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Aydin F, Katkar HH, Morganthaler A, Harker AJ, Kovar DR, Voth GA. Prediction of the essential intermolecular contacts for side-binding of VASP on F-actin. Cytoskeleton (Hoboken) 2024; 81:382-392. [PMID: 38647032 PMCID: PMC11333183 DOI: 10.1002/cm.21864] [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: 12/13/2023] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/25/2024]
Abstract
Vasodilator-stimulated phosphoprotein (VASP) family proteins play a crucial role in mediating the actin network architecture in the cytoskeleton. The Ena/VASP homology 2 (EVH2) domain in each of the four identical arms of the tetrameric VASP consists of a loading poly-Pro region, a G-actin-binding domain (GAB), and an F-actin-binding domain (FAB). Together, the poly-Pro, GAB, and FAB domains allow VASP to bind to sides of actin filaments in a bundle, and recruit profilin-G-actin to processively elongate the filaments. The atomic resolution structure of the ternary complex, consisting of the loading poly-Pro region and GAB domain of VASP with profilin-actin, has been solved over a decade ago; however, a detailed structure of the FAB-F-actin complex has not been resolved to date. Experimental insights, based on homology of the FAB domain with the C region of WASP, have been used to hypothesize that the FAB domain binds to the cleft between subdomains 1 and 3 of F-actin. Here, in order to develop our understanding of the VASP-actin complex, we first augment known structural information about the GAB domain binding to actin with the missing FAB domain-actin structure, which we predict using homology modeling and docking simulations. In earlier work, we used mutagenesis and kinetic modeling to study the role of domain-level binding-unbinding kinetics of Ena/VASP on actin filaments in a bundle, specifically on the side of actin filaments. We further look at the nature of the side-binding of the FAB domain of VASP at the atomistic level using our predicted structure, and tabulate effective mutation sites on the FAB domain that would disrupt the VASP-actin complex. We test the binding affinity of Ena with mutated FAB domain using total internal reflection fluorescence microscopy experiments. The binding affinity of VASP is affected significantly for the mutant, providing additional support for our predicted structure.
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Affiliation(s)
- Fikret Aydin
- Department of Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
| | - Harshwardhan H. Katkar
- Department of Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
| | - Alisha Morganthaler
- Department of Biochemistry and Molecular Biology and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Alyssa J. Harker
- Department of Biochemistry and Molecular Biology and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - David R. Kovar
- Department of Biochemistry and Molecular Biology and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Gregory A. Voth
- Department of Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
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2
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Nozumi M, Sato Y, Nishiyama-Usuda M, Igarashi M. Identification of z-axis filopodia in growth cones using super-resolution microscopy. J Neurochem 2024. [PMID: 38946488 DOI: 10.1111/jnc.16162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 05/02/2024] [Accepted: 06/10/2024] [Indexed: 07/02/2024]
Abstract
A growth cone is a highly motile tip of an extending axon that is crucial for neural network formation. Three-dimensional-structured illumination microscopy, a type of super-resolution light microscopy with a resolution that overcomes the optical diffraction limitation (ca. 200 nm) of conventional light microscopy, is well suited for studying the molecular dynamics of intracellular events. Using this technique, we discovered a novel type of filopodia distributed along the z-axis ("z-filopodia") within the growth cone. Z-filopodia were typically oriented in the direction of axon growth, not attached to the substratum, protruded spontaneously without microtubule invasion, and had a lifetime that was considerably shorter than that of conventional filopodia. Z-filopodia formation and dynamics were regulated by actin-regulatory proteins, such as vasodilator-stimulated phosphoprotein, fascin, and cofilin. Chromophore-assisted laser inactivation of cofilin induced the rapid turnover of z-filopodia. An axon guidance receptor, neuropilin-1, was concentrated in z-filopodia and was transported together with them, whereas its ligand, semaphorin-3A, was selectively bound to them. Membrane domains associated with z-filopodia were also specialized and resembled those of lipid rafts, and their behaviors were closely related to those of neuropilin-1. The results suggest that z-filopodia have unique turnover properties, and unlike xy-filopodia, do not function as force-generating structures for axon extension.
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Affiliation(s)
- Motohiro Nozumi
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
| | - Yuta Sato
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
| | - Miyako Nishiyama-Usuda
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
| | - Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, School of Medicine, and Graduate School of Medical/Dental Sciences, Niigata University, Niigata, Japan
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3
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Boyer NP, Sharma R, Wiesner T, Delamare A, Pelletier F, Leterrier C, Roy S. Spectrin condensates provide a nidus for assembling the periodic axonal structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.05.597638. [PMID: 38895400 PMCID: PMC11185721 DOI: 10.1101/2024.06.05.597638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Coordinated assembly of individual components into higher-order structures is a defining theme in biology, but underlying principles are not well-understood. In neurons, α/β spectrins, adducin, and actinfilaments assemble into a lattice wrapping underneath the axonal plasma membrane, but mechanistic events leading to this periodic axonal structure (PAS) are unclear. Visualizing PAS components in axons as they develop, we found focal patches in distal axons containing spectrins and adducin (but sparse actin filaments) with biophysical properties reminiscent of biomolecular condensation. Overexpressing spectrin-repeats - constituents of α/β-spectrins - in heterologous cells triggered condensate formation, and preventing association of βII-spectrin with actin-filaments/membranes also facilitated condensation. Finally, overexpressing condensate-triggering spectrin repeats in neurons before PAS establishment disrupted the lattice, presumably by competing with innate assembly, supporting a functional role for biomolecular condensation. We propose a condensation-assembly model where PAS components form focal phase-separated condensates that eventually unfurl into a stable lattice-structure by associating with subplasmalemmal actin. By providing local 'depots' of assembly parts, biomolecular condensation may play a wider role in the construction of intricate cytoskeletal structures.
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4
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Chandrasekaran A, Graham K, Stachowiak JC, Rangamani P. Kinetic trapping organizes actin filaments within liquid-like protein droplets. Nat Commun 2024; 15:3139. [PMID: 38605007 PMCID: PMC11009352 DOI: 10.1038/s41467-024-46726-6] [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: 06/05/2023] [Accepted: 03/07/2024] [Indexed: 04/13/2024] Open
Abstract
Several actin-binding proteins (ABPs) phase separate to form condensates capable of curating the actin network shapes. Here, we use computational modeling to understand the principles of actin network organization within VASP condensate droplets. Our simulations reveal that the different actin shapes, namely shells, rings, and mixture states are highly dependent on the kinetics of VASP-actin interactions, suggesting that they arise from kinetic trapping. Specifically, we show that reducing the residence time of VASP on actin filaments reduces degree of bundling, thereby promoting assembly of shells rather than rings. We validate the model predictions experimentally using a VASP-mutant with decreased bundling capability. Finally, we investigate the ring opening within deformed droplets and found that the sphere-to-ellipsoid transition is favored under a wide range of filament lengths while the ellipsoid-to-rod transition is only permitted when filaments have a specific range of lengths. Our findings highlight key mechanisms of actin organization within phase-separated ABPs.
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Affiliation(s)
- Aravind Chandrasekaran
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093-0411, USA
| | - Kristin Graham
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, 78712, USA
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, 78712, USA.
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, 78712, USA.
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093-0411, USA.
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Blake TCA, Fox HM, Urbančič V, Ravishankar R, Wolowczyk A, Allgeyer ES, Mason J, Danuser G, Gallop JL. Filopodial protrusion driven by density-dependent Ena-TOCA-1 interactions. J Cell Sci 2024; 137:jcs261057. [PMID: 38323924 PMCID: PMC11006392 DOI: 10.1242/jcs.261057] [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: 02/08/2023] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
Filopodia are narrow actin-rich protrusions with important roles in neuronal development where membrane-binding adaptor proteins, such as I-BAR- and F-BAR-domain-containing proteins, have emerged as upstream regulators that link membrane interactions to actin regulators such as formins and proteins of the Ena/VASP family. Both the adaptors and their binding partners are part of diverse and redundant protein networks that can functionally compensate for each other. To explore the significance of the F-BAR domain-containing neuronal membrane adaptor TOCA-1 (also known as FNBP1L) in filopodia we performed a quantitative analysis of TOCA-1 and filopodial dynamics in Xenopus retinal ganglion cells, where Ena/VASP proteins have a native role in filopodial extension. Increasing the density of TOCA-1 enhances Ena/VASP protein binding in vitro, and an accumulation of TOCA-1, as well as its coincidence with Ena, correlates with filopodial protrusion in vivo. Two-colour single-molecule localisation microscopy of TOCA-1 and Ena supports their nanoscale association. TOCA-1 clusters promote filopodial protrusion and this depends on a functional TOCA-1 SH3 domain and activation of Cdc42, which we perturbed using the small-molecule inhibitor CASIN. We propose that TOCA-1 clusters act independently of membrane curvature to recruit and promote Ena activity for filopodial protrusion.
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Affiliation(s)
- Thomas C. A. Blake
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Helen M. Fox
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Vasja Urbančič
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Roshan Ravishankar
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Adam Wolowczyk
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Edward S. Allgeyer
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Julia Mason
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jennifer L. Gallop
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
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6
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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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7
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McCormick LE, Suarez C, Herring LE, Cannon KS, Kovar DR, Brown NG, Gupton SL. Multi-monoubiquitylation controls VASP-mediated actin dynamics. J Cell Sci 2024; 137:jcs261527. [PMID: 38277158 PMCID: PMC10917064 DOI: 10.1242/jcs.261527] [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: 07/28/2023] [Accepted: 12/13/2023] [Indexed: 01/13/2024] Open
Abstract
The actin cytoskeleton performs multiple cellular functions, and as such, actin polymerization must be tightly regulated. We previously demonstrated that reversible, non-degradative ubiquitylation regulates the function of the actin polymerase VASP in developing neurons. However, the underlying mechanism of how ubiquitylation impacts VASP activity was unknown. Here, we show that mimicking multi-monoubiquitylation of VASP at K240 and K286 negatively regulates VASP interactions with actin. Using in vitro biochemical assays, we demonstrate the reduced ability of multi-monoubiquitylated VASP to bind, bundle, and elongate actin filaments. However, multi-monoubiquitylated VASP maintained the ability to bind and protect barbed ends from capping protein. Finally, we demonstrate the electroporation of recombinant multi-monoubiquitylated VASP protein altered cell spreading morphology. Collectively, these results suggest a mechanism in which ubiquitylation controls VASP-mediated actin dynamics.
