1
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Advedissian T, Frémont S, Echard A. Cytokinetic abscission requires actin-dependent microtubule severing. Nat Commun 2024; 15:1949. [PMID: 38431632 PMCID: PMC10908825 DOI: 10.1038/s41467-024-46062-9] [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: 05/22/2023] [Accepted: 02/09/2024] [Indexed: 03/05/2024] Open
Abstract
Cell division is completed by the abscission of the intercellular bridge connecting the daughter cells. Abscission requires the polymerization of an ESCRT-III cone close to the midbody to both recruit the microtubule severing enzyme spastin and scission the plasma membrane. Here, we found that the microtubule and the membrane cuts are two separate events that are regulated differently. Using HeLa cells, we uncovered that the F-actin disassembling protein Cofilin-1 controls the disappearance of a transient pool of branched F-actin which is precisely assembled at the tip of the ESCRT-III cone shortly before the microtubule cut. Functionally, Cofilin-1 and Arp2/3-mediated branched F-actin favor abscission by promoting local severing of the microtubules but do not participate later in the membrane scission event. Mechanistically, we propose that branched F-actin functions as a physical barrier that limits ESCRT-III cone elongation and thereby favors stable spastin recruitment. Our work thus reveals that F-actin controls the timely and local disassembly of microtubules required for cytokinetic abscission.
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Affiliation(s)
- Tamara Advedissian
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Stéphane Frémont
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Arnaud Echard
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France.
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2
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Sun ZG, Yadav V, Amiri S, Cao W, De La Cruz EM, Murrell M. Cofilin-mediated actin filament network flexibility facilitates 2D to 3D actomyosin shape change. Eur J Cell Biol 2024; 103:151379. [PMID: 38168598 DOI: 10.1016/j.ejcb.2023.151379] [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: 08/11/2023] [Revised: 12/06/2023] [Accepted: 12/16/2023] [Indexed: 01/05/2024] Open
Abstract
The organization of actin filaments (F-actin) into crosslinked networks determines the transmission of mechanical stresses within the cytoskeleton and subsequent changes in cell and tissue shape. Principally mediated by proteins such as α-actinin, F-actin crosslinking increases both network connectivity and rigidity, thereby facilitating stress transmission at low crosslinking yet attenuating transmission at high crosslinker concentration. Here, we engineer a two-dimensional model of the actomyosin cytoskeleton, in which myosin-induced mechanical stresses are controlled by light. We alter the extent of F-actin crosslinking by the introduction of oligomerized cofilin. At pH 6.5, F-actin severing by cofilin is weak, but cofilin bundles and crosslinks filaments. Given its effect of lowering the F-actin bending stiffness, cofilin- crosslinked networks are significantly more flexible and softer in bending than networks crosslinked by α-actinin. Thus, upon local activation of myosin-induced contractile stress, the network bends out-of-plane in contrast to the in-plane compression as observed with networks crosslinked by α-actinin. Here, we demonstrate that local effects on filament mechanics by cofilin introduces novel large-scale network material properties that enable the sculpting of complex shapes in the cell cytoskeleton.
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Affiliation(s)
- Zachary Gao Sun
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA; Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520, USA
| | - Vikrant Yadav
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Sorosh Amiri
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Mechanical Engineering and Material Science, Yale University, New Haven, CT 06511, USA
| | - Wenxiang Cao
- Department of Molecular Biology & Biophysics, Yale University, New Haven, CT 06511, USA
| | - Enrique M De La Cruz
- Department of Molecular Biology & Biophysics, Yale University, New Haven, CT 06511, USA
| | - Michael Murrell
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA; Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520, USA.
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3
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Sexton JA, Potchernikov T, Bibeau JP, Casanova-Sepúlveda G, Cao W, Lou HJ, Boggon TJ, De La Cruz EM, Turk BE. Distinct functional constraints driving conservation of the cofilin N-terminal regulatory tail. Nat Commun 2024; 15:1426. [PMID: 38365893 PMCID: PMC10873347 DOI: 10.1038/s41467-024-45878-9] [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: 07/31/2023] [Accepted: 02/06/2024] [Indexed: 02/18/2024] Open
Abstract
Cofilin family proteins have essential roles in remodeling the cytoskeleton through filamentous actin depolymerization and severing. The short, unstructured N-terminal region of cofilin is critical for actin binding and harbors the major site of inhibitory phosphorylation. Atypically for a disordered sequence, the N-terminal region is highly conserved, but specific aspects driving this conservation are unclear. Here, we screen a library of 16,000 human cofilin N-terminal sequence variants for their capacity to support growth in S. cerevisiae in the presence or absence of the upstream regulator LIM kinase. Results from the screen and biochemical analysis of individual variants reveal distinct sequence requirements for actin binding and regulation by LIM kinase. LIM kinase recognition only partly explains sequence constraints on phosphoregulation, which are instead driven to a large extent by the capacity for phosphorylation to inactivate cofilin. We find loose sequence requirements for actin binding and phosphoinhibition, but collectively they restrict the N-terminus to sequences found in natural cofilins. Our results illustrate how a phosphorylation site can balance potentially competing sequence requirements for function and regulation.
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Affiliation(s)
- Joel A Sexton
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Tony Potchernikov
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jeffrey P Bibeau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | | | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Hua Jane Lou
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Benjamin E Turk
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06520, USA.
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4
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Ventura Santos C, Rogers SL, Carter AP. CryoET shows cofilactin filaments inside the microtubule lumen. EMBO Rep 2023; 24:e57264. [PMID: 37702953 PMCID: PMC10626427 DOI: 10.15252/embr.202357264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/25/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
Cytoplasmic microtubules are tubular polymers that can harbor small proteins or filaments inside their lumen. The identities of these objects and mechanisms for their accumulation have not been conclusively established. Here, we used cryogenic electron tomography of Drosophila S2 cell protrusions and found filaments inside the microtubule lumen, which resemble those reported recently in human HAP1 cells. The frequency of these filaments increased upon inhibition of the sarco/endoplasmic reticulum Ca2+ ATPase with the small molecule drug thapsigargin. Subtomogram averaging showed that the luminal filaments adopt a helical structure reminiscent of cofilin-bound actin (cofilactin). Consistent with this, we observed cofilin dephosphorylation, an activating modification, in cells under the same conditions that increased luminal filament occurrence. Furthermore, RNA interference knock-down of cofilin reduced the frequency of luminal filaments with cofilactin morphology. These results suggest that cofilin activation stimulates its accumulation on actin filaments inside the microtubule lumen.
