohong Liu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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25
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Narvaez-Ortiz HY, Nolen BJ. Unconcerted conformational changes in Arp2/3 complex integrate multiple activating signals to assemble functional actin networks. Curr Biol 2022; 32:975-987.e6. [PMID: 35090589 PMCID: PMC8930562 DOI: 10.1016/j.cub.2022.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/25/2021] [Accepted: 01/04/2022] [Indexed: 11/16/2022]
Abstract
Arp2/3 complex nucleates branched actin filaments important for processes such as DNA repair, endocytosis, and cellular motility. Multiple factors are required to activate branching nucleation by Arp2/3 complex, including a WASP family protein and a pre-existing actin filament. Activation is achieved through two major conformational changes-subunit flattening and movement into the short pitch conformation-that allow the actin-related proteins (Arps) within the complex (Arp2 and Arp3) to mimic filamentous actin subunits, thereby templating new filament assembly. Some models suggest that these changes are concerted and stimulated cooperatively by WASP and actin filaments, but how Arp2/3 complex integrates signals from multiple factors to drive switch-like activation of branching nucleation has been unknown. Here, we use biochemical assays to show that instead of a concerted mechanism, signal integration by Arp2/3 complex occurs via distinct and unconcerted conformational changes; WASP stimulates the short pitch arrangement of Arp2 and Arp3, while actin filaments trigger a different activation step. An engineered Arp2/3 complex that bypasses the need for WASP but not actin filaments in activation potently assembles isotropic actin networks but fails to assemble sustained force-producing actin networks in bead motility assays. The engineered complex, which is crosslinked into the short pitch conformation, fails to target nucleation to the surface of the bead, creating unproductive branching events that deplete unpolymerized actin and halt assembly. Together, our data demonstrate the requirement for multifactor signal integration by Arp2/3 complex and highlight the importance of both the WASP- and actin filament-mediated activation steps in the assembly of functional actin networks.
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Affiliation(s)
- Heidy Y Narvaez-Ortiz
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Brad J Nolen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.
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26
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Cytoskeleton regulation: Distinct steps in Arp2/3 complex activation. Curr Biol 2022; 32:R220-R222. [DOI: 10.1016/j.cub.2022.01.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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27
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Fregoso FE, van Eeuwen T, Simanov G, Rebowski G, Boczkowska M, Zimmet A, Gautreau AM, Dominguez R. Molecular mechanism of Arp2/3 complex inhibition by Arpin. Nat Commun 2022; 13:628. [PMID: 35110533 PMCID: PMC8810855 DOI: 10.1038/s41467-022-28112-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/09/2022] [Indexed: 11/09/2022] Open
Abstract
Positive feedback loops involving signaling and actin assembly factors mediate the formation and remodeling of branched actin networks in processes ranging from cell and organelle motility to mechanosensation. The Arp2/3 complex inhibitor Arpin controls the directional persistence of cell migration by interrupting a feedback loop involving Rac-WAVE-Arp2/3 complex, but Arpin’s mechanism of inhibition is unknown. Here, we describe the cryo-EM structure of Arpin bound to Arp2/3 complex at 3.24-Å resolution. Unexpectedly, Arpin binds Arp2/3 complex similarly to WASP-family nucleation-promoting factors (NPFs) that activate the complex. However, whereas NPFs bind to two sites on Arp2/3 complex, on Arp2-ArpC1 and Arp3, Arpin only binds to the site on Arp3. Like NPFs, Arpin has a C-helix that binds at the barbed end of Arp3. Mutagenesis studies in vitro and in cells reveal how sequence differences within the C-helix define the molecular basis for inhibition by Arpin vs. activation by NPFs. The Arp2/3 complex inhibitor Arpin controls cell migration by interrupting a feedback loop involving Rac-WAVE-Arp2/3 complex Here, the authors use structural, biochemical, and cellular studies to reveal Arpin’s mechanism of inhibition.
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Affiliation(s)
- Fred E Fregoso
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Trevor van Eeuwen
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.,Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, 10065, USA
| | - Gleb Simanov
- Laboratoire de Biologie Structurale de la Cellule, CNRS, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Grzegorz Rebowski
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Malgorzata Boczkowska
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Austin Zimmet
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Alexis M Gautreau
- Laboratoire de Biologie Structurale de la Cellule, CNRS, Institut Polytechnique de Paris, 91128, Palaiseau, France.,Skolkovo Institute of Science and Technology, 121205, Moscow, Russia
| | - Roberto Dominguez
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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28
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Leung G, Zhou Y, Ostrowski P, Mylvaganam S, Boroumand P, Mulder DJ, Guo C, Muise AM, Freeman SA. ARPC1B binds WASP to control actin polymerization and curtail tonic signaling in B cells. JCI Insight 2021; 6:149376. [PMID: 34673575 PMCID: PMC8675194 DOI: 10.1172/jci.insight.149376] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 10/20/2021] [Indexed: 01/08/2023] Open
Abstract
Immune cells exhibit low-level, constitutive signaling at rest (tonic signaling). Such tonic signals are required for fundamental processes, including the survival of B lymphocytes, but when they are elevated by genetic or environmental causes, they can lead to autoimmunity. Events that control ongoing signal transduction are, therefore, tightly regulated by submembrane cytoskeletal polymers like F-actin. The actin-binding proteins that underpin the process, however, are poorly described. By investigating patients with ARPC1B deficiency, we report that ARPC1B-containing ARP2/3 complexes are stimulated by Wiskott Aldrich Syndrome protein (WASP) to nucleate the branched actin networks that control tonic signaling from the B cell receptor (BCR). Despite an upregulation of ARPC1A, ARPC1B-deficient cells were not capable of WASP-mediated nucleation by ARP2/3, and this caused the loss of WASP-dependent structures, including podosomes in macrophages and lamellipodia in B cells. In the B cell compartment, ARPC1B deficiency also led to weakening of the cortical F-actin cytoskeleton that normally curtails the diffusion of BCRs and ultimately resulted in increased tonic lipid signaling, oscillatory calcium release from the endoplasmic reticulum (ER), and phosphorylated Akt. These events contributed to skewing the threshold for B cell activation in response to microbial-associated molecular patterns (MAMPs). Thus, ARPC1B is critical for ARP2/3 complexes to control steady-state signaling of immune cells.