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Affiliation(s)
- Laura E. McCormick
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Laura E. Herring
- Michael Hooker Proteomics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kevin S. Cannon
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David R. Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Nicholas G. Brown
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Stephanie L. Gupton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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8
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Suarez C, Winkelman JD, Harker AJ, Ye HJ, McCall PM, Morganthaler AN, Gardel ML, Kovar DR. Reconstitution of the transition from a lamellipodia- to filopodia-like actin network with purified proteins. Eur J Cell Biol 2023; 102:151367. [PMID: 37890285 DOI: 10.1016/j.ejcb.2023.151367] [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: 06/22/2023] [Revised: 09/29/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
How cells utilize complex mixtures of actin binding proteins to assemble and maintain functionally diverse actin filament networks with distinct architectures and dynamics within a common cytoplasm is a longstanding question in cell biology. A compelling example of complex and specialized actin structures in cells are filopodia which sense extracellular chemical and mechanical signals to help steer motile cells. Filopodia have distinct actin architecture, composed of long, parallel actin filaments bundled by fascin, which form finger-like membrane protrusions. Elongation of the parallel actin filaments in filopodia can be mediated by two processive actin filament elongation factors, formin and Ena/VASP, which localize to the tips of filopodia. There remains debate as to how the architecture of filopodia are generated, with one hypothesis proposing that filopodia are generated from the lamellipodia, which consists of densely packed, branched actin filaments nucleated by Arp2/3 complex and kept short by capping protein. It remains unclear if different actin filament elongation factors are necessary and sufficient to facilitate the emergence of filopodia with diverse characteristics from a highly dense network of short-branched capped filaments. To address this question, we combined bead motility and micropatterning biomimetic assays with multi-color Total Internal Reflection Fluorescence microscopy imaging, to successfully reconstitute the formation of filopodia-like networks (FLN) from densely-branched lamellipodia-like networks (LLN) with eight purified proteins (actin, profilin, Arp2/3 complex, Wasp pWA, fascin, capping protein, VASP and formin mDia2). Saturating capping protein concentrations inhibit FLN assembly, but the addition of either formin or Ena/VASP differentially rescues the formation of FLN from LLN. Specifically, we found that formin/mDia2-generated FLNs are relatively long and lack capping protein, whereas VASP-generated FLNs are comparatively short and contain capping protein, indicating that the actin elongation factor can affect the architecture and composition of FLN emerging from LLN. Our biomimetic reconstitution systems reveal that formin or VASP are necessary and sufficient to induce the transition from a LLN to a FLN, and establish robust in vitro platforms to investigate FLN assembly mechanisms.
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Affiliation(s)
- Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
| | - Jonathan D Winkelman
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
| | - Alyssa J Harker
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Hannah J Ye
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Patrick M McCall
- Department of Physics, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Alisha N Morganthaler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Department of Physics, The University of Chicago, Chicago, IL 60637, USA; James Franck Institute, The University of Chicago, Chicago, IL 60637, USA; Pritzker School for Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA.
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9
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Li W, Chung WL, Kozlov MM, Medalia O, Geiger B, Bershadsky AD. Chiral growth of adherent filopodia. Biophys J 2023; 122:3704-3721. [PMID: 37301982 PMCID: PMC10541518 DOI: 10.1016/j.bpj.2023.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/03/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023] Open
Abstract
Adherent filopodia are elongated finger-like membrane protrusions, extending from the edges of diverse cell types and participating in cell adhesion, spreading, migration, and environmental sensing. The formation and elongation of filopodia are driven by the polymerization of parallel actin filaments, comprising the filopodia cytoskeletal core. Here, we report that adherent filopodia, formed during the spreading of cultured cells on galectin-8-coated substrates, tend to change the direction of their extension in a chiral fashion, acquiring a left-bent shape. Cryoelectron tomography examination indicated that turning of the filopodia tip to the left is accompanied by the displacement of the actin core bundle to the right of the filopodia midline. Reduction of the adhesion to galectin-8 by treatment with thiodigalactoside abolished this filopodia chirality. By modulating the expression of a variety of actin-associated filopodia proteins, we identified myosin-X and formin DAAM1 as major filopodia chirality promoting factors. Formin mDia1, actin filament elongation factor VASP, and actin filament cross-linker fascin were also shown to be involved. Thus, the simple actin cytoskeleton of filopodia, together with a small number of associated proteins are sufficient to drive a complex navigation process, manifested by the development of left-right asymmetry in these cellular protrusions.
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Affiliation(s)
- Wenhong Li
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Wen-Lu Chung
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Benjamin Geiger
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel.
| | - Alexander D Bershadsky
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel; Mechanobiology Institute, National University of Singapore, Singapore, Singapore.
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10
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Bai Y, Zhao F, Wu T, Chen F, Pang X. Actin polymerization and depolymerization in developing vertebrates. Front Physiol 2023; 14:1213668. [PMID: 37745245 PMCID: PMC10515290 DOI: 10.3389/fphys.2023.1213668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/22/2023] [Indexed: 09/26/2023] Open
Abstract
Development is a complex process that occurs throughout the life cycle. F-actin, a major component of the cytoskeleton, is essential for the morphogenesis of tissues and organs during development. F-actin is formed by the polymerization of G-actin, and the dynamic balance of polymerization and depolymerization ensures proper cellular function. Disruption of this balance results in various abnormalities and defects or even embryonic lethality. Here, we reviewed recent findings on the structure of G-actin and F-actin and the polymerization of G-actin to F-actin. We also focused on the functions of actin isoforms and the underlying mechanisms of actin polymerization/depolymerization in cellular and organic morphogenesis during development. This information will extend our understanding of the role of actin polymerization in the physiologic or pathologic processes during development and may open new avenues for developing therapeutics for embryonic developmental abnormalities or tissue regeneration.
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Affiliation(s)
- Yang Bai
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Feng Zhao
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Tingting Wu
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Fangchun Chen
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Xiaoxiao Pang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
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11
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Benz PM, Frömel T, Laban H, Zink J, Ulrich L, Groneberg D, Boon RA, Poley P, Renne T, de Wit C, Fleming I. Cardiovascular Functions of Ena/VASP Proteins: Past, Present and Beyond. Cells 2023; 12:1740. [PMID: 37443774 PMCID: PMC10340426 DOI: 10.3390/cells12131740] [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: 04/26/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Actin binding proteins are of crucial importance for the spatiotemporal regulation of actin cytoskeletal dynamics, thereby mediating a tremendous range of cellular processes. Since their initial discovery more than 30 years ago, the enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family has evolved as one of the most fascinating and versatile family of actin regulating proteins. The proteins directly enhance actin filament assembly, but they also organize higher order actin networks and link kinase signaling pathways to actin filament assembly. Thereby, Ena/VASP proteins regulate dynamic cellular processes ranging from membrane protrusions and trafficking, and cell-cell and cell-matrix adhesions, to the generation of mechanical tension and contractile force. Important insights have been gained into the physiological functions of Ena/VASP proteins in platelets, leukocytes, endothelial cells, smooth muscle cells and cardiomyocytes. In this review, we summarize the unique and redundant functions of Ena/VASP proteins in cardiovascular cells and discuss the underlying molecular mechanisms.
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Affiliation(s)
- Peter M. Benz
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
| | - Timo Frömel
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Hebatullah Laban
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Joana Zink
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Lea Ulrich
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Dieter Groneberg
- Institute of Physiology I, University of Würzburg, 97070 Würzburg, Germany
| | - Reinier A. Boon
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
- Cardiopulmonary Institute, 60596 Frankfurt am Main, Germany
- Centre of Molecular Medicine, Institute of Cardiovascular Regeneration, Goethe-University, 60596 Frankfurt am Main, Germany
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Centre, 1081 HZ Amsterdam, The Netherlands
| | - Philip Poley
- Institut für Physiologie, Universität zu Lübeck, 23562 Lübeck, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 23562 Lübeck, Germany
| | - Thomas Renne
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- Center for Thrombosis and Hemostasis (CTH), Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, D02 VN51 Dublin, Ireland
| | - Cor de Wit
- Institut für Physiologie, Universität zu Lübeck, 23562 Lübeck, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 23562 Lübeck, Germany
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
- Cardiopulmonary Institute, 60596 Frankfurt am Main, Germany
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12
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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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13
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Parker SS, Ly KT, Grant AD, Sweetland J, Wang AM, Parker JD, Roman MR, Saboda K, Roe DJ, Padi M, Wolgemuth CW, Langlais P, Mouneimne G. EVL and MIM/MTSS1 regulate actin cytoskeletal remodeling to promote dendritic filopodia in neurons. J Cell Biol 2023; 222:e202106081. [PMID: 36828364 PMCID: PMC9998662 DOI: 10.1083/jcb.202106081] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/22/2022] [Accepted: 01/20/2023] [Indexed: 02/25/2023] Open
Abstract
Dendritic spines are the postsynaptic compartment of a neuronal synapse and are critical for synaptic connectivity and plasticity. A developmental precursor to dendritic spines, dendritic filopodia (DF), facilitate synapse formation by sampling the environment for suitable axon partners during neurodevelopment and learning. Despite the significance of the actin cytoskeleton in driving these dynamic protrusions, the actin elongation factors involved are not well characterized. We identified the Ena/VASP protein EVL as uniquely required for the morphogenesis and dynamics of DF. Using a combination of genetic and optogenetic manipulations, we demonstrated that EVL promotes protrusive motility through membrane-direct actin polymerization at DF tips. EVL forms a complex at nascent protrusions and DF tips with MIM/MTSS1, an I-BAR protein important for the initiation of DF. We proposed a model in which EVL cooperates with MIM to coalesce and elongate branched actin filaments, establishing the dynamic lamellipodia-like architecture of DF.