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Affiliation(s)
| | - Stephen L Rogers
- Department of Biology and Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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5
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Cao W, Taylor EW, De La Cruz EM. Cooperative ligand binding to a double-stranded Ising lattice-Application to cofilin binding to actin filaments. PNAS NEXUS 2023; 2:pgad331. [PMID: 37885622 PMCID: PMC10599439 DOI: 10.1093/pnasnexus/pgad331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023]
Abstract
Cooperative ligand binding to linear polymers is fundamental in many scientific disciplines, particularly biological and chemical physics and engineering. Such ligand binding interactions have been widely modeled using infinite one-dimensional (1D) Ising models even in cases where the linear polymers are more complex (e.g. actin filaments and other double-stranded linear polymers). Here, we use sequence-generating and transfer matrix methods to obtain an analytical method for cooperative equilibrium ligand binding to double-stranded Ising lattices. We use this exact solution to evaluate binding properties and features and analyze experimental binding data of cooperative binding of the regulatory protein, cofilin, to actin filaments. This analysis, with additional experimental information about the observed bound cofilin cluster sizes and filament structure, reveals that a bound cofilin promotes cooperative binding to its longitudinal nearest-neighbors but has very modest effects on lateral nearest-neighbors. The bound cofilin cluster sizes calculated from the best fit parameters from the double-stranded model are considerably larger than when calculated with the 1D model, consistent with experimental observations made by electron microscopy and fluorescence imaging. The exact solution obtained and the method for using the solution developed here can be widely used for analysis of variety of multistranded lattice systems.
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Affiliation(s)
- Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Edwin W Taylor
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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6
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Sexton JA, Potchernikov T, Bibeau JP, Casanova-Sepúlveda G, Cao W, Lou HJ, Boggon TJ, De La Cruz EM, Turk BE. Distinct functional constraints driving conservation of the cofilin N-terminal regulatory tail. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.30.547189. [PMID: 37425676 PMCID: PMC10327202 DOI: 10.1101/2023.06.30.547189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Cofilin family proteins have essential roles in remodeling the cytoskeleton through filamentous actin depolymerization and severing. The short unstructured N-terminal region of cofilin is critical for actin binding and harbors the major site of inhibitory phosphorylation. Atypically for a disordered sequence, the N-terminal region is highly conserved, but the aspects of cofilin functionality driving this conservation are not clear. Here, we screened a library of 16,000 human cofilin N-terminal sequence variants for their capacity to support growth in S. cerevisiae in the presence or absence of the upstream regulator LIM kinase. Results from the screen and subsequent biochemical analysis of individual variants revealed distinct sequence requirements for actin binding and regulation by LIM kinase. While the presence of a serine, rather than threonine, phosphoacceptor residue was essential for phosphorylation by LIM kinase, the native cofilin N-terminus was otherwise a suboptimal LIM kinase substrate. This circumstance was not due to sequence requirements for actin binding and severing, but rather appeared primarily to maintain the capacity for phosphorylation to inactivate cofilin. Overall, the individual sequence requirements for cofilin function and regulation were remarkably loose when examined separately, but collectively restricted the N-terminus to sequences found in natural cofilins. Our results illustrate how a regulatory phosphorylation site can balance potentially competing sequence requirements for function and regulation.
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Affiliation(s)
- Joel A. Sexton
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520
| | - Tony Potchernikov
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Jeffrey P. Bibeau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | | | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Hua Jane Lou
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520
| | - Titus J. Boggon
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Enrique M. De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Benjamin E. Turk
- Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520
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7
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Santos CV, Rogers SL, Carter AP. CryoET shows cofilactin filaments inside the microtubule lumen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535077. [PMID: 37034688 PMCID: PMC10081314 DOI: 10.1101/2023.03.31.535077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Cytoplasmic microtubules are tubular polymers that can harbor small proteins or filaments inside their lumen. The identity of these objects and what causes their accumulation has not been conclusively established. Here, we used cryogenic electron tomography (cryoET) of Drosophila S2 cell protrusions and found filaments inside the microtubule lumen, which resemble those reported recently in human HAP1 cells. The frequency of these filaments increased upon inhibition of the sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) with the small-molecule drug thapsigargin. Subtomogram averaging showed that the luminal filaments adopt a helical structure reminiscent of cofilin-bound actin (cofilactin). Consistent with this, cofilin was activated in cells under the same conditions that increased luminal filament occurrence. Furthermore, RNAi knock-down of cofilin reduced the frequency of luminal filaments with cofilactin morphology. These results suggest that cofilin activation stimulates its accumulation on actin filaments inside the microtubule lumen.
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Affiliation(s)
| | - Stephen L. Rogers
- Department of Biology and Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill
| | - Andrew P. Carter
- MRC Laboratory of Molecular Biology, Francis Crick Ave, Cambridge, CB2 0QH, UK
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8
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Abstract
Actin cytoskeleton force generation, sensing, and adaptation are dictated by the bending and twisting mechanics of filaments. Here, we use magnetic tweezers and microfluidics to twist and pull individual actin filaments and evaluate their response to applied loads. Twisted filaments bend and dissipate torsional strain by adopting a supercoiled plectoneme. Pulling prevents plectoneme formation, which causes twisted filaments to sever. Analysis over a range of twisting and pulling forces and direct visualization of filament and single subunit twisting fluctuations yield an actin filament torsional persistence length of ~10 µm, similar to the bending persistence length. Filament severing by cofilin is driven by local twist strain at boundaries between bare and decorated segments and is accelerated by low pN pulling forces. This work explains how contractile forces generated by myosin motors accelerate filament severing by cofilin and establishes a role for filament twisting in the regulation of actin filament stability and assembly dynamics.
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9
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Chetty AK, Ha BH, Boggon TJ. Rho family GTPase signaling through type II p21-activated kinases. Cell Mol Life Sci 2022; 79:598. [PMID: 36401658 PMCID: PMC10105373 DOI: 10.1007/s00018-022-04618-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/07/2022] [Accepted: 10/28/2022] [Indexed: 11/21/2022]
Abstract
Signaling from the Rho family small GTPases controls a wide range of signaling outcomes. Key among the downstream effectors for many of the Rho GTPases are the p21-activated kinases, or PAK group. The PAK family comprises two types, the type I PAKs (PAK1, 2 and 3) and the type II PAKs (PAK4, 5 and 6), which have distinct structures and mechanisms of regulation. In this review, we discuss signal transduction from Rho GTPases with a focus on the type II PAKs. We discuss the role of PAKs in signal transduction pathways and selectivity of Rho GTPases for PAK family members. We consider the less well studied of the Rho GTPases and their PAK-related signaling. We then discuss the molecular basis for kinase domain recognition of substrates and for regulation of signaling. We conclude with a discussion of the role of PAKs in cross talk between Rho family small GTPases and the roles of PAKs in disease.