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Affiliation(s)
- Gabriella Leung
- Program in Cell Biology and.,SickKids Inflammatory Bowel Disease Centre, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | | | - Daniel J Mulder
- Program in Cell Biology and.,SickKids Inflammatory Bowel Disease Centre, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Conghui Guo
- Program in Cell Biology and.,SickKids Inflammatory Bowel Disease Centre, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Aleixo M Muise
- Program in Cell Biology and.,SickKids Inflammatory Bowel Disease Centre, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry and.,Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
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29
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Kamnev A, Lacouture C, Fusaro M, Dupré L. Molecular Tuning of Actin Dynamics in Leukocyte Migration as Revealed by Immune-Related Actinopathies. Front Immunol 2021; 12:750537. [PMID: 34867982 PMCID: PMC8634686 DOI: 10.3389/fimmu.2021.750537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 10/12/2021] [Indexed: 01/13/2023] Open
Abstract
Motility is a crucial activity of immune cells allowing them to patrol tissues as they differentiate, sample or exchange information, and execute their effector functions. Although all immune cells are highly migratory, each subset is endowed with very distinct motility patterns in accordance with functional specification. Furthermore individual immune cell subsets adapt their motility behaviour to the surrounding tissue environment. This review focuses on how the generation and adaptation of diversified motility patterns in immune cells is sustained by actin cytoskeleton dynamics. In particular, we review the knowledge gained through the study of inborn errors of immunity (IEI) related to actin defects. Such pathologies are unique models that help us to uncover the contribution of individual actin regulators to the migration of immune cells in the context of their development and function.
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Affiliation(s)
- Anton Kamnev
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria.,Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Claire Lacouture
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), INSERM, CNRS, Toulouse III Paul Sabatier University, Toulouse, France.,Laboratoire De Physique Théorique, IRSAMC, Université De Toulouse (UPS), CNRS, Toulouse, France
| | - Mathieu Fusaro
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), INSERM, CNRS, Toulouse III Paul Sabatier University, Toulouse, France
| | - Loïc Dupré
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria.,Department of Dermatology, Medical University of Vienna, Vienna, Austria.,Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), INSERM, CNRS, Toulouse III Paul Sabatier University, Toulouse, France
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30
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Fujimoto K, Nakano K, Kuwayama H, Yumura S. Deletion of gmfA induces keratocyte-like migration in Dictyostelium. FEBS Open Bio 2021; 12:306-319. [PMID: 34855306 PMCID: PMC8727941 DOI: 10.1002/2211-5463.13339] [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: 10/05/2021] [Revised: 11/15/2021] [Accepted: 11/30/2021] [Indexed: 11/06/2022] Open
Abstract
Glia maturation factor (GMF) has been established as an inactivating factor of the actin‐related protein 2/3 (Arp2/3) complex, which regulates actin assembly. Regulation of actin assembly and reorganization is crucial for various cellular events, such as cell migration, cell division, and development. Here, to examine the roles of ADF‐H domain‐containing protein (also known as glia maturation factor; GmfA), the product of a single GMF homologous gene in Dictyostelium, gmfA‐null cells were generated. They had moderate defects in cell growth and cytokinesis. Interestingly, they showed a keratocyte‐like fan shape with a broader pseudopod, where Arp3 accumulated at higher levels than in wild‐type cells. They migrated with higher persistence, but their velocities were comparable to those of wild‐type cells. The polar pseudopods during cell division were also broader than those in wild‐type cells. However, GmfA did not localize at the pseudopods in migrating cells or the polar pseudopods in dividing cells. Adhesions of mutant cells to the substratum were much stronger than that of wild‐type cells. Although the mutant cells showed chemotaxis comparable to that of wild‐type cells, they formed disconnected streams during the aggregation stage; however, they finally formed normal fruiting bodies. These results suggest that GmfA plays a crucial role in cell migration.