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Affiliation(s)
- Sara S. Parker
- Department of Cellular and Molecular Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Kenneth Tran Ly
- Department of Cellular and Molecular Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Adam D. Grant
- Cancer Biology Program, University of Arizona Cancer Center, Tucson, AZ, USA
| | - Jillian Sweetland
- Department of Cellular and Molecular Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Ashley M. Wang
- Department of Cellular and Molecular Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - James D. Parker
- Department of Cellular and Molecular Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Mackenzie R. Roman
- Division of Endocrinology, Department of Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Kathylynn Saboda
- University of Arizona Cancer Center and Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
| | - Denise J. Roe
- University of Arizona Cancer Center and Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
| | - Megha Padi
- Cancer Biology Program, University of Arizona Cancer Center, Tucson, AZ, USA
- Department of Molecular and Cellular Biology, College of Science, University of Arizona, Tucson, AZ, USA
| | - Charles W. Wolgemuth
- University of Arizona Cancer Center and Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
- Department of Molecular and Cellular Biology, College of Science, University of Arizona, Tucson, AZ, USA
- Department of Physics, College of Science, University of Arizona, Tucson, AZ, USA
- Johns Hopkins Physical Sciences-Oncology Center, Johns Hopkins University, Baltimore, MD, USA
| | - Paul Langlais
- Division of Endocrinology, Department of Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Ghassan Mouneimne
- Department of Cellular and Molecular Medicine, College of Medicine, University of Arizona, Tucson, AZ, USA
- Cancer Biology Program, University of Arizona Cancer Center, Tucson, AZ, USA
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14
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Graham K, Chandrasekaran A, Wang L, Ladak A, Lafer EM, Rangamani P, Stachowiak JC. Liquid-like VASP condensates drive actin polymerization and dynamic bundling. NATURE PHYSICS 2023; 19:574-585. [PMID: 38405682 PMCID: PMC10887402 DOI: 10.1038/s41567-022-01924-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 12/15/2022] [Indexed: 02/27/2024]
Abstract
The organization of actin filaments into bundles is required for cellular processes such as motility, morphogenesis, and cell division. Filament bundling is controlled by a network of actin-binding proteins. Recently, several proteins that comprise this network have been found to undergo liquid-liquid phase separation. How might liquid-like condensates contribute to filament bundling? Here, we show that the processive actin polymerase and bundling protein, VASP, forms liquid-like droplets under physiological conditions. As actin polymerizes within VASP droplets, elongating filaments partition to the edges of the droplet to minimize filament curvature, forming an actin-rich ring within the droplet. The rigidity of this ring is balanced by the droplet's surface tension, as predicted by a continuum-scale computational model. However, as actin polymerizes and the ring grows thicker, its rigidity increases and eventually overcomes the surface tension of the droplet, deforming into a linear bundle. The resulting bundles contain long, parallel actin filaments that grow from their tips. Significantly, the fluid nature of the droplets is critical for bundling, as more solid droplets resist deformation, preventing filaments from rearranging to form bundles. Once the parallel arrangement of filaments is created within a VASP droplet, it propagates through the addition of new actin monomers to achieve a length that is many times greater than the initial droplet. This droplet-based mechanism of bundling may be relevant to the assembly of cellular architectures rich in parallel actin filaments, such as filopodia, stress fibers, and focal adhesions.
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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
| | - Aly Ladak
- 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
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15
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Visweshwaran SP, Nayab H, Hoffmann L, Gil M, Liu F, Kühne R, Maritzen T. Ena/VASP proteins at the crossroads of actin nucleation pathways in dendritic cell migration. Front Cell Dev Biol 2022; 10:1008898. [PMID: 36274843 PMCID: PMC9581539 DOI: 10.3389/fcell.2022.1008898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/12/2022] [Indexed: 12/05/2022] Open
Abstract
As sentinels of our immune system dendritic cells (DCs) rely on efficient cell migration for patrolling peripheral tissues and delivering sampled antigens to secondary lymphoid organs for the activation of T-cells. Dynamic actin polymerization is key to their macropinocytic and migratory properties. Both major actin nucleation machineries, formins and the Arp2/3 complex, are critical for different aspects of DC functionality, by driving the generation of linear and branched actin filaments, respectively. However, the importance of a third group of actin nucleators, the Ena/VASP family, has not been addressed yet. Here, we show that the two family members Evl and VASP are expressed in murine DCs and that their loss negatively affects DC macropinocytosis, spreading, and migration. Our interactome analysis reveals Ena/VASP proteins to be ideally positioned for orchestrating the different actin nucleation pathways by binding to the formin mDia1 as well as to the WAVE regulatory complex, a stimulator of Arp2/3. In fact, Evl/VASP deficient murine DCs are more vulnerable to inhibition of Arp2/3 demonstrating that Ena/VASP proteins contribute to the robustness and efficiency of DC migration.
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Affiliation(s)
| | - Hafiza Nayab
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Lennart Hoffmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Marine Gil
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Fan Liu
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Ronald Kühne
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Tanja Maritzen
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
- Department of Nanophysiology, Technische Universität Kaiserslautern, Kaiserslautern, Germany
- *Correspondence: Tanja Maritzen,
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16
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Thompson SB, Waldman MM, Jacobelli J. Polymerization power: effectors of actin polymerization as regulators of T lymphocyte migration through complex environments. FEBS J 2022; 289:6154-6171. [PMID: 34273243 PMCID: PMC8761786 DOI: 10.1111/febs.16130] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/24/2021] [Accepted: 07/16/2021] [Indexed: 11/26/2022]
Abstract
During their life span, T cells are tasked with patrolling the body for potential pathogens. To do so, T cells migrate through numerous distinct anatomical sites and tissue environments with different biophysical characteristics. To migrate through these different environments, T cells use various motility strategies that rely on actin network remodeling to generate shape changes and mechanical forces. In this review, we initially discuss the migratory journey of T cells and then cover the actin polymerization effectors at play in T cells, and finally, we focus on the function of these effectors of actin cytoskeleton remodeling in mediating T-cell migration through diverse tissue environments. Specifically, we will discuss the current state of the field pertaining to our understanding of the roles in T-cell migration played by members of the three main families of actin polymerization machinery: the Arp2/3 complex; formin proteins; and Ena/VASP proteins.
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Affiliation(s)
- Scott B. Thompson
- Department of Immunology and Microbiology, University of Colorado School of Medicine
| | - Monique M. Waldman
- Department of Immunology and Microbiology, University of Colorado School of Medicine
- Barbara Davis Research Center, University of Colorado School of Medicine
| | - Jordan Jacobelli
- Department of Immunology and Microbiology, University of Colorado School of Medicine
- Barbara Davis Research Center, University of Colorado School of Medicine
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17
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Triantopoulou N, Vidaki M. Local mRNA translation and cytoskeletal reorganization: Mechanisms that tune neuronal responses. Front Mol Neurosci 2022; 15:949096. [PMID: 35979146 PMCID: PMC9376447 DOI: 10.3389/fnmol.2022.949096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/07/2022] [Indexed: 12/31/2022] Open
Abstract
Neurons are highly polarized cells with significantly long axonal and dendritic extensions that can reach distances up to hundreds of centimeters away from the cell bodies in higher vertebrates. Their successful formation, maintenance, and proper function highly depend on the coordination of intricate molecular networks that allow axons and dendrites to quickly process information, and respond to a continuous and diverse cascade of environmental stimuli, often without enough time for communication with the soma. Two seemingly unrelated processes, essential for these rapid responses, and thus neuronal homeostasis and plasticity, are local mRNA translation and cytoskeletal reorganization. The axonal cytoskeleton is characterized by high stability and great plasticity; two contradictory attributes that emerge from the powerful cytoskeletal rearrangement dynamics. Cytoskeletal reorganization is crucial during nervous system development and in adulthood, ensuring the establishment of proper neuronal shape and polarity, as well as regulating intracellular transport and synaptic functions. Local mRNA translation is another mechanism with a well-established role in the developing and adult nervous system. It is pivotal for axonal guidance and arborization, synaptic formation, and function and seems to be a key player in processes activated after neuronal damage. Perturbations in the regulatory pathways of local translation and cytoskeletal reorganization contribute to various pathologies with diverse clinical manifestations, ranging from intellectual disabilities (ID) to autism spectrum disorders (ASD) and schizophrenia (SCZ). Despite the fact that both processes are essential for the orchestration of pathways critical for proper axonal and dendritic function, the interplay between them remains elusive. Here we review our current knowledge on the molecular mechanisms and specific interaction networks that regulate and potentially coordinate these interconnected processes.
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Affiliation(s)
- Nikoletta Triantopoulou
- Division of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece
| | - Marina Vidaki
- Division of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece
- *Correspondence: Marina Vidaki,
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18
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Application of piconewton forces to individual filopodia reveals mechanosensory role of L-type Ca 2+ channels. Biomaterials 2022; 284:121477. [PMID: 35395455 DOI: 10.1016/j.biomaterials.2022.121477] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 03/18/2022] [Indexed: 11/02/2022]
Abstract
Filopodia are ubiquitous membrane projections that play crucial role in guiding cell migration on rigid substrates and through extracellular matrix by utilizing yet unknown mechanosensing molecular pathways. As recent studies show that Ca2+ channels localized to filopodia play an important role in regulation of their formation and since some Ca2+ channels are known to be mechanosensitive, force-dependent activity of filopodial Ca2+ channels might be linked to filopodia's mechanosensing function. We tested this hypothesis by monitoring changes in the intra-filopodial Ca2+ level in response to application of stretching force to individual filopodia of several cell types using optical tweezers. Results show that stretching forces of tens of pN strongly promote Ca2+ influx into filopodia, causing persistent Ca2+ oscillations that last for minutes even after the force is released. Several known mechanosensitive Ca2+ channels, such as Piezo 1, Piezo 2 and TRPV4, were found to be dispensable for the observed force-dependent Ca2+ influx, while L-type Ca2+ channels appear to be a key player in the discovered phenomenon. As previous studies have shown that intra-filopodial transient Ca2+ signals play an important role in guidance of cell migration, our results suggest that the force-dependent activation of L-type Ca2+ channels may contribute to this process. Overall, our study reveals an intricate interplay between mechanical forces and Ca2+ signaling in filopodia, providing novel mechanistic insights for the force-dependent filopodia functions in guidance of cell migration.
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19
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Faix J, Rottner K. Ena/VASP proteins in cell edge protrusion, migration and adhesion. J Cell Sci 2022; 135:274697. [DOI: 10.1242/jcs.259226] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
ABSTRACT
The tightly coordinated, spatiotemporal control of actin filament remodeling provides the basis of fundamental cellular processes, such as cell migration and adhesion. Specific protein assemblies, composed of various actin-binding proteins, are thought to operate in these processes to nucleate and elongate new filaments, arrange them into complex three-dimensional (3D) arrays and recycle them to replenish the actin monomer pool. Actin filament assembly is not only necessary to generate pushing forces against the leading edge membrane or to propel pathogens through the cytoplasm, but also coincides with the generation of stress fibers (SFs) and focal adhesions (FAs) that generate, transmit and sense mechanical tension. The only protein families known to date that directly enhance the elongation of actin filaments are formins and the family of Ena/VASP proteins. Their mechanisms of action, however, in enhancing processive filament elongation are distinct. The aim of this Review is to summarize our current knowledge on the molecular mechanisms of Ena/VASP-mediated actin filament assembly, and to discuss recent insights into the cell biological functions of Ena/VASP proteins in cell edge protrusion, migration and adhesion.
