1
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Singer A, Ramos A, Keating AE. Elaboration of the Homer1 recognition landscape reveals incomplete divergence of paralogous EVH1 domains. Protein Sci 2024; 33:e5094. [PMID: 38989636 PMCID: PMC11237882 DOI: 10.1002/pro.5094] [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: 02/26/2024] [Revised: 06/11/2024] [Accepted: 06/16/2024] [Indexed: 07/12/2024]
Abstract
Short sequences that mediate interactions with modular binding domains are ubiquitous throughout eukaryotic proteomes. Networks of short linear motifs (SLiMs) and their corresponding binding domains orchestrate many cellular processes, and the low mutational barrier to evolving novel interactions provides a way for biological systems to rapidly sample selectable phenotypes. Mapping SLiM binding specificity and the rules that govern SLiM evolution is fundamental to uncovering the pathways regulated by these networks and developing the tools to manipulate them. We used high-throughput screening of the human proteome to identify sequences that bind to the Enabled/VASP homology 1 (EVH1) domain of the postsynaptic density scaffolding protein Homer1. This expanded our understanding of the determinants of Homer EVH1 binding preferences and defined a new motif that can facilitate the discovery of additional Homer-mediated interactions. Interestingly, the Homer1 EVH1 domain preferentially binds to sequences containing an N-terminally overlapping motif that is bound by the paralogous family of Ena/VASP actin polymerases, and many of these sequences can bind to EVH1 domains from both protein families. We provide evidence from orthologous EVH1 domains in pre-metazoan organisms that the overlap in human Ena/VASP and Homer binding preferences corresponds to an incomplete divergence from a common Ena/VASP ancestor. Given this overlap in binding profiles, promiscuous sequences that can be recognized by both families either achieve specificity through extrinsic regulatory strategies or may provide functional benefits via multi-specificity. This may explain why these paralogs incompletely diverged despite the accessibility of further diverged isoforms.
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Affiliation(s)
- Avinoam Singer
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Alejandra Ramos
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Amy E. Keating
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
- Department of Biological EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
- Koch Institute for Integrative Cancer ResearchMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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2
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Li Y, Zhang Y, Wang M, Su J, Dong X, Yang Y, Wang H, Li Q. The mammalian actin elongation factor ENAH/MENA contributes to autophagosome formation via its actin regulatory function. Autophagy 2024; 20:1798-1814. [PMID: 38705725 PMCID: PMC11262208 DOI: 10.1080/15548627.2024.2347105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 04/19/2024] [Indexed: 05/07/2024] Open
Abstract
Macroautophagy/autophagy is a catabolic process crucial for degrading cytosolic components and damaged organelles to maintain cellular homeostasis, enabling cells to survive in extreme extracellular environments. ENAH/MENA, a member of the Ena/VASP protein family, functions as a highly efficient actin elongation factor. In this study, our objective was to explore the role of ENAH in the autophagy process. Initially, we demonstrated that depleting ENAH in cancer cells inhibits autophagosome formation. Subsequently, we observed ENAH's colocalization with MAP1LC3/LC3 during tumor cell starvation, dependent on actin cytoskeleton polymerization and the interaction between ENAH and BECN1 (beclin 1). Additionally, mammalian ATG9A formed a ring-like structure around ENAH-LC3 puncta during starvation, relying on actin cytoskeleton polymerization. Furthermore, ENAH's EVH1 and EVH2 domains were found to be indispensable for its colocalization with LC3 and BECN1, while the PRD domain played a crucial role in the formation of the ATG9A ring. Finally, our study revealed ENAH-led actin comet tails in autophagosome trafficking. In conclusion, our findings provide initial insights into the regulatory role of the mammalian actin elongation factor ENAH in autophagy.Abbreviations: 3-MA 3-methyladenine; ABPs actin-binding proteins; ATG autophagy related; ATG9A autophagy related 9A; Baf A1 bafilomycin A1; CM complete medium; CytERM endoplasmic reticulum signal-anchor membrane protein; Cyto D cytochalasin D; EBSS Earl's balanced salt solution; ENAH/MENA ENAH actin regulator; EVH1 Ena/VASP homology 1 domain; EVH2 Ena/VASP homology 2 domain; GAPDH glyceraldehyde-3-phosphate dehydrogenase; Lat B latrunculin B; LC3-I unlipidated form of LC3; LC3-II phosphatidylethanolamine-conjugated form of LC3; MAP1LC3/LC3 microtubule associated protein 1 light chain 3; mEGFP monomeric enhanced green fluorescent protein; mTagBFP2 monomeric Tag blue fluorescent protein 2; OSER organized smooth endoplasmic reticulum; PRD proline-rich domain; PtdIns3K class III phosphatidylinositol 3-kinase; WM wortmannin.