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Affiliation(s)
- Koushiro Fujimoto
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Japan
| | - Kentaro Nakano
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan
| | - Hidekazu Kuwayama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan
| | - Shigehiko Yumura
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Japan
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31
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Gautreau AM, Fregoso FE, Simanov G, Dominguez R. Nucleation, stabilization, and disassembly of branched actin networks. Trends Cell Biol 2021; 32:421-432. [PMID: 34836783 PMCID: PMC9018471 DOI: 10.1016/j.tcb.2021.10.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 12/18/2022]
Abstract
Arp2/3 complex is an actin filament nucleation and branching machinery conserved in all eukaryotes from yeast to human. Arp2/3 complex branched networks generate pushing forces that drive cellular processes ranging from membrane remodeling to cell and organelle motility. Several molecules regulate these processes by directly inhibiting or activating Arp2/3 complex and by stabilizing or disassembling branched networks. Here, we review recent advances in our understanding of Arp2/3 complex regulation, including high-resolution cryoelectron microscopy (cryo-EM) structures that illuminate the mechanisms of Arp2/3 complex activation and branch formation, and novel cellular pathways of branch formation, stabilization, and debranching. We also identify major gaps in our understanding of Arp2/3 complex inhibition and branch stabilization and disassembly.
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Affiliation(s)
- Alexis M Gautreau
- Laboratoire de Biologie Structurale de la Cellule, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France.
| | - Fred E Fregoso
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gleb Simanov
- Laboratoire de Biologie Structurale de la Cellule, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Roberto Dominguez
- Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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32
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Kilo L, Stürner T, Tavosanis G, Ziegler AB. Drosophila Dendritic Arborisation Neurons: Fantastic Actin Dynamics and Where to Find Them. Cells 2021; 10:2777. [PMID: 34685757 PMCID: PMC8534399 DOI: 10.3390/cells10102777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/12/2021] [Accepted: 10/12/2021] [Indexed: 01/27/2023] Open
Abstract
Neuronal dendrites receive, integrate, and process numerous inputs and therefore serve as the neuron's "antennae". Dendrites display extreme morphological diversity across different neuronal classes to match the neuron's specific functional requirements. Understanding how this structural diversity is specified is therefore important for shedding light on information processing in the healthy and diseased nervous system. Popular models for in vivo studies of dendrite differentiation are the four classes of dendritic arborization (c1da-c4da) neurons of Drosophila larvae with their class-specific dendritic morphologies. Using da neurons, a combination of live-cell imaging and computational approaches have delivered information on the distinct phases and the time course of dendrite development from embryonic stages to the fully developed dendritic tree. With these data, we can start approaching the basic logic behind differential dendrite development. A major role in the definition of neuron-type specific morphologies is played by dynamic actin-rich processes and the regulation of their properties. This review presents the differences in the growth programs leading to morphologically different dendritic trees, with a focus on the key role of actin modulatory proteins. In addition, we summarize requirements and technological progress towards the visualization and manipulation of such actin regulators in vivo.
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Affiliation(s)
- Lukas Kilo
- Dendrite Differentiation, German Center for Neurodegenerative Diseases, 53115 Bonn, Germany; (L.K.); (G.T.)
| | - Tomke Stürner
- Department of Zoology, University of Cambridge, Cambridge CB2 1TN, UK;
| | - Gaia Tavosanis
- Dendrite Differentiation, German Center for Neurodegenerative Diseases, 53115 Bonn, Germany; (L.K.); (G.T.)
- LIMES-Institute, University of Bonn, 53115 Bonn, Germany
| | - Anna B. Ziegler
- Institute of Neuro- and Behavioral Biology, University of Münster, 48149 Münster, Germany
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33
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Dondi C, Bertin B, Da Ponte JP, Wojtowicz I, Jagla K, Junion G. A polarized nucleus-cytoskeleton-ECM connection in migrating cardioblasts controls heart tube formation in Drosophila. Development 2021; 148:271094. [PMID: 34323270 DOI: 10.1242/dev.192146] [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: 04/30/2020] [Accepted: 06/29/2021] [Indexed: 11/20/2022]
Abstract
The formation of the cardiac tube is a remarkable example of complex morphogenetic processes conserved from invertebrates to humans. It involves coordinated collective migration of contralateral rows of cardiac cells. The molecular processes underlying the specification of cardioblasts (CBs) prior to migration are well established and significant advances have been made in understanding the process of lumen formation. However, the mechanisms of collective cardiac cells migration remain elusive. Here, we have identified CAP and MSP300 as novel actors involved during CB migration. They both exhibit highly similar temporal and spatial expression patterns in Drosophila migrating cardiac cells, and are necessary for the correct number and alignment of CBs, a prerequisite for the coordination of their collective migration. Our data suggest that CAP and MSP300 are part of a protein complex linking focal adhesion sites to nuclei via the actin cytoskeleton that maintains post-mitotic state and correct alignment of CBs.