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Affiliation(s)
- Ashwin K Chetty
- Yale College, New Haven, CT, 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Byung Hak Ha
- Department of Pharmacology, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA.
- Department of Pharmacology, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA.
- Yale Cancer Center, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA.
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10
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Schiavi-Ehrenhaus LJ, Romarowski A, Jabloñski M, Krapf D, Luque GM, Buffone MG. The early molecular events leading to COFILIN phosphorylation during mouse sperm capacitation are essential for acrosomal exocytosis. J Biol Chem 2022; 298:101988. [PMID: 35487245 PMCID: PMC9142561 DOI: 10.1016/j.jbc.2022.101988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 04/18/2022] [Accepted: 04/20/2022] [Indexed: 12/03/2022] Open
Abstract
The actin cytoskeleton reorganization during sperm capacitation is essential for the occurrence of acrosomal exocytosis (AR) in several mammalian species. Here, we demonstrate that in mouse sperm, within the first minutes of exposure upon capacitating conditions, the activity of RHOA/C and RAC1 is essential for LIMK1 and COFILIN phosphorylation. However, we observed that the signaling pathway involving RAC1 and PAK4 is the main player in controlling actin polymerization in the sperm head necessary for the occurrence of AR. Moreover, we show that the transient phosphorylation of COFILIN is also influenced by the Slingshot family of protein phosphatases (SSH1). The activity of SSH1 is regulated by the dual action of two pathways. On one hand, RHOA/C and RAC1 activity promotes SSH1 phosphorylation (inactivation). On the other hand, the activating dephosphorylation is driven by okadaic acid-sensitive phosphatases. This regulatory mechanism is independent of the commonly observed activating mechanisms involving PP2B and emerges as a new finely tuned modulation that is, so far, exclusively observed in mouse sperm. However, persistent phosphorylation of COFILIN by SSH1 inhibition or okadaic acid did not altered actin polymerization and the AR. Altogether, our results highlight the role of small GTPases in modulating actin dynamics required for AR.
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Affiliation(s)
- Liza J Schiavi-Ehrenhaus
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas (IBYME-CONICET), Buenos Aires, Argentina
| | - Ana Romarowski
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Martina Jabloñski
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas (IBYME-CONICET), Buenos Aires, Argentina
| | - Darío Krapf
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Guillermina M Luque
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas (IBYME-CONICET), Buenos Aires, Argentina.
| | - Mariano G Buffone
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas (IBYME-CONICET), Buenos Aires, Argentina.
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11
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Hylton RK, Heebner JE, Grillo MA, Swulius MT. Cofilactin filaments regulate filopodial structure and dynamics in neuronal growth cones. Nat Commun 2022; 13:2439. [PMID: 35508487 PMCID: PMC9068697 DOI: 10.1038/s41467-022-30116-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 04/15/2022] [Indexed: 12/12/2022] Open
Abstract
Cofilin is best known for its ability to sever actin filaments and facilitate cytoskeletal recycling inside of cells, but at higher concentrations in vitro, cofilin stabilizes a more flexible, hyper-twisted state of actin known as “cofilactin”. While this filament state is well studied, a structural role for cofilactin in dynamic cellular processes has not been observed. With a combination of cryo-electron tomography and fluorescence imaging in neuronal growth cones, we observe that filopodial actin filaments switch between a fascin-linked and a cofilin-decorated state, and that cofilactin is associated with a variety of dynamic events within filopodia. The switch to cofilactin filaments occurs in a graded fashion and correlates with a decline in fascin cross-linking within the filopodia, which is associated with curvature in the bundle. Our tomographic data reveal that the hyper-twisting of actin from cofilin binding leads to a rearrangement of filament packing, which largely excludes fascin from the base of filopodia. Our results provide mechanistic insight into the fundamentals of cytoskeletal remodeling inside of confined cellular spaces, and how the interplay between fascin and cofilin regulates the dynamics of searching filopodia. In this manuscript the authors show that Filopodia switch between bundles of fascin-crosslinked actin and cofilin-decorated filaments, which exclude fascin binding due to altered structure and packing, as well as affect filopodial searching dynamics.
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Affiliation(s)
- Ryan K Hylton
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - Jessica E Heebner
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - Michael A Grillo
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - Matthew T Swulius
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA.
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12
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Kumar N, Rath PP, Aggarwal P, Maiti S, Bhavesh NS, Gourinath S. Unravelling the Biology of EhActo as the First Cofilin From Entamoeba histolytica. Front Cell Dev Biol 2022; 10:785680. [PMID: 35281106 PMCID: PMC8914023 DOI: 10.3389/fcell.2022.785680] [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: 09/29/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Actin-depolymerising factors (ADF) are a known family of proteins that regulate actin dynamics. Actin regulation is critical for primitive eukaryotes since it drives their key cellular processes. Entamoeba histolytica, a protist human pathogen harbours eleven proteins within this family, however, with no actin depolymerising protein reported to date. We present here the NMR model of EhActo, the first Cofilin from E. histolytica that severs actin filaments and also participates in cellular events like phagocytosis and pseudopod formation. The model typically represents the ADF-homology domain compared to other cofilins. Uniquely, EhActo lacks the critical Serine3 residue present in all known actophorins mediating its phospho-regulation. The second mode of regulation that cofilin’s are subjected to is via their interaction with 14-3-3 proteins through the phosphorylated Serine residue and a consensus binding motif. We found a unique interaction between EhActo and 14-3-3 without the presence of the consensus motif or the phosphorylated Serine. These interesting results present unexplored newer mechanisms functional in this pathogen to regulate actophorin. Through our structural and biochemical studies we have deciphered the mechanism of action of EhActo, implicating its role in amoebic biology.