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Affiliation(s)
- Yueheng Li
- Department of Pathology, School of Basic Medical Science, Fudan University, Shanghai, China
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Yafei Zhang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
- Department of Infectious Diseases, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui province, China
| | - Menghui Wang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Junhui Su
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Xinjue Dong
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Yuqi Yang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Hongshan Wang
- Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, P. R. China
| | - QingQuan Li
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
- Department of Infectious Diseases, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui province, China
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3
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Tsai FC, Guérin G, Pernier J, Bassereau P. Actin-membrane linkers: Insights from synthetic reconstituted systems. Eur J Cell Biol 2024; 103:151402. [PMID: 38461706 DOI: 10.1016/j.ejcb.2024.151402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/10/2024] [Accepted: 02/28/2024] [Indexed: 03/12/2024] Open
Abstract
At the cell surface, the actin cytoskeleton and the plasma membrane interact reciprocally in a variety of processes related to the remodeling of the cell surface. The actin cytoskeleton has been known to modulate membrane organization and reshape the membrane. To this end, actin-membrane linking molecules play a major role in regulating actin assembly and spatially direct the interaction between the actin cytoskeleton and the membrane. While studies in cells have provided a wealth of knowledge on the molecular composition and interactions of the actin-membrane interface, the complex molecular interactions make it challenging to elucidate the precise actions of the actin-membrane linkers at the interface. Synthetic reconstituted systems, consisting of model membranes and purified proteins, have been a powerful approach to elucidate how actin-membrane linkers direct actin assembly to drive membrane shape changes. In this review, we will focus only on several actin-membrane linkers that have been studied by using reconstitution systems. We will discuss the design principles of these reconstitution systems and how they have contributed to the understanding of the cellular functions of actin-membrane linkers. Finally, we will provide a perspective on future research directions in understanding the intricate actin-membrane interaction.
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Affiliation(s)
- Feng-Ching Tsai
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France.
| | - Gwendal Guérin
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France
| | - Julien Pernier
- Tumor Cell Dynamics Unit, Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif 94800, France
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France.
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4
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Fox S, Gaudreau-LaPierre A, Reshke R, Podinic I, Gibbings DJ, Trinkle-Mulcahy L, Copeland JW. Identification of an FMNL2 Interactome by Quantitative Mass Spectrometry. Int J Mol Sci 2024; 25:5686. [PMID: 38891874 PMCID: PMC11171801 DOI: 10.3390/ijms25115686] [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: 04/09/2024] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 06/21/2024] Open
Abstract
Formin Homology Proteins (Formins) are a highly conserved family of cytoskeletal regulatory proteins that participate in a diverse range of cellular processes. FMNL2 is a member of the Diaphanous-Related Formin sub-group, and previous reports suggest FMNL2's role in filopodia assembly, force generation at lamellipodia, subcellular trafficking, cell-cell junction assembly, and focal adhesion formation. How FMNL2 is recruited to these sites of action is not well understood. To shed light on how FMNL2 activity is partitioned between subcellular locations, we used biotin proximity labeling and proteomic analysis to identify an FMNL2 interactome. The interactome identified known and new FMNL2 interacting proteins with functions related to previously described FMNL2 activities. In addition, our interactome predicts a novel connection between FMNL2 and extracellular vesicle assembly. We show directly that FMNL2 protein is present in exosomes.
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Affiliation(s)
| | | | | | | | | | | | - John W. Copeland
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; (S.F.)
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5
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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. [PMID: 38647032 DOI: 10.1002/cm.21864] [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: 12/13/2023] [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, Illinois, USA
| | - Harshwardhan H Katkar
- Department of Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Alisha Morganthaler
- Department of Biochemistry and Molecular Biology and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
| | - Alyssa J Harker
- Department of Biochemistry and Molecular Biology and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
| | - David R Kovar
- Department of Biochemistry and Molecular Biology and Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
| | - Gregory A Voth
- Department of Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
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6
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Singer A, Ramos A, Keating AE. Elaboration of the Homer1 Recognition Landscape Reveals Incomplete Divergence of Paralogous EVH1 Domains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576863. [PMID: 38645240 PMCID: PMC11030225 DOI: 10.1101/2024.01.23.576863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Short sequences that mediate interactions with modular binding domains are ubiquitous throughout eukaryotic proteomes. Networks of Short Linear Motifs (SLiMs) and their corresponding binding domains orchestrate many cellular processes, and the low mutational barrier to evolving novel interactions provides a way for biological systems to rapidly sample selectable phenotypes. Mapping SLiM binding specificity and the rules that govern SLiM evolution is fundamental to uncovering the pathways regulated by these networks and developing the tools to manipulate them. We used high-throughput screening of the human proteome to identify sequences that bind to the Enabled/VASP homology 1 (EVH1) domain of the postsynaptic density scaffolding protein Homer1. In doing so, we expanded current understanding of the determinants of Homer EVH1 binding preferences and defined a new motif that can facilitate the discovery of additional Homer-mediated interactions. Interestingly, the Homer1 EVH1 domain preferentially binds to sequences containing an N-terminally overlapping motif that is bound by the paralogous family of Ena/VASP actin polymerases, and many of these sequences can bind to EVH1 domains from both protein families. We provide evidence from orthologous EVH1 domains in pre-metazoan organisms that the overlap in human Ena/VASP and Homer binding preferences corresponds to an incomplete divergence from a common Ena/VASP ancestor. Given this overlap in binding profiles, promiscuous sequences that can be recognized by both families either achieve specificity through extrinsic regulatory strategies or may provide functional benefits via multi-specificity. This may explain why these paralogs incompletely diverged despite the accessibility of further diverged isoforms.