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Affiliation(s)
- Cristiana Dondi
- Université Clermont Auvergne, CNRS 6293, Inserm 1103, GReD institute, F-63000 Clermont-Ferrand, France
| | - Benjamin Bertin
- Université Clermont Auvergne, CNRS 6293, Inserm 1103, GReD institute, F-63000 Clermont-Ferrand, France
| | - Jean-Philippe Da Ponte
- Université Clermont Auvergne, CNRS 6293, Inserm 1103, GReD institute, F-63000 Clermont-Ferrand, France
| | - Inga Wojtowicz
- Université Clermont Auvergne, CNRS 6293, Inserm 1103, GReD institute, F-63000 Clermont-Ferrand, France
| | - Krzysztof Jagla
- Université Clermont Auvergne, CNRS 6293, Inserm 1103, GReD institute, F-63000 Clermont-Ferrand, France
| | - Guillaume Junion
- Université Clermont Auvergne, CNRS 6293, Inserm 1103, GReD institute, F-63000 Clermont-Ferrand, France
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34
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Cornelius J, Rottner K, Korte M, Michaelsen-Preusse K. Cortactin Contributes to Activity-Dependent Modulation of Spine Actin Dynamics and Spatial Memory Formation. Cells 2021; 10:cells10071835. [PMID: 34360003 PMCID: PMC8303107 DOI: 10.3390/cells10071835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/21/2023] Open
Abstract
Postsynaptic structures on excitatory neurons, dendritic spines, are actin-rich. It is well known that actin-binding proteins regulate actin dynamics and by this means orchestrate structural plasticity during the development of the brain, as well as synaptic plasticity mediating learning and memory processes. The actin-binding protein cortactin is localized to pre- and postsynaptic structures and translocates in a stimulus-dependent manner between spines and the dendritic compartment, thereby indicating a crucial role for synaptic plasticity and neuronal function. While it is known that cortactin directly binds F-actin, the Arp2/3 complex important for actin nucleation and branching as well as other factors involved in synaptic plasticity processes, its precise role in modulating actin remodeling in neurons needs to be deciphered. In this study, we characterized the general neuronal function of cortactin in knockout mice. Interestingly, we found that the loss of cortactin leads to deficits in hippocampus-dependent spatial memory formation. This impairment is correlated with a prominent dysregulation of functional and structural plasticity. Additional evidence shows impaired long-term potentiation in cortactin knockout mice together with a complete absence of structural spine plasticity. These phenotypes might at least in part be explained by alterations in the activity-dependent modulation of synaptic actin in cortactin-deficient neurons.
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Affiliation(s)
- Jonas Cornelius
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany; (J.C.); (M.K.)
| | - Klemens Rottner
- Research Group Molecular Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
- Division of Molecular Cell Biology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany; (J.C.); (M.K.)
- Research Group Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Kristin Michaelsen-Preusse
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany; (J.C.); (M.K.)
- Correspondence:
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Srivastava S, Macke EL, Swanson LC, Coulter D, Klee EW, Mullegama SV, Xie Y, Lanpher BC, Bedoukian EC, Skraban CM, Villard L, Milh M, Leppert MLO, Cohen JS. Expansion of the Genotypic and Phenotypic Spectrum of WASF1-Related Neurodevelopmental Disorder. Brain Sci 2021; 11:brainsci11070931. [PMID: 34356165 PMCID: PMC8307306 DOI: 10.3390/brainsci11070931] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Accepted: 07/05/2021] [Indexed: 11/18/2022] Open
Abstract
In humans, de novo truncating variants in WASF1 (Wiskott–Aldrich syndrome protein family member 1) have been linked to presentations of moderate-to-profound intellectual disability (ID), autistic features, and epilepsy. Apart from one case series, there is limited information on the phenotypic spectrum and genetic landscape of WASF1-related neurodevelopmental disorder (NDD). In this report, we describe detailed clinical characteristics of six individuals with WASF1-related NDD. We demonstrate a broader spectrum of neurodevelopmental impairment including more mildly affected individuals. Further, we report new variant types, including a copy number variant (CNV), resulting in the partial deletion of WASF1 in monozygotic twins, and three missense variants, two of which alter the same residue, p.W161. This report adds further evidence that de novo variants in WASF1 cause an autosomal dominant NDD.
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Affiliation(s)
- Siddharth Srivastava
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (S.S.); (L.C.S.); (D.C.)
| | - Erica L. Macke
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55902, USA; (E.L.M.); (E.W.K.); (B.C.L.)
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55902, USA
| | - Lindsay C. Swanson
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (S.S.); (L.C.S.); (D.C.)
| | - David Coulter
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (S.S.); (L.C.S.); (D.C.)
| | - Eric W. Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55902, USA; (E.L.M.); (E.W.K.); (B.C.L.)
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN 55902, USA
| | | | - Yili Xie
- GeneDx Inc., Gaithersburg, MD 20877, USA; (S.V.M.); (Y.X.)
| | - Brendan C. Lanpher
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55902, USA; (E.L.M.); (E.W.K.); (B.C.L.)
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55902, USA
| | - Emma C. Bedoukian
- Roberts Individualized Medical Genetics Center, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (E.C.B.); (C.M.S.)
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Cara M. Skraban
- Roberts Individualized Medical Genetics Center, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (E.C.B.); (C.M.S.)
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Laurent Villard
- Department of Medical Genetics, AP-HM, La Timone Children’s Hospital, 13385 Marseille, France;
- Inserm, Marseille Medical Genetics Center, Faculté de Médecine de Marseille, Aix Marseille University, 13385 Marseille, France;
| | - Mathieu Milh
- Inserm, Marseille Medical Genetics Center, Faculté de Médecine de Marseille, Aix Marseille University, 13385 Marseille, France;
- Department of Pediatric Neurology, AP-HM, La Timone Children’s Hospital, 13385 Marseille, France
| | - Mary L. O. Leppert
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA;
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Julie S. Cohen
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA;
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Correspondence:
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Sun H, Zhu X, Li C, Ma Z, Han X, Luo Y, Yang L, Yu J, Miao Y. Xanthomonas effector XopR hijacks host actin cytoskeleton via complex coacervation. Nat Commun 2021; 12:4064. [PMID: 34210966 PMCID: PMC8249405 DOI: 10.1038/s41467-021-24375-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 06/11/2021] [Indexed: 01/09/2023] Open
Abstract
The intrinsically disordered region (IDR) is a preserved signature of phytobacterial type III effectors (T3Es). The T3E IDR is thought to mediate unfolding during translocation into the host cell and to avoid host defense by sequence diversification. Here, we demonstrate a mechanism of host subversion via the T3E IDR. We report that the Xanthomonas campestris T3E XopR undergoes liquid-liquid phase separation (LLPS) via multivalent IDR-mediated interactions that hijack the Arabidopsis actin cytoskeleton. XopR is gradually translocated into host cells during infection and forms a macromolecular complex with actin-binding proteins at the cell cortex. By tuning the physical-chemical properties of XopR-complex coacervates, XopR progressively manipulates multiple steps of actin assembly, including formin-mediated nucleation, crosslinking of F-actin, and actin depolymerization, which occurs through competition for actin-depolymerizing factor and depends on constituent stoichiometry. Our findings unravel a sophisticated strategy in which bacterial T3E subverts the host actin cytoskeleton via protein complex coacervation.