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Affiliation(s)
- Nitesh Kumar
- Department of Pathology, Indira Gandhi Institute of Medical Sciences, Patna, India
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- *Correspondence: Nitesh Kumar, ; Samudrala Gourinath,
| | | | - Priyanka Aggarwal
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Sankar Maiti
- Indian Institute of Science, Education and Research, Kolkata, India
| | - Neel Sarovar Bhavesh
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Samudrala Gourinath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- *Correspondence: Nitesh Kumar, ; Samudrala Gourinath,
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13
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Vignier N, Chatzifrangkeskou M, Pinton L, Wioland H, Marais T, Lemaitre M, Le Dour C, Peccate C, Cardoso D, Schmitt A, Wu W, Biferi MG, Naouar N, Macquart C, Beuvin M, Decostre V, Bonne G, Romet-Lemonne G, Worman HJ, Tedesco FS, Jégou A, Muchir A. The non-muscle ADF/cofilin-1 controls sarcomeric actin filament integrity and force production in striated muscle laminopathies. Cell Rep 2021; 36:109601. [PMID: 34433058 PMCID: PMC8411111 DOI: 10.1016/j.celrep.2021.109601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/09/2021] [Accepted: 08/04/2021] [Indexed: 12/11/2022] Open
Abstract
Cofilins are important for the regulation of the actin cytoskeleton, sarcomere organization, and force production. The role of cofilin-1, the non-muscle-specific isoform, in muscle function remains unclear. Mutations in LMNA encoding A-type lamins, intermediate filament proteins of the nuclear envelope, cause autosomal Emery-Dreifuss muscular dystrophy (EDMD). Here, we report increased cofilin-1 expression in LMNA mutant muscle cells caused by the inability of proteasome degradation, suggesting a protective role by ERK1/2. It is known that phosphorylated ERK1/2 directly binds to and catalyzes phosphorylation of the actin-depolymerizing factor cofilin-1 on Thr25. In vivo ectopic expression of cofilin-1, as well as its phosphorylated form on Thr25, impairs sarcomere structure and force generation. These findings present a mechanism that provides insight into the molecular pathogenesis of muscular dystrophies caused by LMNA mutations.
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Affiliation(s)
- Nicolas Vignier
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Maria Chatzifrangkeskou
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Luca Pinton
- Department of Cell and Developmental Biology, University College London, London, UK; Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Hugo Wioland
- Université de Paris, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Thibaut Marais
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Mégane Lemaitre
- Sorbonne Université, UMS28, Phénotypage du Petit Animal, Paris, France
| | - Caroline Le Dour
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Cécile Peccate
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Déborah Cardoso
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Alain Schmitt
- Université de Paris, INSERM, CNRS, Institut Cochin, 75005 Paris, France
| | - Wei Wu
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Maria-Grazia Biferi
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Naïra Naouar
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Coline Macquart
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Maud Beuvin
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Valérie Decostre
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | | | - Howard J Worman
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Francesco Saverio Tedesco
- Department of Cell and Developmental Biology, University College London, London, UK; Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; The Francis Crick Institute, London, UK
| | - Antoine Jégou
- Université de Paris, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France.
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14
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Kadzik RS, Homa KE, Kovar DR. F-Actin Cytoskeleton Network Self-Organization Through Competition and Cooperation. Annu Rev Cell Dev Biol 2021; 36:35-60. [PMID: 33021819 DOI: 10.1146/annurev-cellbio-032320-094706] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many fundamental cellular processes such as division, polarization, endocytosis, and motility require the assembly, maintenance, and disassembly of filamentous actin (F-actin) networks at specific locations and times within the cell. The particular function of each network is governed by F-actin organization, size, and density as well as by its dynamics. The distinct characteristics of different F-actin networks are determined through the coordinated actions of specific sets of actin-binding proteins (ABPs). Furthermore, a cell typically assembles and uses multiple F-actin networks simultaneously within a common cytoplasm, so these networks must self-organize from a common pool of shared globular actin (G-actin) monomers and overlapping sets of ABPs. Recent advances in multicolor imaging and analysis of ABPs and their associated F-actin networks in cells, as well as the development of sophisticated in vitro reconstitutions of networks with ensembles of ABPs, have allowed the field to start uncovering the underlying principles by which cells self-organize diverse F-actin networks to execute basic cellular functions.
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Affiliation(s)
- Rachel S Kadzik
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; , .,Department of Molecular BioSciences, Northwestern University, Evanston, Illinois 60208, USA;
| | - Kaitlin E Homa
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; ,
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; , .,Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA
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15
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Wang Z, Mim C. CryoEM reveals BIN1 (isoform 8) does not bind to single actin filaments in vitro. MICROPUBLICATION BIOLOGY 2021; 2021. [PMID: 34104877 PMCID: PMC8178704 DOI: 10.17912/micropub.biology.000404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cells change their appearance by a concerted action of the cytoskeleton and the plasma membrane. The machinery that bends the membrane includes Bin/Amphiphysin/Rvs (BAR) domain proteins. Recently BAR domain proteins garnered attention as actin regulators, either by recruiting actin regulating proteins or through binding to actin directly. BIN1 (an important protein in Alzheimer’s Disease, heart disease and cancer) is one of the few BAR proteins that bind to actin directly. Here, we imaged a complex of BIN1 and actin with cryoEM. Our results reveal that BIN1 cannot be found on single actin filaments.
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Affiliation(s)
- Zuoneng Wang
- Royal Technical Institute (KTH), Dept. for Biomedical Engineering and Health Systems, Stockholm, Sweden
| | - Carsten Mim
- Royal Technical Institute (KTH), Dept. for Biomedical Engineering and Health Systems, Stockholm, Sweden
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16
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Bolger-Munro M, Choi K, Cheung F, Liu YT, Dang-Lawson M, Deretic N, Keane C, Gold MR. The Wdr1-LIMK-Cofilin Axis Controls B Cell Antigen Receptor-Induced Actin Remodeling and Signaling at the Immune Synapse. Front Cell Dev Biol 2021; 9:649433. [PMID: 33928084 PMCID: PMC8076898 DOI: 10.3389/fcell.2021.649433] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/12/2021] [Indexed: 12/27/2022] Open
Abstract
When B cells encounter membrane-bound antigens, the formation and coalescence of B cell antigen receptor (BCR) microclusters amplifies BCR signaling. The ability of B cells to probe the surface of antigen-presenting cells (APCs) and respond to APC-bound antigens requires remodeling of the actin cytoskeleton. Initial BCR signaling stimulates actin-related protein (Arp) 2/3 complex-dependent actin polymerization, which drives B cell spreading as well as the centripetal movement and coalescence of BCR microclusters at the B cell-APC synapse. Sustained actin polymerization depends on concomitant actin filament depolymerization, which enables the recycling of actin monomers and Arp2/3 complexes. Cofilin-mediated severing of actin filaments is a rate-limiting step in the morphological changes that occur during immune synapse formation. Hence, regulators of cofilin activity such as WD repeat-containing protein 1 (Wdr1), LIM domain kinase (LIMK), and coactosin-like 1 (Cotl1) may also be essential for actin-dependent processes in B cells. Wdr1 enhances cofilin-mediated actin disassembly. Conversely, Cotl1 competes with cofilin for binding to actin and LIMK phosphorylates cofilin and prevents it from binding to actin filaments. We now show that Wdr1 and LIMK have distinct roles in BCR-induced assembly of the peripheral actin structures that drive B cell spreading, and that cofilin, Wdr1, and LIMK all contribute to the actin-dependent amplification of BCR signaling at the immune synapse. Depleting Cotl1 had no effect on these processes. Thus, the Wdr1-LIMK-cofilin axis is critical for BCR-induced actin remodeling and for B cell responses to APC-bound antigens.