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Affiliation(s)
- Avinoam Singer
- MIT Department of Biology, Cambridge, Massachusetts, USA
| | | | - Amy E. Keating
- MIT Department of Biology, Cambridge, Massachusetts, USA
- MIT Department of Biological Engineering, Cambridge, Massachusetts, USA
- Koch Institute for Integrative Cancer Research, Cambridge, Massachusetts, USA
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7
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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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8
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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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9
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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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10
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Donath S, Seidler AE, Mundin K, Wenzel J, Scholz J, Gentemann L, Kalies J, Faix J, Ngezahayo A, Bleich A, Heisterkamp A, Buettner M, Kalies S. Epithelial restitution in 3D - Revealing biomechanical and physiochemical dynamics in intestinal organoids via fs laser nanosurgery. iScience 2023; 26:108139. [PMID: 37867948 PMCID: PMC10585398 DOI: 10.1016/j.isci.2023.108139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/29/2023] [Accepted: 10/02/2023] [Indexed: 10/24/2023] Open
Abstract
Intestinal organoids represent a three-dimensional cell culture system mimicking the mammalian intestine. The application of single-cell ablation for defined wounding via a femtosecond laser system within the crypt base allowed us to study cell dynamics during epithelial restitution. Neighboring cells formed a contractile actin ring encircling the damaged cell, changed the cellular aspect ratio, and immediately closed the barrier. Using traction force microscopy, we observed major forces at the ablation site and additional forces on the crypt sides. Inhibitors of the actomyosin-based mobility of the cells led to the failure of restoring the barrier. Close to the ablation site, high-frequency calcium flickering and propagation of calcium waves occured that synchronized with the contraction of the epithelial layer. We observed an increased signal and nuclear translocation of YAP-1. In conclusion, our approach enabled, for the first time, to unveil the intricacies of epithelial restitution beyond in vivo models by employing precise laser-induced damage in colonoids.
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Affiliation(s)
- Sören Donath
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Anna Elisabeth Seidler
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Karlina Mundin
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Johannes Wenzel
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Jonas Scholz
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Lara Gentemann
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, 30625 Hannover, Germany
| | - Julia Kalies
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Anaclet Ngezahayo
- Institute of Biophysics, Leibniz University Hannover, 30167 Hannover, Germany
| | - André Bleich
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, 30625 Hannover, Germany
- Institute for Laboratory Animal Science, Hannover Medical School, 30625 Hannover, Germany
| | - Alexander Heisterkamp
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
| | - Manuela Buettner
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, 30625 Hannover, Germany
- Institute for Laboratory Animal Science, Hannover Medical School, 30625 Hannover, Germany
| | - Stefan Kalies
- Institute of Quantum Optics, Leibniz University Hannover, 30167 Hannover, Germany
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), 30625 Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, 30625 Hannover, Germany
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11
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Jimeno D, Lillo C, de la Villa P, Calzada N, Santos E, Fernández-Medarde A. GRF2 Is Crucial for Cone Photoreceptor Viability and Ribbon Synapse Formation in the Mouse Retina. Cells 2023; 12:2574. [PMID: 37947653 PMCID: PMC10650203 DOI: 10.3390/cells12212574] [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: 10/10/2023] [Revised: 10/27/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023] Open
Abstract
Using constitutive GRF1/2 knockout mice, we showed previously that GRF2 is a key regulator of nuclear migration in retinal cone photoreceptors. To evaluate the functional relevance of that cellular process for two putative targets of the GEF activity of GRF2 (RAC1 and CDC42), here we compared the structural and functional retinal phenotypes resulting from conditional targeting of RAC1 or CDC42 in the cone photoreceptors of constitutive GRF2KO and GRF2WT mice. We observed that single RAC1 disruption did not cause any obvious morphological or physiological changes in the retinas of GRF2WT mice, and did not modify either the phenotypic alterations previously described in the retinal photoreceptor layer of GRF2KO mice. In contrast, the single ablation of CDC42 in the cone photoreceptors of GRF2WT mice resulted in clear alterations of nuclear movement that, unlike those of the GRF2KO retinas, were not accompanied by electrophysiological defects or slow, progressive cone cell degeneration. On the other hand, the concomitant disruption of GRF2 and CDC42 in the cone photoreceptors resulted, somewhat surprisingly, in a normalized pattern of nuclear positioning/movement, similar to that physiologically observed in GRF2WT mice, along with worsened patterns of electrophysiological responses and faster rates of cell death/disappearance than those previously recorded in single GRF2KO cone cells. Interestingly, the increased rates of cone cell apoptosis/death observed in single GRF2KO and double-knockout GRF2KO/CDC42KO retinas correlated with the electron microscopic detection of significant ultrastructural alterations (flattening) of their retinal ribbon synapses that were not otherwise observed at all in single-knockout CDC42KO retinas. Our observations identify GRF2 and CDC42 (but not RAC1) as key regulators of retinal processes controlling cone photoreceptor nuclear positioning and survival, and support the notion of GRF2 loss-of-function mutations as potential drivers of cone retinal dystrophies.