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Affiliation(s)
- Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
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20
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Lyu J, Cheng C. Regulation of Alternative Splicing during Epithelial-Mesenchymal Transition. Cells Tissues Organs 2022; 211:238-251. [PMID: 34348273 PMCID: PMC8741878 DOI: 10.1159/000518249] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 06/28/2021] [Indexed: 01/03/2023] Open
Abstract
Alternative splicing is an essential mechanism of gene regulation, giving rise to remarkable protein diversity in higher eukaryotes. Epithelial-mesenchymal transition (EMT) is a developmental process that plays an essential role in metazoan embryogenesis. Recent studies have revealed that alternative splicing serves as a fundamental layer of regulation that governs cells to undergo EMT. In this review, we summarize recent findings on the functional impact of alternative splicing in EMT and EMT-associated activities. We then discuss the regulatory mechanisms that control alternative splicing changes during EMT.
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Affiliation(s)
- Jingyi Lyu
- Lester and Sue Smith Breast Center, Department of Molecular
& Human Genetics, Department of Molecular & Cellular Biology, Baylor College
of Medicine, Houston, TX 77030, USA,Integrative Molecular and Biomedical Sciences Graduate
Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chonghui Cheng
- Lester and Sue Smith Breast Center, Department of Molecular
& Human Genetics, Department of Molecular & Cellular Biology, Baylor College
of Medicine, Houston, TX 77030, USA,Integrative Molecular and Biomedical Sciences Graduate
Program, Baylor College of Medicine, Houston, TX 77030, USA.,To whom correspondence should be addressed:
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21
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Ganguly A, Sharma R, Boyer NP, Wernert F, Phan S, Boassa D, Parra L, Das U, Caillol G, Han X, Yates JR, Ellisman MH, Leterrier C, Roy S. Clathrin packets move in slow axonal transport and deliver functional payloads to synapses. Neuron 2021; 109:2884-2901.e7. [PMID: 34534453 DOI: 10.1016/j.neuron.2021.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 06/10/2021] [Accepted: 08/13/2021] [Indexed: 12/25/2022]
Abstract
In non-neuronal cells, clathrin has established roles in endocytosis, with clathrin cages enclosing plasma membrane infoldings, followed by rapid disassembly and reuse of monomers. However, in neurons, clathrin is conveyed in slow axonal transport over days to weeks, and the underlying transport/targeting mechanisms, mobile cargo structures, and even its precise presynaptic localization and physiologic role are unclear. Combining live imaging, photobleaching/conversion, mass spectrometry, electron microscopy, and super-resolution imaging, we found that unlike in dendrites, where clathrin cages rapidly assemble and disassemble, in axons, clathrin and related proteins organize into stable "transport packets" that are unrelated to endocytosis and move intermittently on microtubules, generating an overall slow anterograde flow. At synapses, multiple clathrin packets abut synaptic vesicle (SV) clusters, and clathrin packets also exchange between synaptic boutons in a microtubule-dependent "superpool." Within synaptic boundaries, clathrin is surprisingly dynamic, continuously exchanging between local clathrin assemblies, and its depletion impairs SV recycling. Our data provide a conceptual framework for understanding clathrin trafficking and presynaptic targeting that has functional implications.
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Affiliation(s)
- Archan Ganguly
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Rohan Sharma
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Nicholas P Boyer
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Florian Wernert
- Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, Marseille, France
| | - Sébastien Phan
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, USA
| | - Daniela Boassa
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, USA
| | - Leonardo Parra
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Utpal Das
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA; Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Ghislaine Caillol
- Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, Marseille, France
| | - Xuemei Han
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - John R Yates
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Mark H Ellisman
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, USA
| | | | - Subhojit Roy
- Department of Pathology, University of California, San Diego, La Jolla, CA, USA; Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA.
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22
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Structural analysis of receptors and actin polarity in platelet protrusions. Proc Natl Acad Sci U S A 2021; 118:2105004118. [PMID: 34504018 PMCID: PMC8449362 DOI: 10.1073/pnas.2105004118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2021] [Indexed: 11/18/2022] Open
Abstract
During activation the platelet cytoskeleton is reorganized, inducing adhesion to the extracellular matrix and cell spreading. These processes are critical for wound healing and clot formation. Initially, this task relies on the formation of strong cellular-extracellular matrix interactions, exposed in subendothelial lesions. Despite the medical relevance of these processes, there is a lack of high-resolution structural information on the platelet cytoskeleton controlling cell spreading and adhesion. Here, we present in situ structural analysis of membrane receptors and the underlying cytoskeleton in platelet protrusions by applying cryoelectron tomography to intact platelets. We utilized three-dimensional averaging procedures to study receptors at the plasma membrane. Analysis of substrate interaction-free receptors yielded one main structural class resolved to 26 Å, resembling the αIIbβ3 integrin folded conformation. Furthermore, structural analysis of the actin network in pseudopodia indicates a nonuniform polarity of filaments. This organization would allow generation of the contractile forces required for integrin-mediated cell adhesion.
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23
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Arthur AL, Crawford A, Houdusse A, Titus MA. VASP-mediated actin dynamics activate and recruit a filopodia myosin. eLife 2021; 10:68082. [PMID: 34042588 PMCID: PMC8352590 DOI: 10.7554/elife.68082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 11/17/2022] Open
Abstract
Filopodia are thin, actin-based structures that cells use to interact with their environments. Filopodia initiation requires a suite of conserved proteins but the mechanism remains poorly understood. The actin polymerase VASP and a MyTH-FERM (MF) myosin, DdMyo7 in amoeba, are essential for filopodia initiation. DdMyo7 is localized to dynamic regions of the actin-rich cortex. Analysis of VASP mutants and treatment of cells with anti-actin drugs shows that myosin recruitment and activation in Dictyostelium requires localized VASP-dependent actin polymerization. Targeting of DdMyo7 to the cortex alone is not sufficient for filopodia initiation; VASP activity is also required. The actin regulator locally produces a cortical actin network that activates myosin and together they shape the actin network to promote extension of parallel bundles of actin during filopodia formation. This work reveals how filopodia initiation requires close collaboration between an actin-binding protein, the state of the actin cytoskeleton and MF myosin activity.
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Affiliation(s)
- Ashley L Arthur
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Amy Crawford
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, Paris, France
| | - Margaret A Titus
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
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24
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Trefzer R, Elpeleg O, Gabrusskaya T, Stepensky P, Mor-Shaked H, Grosse R, Brandt DT. Characterization of a L136P mutation in Formin-like 2 (FMNL2) from a patient with chronic inflammatory bowel disease. PLoS One 2021; 16:e0252428. [PMID: 34043722 PMCID: PMC8158924 DOI: 10.1371/journal.pone.0252428] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 05/16/2021] [Indexed: 12/19/2022] Open
Abstract
Diaphanous related formins are highly conserved proteins regulated by Rho-GTPases that act as actin nucleation and assembly factors. Here we report the functional characterization of a non-inherited heterozygous FMNL2 p.L136P mutation carried by a patient who presented with severe very early onset inflammatory bowel disease (IBD). We found that the FMNL2 L136P protein displayed subcellular mislocalization and deregulated protein autoinhibition indicating gain-of-function mechanism. Expression of FMNL2 L136P impaired cell spreading as well as filopodia formation. THP-1 macrophages expressing FMNL2 L136P revealed dysregulated podosome formation and a defect in matrix degradation. Our data indicate that the L136P mutation affects cellular actin dynamics in fibroblasts and immune cells such as macrophages.
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Affiliation(s)
- Raphael Trefzer
- Institute of Pharmacology, University of Marburg, Marburg, Germany
| | - Orly Elpeleg
- Department of Genetics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Tatyana Gabrusskaya
- Department of Gastroenterology, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
| | - Polina Stepensky
- Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Hagar Mor-Shaked
- Department of Genetics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Robert Grosse
- Institute of Pharmacology, University of Marburg, Marburg, Germany
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
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25
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Dobramysl U, Jarsch IK, Inoue Y, Shimo H, Richier B, Gadsby JR, Mason J, Szałapak A, Ioannou PS, Correia GP, Walrant A, Butler R, Hannezo E, Simons BD, Gallop JL. Stochastic combinations of actin regulatory proteins are sufficient to drive filopodia formation. J Cell Biol 2021; 220:e202003052. [PMID: 33740033 PMCID: PMC7980258 DOI: 10.1083/jcb.202003052] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 11/23/2020] [Accepted: 01/12/2021] [Indexed: 11/22/2022] Open
Abstract
Assemblies of actin and its regulators underlie the dynamic morphology of all eukaryotic cells. To understand how actin regulatory proteins work together to generate actin-rich structures such as filopodia, we analyzed the localization of diverse actin regulators within filopodia in Drosophila embryos and in a complementary in vitro system of filopodia-like structures (FLSs). We found that the composition of the regulatory protein complex where actin is incorporated (the filopodial tip complex) is remarkably heterogeneous both in vivo and in vitro. Our data reveal that different pairs of proteins correlate with each other and with actin bundle length, suggesting the presence of functional subcomplexes. This is consistent with a theoretical framework where three or more redundant subcomplexes join the tip complex stochastically, with any two being sufficient to drive filopodia formation. We provide an explanation for the observed heterogeneity and suggest that a mechanism based on multiple components allows stereotypical filopodial dynamics to arise from diverse upstream signaling pathways.