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Affiliation(s)
- Madison Bolger-Munro
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Kate Choi
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Faith Cheung
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Yi Tian Liu
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - May Dang-Lawson
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Nikola Deretic
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Connor Keane
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Michael R Gold
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
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17
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Bibeau JP, Gray S, De La Cruz EM. Clusters of a Few Bound Cofilins Sever Actin Filaments. J Mol Biol 2021; 433:166833. [PMID: 33524412 DOI: 10.1016/j.jmb.2021.166833] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 02/06/2023]
Abstract
Cofilin is an essential actin filament severing protein that accelerates the assembly dynamics and turnover of actin networks by increasing the number of filament ends where subunits add and dissociate. It binds filament subunits stoichiometrically and cooperatively, forming clusters of contiguously-bound cofilin at sub-saturating occupancies. Filaments partially occupied with cofilin sever at boundaries between bare and cofilin-decorated segments. Imaging studies concluded that bound clusters must reach a critical size (Cc) of 13-100 cofilins to sever filaments. In contrast, structural and modeling studies suggest that a few or even a single cofilin can sever filaments, possibly with different severing rate constants. How clusters grow through the cooperative incorporation of additional cofilin molecules, specifically if they elongate asymmetrically or uniformly from both ends and if they are modulated by filament shape and external force, also lacks consensus. Here, using hydrodynamic flow to visualize individual actin filaments with TIRF microscopy, we found that neither flow-induced filament bending, tension, nor surface attachment conditions substantially affected the kinetics of cofilin binding to actin filaments. Clusters of bound cofilin preferentially extended toward filament pointed ends and displayed severing competency at small sizes (Cc < 3), with no detectable severing dependence on cluster size. These data support models in which small clusters of cofilin introduce local, but asymmetric, structural changes in actin filaments that promote filament severing with a rate constant that depends weakly on the size of the cluster.
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Affiliation(s)
- Jeffrey P Bibeau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States
| | - Shawn Gray
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States.
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18
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Wioland H, Frémont S, Guichard B, Echard A, Jégou A, Romet-Lemonne G. Actin filament oxidation by MICAL1 suppresses protections from cofilin-induced disassembly. EMBO Rep 2021; 22:e50965. [PMID: 33393173 DOI: 10.15252/embr.202050965] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 11/18/2020] [Accepted: 11/27/2020] [Indexed: 02/01/2023] Open
Abstract
Proteins of the ADF/cofilin family play a central role in the disassembly of actin filaments, and their activity must be tightly regulated in cells. Recently, the oxidation of actin filaments by the enzyme MICAL1 was found to amplify the severing action of cofilin through unclear mechanisms. Using single filament experiments in vitro, we found that actin filament oxidation by MICAL1 increases, by several orders of magnitude, both cofilin binding and severing rates, explaining the dramatic synergy between oxidation and cofilin for filament disassembly. Remarkably, we found that actin oxidation bypasses the need for cofilin activation by dephosphorylation. Indeed, non-activated, phosphomimetic S3D-cofilin binds and severs oxidized actin filaments rapidly, in conditions where non-oxidized filaments are unaffected. Finally, tropomyosin Tpm1.8 loses its ability to protect filaments from cofilin severing activity when actin is oxidized by MICAL1. Together, our results show that MICAL1-induced oxidation of actin filaments suppresses their physiological protection from the action of cofilin. We propose that, in cells, direct post-translational modification of actin filaments by oxidation is a way to trigger their disassembly.
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Affiliation(s)
- Hugo Wioland
- Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Stéphane Frémont
- Membrane Traffic and Cell Division Lab, Institut Pasteur, UMR3691, CNRS, Paris, France
| | | | - Arnaud Echard
- Membrane Traffic and Cell Division Lab, Institut Pasteur, UMR3691, CNRS, Paris, France
| | - Antoine Jégou
- Université de Paris, CNRS, Institut Jacques Monod, Paris, France
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19
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Hocky GM, Sindelar CV, Cao W, Voth GA, De La Cruz EM. Structural basis of fast- and slow-severing actin-cofilactin boundaries. J Biol Chem 2021; 296:100337. [PMID: 33508320 PMCID: PMC7961102 DOI: 10.1016/j.jbc.2021.100337] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 01/24/2023] Open
Abstract
Members of the ADF/cofilin family of regulatory proteins bind actin filaments cooperatively, locally change actin subunit conformation and orientation, and sever filaments at "boundaries" between bare and cofilin-occupied segments. A cluster of bound cofilin introduces two distinct classes of boundaries due to the intrinsic polarity of actin filaments, one at the "pointed" end side and the other at the "barbed" end-side of the cluster; severing occurs more readily at the pointed end side of the cluster ("fast-severing" boundary) than the barbed end side ("slow-severing" boundary). A recent electron-cryomicroscopy (cryo-EM) model of the slow-severing boundary revealed structural "defects" at the interface that potentially contribute to severing. However, the structure of the fast-severing boundary remains uncertain. Here, we use extensive molecular dynamics simulations to produce atomic resolution models of both severing boundaries. Our equilibrated simulation model of the slow-severing boundary is consistent with the cryo-EM structural model. Simulations indicate that actin subunits at both boundaries adopt structures intermediate between those of bare and cofilin-bound actin subunits. These "intermediate" states have compromised intersubunit contacts, but those at the slow-severing boundary are stabilized by cofilin bridging interactions, accounting for its lower fragmentation probability. Simulations where cofilin proteins are removed from cofilactin filaments favor a mechanism in which a cluster of two contiguously bound cofilins is needed to fully stabilize the cofilactin conformation, promote cooperative binding interactions, and accelerate filament severing. Together, these studies provide a molecular-scale foundation for developing coarse-grained and theoretical descriptions of cofilin-mediated actin filament severing.