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Affiliation(s)
- David Jimeno
- Centro de Investigación del Cáncer-Instituto de Biologıá Molecular y Celular del Cáncer (CSIC–Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | | | - Pedro de la Villa
- Departamento de Biología de Sistemas, Universidad de Alcalá, 28871 Alcalá de Henares, and IRYCIS, 28034 Madrid, Spain
| | - Nuria Calzada
- Centro de Investigación del Cáncer-Instituto de Biologıá Molecular y Celular del Cáncer (CSIC–Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - Eugenio Santos
- Centro de Investigación del Cáncer-Instituto de Biologıá Molecular y Celular del Cáncer (CSIC–Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
| | - Alberto Fernández-Medarde
- Centro de Investigación del Cáncer-Instituto de Biologıá Molecular y Celular del Cáncer (CSIC–Universidad de Salamanca) and CIBERONC, 37007 Salamanca, Spain
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12
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Dobson L, Barrell WB, Seraj Z, Lynham S, Wu SY, Krause M, Liu KJ. GSK3 and lamellipodin balance lamellipodial protrusions and focal adhesion maturation in mouse neural crest migration. Cell Rep 2023; 42:113030. [PMID: 37632751 DOI: 10.1016/j.celrep.2023.113030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 07/06/2023] [Accepted: 08/09/2023] [Indexed: 08/28/2023] Open
Abstract
Neural crest cells are multipotent cells that delaminate from the neuroepithelium, migrating throughout the embryo. Aberrant migration causes developmental defects. Animal models are improving our understanding of neural crest anomalies, but in vivo migration behaviors are poorly understood. Here, we demonstrate that murine neural crest cells display actin-based lamellipodia and filopodia in vivo. Using neural crest-specific knockouts or inhibitors, we show that the serine-threonine kinase glycogen synthase kinase-3 (GSK3) and the cytoskeletal regulator lamellipodin (Lpd) are required for lamellipodia formation while preventing focal adhesion maturation. Lpd is a substrate of GSK3, and phosphorylation of Lpd favors interactions with the Scar/WAVE complex (lamellipodia formation) at the expense of VASP and Mena interactions (adhesion maturation and filopodia formation). This improved understanding of cytoskeletal regulation in mammalian neural crest migration has general implications for neural crest anomalies and cancer.
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Affiliation(s)
- Lisa Dobson
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK; Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - William B Barrell
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK; Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Zahra Seraj
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Steven Lynham
- Centre for Excellence for Mass Spectrometry, King's College London, London SE5 9NU, UK
| | - Sheng-Yuan Wu
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Matthias Krause
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK.
| | - Karen J Liu
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK.
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13
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Sadhu RK, Hernandez-Padilla C, Eisenbach YE, Penič S, Zhang L, Vishwasrao HD, Behkam B, Konstantopoulos K, Shroff H, Iglič A, Peles E, Nain AS, Gov NS. Experimental and theoretical model for the origin of coiling of cellular protrusions around fibers. Nat Commun 2023; 14:5612. [PMID: 37699891 PMCID: PMC10497540 DOI: 10.1038/s41467-023-41273-y] [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: 08/26/2022] [Accepted: 08/29/2023] [Indexed: 09/14/2023] Open
Abstract
Protrusions at the leading-edge of a cell play an important role in sensing the extracellular cues during cellular spreading and motility. Recent studies provided indications that these protrusions wrap (coil) around the extracellular fibers. However, the physics of this coiling process, and the mechanisms that drive it, are not well understood. We present a combined theoretical and experimental study of the coiling of cellular protrusions on fibers of different geometry. Our theoretical model describes membrane protrusions that are produced by curved membrane proteins that recruit the protrusive forces of actin polymerization, and identifies the role of bending and adhesion energies in orienting the leading-edges of the protrusions along the azimuthal (coiling) direction. Our model predicts that the cell's leading-edge coils on fibers with circular cross-section (above some critical radius), but the coiling ceases for flattened fibers of highly elliptical cross-section. These predictions are verified by 3D visualization and quantitation of coiling on suspended fibers using Dual-View light-sheet microscopy (diSPIM). Overall, we provide a theoretical framework, supported by experiments, which explains the physical origin of the coiling phenomenon.
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Affiliation(s)
- Raj Kumar Sadhu
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Institut Curie, PSL Research University, CNRS, UMR 168, Paris, France.
| | | | - Yael Eshed Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Samo Penič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Lixia Zhang
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Harshad D Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Bahareh Behkam
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | | | - Hari Shroff
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Amrinder S Nain
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
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14
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Lambert C, Schmidt K, Karger M, Stadler M, Stradal TEB, Rottner K. Cytochalasans and Their Impact on Actin Filament Remodeling. Biomolecules 2023; 13:1247. [PMID: 37627312 PMCID: PMC10452583 DOI: 10.3390/biom13081247] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 07/28/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
The eukaryotic actin cytoskeleton comprises the protein itself in its monomeric and filamentous forms, G- and F-actin, as well as multiple interaction partners (actin-binding proteins, ABPs). This gives rise to a temporally and spatially controlled, dynamic network, eliciting a plethora of motility-associated processes. To interfere with the complex inter- and intracellular interactions the actin cytoskeleton confers, small molecular inhibitors have been used, foremost of all to study the relevance of actin filaments and their turnover for various cellular processes. The most prominent inhibitors act by, e.g., sequestering monomers or by interfering with the polymerization of new filaments and the elongation of existing filaments. Among these inhibitors used as tool compounds are the cytochalasans, fungal secondary metabolites known for decades and exploited for their F-actin polymerization inhibitory capabilities. In spite of their application as tool compounds for decades, comprehensive data are lacking that explain (i) how the structural deviances of the more than 400 cytochalasans described to date influence their bioactivity mechanistically and (ii) how the intricate network of ABPs reacts (or adapts) to cytochalasan binding. This review thus aims to summarize the information available concerning the structural features of cytochalasans and their influence on the described activities on cell morphology and actin cytoskeleton organization in eukaryotic cells.