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Affiliation(s)
- Ulrich Dobramysl
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Iris Katharina Jarsch
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Yoshiko Inoue
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Hanae Shimo
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Benjamin Richier
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jonathan R. Gadsby
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Julia Mason
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alicja Szałapak
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Pantelis Savvas Ioannou
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Astrid Walrant
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Richard Butler
- Gurdon Institute, University of Cambridge, Cambridge, UK
| | - Edouard Hannezo
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Benjamin D. Simons
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - Jennifer L. Gallop
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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26
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Hu H, Li C, Zhang H, Wu G, Huang Y. Role of vasodilator-stimulated phosphoprotein in RANKL-differentiated murine macrophage RAW264.7 cells: Modulation of NF-κB, c-Fos and NFATc1 transcription factors. Exp Ther Med 2021; 21:412. [PMID: 33747153 PMCID: PMC7967814 DOI: 10.3892/etm.2021.9856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 09/22/2020] [Indexed: 12/16/2022] Open
Abstract
Vasodilator-stimulated phosphoprotein (VASP) is essential for osteoclast differentiation, and reduced VASP expression results in depressed osteoclast differentiation. Previously, we demonstrated the importance of VASP and Ras-related C3 botulinum toxin substrate 1 interactions in osteosarcoma cell migration and metastasis using Mg-63 and Saos2 cells. However, the molecular details of the functional role of VASP in cell motility and migration remain to be elucidated. The present study demonstrated that VASP affects the expression of αV-integrin, tartrate-resistant acid phosphatase (TRAP) and lamellipodia protrusion in RAW 264.7 murine macrophage cells. The RAW 264.7 mouse monocyte macrophage cell line was used as an osteoclast precursor. RAW 264.7 cells were treated with 50 ng/ml of receptor activator of nuclear factor κ-Β ligand (RANKL) in order to induce cell differentiation (osteoclastogenesis). Small interfering RNA (siRNA) was used to silence VASP, and RT-PCR and western blotting were used to determine the expression for genes and proteins, respectively. TRAP staining as a histochemical marker for osteoclast and fluorescent microscopy for lamellipodia protrusion was performed. RANKL treatment significantly increased the gene and protein expression of VASP, αV-integrin and TRAP in RAW 264.7 cells. Silencing of VASP significantly reduced the RANKL-induced expression of αV-integrin, TRAP and lamellipodia protrusion. In addition, knockdown of VASP attenuated RANKL-stimulated activation of NF-κB, c-Fos and nuclear factor of activated T cells cytoplasmic 1 transcription factors, and the phosphorylation of the p65 and IκBα. These results suggest the critical role of VASP in regulating osteoclast differentiation, which should be further explored in osteosarcoma research.
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Affiliation(s)
- Hao Hu
- Department of Traditional Chinese Traumatology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430061, P.R. China.,Department of Traditional Chinese Traumatology, Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei 430070, P.R. China
| | - Chao Li
- Department of Traditional Chinese Traumatology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430061, P.R. China.,Department of Traditional Chinese Traumatology, Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei 430070, P.R. China
| | - Haitao Zhang
- Department of Traditional Chinese Traumatology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430061, P.R. China.,Department of Traditional Chinese Traumatology, Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei 430070, P.R. China
| | - Gang Wu
- Department of Traditional Chinese Traumatology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430061, P.R. China.,Department of Traditional Chinese Traumatology, Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei 430070, P.R. China
| | - Yong Huang
- Department of Traditional Chinese Traumatology, Hubei Provincial Hospital of Traditional Chinese Medicine, Wuhan, Hubei 430061, P.R. China.,Department of Traditional Chinese Traumatology, Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei 430070, P.R. China
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27
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Zink J, Frye M, Frömel T, Carlantoni C, John D, Schreier D, Weigert A, Laban H, Salinas G, Stingl H, Günther L, Popp R, Hu J, Vanhollebeke B, Schmidt H, Acker-Palmer A, Renné T, Fleming I, Benz PM. EVL regulates VEGF receptor-2 internalization and signaling in developmental angiogenesis. EMBO Rep 2021; 22:e48961. [PMID: 33512764 PMCID: PMC7857432 DOI: 10.15252/embr.201948961] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Endothelial tip cells are essential for VEGF‐induced angiogenesis, but underlying mechanisms are elusive. The Ena/VASP protein family, consisting of EVL, VASP, and Mena, plays a pivotal role in axon guidance. Given that axonal growth cones and endothelial tip cells share many common features, from the morphological to the molecular level, we investigated the role of Ena/VASP proteins in angiogenesis. EVL and VASP, but not Mena, are expressed in endothelial cells of the postnatal mouse retina. Global deletion of EVL (but not VASP) compromises the radial sprouting of the vascular plexus in mice. Similarly, endothelial‐specific EVL deletion compromises the radial sprouting of the vascular plexus and reduces the endothelial tip cell density and filopodia formation. Gene sets involved in blood vessel development and angiogenesis are down‐regulated in EVL‐deficient P5‐retinal endothelial cells. Consistently, EVL deletion impairs VEGF‐induced endothelial cell proliferation and sprouting, and reduces the internalization and phosphorylation of VEGF receptor 2 and its downstream signaling via the MAPK/ERK pathway. Together, we show that endothelial EVL regulates sprouting angiogenesis via VEGF receptor‐2 internalization and signaling.
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Affiliation(s)
- Joana Zink
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Maike Frye
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Timo Frömel
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Claudia Carlantoni
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - David John
- German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany.,Insitute for Cardiovascular Regeneration, Goethe University, Frankfurt am Main, Germany
| | - Danny Schreier
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas Weigert
- Institute of Biochemistry I-Pathobiochemistry, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
| | - Hebatullah Laban
- Department of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Gabriela Salinas
- NGS-Integrative Genomics Core Unit (NIG), Institute of Human Genetics, University Medical Center Göttingen (UMG), Göttingen, Germany
| | - Heike Stingl
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Lea Günther
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Rüdiger Popp
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Jiong Hu
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Benoit Vanhollebeke
- Laboratory of Neurovascular Signaling, ULB Neuroscience Institute Department of Molecular Biology, University of Brussels, Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Amparo Acker-Palmer
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt am Main, Germany
| | - Thomas Renné
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ingrid Fleming
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Peter M Benz
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
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28
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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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29
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Borriello L, Karagiannis GS, Duran CL, Coste A, Oktay MH, Entenberg D, Condeelis JS. The role of the tumor microenvironment in tumor cell intravasation and dissemination. Eur J Cell Biol 2020; 99:151098. [PMID: 32800278 DOI: 10.1016/j.ejcb.2020.151098] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/15/2020] [Accepted: 06/29/2020] [Indexed: 01/11/2023] Open
Abstract
Metastasis, a process that requires tumor cell dissemination followed by tumor growth, is the primary cause of death in cancer patients. An essential step of tumor cell dissemination is intravasation, a process by which tumor cells cross the blood vessel endothelium and disseminate to distant sites. Studying this process is of utmost importance given that intravasation in the primary tumor, as well as the secondary and tertiary metastases, is the key step in the systemic spread of tumor cells, and that this process continues even after removal of the primary tumor. High-resolution intravital imaging of the tumor microenvironment of breast carcinoma has revealed that tumor cell intravasation exclusively occurs at doorways, termed "Tumor MicroEnvironment of Metastasis" (TMEM), composed of three different cell types: a Tie2high/VEGFhigh perivascular macrophage, a Mena overexpressing tumor cell, and an endothelial cell, all in direct contact. In this review article, we discuss the interactions between these cell types, the subsequent signaling events which lead to tumor cell intravasation, and the role of invadopodia in supporting tumor cell invasion and dissemination. We end our review by discussing how the knowledge acquired from the use of intravital imaging is now leading to new clinical trials targeting tumor cell dissemination and preventing metastatic progression.
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Affiliation(s)
- Lucia Borriello
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA.
| | - George S Karagiannis
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Integrated Imaging Program, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA
| | - Camille L Duran
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Integrated Imaging Program, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA
| | - Anouchka Coste
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Department of Surgery, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA
| | - Maja H Oktay
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Integrated Imaging Program, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Department of Pathology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA
| | - David Entenberg
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Integrated Imaging Program, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA.
| | - John S Condeelis
- Department of Anatomy and Structural Biology, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Gruss-Lipper Biophotonics Center, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Integrated Imaging Program, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA; Department of Surgery, Einstein College of Medicine, Montefiore Medical Center, Bronx, NY, USA.
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30
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Gallop J. Filopodia and their links with membrane traffic and cell adhesion. Semin Cell Dev Biol 2020; 102:81-89. [DOI: 10.1016/j.semcdb.2019.11.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/14/2019] [Accepted: 11/28/2019] [Indexed: 01/24/2023]
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32
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Khalid Z, Sezerman OU. A comprehensive study on identifying the structural and functional SNPs of human neuronal membrane glycoprotein M6A (GPM6A). J Biomol Struct Dyn 2020; 39:2693-2701. [PMID: 32248748 DOI: 10.1080/07391102.2020.1751712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glycoprotein M6A, a stress related gene, plays an important role in synapse and filopodia formation. Filopodia formation is vital for development, immunity, angiogenesis, wound healing and metastasis. In this study, structural and functional analysis of high-risk SNPs associated with Glycoprotein M6-A were evaluated using six different bioinformatics tools. Results classified T210I, T134I, Y153H, I215T, F156L, T160I, I226T, R247W, R178C, W159R, N157S and P151L as deleterious mutants that are crucial for the structure and function of the protein causing malfunction of M6-a and ultimately leads to disease development. The three-dimensional structure of wild-type M6-a and mutant M6-a were also predicted. Furthermore, the effects of high risk substitutions were also analyzed with interaction with valproic acid. Based on structural models obtained, the binding pocket of ligand bound glycoprotein M6-A structure showed few core interacting residues which are different in the mutant models. Among all substitutions, F156L showed complete loss of binding pocket when interacting with valproic acid as compared to the wild type model. Up to the best of our knowledge this is the first comprehensive study where GPM6A mutations were analyzed. The mechanism of action of GPM6A is still not fully defined which limits the understanding of functional details encoding M6-A. Our results may help enlighten some molecular aspects underlying glycoprotein M6-A. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Zoya Khalid
- National University of Computers and Emerging Sciences, FAST-NU, Islamabad, Pakistan
| | - Osman Ugur Sezerman
- Department of Biostatistics and Medical Informatics, Acibadem University, Istanbul, Turkey
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33
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Bocanegra JL, Fujita BM, Melton NR, Cowan JM, Schinski EL, Tamir TY, Major MB, Quintero OA. The MyMOMA domain of MYO19 encodes for distinct Miro-dependent and Miro-independent mechanisms of interaction with mitochondrial membranes. Cytoskeleton (Hoboken) 2020; 77:149-166. [PMID: 31479585 PMCID: PMC8556674 DOI: 10.1002/cm.21560] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/13/2019] [Accepted: 08/31/2019] [Indexed: 08/19/2023]
Abstract
MYO19 interacts with mitochondria through a C-terminal membrane association domain (MyMOMA). Specific mechanisms for localization of MYO19 to mitochondria are poorly understood. Using promiscuous biotinylation data in combination with existing affinity-capture databases, we have identified a number of putative MYO19-interacting proteins. We chose to explore the interaction between MYO19 and the mitochondrial GTPase Miro2 by expressing mchr-Miro2 in combination with GFP-tagged fragments of the MyMOMA domain and assaying for recruitment of MYO19-GFP to mitochondria. Coexpression of MYO19898-970 -GFP with mchr-Miro2 enhanced MYO19898-970 -GFP localization to mitochondria. Mislocalizing Miro2 to filopodial tips or the cytosolic face of the nuclear envelope did not recruit MYO19898-970 -GFP to either location. To address the kinetics of the Miro2/MYO19 interaction, we used FRAP analysis and permeabilization-activated reduction in fluorescence analysis. MyMOMA constructs containing a putative membrane-insertion motif but lacking the Miro2-interacting region displayed slow exchange kinetics. MYO19898-970 -GFP, which does not include the membrane-insertion motif, displayed rapid exchange kinetics, suggesting that MYO19 interacting with Miro2 has higher mobility than MYO19 inserted into the mitochondrial outer membrane. Mutation of well-conserved, charged residues within MYO19 or within the switch I and II regions of Miro2 abolished the enhancement of MYO19898-970 -GFP localization in cells ectopically expressing mchr-Miro2. Additionally, expressing mutant versions of Miro2 thought to represent particular nucleotide states indicated that the enhancement of MYO19898-970 -GFP localization is dependent on Miro2 nucleotide state. Taken together, these data suggest that membrane-inserted MYO19 is part of a larger complex, and that Miro2 plays a role in integration of actin- and microtubule-based mitochondrial activities.