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Affiliation(s)
- He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xinlu Zhu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Chuanxi Li
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yuanyuan Luo
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jing Yu
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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Actin cytoskeleton deregulation confers midostaurin resistance in FLT3-mutant acute myeloid leukemia. Commun Biol 2021; 4:799. [PMID: 34172833 PMCID: PMC8233337 DOI: 10.1038/s42003-021-02215-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 05/07/2021] [Indexed: 12/12/2022] Open
Abstract
The presence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with an unfavorable prognosis. FLT3 inhibitors, such as midostaurin, are used clinically but fail to entirely eradicate FLT3-ITD + AML. This study introduces a new perspective and highlights the impact of RAC1-dependent actin cytoskeleton remodeling on resistance to midostaurin in AML. RAC1 hyperactivation leads resistance via hyperphosphorylation of the positive regulator of actin polymerization N-WASP and antiapoptotic BCL-2. RAC1/N-WASP, through ARP2/3 complex activation, increases the number of actin filaments, cell stiffness and adhesion forces to mesenchymal stromal cells (MSCs) being identified as a biomarker of resistance. Midostaurin resistance can be overcome by a combination of midostaruin, the BCL-2 inhibitor venetoclax and the RAC1 inhibitor Eht1864 in midostaurin-resistant AML cell lines and primary samples, providing the first evidence of a potential new treatment approach to eradicate FLT3-ITD + AML. Garitano-Trojaola et al. used a combination of human acute myeloid leukemia (AML) cell lines and primary samples to show that RAC1-dependent actin cytoskeleton remodeling through BCL2 family plays a key role in resistance to the FLT3 inhibitor, Midostaurin in AML. They showed that by targeting RAC1 and BCL2, Midostaurin resistance was diminished, which potentially paves the way for an innovate treatment approach for FLT3 mutant AML.
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38
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The multiple roles of actin-binding proteins at invadopodia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021. [PMID: 33962752 DOI: 10.1016/bs.ircmb.2021.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Invadopodia are actin-rich membrane protrusions that facilitate cancer cell dissemination by focusing on proteolytic activity and clearing paths for migration through physical barriers, such as basement membranes, dense extracellular matrices, and endothelial cell junctions. Invadopodium formation and activity require spatially and temporally regulated changes in actin filament organization and dynamics. About three decades of research have led to a remarkable understanding of how these changes are orchestrated by sequential recruitment and coordinated activity of different sets of actin-binding proteins. In this chapter, we provide an update on the roles of the actin cytoskeleton during the main stages of invadopodium development with a particular focus on actin polymerization machineries and production of pushing forces driving extracellular matrix remodeling.
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39
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Ma Z, Liu X, Nath S, Sun H, Tran TM, Yang L, Mayor S, Miao Y. Formin nanoclustering-mediated actin assembly during plant flagellin and DSF signaling. Cell Rep 2021; 34:108884. [PMID: 33789103 DOI: 10.1016/j.celrep.2021.108884] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/11/2021] [Accepted: 02/25/2021] [Indexed: 12/19/2022] Open
Abstract
Plants respond to bacterial infection acutely with actin remodeling during plant immune responses. The mechanisms by which bacterial virulence factors (VFs) modulate plant actin polymerization remain enigmatic. Here, we show that plant-type-I formin serves as the molecular sensor for actin remodeling in response to two bacterial VFs: Xanthomonas campestris pv. campestris (Xcc) diffusible signal factor (DSF), and pathogen-associated molecular pattern (PAMP) flagellin in pattern-triggered immunity (PTI). Both VFs regulate actin assembly by tuning the clustering and nucleation activity of formin on the plasma membrane (PM) at the nano-sized scale. By being integrated within the cell-wall-PM-actin cytoskeleton (CW-PM-AC) continuum, the dynamic behavior and function of formins are highly dependent on each scaffold layer's composition within the CW-PM-AC continuum during both DSF and PTI signaling. Our results reveal a central mechanism for rapid actin remodeling during plant-bacteria interactions, in which bacterial signaling molecules fine tune plant formin nanoclustering in a host mechanical-structure-dependent manner.