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Affiliation(s)
- Christopher Lambert
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
- Department of Microbial Drugs, Helmholtz Centre for Infection Research and German Centre for Infection Research (DZIF), Partner Site Hannover/Braunschweig, Inhoffenstrasse 7, 38124 Braunschweig, Germany;
| | - Katharina Schmidt
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Marius Karger
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Marc Stadler
- Department of Microbial Drugs, Helmholtz Centre for Infection Research and German Centre for Infection Research (DZIF), Partner Site Hannover/Braunschweig, Inhoffenstrasse 7, 38124 Braunschweig, Germany;
| | - Theresia E. B. Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Klemens Rottner
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, 38124 Braunschweig, Germany
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), 38106 Braunschweig, Germany
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15
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McCormick LE, Suarez C, Herring LE, Cannon KS, Kovar DR, Brown NG, Gupton SL. Multi-monoubiquitination controls VASP-mediated actin dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.16.549237. [PMID: 37503134 PMCID: PMC10370145 DOI: 10.1101/2023.07.16.549237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The actin cytoskeleton performs multiple cellular functions, and as such, actin polymerization must be tightly regulated. We previously demonstrated that reversible, non-degradative ubiquitination regulates the function of the actin polymerase VASP in developing neurons. However, the underlying mechanism of how ubiquitination impacts VASP activity was unknown. Here we show that mimicking multi-monoubiquitination of VASP at K240 and K286 negatively regulates VASP interactions with actin. Using in vitro biochemical assays, we demonstrate the reduced ability of multi-monoubiquitinated VASP to bind, bundle, and elongate actin filaments. However, multi-monoubiquitinated VASP maintained the ability to bind and protect barbed ends from capping protein. Lastly, we demonstrate the introduction of recombinant multi-monoubiquitinated VASP protein altered cell spreading morphology. Collectively, these results suggest a mechanism in which ubiquitination 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
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Laura E Herring
- Michael Hooker Proteomics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kevin S Cannon
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Nicholas G Brown
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephanie L Gupton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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16
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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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17
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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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18
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Ravid Y, Penič S, Mimori-Kiyosue Y, Suetsugu S, Iglič A, Gov NS. Theoretical model of membrane protrusions driven by curved active proteins. Front Mol Biosci 2023; 10:1153420. [PMID: 37228585 PMCID: PMC10203436 DOI: 10.3389/fmolb.2023.1153420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 04/21/2023] [Indexed: 05/27/2023] Open
Abstract
Eukaryotic cells intrinsically change their shape, by changing the composition of their membrane and by restructuring their underlying cytoskeleton. We present here further studies and extensions of a minimal physical model, describing a closed vesicle with mobile curved membrane protein complexes. The cytoskeletal forces describe the protrusive force due to actin polymerization which is recruited to the membrane by the curved protein complexes. We characterize the phase diagrams of this model, as function of the magnitude of the active forces, nearest-neighbor protein interactions and the proteins' spontaneous curvature. It was previously shown that this model can explain the formation of lamellipodia-like flat protrusions, and here we explore the regimes where the model can also give rise to filopodia-like tubular protrusions. We extend the simulation with curved components of both convex and concave species, where we find the formation of complex ruffled clusters, as well as internalized invaginations that resemble the process of endocytosis and macropinocytosis. We alter the force model representing the cytoskeleton to simulate the effects of bundled instead of branched structure, resulting in shapes which resemble filopodia.
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Affiliation(s)
- Yoav Ravid
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Samo Penič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Yuko Mimori-Kiyosue
- Laboratory for Molecular and Cellular Dynamics, RIKEN Center for Biosystems Dynamics Research, Minatojima-minaminachi, Kobe, Hyogo, Japan
| | - Shiro Suetsugu
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
- Data Science Center, Nara Institute of Science and Technology, Ikoma, Japan
- Center for Digital Green-innovation, Nara Institute of Science and Technology, Ikoma, Japan
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Nir S. Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
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19
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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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20
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Hein JI, Scholz J, Körber S, Kaufmann T, Faix J. Unleashed Actin Assembly in Capping Protein-Deficient B16-F1 Cells Enables Identification of Multiple Factors Contributing to Filopodium Formation. Cells 2023; 12:cells12060890. [PMID: 36980231 PMCID: PMC10047565 DOI: 10.3390/cells12060890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
Background: Filopodia are dynamic, finger-like actin-filament bundles that overcome membrane tension by forces generated through actin polymerization at their tips to allow extension of these structures a few microns beyond the cell periphery. Actin assembly of these protrusions is regulated by accessory proteins including heterodimeric capping protein (CP) or Ena/VASP actin polymerases to either terminate or promote filament growth. Accordingly, the depletion of CP in B16-F1 melanoma cells was previously shown to cause an explosive formation of filopodia. In Ena/VASP-deficient cells, CP depletion appeared to result in ruffling instead of inducing filopodia, implying that Ena/VASP proteins are absolutely essential for filopodia formation. However, this hypothesis was not yet experimentally confirmed. Methods: Here, we used B16-F1 cells and CRISPR/Cas9 technology to eliminate CP either alone or in combination with Ena/VASP or other factors residing at filopodia tips, followed by quantifications of filopodia length and number. Results: Unexpectedly, we find massive formations of filopodia even in the absence of CP and Ena/VASP proteins. Notably, combined inactivation of Ena/VASP, unconventional myosin-X and the formin FMNL3 was required to markedly impair filopodia formation in CP-deficient cells. Conclusions: Taken together, our results reveal that, besides Ena/VASP proteins, numerous other factors contribute to filopodia formation.