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Affiliation(s)
| | | | | | - James M. Cowan
- Department of Biology, University of Richmond, Richmond, Virginia
| | | | - Tigist Y. Tamir
- Department of Pharmacology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina
| | - Michael B. Major
- Department of Pharmacology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina
- Department of Cell Biology and Physiology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina
- Lineberger Comprehensive Cancer Center, University of North Carolina Chapel Hill, Chapel Hill, North Carolina
| | - Omar A. Quintero
- Department of Biology, University of Richmond, Richmond, Virginia
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34
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Iwasaki K, Obashi K, Okabe S. Vasodilator‐stimulated phosphoprotein (VASP) is recruited into dendritic spines via G‐actin‐dependent mechanism and contributes to spine enlargement and stabilization. Eur J Neurosci 2019; 51:806-821. [DOI: 10.1111/ejn.14634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 11/11/2019] [Accepted: 11/26/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Kanako Iwasaki
- Department of Cellular Neurobiology Graduate School of Medicine The University of Tokyo Tokyo Japan
| | - Kazuki Obashi
- Department of Cellular Neurobiology Graduate School of Medicine The University of Tokyo Tokyo Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology Graduate School of Medicine The University of Tokyo Tokyo Japan
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35
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Boyer NP, McCormick LE, Menon S, Urbina FL, Gupton SL. A pair of E3 ubiquitin ligases compete to regulate filopodial dynamics and axon guidance. J Biophys Biochem Cytol 2019; 219:132731. [PMID: 31820781 PMCID: PMC7039193 DOI: 10.1083/jcb.201902088] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 09/25/2019] [Accepted: 10/25/2019] [Indexed: 02/08/2023] Open
Abstract
Appropriate axon guidance is necessary to form accurate neuronal connections. Axon guidance cues that stimulate cytoskeletal reorganization within the growth cone direct axon navigation. Filopodia at the growth cone periphery have long been considered sensors for axon guidance cues, yet how they respond to extracellular cues remains ill defined. Our previous work found that the filopodial actin polymerase VASP and consequently filopodial stability are negatively regulated via nondegradative TRIM9-dependent ubiquitination. Appropriate VASP ubiquitination and deubiquitination are required for axon turning in response to the guidance cue netrin-1. Here we show that the TRIM9-related protein TRIM67 outcompetes TRIM9 for interacting with VASP and antagonizes TRIM9-dependent VASP ubiquitination. The surprising antagonistic roles of two closely related E3 ubiquitin ligases are required for netrin-1-dependent filopodial responses, axon turning and branching, and fiber tract formation. We suggest a novel model in which coordinated regulation of VASP ubiquitination by a pair of interfering ligases is a critical element of VASP dynamics, filopodial stability, and axon guidance.
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Affiliation(s)
- Nicholas P. Boyer
- Neurobiology Curriculum, University of North Carolina, Chapel Hill, Chapel Hill, NC
| | - Laura E. McCormick
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, Chapel Hill, NC
| | - Shalini Menon
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, Chapel Hill, NC
| | - Fabio L. Urbina
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, Chapel Hill, NC
| | - Stephanie L. Gupton
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, Chapel Hill, NC,Neuroscience Center, University of North Carolina, Chapel Hill, Chapel Hill, NC,Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, NC,Correspondence to Stephanie L. Gupton:
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36
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Alieva NO, Efremov AK, Hu S, Oh D, Chen Z, Natarajan M, Ong HT, Jégou A, Romet-Lemonne G, Groves JT, Sheetz MP, Yan J, Bershadsky AD. Myosin IIA and formin dependent mechanosensitivity of filopodia adhesion. Nat Commun 2019; 10:3593. [PMID: 31399564 PMCID: PMC6689027 DOI: 10.1038/s41467-019-10964-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 06/07/2019] [Indexed: 12/21/2022] Open
Abstract
Filopodia, dynamic membrane protrusions driven by polymerization of an actin filament core, can adhere to the extracellular matrix and experience both external and cell-generated pulling forces. The role of such forces in filopodia adhesion is however insufficiently understood. Here, we study filopodia induced by overexpression of myosin X, typical for cancer cells. The lifetime of such filopodia positively correlates with the presence of myosin IIA filaments at the filopodia bases. Application of pulling forces to the filopodia tips through attached fibronectin-coated laser-trapped beads results in sustained growth of the filopodia. Pharmacological inhibition or knockdown of myosin IIA abolishes the filopodia adhesion to the beads. Formin inhibitor SMIFH2, which causes detachment of actin filaments from formin molecules, produces similar effect. Thus, centripetal force generated by myosin IIA filaments at the base of filopodium and transmitted to the tip through actin core in a formin-dependent fashion is required for filopodia adhesion.
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Affiliation(s)
- N O Alieva
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - A K Efremov
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Center for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117557, Singapore
| | - S Hu
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - D Oh
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Z Chen
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - M Natarajan
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - H T Ong
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - A Jégou
- Institut Jacques Monod, CNRS, Université de Paris, 15 rue Helene Brion, F-75013, Paris, France
| | - G Romet-Lemonne
- Institut Jacques Monod, CNRS, Université de Paris, 15 rue Helene Brion, F-75013, Paris, France
| | - J T Groves
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - M P Sheetz
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
| | - J Yan
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Center for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117557, Singapore.,Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - A D Bershadsky
- Mechanobiology Institute, National University of Singapore, T-lab, 5A Engineering Drive 1, Singapore, 117411, Singapore. .,Weizmann Institute of Science, Herzl St 234, Rehovot, 7610001, Israel.
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37
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Rachubik P, Piwkowska A. The role of vasodilator‐stimulated phosphoprotein in podocyte functioning. Cell Biol Int 2019; 43:1092-1101. [DOI: 10.1002/cbin.11149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 04/06/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Patrycja Rachubik
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research CentrePolish Academy of Sciences Wita Stwosza 63, 80‐308 Gdańsk Poland
| | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research CentrePolish Academy of Sciences Wita Stwosza 63, 80‐308 Gdańsk Poland
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Chandrasekaran A, Upadhyaya A, Papoian GA. Remarkable structural transformations of actin bundles are driven by their initial polarity, motor activity, crosslinking, and filament treadmilling. PLoS Comput Biol 2019; 15:e1007156. [PMID: 31287817 PMCID: PMC6615854 DOI: 10.1371/journal.pcbi.1007156] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
Bundled actin structures play a key role in maintaining cellular shape, in aiding force transmission to and from extracellular substrates, and in affecting cellular motility. Recent studies have also brought to light new details on stress generation, force transmission and contractility of actin bundles. In this work, we are primarily interested in the question of what determines the stability of actin bundles and what network geometries do unstable bundles eventually transition to. To address this problem, we used the MEDYAN mechano-chemical force field, modeling several micron-long actin bundles in 3D, while accounting for a comprehensive set of chemical, mechanical and transport processes. We developed a hierarchical clustering algorithm for classification of the different long time scale morphologies in our study. Our main finding is that initially unipolar bundles are significantly more stable compared with an apolar initial configuration. Filaments within the latter bundles slide easily with respect to each other due to myosin activity, producing a loose network that can be subsequently severely distorted. At high myosin concentrations, a morphological transition to aster-like geometries was observed. We also investigated how actin treadmilling rates influence bundle dynamics, and found that enhanced treadmilling leads to network fragmentation and disintegration, while this process is opposed by myosin and crosslinking activities. Interestingly, treadmilling bundles with an initial apolar geometry eventually evolve to a whole gamut of network morphologies based on relative positions of filament ends, such as sarcomere-like organization. We found that apolar bundles show a remarkable sensitivity to environmental conditions, which may be important in enabling rapid cytoskeletal structural reorganization and adaptation in response to intracellular and extracellular cues.
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Affiliation(s)
- Aravind Chandrasekaran
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States of America
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, United States of America
| | - Arpita Upadhyaya
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, United States of America
- Department of Physics, University of Maryland, College Park, United States of America
| | - Garegin A. Papoian
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, United States of America
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, United States of America
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39
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Sundararajan L, Smith CJ, Watson JD, Millis BA, Tyska MJ, Miller DM. Actin assembly and non-muscle myosin activity drive dendrite retraction in an UNC-6/Netrin dependent self-avoidance response. PLoS Genet 2019; 15:e1008228. [PMID: 31220078 PMCID: PMC6605669 DOI: 10.1371/journal.pgen.1008228] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/02/2019] [Accepted: 06/04/2019] [Indexed: 01/08/2023] Open
Abstract
Dendrite growth is constrained by a self-avoidance response that induces retraction but the downstream pathways that balance these opposing mechanisms are unknown. We have proposed that the diffusible cue UNC-6(Netrin) is captured by UNC-40(DCC) for a short-range interaction with UNC-5 to trigger self-avoidance in the C. elegans PVD neuron. Here we report that the actin-polymerizing proteins UNC-34(Ena/VASP), WSP-1(WASP), UNC-73(Trio), MIG-10(Lamellipodin) and the Arp2/3 complex effect dendrite retraction in the self-avoidance response mediated by UNC-6(Netrin). The paradoxical idea that actin polymerization results in shorter rather than longer dendrites is explained by our finding that NMY-1 (non-muscle myosin II) is necessary for retraction and could therefore mediate this effect in a contractile mechanism. Our results also show that dendrite length is determined by the antagonistic effects on the actin cytoskeleton of separate sets of effectors for retraction mediated by UNC-6(Netrin) versus outgrowth promoted by the DMA-1 receptor. Thus, our findings suggest that the dendrite length depends on an intrinsic mechanism that balances distinct modes of actin assembly for growth versus retraction. Neurons may extend highly branched dendrites to detect input over a broad receptive field. The formation of actin filaments may drive dendrite elongation. The architecture of the dendritic arbor also depends on mechanisms that limit expansion. For example, sister dendrites from a single neuron usually do not overlap due to self-avoidance. Although cell surface proteins are known to mediate self-avoidance, the downstream pathways that drive dendrite retraction in this phenomenon are largely unknown. Studies of the highly branched PVD sensory neuron in C. elegans have suggested a model of self-avoidance in which the UNC-40/DCC receptor captures the diffusible cue UNC-6/Netrin at the tips of PVD dendrites where it interacts with the UNC-5 receptor on an opposing sister dendrite to induce retraction. Here we report genetic evidence that UNC-5-dependent retraction requires downstream actin polymerization. This finding evokes a paradox: How might actin polymerization drive both dendrite growth and retraction? We propose two answers: (1) Distinct sets of effectors are involved in actin assembly for growth vs retraction; (2) Non-muscle myosin interacts with a nascent actin assemblage to trigger retraction. Our results show that dendrite length depends on the balanced effects of specific molecular components that induce growth vs retraction.