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Affiliation(s)
- Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xiaolin Liu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Sangeeta Nath
- Institute for Stem Cell Biology and Regenerative Medicine, Bellary Road, Bangalore 560065, India; Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore 560065, India
| | - He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Tuan Minh Tran
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Blvd., Nanshan District, Shenzhen 518055, China
| | - Satyajit Mayor
- Institute for Stem Cell Biology and Regenerative Medicine, Bellary Road, Bangalore 560065, India; National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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40
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Fäßler F, Dimchev G, Hodirnau VV, Wan W, Schur FKM. Cryo-electron tomography structure of Arp2/3 complex in cells reveals new insights into the branch junction. Nat Commun 2020; 11:6437. [PMID: 33353942 PMCID: PMC7755917 DOI: 10.1038/s41467-020-20286-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/24/2020] [Indexed: 12/21/2022] Open
Abstract
The actin-related protein (Arp)2/3 complex nucleates branched actin filament networks pivotal for cell migration, endocytosis and pathogen infection. Its activation is tightly regulated and involves complex structural rearrangements and actin filament binding, which are yet to be understood. Here, we report a 9.0 Å resolution structure of the actin filament Arp2/3 complex branch junction in cells using cryo-electron tomography and subtomogram averaging. This allows us to generate an accurate model of the active Arp2/3 complex in the branch junction and its interaction with actin filaments. Notably, our model reveals a previously undescribed set of interactions of the Arp2/3 complex with the mother filament, significantly different to the previous branch junction model. Our structure also indicates a central role for the ArpC3 subunit in stabilizing the active conformation.
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Affiliation(s)
- Florian Fäßler
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | - Georgi Dimchev
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | | | - William Wan
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, United States of America
| | - Florian K M Schur
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.
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41
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Aliyu IA, Kumurya AS, Bala JA, Yahaya H, Saidu H. Proteomes, kinases and signalling pathways in virus-induced filopodia, as potential antiviral therapeutics targets. Rev Med Virol 2020; 31:1-9. [PMID: 33314425 PMCID: PMC7883202 DOI: 10.1002/rmv.2202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 11/29/2020] [Accepted: 11/30/2020] [Indexed: 12/17/2022]
Abstract
Filopodia are thin finger-like protrusions at the surface of cells that are internally occupied with bundles of tightly parallel actin filaments. They play significant roles in cellular physiological processes, such as adhesion to extracellular matrix, guidance towards chemo-attractants and in wound healing. Filopodia were recently reported to play important roles in viral infection including initial viral attachment to host cells, cell surfing, viral trafficking, internalization, budding, virus release and spread to other cells in a form that would avoid the host immune system. The detailed virus-host protein interactions underlying most of these processes remain to be elucidated. This review will describe some reported virus-host protein interactions on filopodia with the aim of identifying potential new anti-virus therapeutic targets. Exploring this research area may lead to the development of novel classes of anti-viral therapeutics that can block signalling pathways used by the virus to trigger filopodia formation. Successful compounds would inhibit initial virus attachment, formation of filopodia, expression of putative virus binding protein, extracellular virus trafficking, and budding.
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Affiliation(s)
- Isah Abubakar Aliyu
- Department of Medical Laboratory Science, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, Kano State, Nigeria
| | - Abdulhadi Sale Kumurya
- Department of Medical Laboratory Science, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, Kano State, Nigeria
| | - Jamilu Abubakar Bala
- Department of Medical Laboratory Science, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, Kano State, Nigeria.,Virology Unit, Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University Putra Malaysia, Selangor, Malaysia
| | - Hassan Yahaya
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Science, University Putra Malaysia, Selangor, Malaysia.,Department of Medical Laboratory Science, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, Kano State, Nigeria
| | - Hayatu Saidu
- Department of Medical Laboratory Science, Faculty of Allied Health Sciences, College of Health Sciences, Bayero University Kano, Kano State, Nigeria
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42
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Ma Z, Miao Y. Review: F-Actin remodelling during plant signal transduction via biomolecular assembly. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 301:110663. [PMID: 33218630 DOI: 10.1016/j.plantsci.2020.110663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
During signal transduction, multivalent interactions establish dynamic molecular connectivities that propagate molecular cascades throughout the entire signaling pathway. Such multivalent interactions include the initial activation, cascade signal transduction, and the amplification and assembly of structural machinery. For example, plants rapidly remodel the actin cytoskeleton during signal transduction by perceiving a wide range of mechanical and chemical cues from developmental and defense pathways. Actin treadmilling is stepwise-regulated by interactions between actin and actin-binding proteins (ABPs). Emerging evidence shows that intrinsically disordered regions (IDRs) enable flexible and promiscuous interactions that serve as the functional hub for generating cellular interactomes underlying various signaling events. Though IDRs are present in a majority of ABPs, few of the functional roles of IDR in the interaction and functions of ABPs have been defined. The distinct features of IDRs create diverse and dynamic molecular interactions that introduce a new paradigm to our understanding of the structure-function relationships for actin assembly. In this review, we will create a snapshot of recent advances in IDR-mediated plant actin remodeling and discuss future research directions in studying the complexity of actin assembly via multifaceted biomolecular assembly during signal transduction.