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Affiliation(s)
| | | | | | | | - Jan Faix
- Correspondence: ; Tel.: +49-511-532-2928
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21
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Campellone KG, Lebek NM, King VL. Branching out in different directions: Emerging cellular functions for the Arp2/3 complex and WASP-family actin nucleation factors. Eur J Cell Biol 2023; 102:151301. [PMID: 36907023 DOI: 10.1016/j.ejcb.2023.151301] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 02/07/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis, motility, and division. The structural and dynamic properties of the actin cytoskeleton are also crucial for establishing, maintaining, and changing the organization of membrane-bound organelles and other intracellular structures. Such activities are important in nearly all animal cells and tissues, although distinct anatomical regions and physiological systems rely on different regulatory factors. Recent work indicates that the Arp2/3 complex, a broadly expressed actin nucleator, drives actin assembly during several intracellular stress response pathways. These newly described Arp2/3-mediated cytoskeletal rearrangements are coordinated by members of the Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation-promoting factors. Thus, the Arp2/3 complex and WASP-family proteins are emerging as crucial players in cytoplasmic and nuclear activities including autophagy, apoptosis, chromatin dynamics, and DNA repair. Characterizations of the functions of the actin assembly machinery in such stress response mechanisms are advancing our understanding of both normal and pathogenic processes, and hold great promise for providing insights into organismal development and interventions for disease.
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Affiliation(s)
- Kenneth G Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA.
| | - Nadine M Lebek
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
| | - Virginia L King
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
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22
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Wirshing AC, Rodriguez SG, Goode BL. Evolutionary tuning of barbed end competition allows simultaneous construction of architecturally distinct actin structures. J Cell Biol 2023; 222:213854. [PMID: 36729023 PMCID: PMC9929936 DOI: 10.1083/jcb.202209105] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/01/2022] [Accepted: 01/13/2023] [Indexed: 02/03/2023] Open
Abstract
How cells simultaneously assemble actin structures of distinct sizes, shapes, and filamentous architectures is still not well understood. Here, we used budding yeast as a model to investigate how competition for the barbed ends of actin filaments might influence this process. We found that while vertebrate capping protein (CapZ) and formins can simultaneously associate with barbed ends and catalyze each other's displacement, yeast capping protein (Cap1/2) poorly displaces both yeast and vertebrate formins. Consistent with these biochemical differences, in vivo formin-mediated actin cable assembly was strongly attenuated by the overexpression of CapZ but not Cap1/2. Multiwavelength live cell imaging further revealed that actin patches in cap2∆ cells acquire cable-like features over time, including recruitment of formins and tropomyosin. Together, our results suggest that the activities of S. cerevisiae Cap1/2 have been tuned across evolution to allow robust cable assembly by formins in the presence of high cytosolic levels of Cap1/2, which conversely limit patch growth and shield patches from formins.
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Affiliation(s)
- Alison C.E. Wirshing
- https://ror.org/05abbep66Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Sofia Gonzalez Rodriguez
- https://ror.org/05abbep66Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Bruce L. Goode
- https://ror.org/05abbep66Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA,Correspondence to Bruce L. Goode:
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23
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Fäßler F, Javoor MG, Datler J, Döring H, Hofer FW, Dimchev G, Hodirnau VV, Faix J, Rottner K, Schur FK. ArpC5 isoforms regulate Arp2/3 complex-dependent protrusion through differential Ena/VASP positioning. SCIENCE ADVANCES 2023; 9:eadd6495. [PMID: 36662867 PMCID: PMC9858492 DOI: 10.1126/sciadv.add6495] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 12/20/2022] [Indexed: 05/10/2023]
Abstract
Regulation of the Arp2/3 complex is required for productive nucleation of branched actin networks. An emerging aspect of regulation is the incorporation of subunit isoforms into the Arp2/3 complex. Specifically, both ArpC5 subunit isoforms, ArpC5 and ArpC5L, have been reported to fine-tune nucleation activity and branch junction stability. We have combined reverse genetics and cellular structural biology to describe how ArpC5 and ArpC5L differentially affect cell migration. Both define the structural stability of ArpC1 in branch junctions and, in turn, by determining protrusion characteristics, affect protein dynamics and actin network ultrastructure. ArpC5 isoforms also affect the positioning of members of the Ena/Vasodilator-stimulated phosphoprotein (VASP) family of actin filament elongators, which mediate ArpC5 isoform-specific effects on the actin assembly level. Our results suggest that ArpC5 and Ena/VASP proteins are part of a signaling pathway enhancing cell migration.