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Affiliation(s)
- Lakshmi Sundararajan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Cody J. Smith
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Joseph D. Watson
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
| | - Bryan A. Millis
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Cell Imaging Shared Resource, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
- Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - David M. Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Nashville, Tennessee, United States of America
- * E-mail:
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40
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O'Connell ME, Sridharan D, Driscoll T, Krishnamurthy I, Perry WG, Applewhite DA. The Drosophila protein, Nausicaa, regulates lamellipodial actin dynamics in a Cortactin-dependent manner. Biol Open 2019; 8:bio.038232. [PMID: 31164339 PMCID: PMC6602326 DOI: 10.1242/bio.038232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Drosophila CG10915 is an uncharacterized protein coding gene with sequence similarity to human Cortactin-binding protein 2 (CTTNBP2) and Cortactin-binding protein 2 N-terminal-like (CTTNBP2NL). Here, we have named this gene Nausicaa (naus) and characterize it through a combination of quantitative live-cell total internal reflection fluorescence microscopy, electron microscopy, RNAi depletion and genetics. We found that Naus co-localizes with F-actin and Cortactin in the lamellipodia of Drosophila S2R+ and D25c2 cells and this localization is lost following Cortactin or Arp2/3 depletion or by mutations that disrupt a conserved proline patch found in its mammalian homologs. Using permeabilization activated reduction in fluorescence and fluorescence recovery after photobleaching, we find that depletion of Cortactin alters Naus dynamics leading to a decrease in its half-life. Furthermore, we discovered that Naus depletion in S2R+ cells led to a decrease in actin retrograde flow and a lamellipodia characterized by long, unbranched filaments. We demonstrate that these alterations to the dynamics and underlying actin architecture also affect D25c2 cell migration and decrease arborization in Drosophila neurons. We present the hypothesis that Naus functions to slow Cortactin's disassociation from Arp2/3 nucleated branch junctions, thereby increasing both branch nucleation and junction stability.
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Affiliation(s)
- Meghan E O'Connell
- Department of Biology, Reed College, Portland, Oregon 97202, USA.,Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637, USA
| | - Divya Sridharan
- Department of Biology, Reed College, Portland, Oregon 97202, USA.,Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Tristan Driscoll
- Department of Cardiovascular Medicine, Yale University, New Haven, Connecticut 06511, USA
| | | | - Wick G Perry
- Department of Biology, Reed College, Portland, Oregon 97202, USA
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41
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Isogai T, Danuser G. Discovery of functional interactions among actin regulators by analysis of image fluctuations in an unperturbed motile cell system. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0110. [PMID: 29632262 DOI: 10.1098/rstb.2017.0110] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/30/2017] [Indexed: 01/06/2023] Open
Abstract
Cell migration is driven by propulsive forces derived from polymerizing actin that pushes and extends the plasma membrane. The underlying actin network is constantly undergoing adaptation to new mechano-chemical environments and intracellular conditions. As such, mechanisms that regulate actin dynamics inherently contain multiple feedback loops and redundant pathways. Given the highly adaptable nature of such a system, studies that use only perturbation experiments (e.g. knockdowns, overexpression, pharmacological activation/inhibition, etc.) are challenged by the nonlinearity and redundancy of the pathway. In these pathway configurations, perturbation experiments at best describe the function(s) of a molecular component in an adapting (e.g. acutely drug-treated) or fully adapted (e.g. permanent gene silenced) cell system, where the targeted component now resides in a non-native equilibrium. Here, we propose how quantitative live-cell imaging and analysis of constitutive fluctuations of molecular activities can overcome these limitations. We highlight emerging actin filament barbed-end biology as a prime example of a complex, nonlinear molecular process that requires a fluctuation analytic approach, especially in an unperturbed cellular system, to decipher functional interactions of barbed-end regulators, actin polymerization and membrane protrusion.This article is part of the theme issue 'Self-organization in cell biology'.
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Affiliation(s)
- Tadamoto Isogai
- Department of Cell Biology, Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gaudenz Danuser
- Department of Cell Biology, Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
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42
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Harker AJ, Katkar HH, Bidone TC, Aydin F, Voth GA, Applewhite DA, Kovar DR. Ena/VASP processive elongation is modulated by avidity on actin filaments bundled by the filopodia cross-linker fascin. Mol Biol Cell 2019; 30:851-862. [PMID: 30601697 PMCID: PMC6589784 DOI: 10.1091/mbc.e18-08-0500] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Ena/VASP tetramers are processive actin elongation factors that localize to diverse F-actin networks composed of filaments bundled by different cross-linking proteins, such as filopodia (fascin), lamellipodia (fimbrin), and stress fibers (α-actinin). Previously, we found that Ena takes approximately threefold longer processive runs on trailing barbed ends of fascin-bundled F-actin. Here, we used single-molecule TIRFM (total internal reflection fluorescence microscopy) and developed a kinetic model to further dissect Ena/VASP’s processive mechanism on bundled filaments. We discovered that Ena’s enhanced processivity on trailing barbed ends is specific to fascin bundles, with no enhancement on fimbrin or α-actinin bundles. Notably, Ena/VASP’s processive run length increases with the number of both fascin-bundled filaments and Ena “arms,” revealing avidity facilitates enhanced processivity. Consistently, Ena tetramers form more filopodia than mutant dimer and trimers in Drosophila culture cells. Moreover, enhanced processivity on trailing barbed ends of fascin-bundled filaments is an evolutionarily conserved property of Ena/VASP homologues, including human VASP and Caenorhabditis elegans UNC-34. These results demonstrate that Ena tetramers are tailored for enhanced processivity on fascin bundles and that avidity of multiple arms associating with multiple filaments is critical for this process. Furthermore, we discovered a novel regulatory process whereby bundle size and bundling protein specificity control activities of a processive assembly factor.
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Affiliation(s)
- Alyssa J Harker
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Harshwardhan H Katkar
- Department of Chemistry, cThe James Franck Institute, and dInstitute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637.,Department of Biology, Reed College, Portland, OR 97202
| | - Tamara C Bidone
- Department of Chemistry, cThe James Franck Institute, and dInstitute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637.,Department of Biology, Reed College, Portland, OR 97202
| | - Fikret Aydin
- Department of Chemistry, cThe James Franck Institute, and dInstitute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637.,Department of Biology, Reed College, Portland, OR 97202
| | - Gregory A Voth
- Department of Chemistry, cThe James Franck Institute, and dInstitute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637.,Department of Biology, Reed College, Portland, OR 97202
| | | | - David R Kovar
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637.,Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
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43
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New insights into the regulation of the actin cytoskeleton dynamics by GPCR/β-arrestin in cancer invasion and metastasis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 346:129-155. [DOI: 10.1016/bs.ircmb.2019.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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44
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Young LE, Latario CJ, Higgs HN. Roles for Ena/VASP proteins in FMNL3-mediated filopodial assembly. J Cell Sci 2018; 131:131/21/jcs220814. [PMID: 30373894 DOI: 10.1242/jcs.220814] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 09/25/2018] [Indexed: 02/01/2023] Open
Abstract
Filopodia are actin-dependent finger-like structures that protrude from the plasma membrane. Actin filament barbed-end-binding proteins localized to filopodial tips are key to filopodial assembly. Two classes of barbed-end-binding proteins are formins and Ena/VASP proteins, and both classes have been localized to filopodial tips in specific cellular contexts. Here, we examine the filopodial roles of the FMNL formins and Ena/VASP proteins in U2OS cells. FMNL3 suppression reduces filopodial assembly by 90%, and FMNL3 is enriched at >95% of filopodial tips. Suppression of VASP or Mena (also known as ENAH) reduces filopodial assembly by >75%. However, VASP and Mena do not display consistent filopodial tip localization, but are enriched in focal adhesions (FAs). Interestingly, >85% of FMNL3-containing filopodia are associated with FAs. Two situations increase Ena/VASP filopodial localization: (1) expression of myosin-X, and (2) actively spreading cells. In spreading cells, filopodia often mark sites of nascent adhesions. Interestingly, VASP suppression in spreading cells causes a significant increase in adhesion assembly at filopodial tips. This work demonstrates that, in U2OS cells, Ena/VASP proteins play roles in filopodia beyond those at filopodial tips.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Lorna E Young
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Casey J Latario
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Henry N Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
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45
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Boyer NP, Gupton SL. Revisiting Netrin-1: One Who Guides (Axons). Front Cell Neurosci 2018; 12:221. [PMID: 30108487 PMCID: PMC6080411 DOI: 10.3389/fncel.2018.00221] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/09/2018] [Indexed: 12/28/2022] Open
Abstract
Proper patterning of the nervous system requires that developing axons find appropriate postsynaptic partners; this entails microns to meters of extension through an extracellular milieu exhibiting a wide range of mechanical and chemical properties. Thus, the elaborate networks of fiber tracts and non-fasciculated axons evident in mature organisms are formed via complex pathfinding. The macroscopic structures of axon projections are highly stereotyped across members of the same species, indicating precise mechanisms guide their formation. The developing axon exhibits directionally biased growth toward or away from external guidance cues. One of the most studied guidance cues is netrin-1, however, its presentation in vivo remains debated. Guidance cues can be secreted to form soluble or chemotactic gradients or presented bound to cells or the extracellular matrix to form haptotactic gradients. The growth cone, a highly specialized dynamic structure at the end of the extending axon, detects these guidance cues via transmembrane receptors, such as the netrin-1 receptors deleted in colorectal cancer (DCC) and UNC5. These receptors orchestrate remodeling of the cytoskeleton and cell membrane through both chemical and mechanotransductive pathways, which result in traction forces generated by the cytoskeleton against the extracellular environment and translocation of the growth cone. Through intracellular signaling responses, netrin-1 can trigger either attraction or repulsion of the axon. Here we review the mechanisms by which the classical guidance cue netrin-1 regulates intracellular effectors to respond to the extracellular environment in the context of axon guidance during development of the central nervous system and discuss recent findings that demonstrate the critical importance of mechanical forces in this process.