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Affiliation(s)
- Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
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43
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Nuclear F-actin counteracts nuclear deformation and promotes fork repair during replication stress. Nat Cell Biol 2020; 22:1460-1470. [PMID: 33257806 DOI: 10.1038/s41556-020-00605-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 10/26/2020] [Indexed: 12/25/2022]
Abstract
Filamentous actin (F-actin) provides cells with mechanical support and promotes the mobility of intracellular structures. Although F-actin is traditionally considered to be cytoplasmic, here we reveal that nuclear F-actin participates in the replication stress response. Using live and super-resolution imaging, we find that nuclear F-actin is polymerized in response to replication stress through a pathway regulated by ATR-dependent activation of mTORC1, and nucleation through IQGAP1, WASP and ARP2/3. During replication stress, nuclear F-actin increases the nuclear volume and sphericity to counteract nuclear deformation. Furthermore, F-actin and myosin II promote the mobility of stressed-replication foci to the nuclear periphery through increasingly diffusive motion and directed movements along the nuclear actin filaments. These actin functions promote replication stress repair and suppress chromosome and mitotic abnormalities. Moreover, we find that nuclear F-actin is polymerized in vivo in xenograft tumours after treatment with replication-stress-inducing chemotherapeutic agents, indicating that this pathway has a role in human disease.
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44
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Balzer CJ, James ML, Narvaez-Ortiz HY, Helgeson LA, Sirotkin V, Nolen BJ. Synergy between Wsp1 and Dip1 may initiate assembly of endocytic actin networks. eLife 2020; 9:60419. [PMID: 33179595 PMCID: PMC7707826 DOI: 10.7554/elife.60419] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/10/2020] [Indexed: 12/30/2022] Open
Abstract
The actin filament nucleator Arp2/3 complex is activated at cortical sites in Schizosaccharomyces pombe to assemble branched actin networks that drive endocytosis. Arp2/3 complex activators Wsp1 and Dip1 are required for proper actin assembly at endocytic sites, but how they coordinately control Arp2/3-mediated actin assembly is unknown. Alone, Dip1 activates Arp2/3 complex without preexisting actin filaments to nucleate ‘seed’ filaments that activate Wsp1-bound Arp2/3 complex, thereby initiating branched actin network assembly. In contrast, because Wsp1 requires preexisting filaments to activate, it has been assumed to function exclusively in propagating actin networks by stimulating branching from preexisting filaments. Here we show that Wsp1 is important not only for propagation but also for initiation of endocytic actin networks. Using single molecule total internal reflection fluorescence microscopy we show that Wsp1 synergizes with Dip1 to co-activate Arp2/3 complex. Synergistic co-activation does not require preexisting actin filaments, explaining how Wsp1 contributes to actin network initiation in cells.
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Affiliation(s)
- Connor J Balzer
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, United States
| | - Michael L James
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, United States
| | - Heidy Y Narvaez-Ortiz
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, United States
| | - Luke A Helgeson
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, United States
| | - Vladimir Sirotkin
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, United States
| | - Brad J Nolen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon, Eugene, United States
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45
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Involvement of Actin and Actin-Binding Proteins in Carcinogenesis. Cells 2020; 9:cells9102245. [PMID: 33036298 PMCID: PMC7600575 DOI: 10.3390/cells9102245] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/18/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022] Open
Abstract
The actin cytoskeleton plays a crucial role in many cellular processes while its reorganization is important in maintaining cell homeostasis. However, in the case of cancer cells, actin and ABPs (actin-binding proteins) are involved in all stages of carcinogenesis. Literature has reported that ABPs such as SATB1 (special AT-rich binding protein 1), WASP (Wiskott-Aldrich syndrome protein), nesprin, and villin take part in the initial step of carcinogenesis by regulating oncogene expression. Additionally, changes in actin localization promote cell proliferation by inhibiting apoptosis (SATB1). In turn, migration and invasion of cancer cells are based on the formation of actin-rich protrusions (Arp2/3 complex, filamin A, fascin, α-actinin, and cofilin). Importantly, more and more scientists suggest that microfilaments together with the associated proteins mediate tumor vascularization. Hence, the presented article aims to summarize literature reports in the context of the potential role of actin and ABPs in all steps of carcinogenesis.
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46
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Tang Q, Schaks M, Koundinya N, Yang C, Pollard LW, Svitkina TM, Rottner K, Goode BL. WAVE1 and WAVE2 have distinct and overlapping roles in controlling actin assembly at the leading edge. Mol Biol Cell 2020; 31:2168-2178. [PMID: 32697617 PMCID: PMC7550694 DOI: 10.1091/mbc.e19-12-0705] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
SCAR/WAVE proteins and Arp2/3 complex assemble branched actin networks at the leading edge. Two isoforms of SCAR/WAVE, WAVE1 and WAVE2, reside at the leading edge, yet it has remained unclear whether they perform similar or distinct roles. Further, there have been conflicting reports about the Arp2/3-independent biochemical activities of WAVE1 on actin filament elongation. To investigate this in vivo, we knocked out WAVE1 and WAVE2 genes, individually and together, in B16-F1 melanoma cells. We demonstrate that WAVE1 and WAVE2 are redundant for lamellipodia formation and motility. However, there is a significant decrease in the rate of leading edge actin extension in WAVE2 KO cells, and an increase in WAVE1 KO cells. The faster rates of actin extension in WAVE1 KO cells are offset by faster retrograde flow, and therefore do not translate into faster lamellipodium protrusion. Thus, WAVE1 restricts the rate of actin extension at the leading edge, and appears to couple actin networks to the membrane to drive protrusion. Overall, these results suggest that WAVE1 and WAVE2 have redundant roles in promoting Arp2/3-dependent actin nucleation and lamellipodia formation, but distinct roles in controlling actin network extension and harnessing network growth to cell protrusion.