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Affiliation(s)
- Glen M Hocky
- Department of Chemistry, New York University, New York, New York, USA.
| | - Charles V Sindelar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
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20
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Tsai C, Chang C, Lin B, Wu Y, Wu M, Lin L, Huang W, Holz JD, Sheu T, Lee J, Kitsis RN, Tai P, Lee Y. Up-regulation of cofilin-1 in cell senescence associates with morphological change and p27 kip1 -mediated growth delay. Aging Cell 2021; 20:e13288. [PMID: 33336885 PMCID: PMC7811848 DOI: 10.1111/acel.13288] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/05/2020] [Accepted: 11/27/2020] [Indexed: 01/10/2023] Open
Abstract
Morphological change is an explicit characteristic of cell senescence, but the underlying mechanisms remains to be addressed. Here, we demonstrated, after a survey of various actin-binding proteins, that the post-translational up-regulation of cofilin-1 was essential for the reduced rate of actin depolymerization morphological enlargement in senescent cells. Additionally, up-regulated cofilin-1 mainly existed in the serine-3 phosphorylated form, according to the 2D gel immunoblotting assay. The up-regulation of cofilin-1 was also detected in aged mammalian tissues. The over-expression of wild-type cofilin-1 and constitutively phosphorylated cofilin-1 promoted cell senescence with an increased cell size. Additionally, senescent phenotypes were also reduced by knockdown of total cofilin-1, which led to a decrease in phosphorylated cofilin-1. The senescence induced by the over-expression of cofilin-1 was dependent on p27Kip1 , but not on the p53 and p16INK4 expressions. The knockdown of p27Kip1 alleviated cell senescence induced by oxidative stress or replicative stress. We also found that the over-expression of cofilin-1 induced the expression of p27Kip1 through transcriptional suppression of the transcriptional enhancer factors domain 1 (TEAD1) transcription factor. The TEAD1 transcription factor played a transrepressive role in the p27Kip1 gene promoter, as determined by the promoter deletion reporter gene assay. Interestingly, the down-regulation of TEAD1 was accompanied by the up-regulation of cofilin-1 in senescence. The knockdown and restoration of TEAD1 in young cells and old cells could induce and inhibit p27Kip1 and senescent phenotypes, respectively. Taken together, the current data suggest that cofilin-1/TEAD1/p27Kip1 signaling is involved in senescence-related morphological change and growth arrest.
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Affiliation(s)
- Cheng‐Han Tsai
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Chun‐Yuan Chang
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Bing‐Ze Lin
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Yu‐Lou Wu
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Meng‐Hsiu Wu
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Liang‐Tin Lin
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Wen‐Chien Huang
- Department of Surgery Division of Thoracic Surgery MacKay Memorial Hospital Taipei Taiwan
| | - Jonathan D. Holz
- Department of Biology University of Rochester Rochester NY14642USA
| | - Tzong‐Jen Sheu
- Department of Orthopaedics Center for Musculoskeletal Research University of Rochester School of Medicine Rochester NY14642USA
| | - Jhih‐Shian Lee
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
| | - Richard N. Kitsis
- Departments of Medicine (Cardiology) and Cell Biology and Wilf Family Cardiovascular Research Institute Albert Einstein College of Medicine Bronx, New York NY USA
| | - Pei‐Han Tai
- Graduate Institute of Oral Biology School of Dentistry National Taiwan University Taipei Taiwan
| | - Yi‐Jang Lee
- Department of Biomedical Imaging and Radiological Sciences National Yang‐Ming University Taipei Taiwan
- Cancer Progression Research Center National Yang‐Ming University Taipei11221Taiwan
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21
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Force and phosphate release from Arp2/3 complex promote dissociation of actin filament branches. Proc Natl Acad Sci U S A 2020; 117:13519-13528. [PMID: 32461373 DOI: 10.1073/pnas.1911183117] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Networks of branched actin filaments formed by Arp2/3 complex generate and experience mechanical forces during essential cellular functions, including cell motility and endocytosis. External forces regulate the assembly and architecture of branched actin networks both in vitro and in cells. Considerably less is known about how mechanical forces influence the disassembly of actin filament networks, specifically, the dissociation of branches. We used microfluidics to apply force to branches formed from purified muscle actin and fission yeast Arp2/3 complex and observed debranching events in real time with total internal reflection fluorescence microscopy. Low forces in the range of 0 pN to 2 pN on branches accelerated their dissociation from mother filaments more than two orders of magnitude, from hours to <1 min. Neither force on the mother filament nor thermal fluctuations in mother filament shape influenced debranching. Arp2/3 complex at branch junctions adopts two distinct mechanical states with different sensitivities to force, which we name "young/strong" and "old/weak." The "young/strong" state 1 has adenosine 5'-diphosphate (ADP)-P i bound to Arp2/3 complex. Phosphate release converts Arp2/3 complex into the "old/weak" state 2 with bound ADP, which is 20 times more sensitive to force than state 1. Branches with ADP-Arp2/3 complex are more sensitive to debranching by fission yeast GMF (glia maturation factor) than branches with ADP-P i -Arp2/3 complex. These findings suggest that aging of branch junctions by phosphate release from Arp2/3 complex and mechanical forces contribute to disassembling "old" actin filament branches in cells.
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22
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Jermyn AS, Cao W, Elam WA, De La Cruz EM, Lin MM. Directional allosteric regulation of protein filament length. Phys Rev E 2020; 101:032409. [PMID: 32290018 PMCID: PMC7758089 DOI: 10.1103/physreve.101.032409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 02/10/2020] [Indexed: 06/11/2023]
Abstract
Cofilin and ADF are cytoskeleton remodeling proteins that cooperatively bind and fragment actin filaments. Bound cofilin molecules do not directly interact with each other, indicating that cooperative binding of cofilin is mediated by the actin filament lattice. Cofilactin is therefore a model system for studying allosteric regulation of self-assembly. How cofilin binding changes structural and mechanical properties of actin filaments is well established. Less is known about the interaction energies and the thermodynamics of filament fragmentation, which describes the collective manner in which the cofilin concentration controls mean actin filament length. Here, we provide a general thermodynamic framework for allosteric regulation of self-assembly, and we use the theory to predict the interaction energies of experimental actin filament length distributions over a broad range of cofilin binding densities and for multiple cofilactin variants. We find that bound cofilin induces changes in nearby actin-actin interactions, and that these allosteric effects are propagated along the filament to affect up to four neighboring cofilin-binding sites (i.e., beyond nearest-neighbor allostery). The model also predicts that cofilin differentially stabilizes and destabilizes longitudinal versus lateral actin-actin interactions, and that the magnitude, range, asymmetry, and even the sign of these interaction energies can be altered using different actin and cofilin mutational variants. These results demonstrate that the theoretical framework presented here can provide quantitative thermodynamic information governing cooperative protein binding and filament length regulation, thus revealing nanometer length-scale interactions from micron length-scale "wet-lab" measurements.