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Affiliation(s)
- Nicholas P. Boyer
- Neurobiology Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Stephanie L. Gupton
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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46
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Borovac J, Bosch M, Okamoto K. Regulation of actin dynamics during structural plasticity of dendritic spines: Signaling messengers and actin-binding proteins. Mol Cell Neurosci 2018; 91:122-130. [PMID: 30004015 DOI: 10.1016/j.mcn.2018.07.001] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 06/25/2018] [Accepted: 07/06/2018] [Indexed: 12/17/2022] Open
Abstract
Activity-dependent plasticity of synaptic structure and function plays an essential role in neuronal development and in cognitive functions including learning and memory. The formation, maintenance and modulation of dendritic spines are mainly controlled by the dynamics of actin filaments (F-actin) through interaction with various actin-binding proteins (ABPs) and postsynaptic signaling messengers. Induction of long-term potentiation (LTP) triggers a cascade of events involving Ca2+ signaling, intracellular pathways such as cAMP and cGMP, and regulation of ABPs such as CaMKII, Cofilin, Aip1, Arp2/3, α-actinin, Profilin and Drebrin. We review here how these ABPs modulate the rate of assembly, disassembly, stabilization and bundling of F-actin during LTP induction. We highlight the crucial role that CaMKII exerts in both functional and structural plasticity by directly coupling Ca2+ signaling with F-actin dynamics through the β subunit. Moreover, we show how cAMP and cGMP second messengers regulate postsynaptic structural potentiation. Brain disorders such as Alzheimer's disease, schizophrenia or autism, are associated with alterations in the regulation of F-actin dynamics by these ABPs and signaling messengers. Thus, a better understanding of the molecular mechanisms controlling actin cytoskeleton can provide cues for the treatment of these disorders.
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Affiliation(s)
- Jelena Borovac
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Miquel Bosch
- Institute for Bioengineering of Catalonia, Barcelona 08028, Spain.
| | - Kenichi Okamoto
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1X5, Canada.
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47
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He K, Sakai T, Tsukasaki Y, Watanabe TM, Ikebe M. Myosin X is recruited to nascent focal adhesions at the leading edge and induces multi-cycle filopodial elongation. Sci Rep 2017; 7:13685. [PMID: 29057977 PMCID: PMC5651867 DOI: 10.1038/s41598-017-06147-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/16/2017] [Indexed: 12/16/2022] Open
Abstract
Filopodia protrude from the leading edge of cells and play important roles in cell motility. Here we report the mechanism of myosin X (encoded by Myo10)-induced multi-cycle filopodia extension. We found that actin, Arp2/3, vinculin and integrin-β first accumulated at the cell's leading edge. Myosin X was then gathered at these sites, gradually clustered by lateral movement, and subsequently initiated filopodia formation. During filopodia extension, we found the translocation of Arp2/3 and integrin-β along filopodia. Arp2/3 and integrin-β then became localized at the tip of filopodia, from where myosin X initiated the second extension of filopodia with a change in extension direction, thus producing long filopodia. Elimination of integrin-β, Arp2/3 and vinculin by siRNA significantly attenuated the myosin-X-induced long filopodia formation. We propose the following mechanism. Myosin X accumulates at nascent focal adhesions at the cell's leading edge, where myosin X promotes actin convergence to create the base of filopodia. Then myosin X moves to the filopodia tip and attracts integrin-β and Arp2/3 for further actin nucleation. The tip-located myosin X then initiates the second cycle of filopodia elongation to produce the long filopodia.
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Affiliation(s)
- Kangmin He
- Institute of Vascular Medicine, Peking University Third Hospital and Academy for Advanced Interdisciplinary Studies, Peking University, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, 100191, China.,Graduate School of Frontier Biosciences, Osaka University, Osaka, 5650871, Japan.,Department of Cell Biology, Harvard Medical School, and Cellular and Molecular Medicine Program, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Tsuyoshi Sakai
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, TX75708, USA
| | - Yoshikazu Tsukasaki
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, TX75708, USA.,Laboratory for Comprehensive Bioimaging, RIKEN Quantitative Biology Center (QBiC), Osaka, 5650874, Japan.,Department of Pharmacology, University of Illinois Chicago College of Medicine, Boston Children's Hospital, Chicago, Illinois 60612, USA
| | - Tomonobu M Watanabe
- Graduate School of Frontier Biosciences, Osaka University, Osaka, 5650871, Japan. .,Laboratory for Comprehensive Bioimaging, RIKEN Quantitative Biology Center (QBiC), Osaka, 5650874, Japan. .,World Premier International Research Center Initiative, iFReC, Osaka University, Osaka, 5650871, Japan.
| | - Mitsuo Ikebe
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, TX75708, USA.
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48
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Urbančič V, Butler R, Richier B, Peter M, Mason J, Livesey FJ, Holt CE, Gallop JL. Filopodyan: An open-source pipeline for the analysis of filopodia. J Cell Biol 2017; 216:3405-3422. [PMID: 28760769 PMCID: PMC5626553 DOI: 10.1083/jcb.201705113] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/28/2017] [Accepted: 07/06/2017] [Indexed: 02/07/2023] Open
Abstract
Filopodia have important sensory and mechanical roles in motile cells. The recruitment of actin regulators, such as ENA/VASP proteins, to sites of protrusion underlies diverse molecular mechanisms of filopodia formation and extension. We developed Filopodyan (filopodia dynamics analysis) in Fiji and R to measure fluorescence in filopodia and at their tips and bases concurrently with their morphological and dynamic properties. Filopodyan supports high-throughput phenotype characterization as well as detailed interactive editing of filopodia reconstructions through an intuitive graphical user interface. Our highly customizable pipeline is widely applicable, capable of detecting filopodia in four different cell types in vitro and in vivo. We use Filopodyan to quantify the recruitment of ENA and VASP preceding filopodia formation in neuronal growth cones, and uncover a molecular heterogeneity whereby different filopodia display markedly different responses to changes in the accumulation of ENA and VASP fluorescence in their tips over time.
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Affiliation(s)
- Vasja Urbančič
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Richard Butler
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
| | - Benjamin Richier
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Manuel Peter
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Julia Mason
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Frederick J Livesey
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
| | - Christine E Holt
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, England, UK
| | - Jennifer L Gallop
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, England, UK
- Department of Biochemistry, University of Cambridge, Cambridge, England, UK
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49
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Shutova MS, Asokan SB, Talwar S, Assoian RK, Bear JE, Svitkina TM. Self-sorting of nonmuscle myosins IIA and IIB polarizes the cytoskeleton and modulates cell motility. J Cell Biol 2017; 216:2877-2889. [PMID: 28701425 PMCID: PMC5584186 DOI: 10.1083/jcb.201705167] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 01/21/2023] Open
Abstract
Nonmuscle myosin II (NMII) is uniquely responsible for cell contractility and thus defines multiple aspects of cell behavior. To generate contraction, NMII molecules polymerize into bipolar minifilaments. Different NMII paralogs are often coexpressed in cells and can copolymerize, suggesting that they may cooperate to facilitate cell motility. However, whether such cooperation exists and how it may work remain unknown. We show that copolymerization of NMIIA and NMIIB followed by their differential turnover leads to self-sorting of NMIIA and NMIIB along the front-rear axis, thus producing a polarized actin-NMII cytoskeleton. Stress fibers newly formed near the leading edge are enriched in NMIIA, but over time, they become progressively enriched with NMIIB because of faster NMIIA turnover. In combination with retrograde flow, this process results in posterior accumulation of more stable NMIIB-rich stress fibers, thus strengthening cell polarity. By copolymerizing with NMIIB, NMIIA accelerates the intrinsically slow NMIIB dynamics, thus increasing cell motility and traction and enabling chemotaxis.
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Affiliation(s)
- Maria S Shutova
- Department of Biology, University of Pennsylvania, Philadelphia, PA
| | - Sreeja B Asokan
- Department of Cell Biology and Physiology, UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Shefali Talwar
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA
| | - Richard K Assoian
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA
| | - James E Bear
- Department of Cell Biology and Physiology, UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Yu-Kemp HC, Kemp JP, Brieher WM. CRMP-1 enhances EVL-mediated actin elongation to build lamellipodia and the actin cortex. J Cell Biol 2017. [PMID: 28630144 PMCID: PMC5551698 DOI: 10.1083/jcb.201606084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
CRMP proteins regulate the cytoskeleton, but the underlying mechanisms are poorly understood. Yu-Kemp et al. show that CRMP-1 helps Ena/VASP proteins elongate actin filaments to assemble actin networks that are necessary for the integrity of epithelial sheets. Cells can control actin polymerization by nucleating new filaments or elongating existing ones. We recently identified CRMP-1 as a factor that stimulates the formation of Listeria monocytogenes actin comet tails, thereby implicating it in actin assembly. We now show that CRMP-1 is a major contributor to actin assembly in epithelial cells, where it works with the Ena/VASP family member EVL to assemble the actin cytoskeleton in the apical cortex and in protruding lamellipodia. CRMP-1 and EVL bind to one another and together accelerate actin filament barbed-end elongation. CRMP-1 also stimulates actin assembly in the presence of VASP and Mena in vitro, but CRMP-1–dependent actin assembly in MDCK cells is EVL specific. Our results identify CRMP-1 as a novel regulator of actin filament elongation and reveal a surprisingly important role for CRMP-1, EVL, and actin polymerization in maintaining the structural integrity of epithelial sheets.
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Affiliation(s)
- Hui-Chia Yu-Kemp
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, IL
| | - James P Kemp
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, IL
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, IL
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