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Affiliation(s)
- Florian Fäßler
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | | | - Julia Datler
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Hermann Döring
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Florian W. Hofer
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Georgi Dimchev
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | | | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Klemens Rottner
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Florian K.M. Schur
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
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24
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Pokrant T, Hein JI, Körber S, Disanza A, Pich A, Scita G, Rottner K, Faix J. Ena/VASP clustering at microspike tips involves lamellipodin but not I-BAR proteins, and absolutely requires unconventional myosin-X. Proc Natl Acad Sci U S A 2023. [PMID: 36598940 DOI: 10.1101/2022.05.12.491613] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
Sheet-like membrane protrusions at the leading edge, termed lamellipodia, drive 2D-cell migration using active actin polymerization. Microspikes comprise actin-filament bundles embedded within lamellipodia, but the molecular mechanisms driving their formation and their potential functional relevance have remained elusive. Microspike formation requires the specific activity of clustered Ena/VASP proteins at their tips to enable processive actin assembly in the presence of capping protein, but the factors and mechanisms mediating Ena/VASP clustering are poorly understood. Systematic analyses of B16-F1 melanoma mutants lacking potential candidate proteins revealed that neither inverse BAR-domain proteins, nor lamellipodin or Abi is essential for clustering, although they differentially contribute to lamellipodial VASP accumulation. In contrast, unconventional myosin-X (MyoX) identified here as proximal to VASP was obligatory for Ena/VASP clustering and microspike formation. Interestingly, and despite the invariable distribution of other relevant marker proteins, the width of lamellipodia in MyoX-KO mutants was significantly reduced as compared with B16-F1 control, suggesting that microspikes contribute to lamellipodium stability. Consistently, MyoX removal caused marked defects in protrusion and random 2D-cell migration. Strikingly, Ena/VASP-deficiency also uncoupled MyoX cluster dynamics from actin assembly in lamellipodia, establishing their tight functional association in microspike formation.
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Affiliation(s)
- Thomas Pokrant
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Jens Ingo Hein
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Sarah Körber
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Andrea Disanza
- IFOM ETS (Istituto Fondazione di Oncologia Molecolare ETS), - The AIRC (Italian Association for Cancer Research) Institute of Molecular Oncology, 20139 Milan, Italy
| | - Andreas Pich
- Research Core Unit Proteomics, Hannover Medical School, 30625 Hannover, Germany
| | - Giorgio Scita
- IFOM ETS (Istituto Fondazione di Oncologia Molecolare ETS), - The AIRC (Italian Association for Cancer Research) Institute of Molecular Oncology, 20139 Milan, Italy
- Department of Oncology and Haemato-Oncology, University of Milan, 20139 Milan, Italy
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
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25
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Phosphoserine-86-HSPB1 (pS86-HSPB1) is cytoplasmic and highly induced in rat myometrium at labour. Histochem Cell Biol 2023; 159:149-162. [PMID: 36260112 PMCID: PMC9922239 DOI: 10.1007/s00418-022-02158-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2022] [Indexed: 11/04/2022]
Abstract
Uterine myocytes during pregnancy proceed through a series of adaptations and collectively transform into a powerfully contractile tissue by term. Previous work has indicated that members of the heat shock protein (HSP) B family of stress proteins are associated with the process of adaptation and transformation. Utilizing immunoblot analyses, widefield epifluorescence and total internal reflection (TIRF) microscopy, this study investigated the temporal and spatial detection of HSPB1 phosphorylated on serine-86 (pS86-HSPB1) in rat myometrium during pregnancy, the role of uterine distension in regulation of pS86-HSPB1, and the comparative localization with pS15-HSPB1 in rat myometrial tissue as well as in an immortalized human myometrial cell line. Immunoblot detection of pS86-HSPB1 was significantly elevated during late pregnancy and labour. In particular, pS86-HSPB1 was significantly increased at day (d)22 and d23 (labour) compared with all other timepoints assessed. Localization of pS86-HSPB1 in myometrium became prominent at d22 and d23 with cytoplasmic detection around myometrial cell nuclei. Furthermore, pS86-HSPB1 detection was found to be significantly elevated in the gravid rat uterine myometrium compared with the non-gravid tissue at d19 and d23. Both widefield epifluorescence and TIRF microscopy examination of human myometrial cells demonstrated that pS15-HSPB1 was prominently localized to focal adhesions, while pS82-HSPB1 (homologous to rodent pS86-HSPB1) was primarily located in the cell cytoplasm. Our data demonstrate that levels of phosphorylated HSPB1 increase just prior to and during labour, and that uterine distension is a stress-inducing signal for HSPB1 phosphorylation. The exact roles of these phosphorylated forms in myometrial cells remain to be determined.
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26
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Lappalainen P, Kotila T, Jégou A, Romet-Lemonne G. Biochemical and mechanical regulation of actin dynamics. Nat Rev Mol Cell Biol 2022; 23:836-852. [PMID: 35918536 DOI: 10.1038/s41580-022-00508-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 12/30/2022]
Abstract
Polymerization of actin filaments against membranes produces force for numerous cellular processes, such as migration, morphogenesis, endocytosis, phagocytosis and organelle dynamics. Consequently, aberrant actin cytoskeleton dynamics are linked to various diseases, including cancer, as well as immunological and neurological disorders. Understanding how actin filaments generate forces in cells, how force production is regulated by the interplay between actin-binding proteins and how the actin-regulatory machinery responds to mechanical load are at the heart of many cellular, developmental and pathological processes. During the past few years, our understanding of the mechanisms controlling actin filament assembly and disassembly has evolved substantially. It has also become evident that the activities of key actin-binding proteins are not regulated solely by biochemical signalling pathways, as mechanical regulation is critical for these proteins. Indeed, the architecture and dynamics of the actin cytoskeleton are directly tuned by mechanical load. Here we discuss the general mechanisms by which key actin regulators, often in synergy with each other, control actin filament assembly, disassembly, and monomer recycling. By using an updated view of actin dynamics as a framework, we discuss how the mechanics and geometry of actin networks control actin-binding proteins, and how this translates into force production in endocytosis and mesenchymal cell migration.