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Affiliation(s)
- Qing Tang
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Matthias Schaks
- Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Neha Koundinya
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Tatyana M Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Klemens Rottner
- Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA 02454
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47
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Orbach R, Su X. Surfing on Membrane Waves: Microvilli, Curved Membranes, and Immune Signaling. Front Immunol 2020; 11:2187. [PMID: 33013920 PMCID: PMC7516127 DOI: 10.3389/fimmu.2020.02187] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/11/2020] [Indexed: 01/22/2023] Open
Abstract
Microvilli are finger-like membrane protrusions, supported by the actin cytoskeleton, and found on almost all cell types. A growing body of evidence suggests that the dynamic lymphocyte microvilli, with their highly curved membranes, play an important role in signal transduction leading to immune responses. Nevertheless, challenges in modulating local membrane curvature and monitoring the high dynamicity of microvilli hampered the investigation of the curvature-generation mechanism and its functional consequences in signaling. These technical barriers have been partially overcome by recent advancements in adapted super-resolution microscopy. Here, we review the up-to-date progress in understanding the mechanisms and functional consequences of microvillus formation in T cell signaling. We discuss how the deformation of local membranes could potentially affect the organization of signaling proteins and their biochemical activities. We propose that curved membranes, together with the underlying cytoskeleton, shape microvilli into a unique compartment that sense and process signals leading to lymphocyte activation.
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Affiliation(s)
- Ron Orbach
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, United States
| | - Xiaolei Su
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, United States
- Yale Cancer Center, Yale University, New Haven, CT, United States
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Shaaban M, Chowdhury S, Nolen BJ. Cryo-EM reveals the transition of Arp2/3 complex from inactive to nucleation-competent state. Nat Struct Mol Biol 2020; 27:1009-1016. [PMID: 32839613 DOI: 10.1038/s41594-020-0481-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/10/2020] [Indexed: 12/29/2022]
Abstract
Arp2/3 complex, a crucial actin filament nucleator, undergoes structural rearrangements during activation by nucleation-promoting factors (NPFs). However, the conformational pathway leading to the nucleation-competent state is unclear due to lack of high-resolution structures of the activated state. Here we report a ~3.9 Å resolution cryo-EM structure of activated Schizosaccharomyces pombe Arp2/3 complex bound to the S. pombe NPF Dip1 and attached to the end of the nucleated actin filament. The structure reveals global and local conformational changes that allow the two actin-related proteins in Arp2/3 complex to mimic a filamentous actin dimer and template nucleation. Activation occurs through a clamp-twisting mechanism, in which Dip1 forces two core subunits in Arp2/3 complex to pivot around one another, shifting half of the complex into a new activated position. By showing how Dip1 stimulates activation, the structure reveals how NPFs can activate Arp2/3 complex in diverse cellular processes.
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Affiliation(s)
- Mohammed Shaaban
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Saikat Chowdhury
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
| | - Brad J Nolen
- Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA.
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Zimmet A, Van Eeuwen T, Boczkowska M, Rebowski G, Murakami K, Dominguez R. Cryo-EM structure of NPF-bound human Arp2/3 complex and activation mechanism. SCIENCE ADVANCES 2020; 6:6/23/eaaz7651. [PMID: 32917641 PMCID: PMC7274804 DOI: 10.1126/sciadv.aaz7651] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 04/16/2020] [Indexed: 05/12/2023]
Abstract
Actin-related protein (Arp) 2/3 complex nucleates branched actin networks that drive cell motility. It consists of seven proteins, including two actin-related subunits (Arp2 and Arp3). Two nucleation-promoting factors (NPFs) bind Arp2/3 complex during activation, but the order, specific interactions, and contribution of each NPF to activation are unresolved. Here, we report the cryo-electron microscopy structure of recombinantly expressed human Arp2/3 complex with two WASP family NPFs bound and address the mechanism of activation. A cross-linking assay that captures the transition of the Arps into the activated filament-like conformation shows that actin binding to NPFs favors this transition. Actin-NPF binding to Arp2 precedes binding to Arp3 and is sufficient to promote the filament-like conformation but not activation. Structure-guided mutagenesis of the NPF-binding sites reveals their distinct roles in activation and shows that, contrary to budding yeast Arp2/3 complex, NPF-mediated delivery of actin at the barbed end of both Arps is required for activation of human Arp2/3 complex.
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Affiliation(s)
- Austin Zimmet
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Trevor Van Eeuwen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Grzegorz Rebowski
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Abstract
Cell migration is an essential process, both in unicellular organisms such as amoeba and as individual or collective motility in highly developed multicellular organisms like mammals. It is controlled by a variety of activities combining protrusive and contractile forces, normally generated by actin filaments. Here, we summarize actin filament assembly and turnover processes, and how respective biochemical activities translate into different protrusion types engaged in migration. These actin-based plasma membrane protrusions include actin-related protein 2/3 complex-dependent structures such as lamellipodia and membrane ruffles, filopodia as well as plasma membrane blebs. We also address observed antagonisms between these protrusion types, and propose a model - also inspired by previous literature - in which a complex balance between specific Rho GTPase signaling pathways dictates the protrusion mechanism employed by cells. Furthermore, we revisit published work regarding the fascinating antagonism between Rac and Rho GTPases, and how this intricate signaling network can define cell behavior and modes of migration. Finally, we discuss how the assembly of actin filament networks can feed back onto their regulators, as exemplified for the lamellipodial factor WAVE regulatory complex, tightly controlling accumulation of this complex at specific subcellular locations as well as its turnover.
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