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Affiliation(s)
- Adam S Jermyn
- Center for Computational Astrophysics,Flatiron Institute, New York, New York, 10010, USA
- Green Center for Molecular, Computational, and Systems Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Wenxiang Cao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - W Austin Elam
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | - Milo M Lin
- Green Center for Molecular, Computational, and Systems Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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23
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Structures of cofilin-induced structural changes reveal local and asymmetric perturbations of actin filaments. Proc Natl Acad Sci U S A 2020; 117:1478-1484. [PMID: 31900364 DOI: 10.1073/pnas.1915987117] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Members of the cofilin/ADF family of proteins sever actin filaments, increasing the number of filament ends available for polymerization or depolymerization. Cofilin binds actin filaments with positive cooperativity, forming clusters of contiguously bound cofilin along the filament lattice. Filament severing occurs preferentially at boundaries between bare and cofilin-decorated (cofilactin) segments and is biased at 1 side of a cluster. A molecular understanding of cooperative binding and filament severing has been impeded by a lack of structural data describing boundaries. Here, we apply methods for analyzing filament cryo-electron microscopy (cryo-EM) data at the single subunit level to directly investigate the structure of boundaries within partially decorated cofilactin filaments. Subnanometer resolution maps of isolated, bound cofilin molecules and an actin-cofilactin boundary indicate that cofilin-induced actin conformational changes are local and limited to subunits directly contacting bound cofilin. An isolated, bound cofilin compromises longitudinal filament contacts of 1 protofilament, consistent with a single cofilin having filament-severing activity. An individual, bound phosphomimetic (S3D) cofilin with weak severing activity adopts a unique binding mode that does not perturb actin structure. Cofilin clusters disrupt both protofilaments, consistent with a higher severing activity at boundaries compared to single cofilin. Comparison of these structures indicates that this disruption is substantially greater at pointed end sides of cofilactin clusters than at the barbed end. These structures, with the distribution of bound cofilin clusters, suggest that maximum binding cooperativity is achieved when 2 cofilins occupy adjacent sites. These results reveal the structural origins of cooperative cofilin binding and actin filament severing.
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24
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ADF/cofilin regulation from a structural viewpoint. J Muscle Res Cell Motil 2019; 41:141-151. [DOI: 10.1007/s10974-019-09546-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/17/2019] [Indexed: 01/11/2023]
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25
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Schramm AC, Hocky GM, Voth GA, Martiel JL, De La Cruz EM. Plastic Deformation and Fragmentation of Strained Actin Filaments. Biophys J 2019; 117:453-463. [PMID: 31301801 DOI: 10.1016/j.bpj.2019.06.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/17/2019] [Accepted: 06/19/2019] [Indexed: 10/26/2022] Open
Abstract
The assembly of actin filaments and filament networks generate forces that drive cell and vesicle movement. These structures and the comprising actin filaments must be mechanically stable to sustain these forces and maintain their structural integrity. Filaments in these dynamic structures must also be disassembled to recycle and replenish the pool of actin monomers available for polymerization. Actin-severing proteins such as cofilin and contractile myosin motor proteins fragment these nominally stable structures. We developed a mesoscopic-length-scale actin filament model to investigate force-induced filament fragmentation. We show that fragmentation in our model occurs at curvatures similar to previous measurements of fragmentation within (cofil)actin and actin-cofilactin boundaries. Boundaries between bare and cofilin-decorated segments are brittle and fragment at small bending and twisting deformations. Extending filaments disperses strain uniformly over subunit interfaces, and filaments fragment with no detectable partial rupture or plastic deformation. In contrast, bending or twisting filaments imposes nonuniform interface strain and leads to partial interface rupture, accelerating filament fragmentation. As a result, the rupture force under compressive loads is an order of magnitude lower than under tensile loads. Partial interface rupture may be a primary mechanism of accelerating actin filament fragmentation by other actin-destabilizing proteins.
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Affiliation(s)
- Anthony C Schramm
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | - Glen M Hocky
- Department of Chemistry, New York University, New York, New York
| | - Gregory A Voth
- Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, University of Chicago, Chicago, Illinois
| | - Jean-Louis Martiel
- TIMC-IMAG Lab, UMR 5525, Inserm/CNRS/Université Grenoble-Alpes, Tronche, France.
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut.
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26
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Zhang XF, Ajeti V, Tsai N, Fereydooni A, Burns W, Murrell M, De La Cruz EM, Forscher P. Regulation of axon growth by myosin II-dependent mechanocatalysis of cofilin activity. J Cell Biol 2019; 218:2329-2349. [PMID: 31123185 PMCID: PMC6605792 DOI: 10.1083/jcb.201810054] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/26/2019] [Accepted: 05/06/2019] [Indexed: 12/24/2022] Open
Abstract
Synergism between myosin II contractility and cofilin activity modulates serotonin-dependent axon growth. Normally, cofilin-dependent decreases in actin density are compensated by increases in point contact density and traction force; however, myosin hyperactivation leads to catastrophic decreases in actin network density and neurite retraction. Serotonin (5-HT) is known to increase the rate of growth cone advance via cofilin-dependent increases in retrograde actin network flow and nonmuscle myosin II activity. We report that myosin II activity is regulated by PKC during 5-HT responses and that PKC activity is necessary for increases in traction force normally associated with these growth responses. 5-HT simultaneously induces cofilin-dependent decreases in actin network density and PKC-dependent increases in point contact density. These reciprocal effects facilitate increases in traction force production in domains exhibiting decreased actin network density. Interestingly, when PKC activity was up-regulated, 5-HT treatments resulted in myosin II hyperactivation accompanied by catastrophic cofilin-dependent decreases in actin filament density, sudden decreases in traction force, and neurite retraction. These results reveal a synergistic relationship between cofilin and myosin II that is spatiotemporally regulated in the growth cone via mechanocatalytic effects to modulate neurite growth.
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Affiliation(s)
- Xiao-Feng Zhang
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| | - Visar Ajeti
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT.,Department of Biomedical Engineering, University of Connecticut Health Center, Farmington, CT
| | - Nicole Tsai
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT.,Department of Ophthalmology, University of California, San Francisco, California, CA
| | - Arash Fereydooni
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| | - William Burns
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
| | - Michael Murrell
- Department of Biomedical Engineering, Yale University, New Haven, CT
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Paul Forscher
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT
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27
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Torsional stress generated by ADF/cofilin on cross-linked actin filaments boosts their severing. Proc Natl Acad Sci U S A 2019; 116:2595-2602. [PMID: 30692249 PMCID: PMC6377502 DOI: 10.1073/pnas.1812053116] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Actin filaments assemble into ordered networks able to exert forces and shape cells. In response, filaments are exposed to mechanical stress which can potentially modulate their interactions with regulatory proteins. We developed in vitro tools to manipulate single filaments and study the impact of mechanics on the activity of actin depolymerizing factor (ADF)/cofilin, the central player in actin disassembly. While tension has almost no effect, curvature enhances severing by ADF/cofilin. We also discovered a mechanism that boosts the severing of anchored filaments: When binding to these filaments, ADF/cofilin locally increases their natural helicity, generating a torque that accelerates filament fragmentation up to 100-fold. As a consequence, interconnected filament networks are severed far more efficiently than independent filaments. Proteins of the actin depolymerizing factor (ADF)/cofilin family are the central regulators of actin filament disassembly. A key function of ADF/cofilin is to sever actin filaments. However, how it does so in a physiological context, where filaments are interconnected and under mechanical stress, remains unclear. Here, we monitor and quantify the action of ADF/cofilin in different mechanical situations by using single-molecule, single-filament, and filament network techniques, coupled to microfluidics. We find that local curvature favors severing, while tension surprisingly has no effect on cofilin binding and weakly enhances severing. Remarkably, we observe that filament segments that are held between two anchoring points, thereby constraining their twist, experience a mechanical torque upon cofilin binding. We find that this ADF/cofilin-induced torque does not hinder ADF/cofilin binding, but dramatically enhances severing. A simple model, which faithfully recapitulates our experimental observations, indicates that the ADF/cofilin-induced torque increases the severing rate constant 100-fold. A consequence of this mechanism, which we verify experimentally, is that cross-linked filament networks are severed by cofilin far more efficiently than nonconnected filaments. We propose that this mechanochemical mechanism is critical to boost ADF/cofilin’s ability to sever highly connected filament networks in cells.