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Affiliation(s)
- Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland.
| | - Tommi Kotila
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland
| | - Antoine Jégou
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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27
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Tsai FC, Henderson JM, Jarin Z, Kremneva E, Senju Y, Pernier J, Mikhajlov O, Manzi J, Kogan K, Le Clainche C, Voth GA, Lappalainen P, Bassereau P. Activated I-BAR IRSp53 clustering controls the formation of VASP-actin-based membrane protrusions. SCIENCE ADVANCES 2022; 8:eabp8677. [PMID: 36240267 PMCID: PMC9565809 DOI: 10.1126/sciadv.abp8677] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (insulin receptor substrate protein of 53 kDa). We showed that full-length IRSp53 self-assembles into clusters on membranes depending on PIP2. Using well-controlled in vitro reconstitution systems, we demonstrated that IRSp53 clusters recruit the actin polymerase VASP (vasodilator-stimulated phosphoprotein) to assemble actin filaments locally on membranes, leading to the generation of actin-filled membrane protrusions reminiscent of filopodia. By pulling membrane nanotubes from live cells, we observed that IRSp53 can only be enriched and trigger actin assembly in nanotubes at highly dynamic membrane regions. Our work supports a regulation mechanism of IRSp53 in its attributes of curvature sensation and partner recruitment to ensure a precise spatial-temporal control of filopodium initiation.
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Affiliation(s)
- Feng-Ching Tsai
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
| | - J. Michael Henderson
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Unité de Trafic Membranaire et Pathogénèse, Département de Biologie Cellulaire et Infection, Institut Pasteur, Université de Paris, CNRS UMR 3691, 75015 Paris, France
| | - Zack Jarin
- Pritzker School for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Elena Kremneva
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Yosuke Senju
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, Japan
| | - Julien Pernier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Oleg Mikhajlov
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - John Manzi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Konstantin Kogan
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Christophe Le Clainche
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gregory A. Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
| | - Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
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28
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Fuchs J, Bareesel S, Kroon C, Polyzou A, Eickholt BJ, Leondaritis G. Plasma membrane phospholipid phosphatase-related proteins as pleiotropic regulators of neuron growth and excitability. Front Mol Neurosci 2022; 15:984655. [PMID: 36187351 PMCID: PMC9520309 DOI: 10.3389/fnmol.2022.984655] [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: 07/02/2022] [Accepted: 08/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neuronal plasma membrane proteins are essential for integrating cell extrinsic and cell intrinsic signals to orchestrate neuronal differentiation, growth and plasticity in the developing and adult nervous system. Here, we shed light on the family of plasma membrane proteins phospholipid phosphatase-related proteins (PLPPRs) (alternative name, PRGs; plasticity-related genes) that fine-tune neuronal growth and synaptic transmission in the central nervous system. Several studies uncovered essential functions of PLPPRs in filopodia formation, axon guidance and branching during nervous system development and regeneration, as well as in the control of dendritic spine number and excitability. Loss of PLPPR expression in knockout mice increases susceptibility to seizures, and results in defects in sensory information processing, development of psychiatric disorders, stress-related behaviors and abnormal social interaction. However, the exact function of PLPPRs in the context of neurological diseases is largely unclear. Although initially described as active lysophosphatidic acid (LPA) ecto-phosphatases that regulate the levels of this extracellular bioactive lipid, PLPPRs lack catalytic activity against LPA. Nevertheless, they emerge as atypical LPA modulators, by regulating LPA mediated signaling processes. In this review, we summarize the effects of this protein family on cellular morphology, generation and maintenance of cellular protrusions as well as highlight their known neuronal functions and phenotypes of KO mice. We discuss the molecular mechanisms of PLPPRs including the deployment of phospholipids, actin-cytoskeleton and small GTPase signaling pathways, with a focus on identifying gaps in our knowledge to stimulate interest in this understudied protein family.
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Affiliation(s)
- Joachim Fuchs
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Shannon Bareesel
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Cristina Kroon
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alexandra Polyzou
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Britta J. Eickholt
- Institute of Molecular Biology and Biochemistry, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- *Correspondence: Britta J. Eickholt,
| | - George Leondaritis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
- Institute of Biosciences, University Research Center Ioannina, University of Ioannina, Ioannina, Greece
- George Leondaritis,
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29
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Svec KV, Howe AK. Protein Kinase A in cellular migration—Niche signaling of a ubiquitous kinase. Front Mol Biosci 2022; 9:953093. [PMID: 35959460 PMCID: PMC9361040 DOI: 10.3389/fmolb.2022.953093] [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: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 12/28/2022] Open
Abstract
Cell migration requires establishment and maintenance of directional polarity, which in turn requires spatial heterogeneity in the regulation of protrusion, retraction, and adhesion. Thus, the signaling proteins that regulate these various structural processes must also be distinctly regulated in subcellular space. Protein Kinase A (PKA) is a ubiquitous serine/threonine kinase involved in innumerable cellular processes. In the context of cell migration, it has a paradoxical role in that global inhibition or activation of PKA inhibits migration. It follows, then, that the subcellular regulation of PKA is key to bringing its proper permissive and restrictive functions to the correct parts of the cell. Proper subcellular regulation of PKA controls not only when and where it is active but also specifies the targets for that activity, allowing the cell to use a single, promiscuous kinase to exert distinct functions within different subcellular niches to facilitate cell movement. In this way, understanding PKA signaling in migration is a study in context and in the elegant coordination of distinct functions of a single protein in a complex cellular process.
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Affiliation(s)
- Kathryn V. Svec
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
| | - Alan K. Howe
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, V T, United States
- University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
- *Correspondence: Alan K. Howe,
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