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28
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Nicole O, Bell DM, Leste-Lasserre T, Doat H, Guillemot F, Pacary E. A novel role for CAMKIIβ in the regulation of cortical neuron migration: implications for neurodevelopmental disorders. Mol Psychiatry 2018; 23:2209-2226. [PMID: 29712998 PMCID: PMC6129389 DOI: 10.1038/s41380-018-0046-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/11/2018] [Accepted: 02/28/2018] [Indexed: 12/19/2022]
Abstract
Perturbation of CaMKIIβ expression has been associated with multiple neuropsychiatric diseases, highlighting CaMKIIβ as a gene of interest. Yet, in contrast to CaMKIIα, the specific functions of CaMKIIβ in the brain remain poorly explored. Here, we reveal a novel function for this CaMKII isoform in vivo during neuronal development. By using in utero electroporation, we show that CaMKIIβ is an important regulator of radial migration of projection neurons during cerebral cortex development. Knockdown of CaMKIIβ causes accelerated migration of nascent pyramidal neurons, whereas overexpression of CaMKIIβ inhibits migration, demonstrating that precise regulation of CaMKIIβ expression is required for correct neuronal migration. More precisely, CaMKIIβ controls the multipolar-bipolar transition in the intermediate zone and locomotion in the cortical plate through its actin-binding and -bundling activities. In addition, our data indicate that a fine-tuned balance between CaMKIIβ and cofilin activities is necessary to ensure proper migration of cortical neurons. Thus, our findings define a novel isoform-specific function for CaMKIIβ, demonstrating that CaMKIIβ has a major biological function in the developing brain.
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Affiliation(s)
- Olivier Nicole
- CNRS, UMR5293, Institut des Maladies Neurodégénératives, F-33000 Bordeaux, France,Université de Bordeaux, F-33000 Bordeaux, France
| | - Donald M. Bell
- Confocal and Image Analysis Facility, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Hélène Doat
- Transcriptome Facility, INSERM U1215, Neurocentre Magendie, F-33000 Bordeaux, France
| | | | - Emilie Pacary
- Université de Bordeaux, F-33000, Bordeaux, France. .,INSERM U1215, Neurocentre Magendie, F-33000, Bordeaux, France.
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29
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Goode BL, Sweeney MO, Eskin JA. GMF as an Actin Network Remodeling Factor. Trends Cell Biol 2018; 28:749-760. [PMID: 29779865 DOI: 10.1016/j.tcb.2018.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/22/2018] [Accepted: 04/23/2018] [Indexed: 10/24/2022]
Abstract
Glia maturation factor (GMF) has recently been established as a regulator of the actin cytoskeleton with a unique role in remodeling actin network architecture. Conserved from yeast to mammals, GMF is one of five members of the ADF-H family of actin regulatory proteins, which includes ADF/cofilin, Abp1/Drebrin, Twinfilin, and Coactosin. GMF does not bind actin, but instead binds the Arp2/3 complex with high affinity. Through this association, GMF catalyzes the debranching of actin filament networks and inhibits actin nucleation by Arp2/3 complex. Here, we discuss GMF's emerging role in controlling actin filament spatial organization and dynamics underlying cell motility, endocytosis, and other biological processes. Further, we attempt to reconcile these functions with its earlier characterization as a cell differentiation factor.
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Affiliation(s)
- Bruce L Goode
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South Street, Waltham, MA 02454 USA.
| | - Meredith O Sweeney
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South Street, Waltham, MA 02454 USA
| | - Julian A Eskin
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South Street, Waltham, MA 02454 USA
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30
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Huehn A, Cao W, Elam WA, Liu X, De La Cruz EM, Sindelar CV. The actin filament twist changes abruptly at boundaries between bare and cofilin-decorated segments. J Biol Chem 2018; 293:5377-5383. [PMID: 29463680 DOI: 10.1074/jbc.ac118.001843] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/16/2018] [Indexed: 12/14/2022] Open
Abstract
Cofilin/ADF proteins are actin-remodeling proteins, essential for actin disassembly in various cellular processes, including cell division, intracellular transport, and motility. Cofilins bind actin filaments cooperatively and sever them preferentially at boundaries between bare and cofilin-decorated (cofilactin) segments. The cooperative binding to actin has been proposed to originate from conformational changes that propagate allosterically from clusters of bound cofilin to bare actin segments. Estimates of the lengths over which these cooperative conformational changes propagate vary dramatically, ranging from 2 to >100 subunits. Here, we present a general, structure-based method for detecting from cryo-EM micrographs small variations in filament geometry (i.e. twist) with single-subunit precision. How these variations correlate with regulatory protein occupancy reveals how far allosteric, conformational changes propagate along filaments. We used this method to determine the effects of cofilin on the actin filament twist. Our results indicate that cofilin-induced changes in filament twist propagate only 1-2 subunits from the boundary into the bare actin segment, independently of the boundary polarity (i.e. irrespective of whether or not the bare actin segment flanks the pointed or barbed-end side of the boundary) and the pyrene fluorophore labeling of actin. These observations indicate that the filament twist changes abruptly at boundaries between bare and cofilin-decorated segments, thereby constraining mechanistic models of cooperative actin filament interactions and severing by cofilin. The methods presented here extend the capability of cryo-EM to analyze biologically relevant deviations from helical symmetry in actin as well as other classes of linear polymers.
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Affiliation(s)
- Andrew Huehn
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Wenxiang Cao
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - W Austin Elam
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Xueqi Liu
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Enrique M De La Cruz
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Charles V Sindelar
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
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