1
|
Koundinya N, Aguilar RM, Wetzel K, Tomasso MR, Nagarajan P, McGuirk ER, Padrick SB, Goode BL. Two ligands of Arp2/3 complex, yeast coronin and GMF, interact and synergize in pruning branched actin networks. J Biol Chem 2025; 301:108191. [PMID: 39826693 PMCID: PMC11872438 DOI: 10.1016/j.jbc.2025.108191] [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: 10/20/2024] [Revised: 12/16/2024] [Accepted: 12/20/2024] [Indexed: 01/22/2025] Open
Abstract
The rapid turnover of branched actin networks underlies key in vivo processes such as lamellipodial extension, endocytosis, phagocytosis, and intracellular transport. However, our understanding of the mechanisms used to dissociate, or "prune," branched filaments has remained limited. Glia maturation factor (GMF) is a cofilin family protein that binds to the Arp2/3 complex and catalyzes branch dissociation. Here, we show that another ligand of Arp2/3 complex, Saccharomyces cerevisiae coronin (Crn1), enhances Gmf1-mediated debranching by 8- to 10-fold, and that these effects depend on Arp2/3-binding "C" and "A" motifs in Crn1. Further, we show that Crn1 directly binds with high affinity (KD = 1.4 nM) to S. cerevisiae GMF (Gmf1), and together they form a stable ternary Crn1-Gmf1-Arp2/3 complex in solution. Using single-molecule analysis, we show that Gmf1 binds transiently and multiple times to F-actin branch junctions prior to debranching. These and other results suggest a mechanism of mutual recruitment, in which Crn1 increases the on-rate of Gmf1 for branch junctions and Gmf1 blocks Crn1 binding to actin filament sides, increasing its availability to bind branch junctions. Taken together, these observations reveal an unanticipated mechanism in which two distinct ligands of the Arp2/3 complex bind to each other and synergize to prune actin branches.
Collapse
Affiliation(s)
- Neha Koundinya
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Rey M Aguilar
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Kathryn Wetzel
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Meagan R Tomasso
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Priyashree Nagarajan
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Emma R McGuirk
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Shae B Padrick
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA.
| |
Collapse
|
2
|
Towsif EM, Miller BA, Ulrichs H, Shekhar S. Multicomponent depolymerization of actin filament pointed ends by cofilin and cyclase-associated protein depends upon filament age. Eur J Cell Biol 2024; 103:151423. [PMID: 38796920 PMCID: PMC12045339 DOI: 10.1016/j.ejcb.2024.151423] [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: 10/02/2023] [Revised: 05/18/2024] [Accepted: 05/19/2024] [Indexed: 05/29/2024] Open
Abstract
Intracellular actin networks assemble through the addition of ATP-actin subunits at the growing barbed ends of actin filaments. This is followed by "aging" of the filament via ATP hydrolysis and subsequent phosphate release. Aged ADP-actin subunits thus "treadmill" through the filament before being released back into the cytoplasmic monomer pool as a result of depolymerization at filament pointed ends. The necessity for aging before filament disassembly is reinforced by preferential binding of cofilin to aged ADP-actin subunits over newly-assembled ADP-Pi actin subunits in the filament. Consequently, investigations into how cofilin influences pointed-end depolymerization have, thus far, focused exclusively on aged ADP-actin filaments. Using microfluidics-assisted Total Internal Reflection Fluorescence (mf-TIRF) microscopy, we reveal that, similar to their effects on ADP filaments, cofilin and cyclase-associated protein (CAP) also promote pointed-end depolymerization of ADP-Pi filaments. Interestingly, the maximal rates of ADP-Pi filament depolymerization by CAP and cofilin together remain approximately 20-40 times lower than for ADP filaments. Further, we find that the promotion of ADP-Pi pointed-end depolymerization is conserved for all three mammalian cofilin isoforms. Taken together, the mechanisms presented here open the possibility of newly-assembled actin filaments being directly disassembled from their pointed-ends, thus bypassing the slow step of Pi release in the aging process.
Collapse
Affiliation(s)
- Ekram M Towsif
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Blake Andrew Miller
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Heidi Ulrichs
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Shashank Shekhar
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322, USA.
| |
Collapse
|
3
|
Towsif EM, Miller BA, Ulrichs H, Shekhar S. Multicomponent depolymerization of actin filament pointed ends by cofilin and cyclase-associated protein depends upon filament age. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.15.589566. [PMID: 38659736 PMCID: PMC11042253 DOI: 10.1101/2024.04.15.589566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Intracellular actin networks assemble through the addition of ATP-actin subunits at the growing barbed ends of actin filaments. This is followed by "aging" of the filament via ATP hydrolysis and subsequent phosphate release. Aged ADP-actin subunits thus "treadmill" through the filament before being released back into the cytoplasmic monomer pool as a result of depolymerization at filament pointed ends. The necessity for aging before filament disassembly is reinforced by preferential binding of cofilin to aged ADP-actin subunits over newly-assembled ADP-Pi actin subunits in the filament. Consequently, investigations into how cofilin influences pointed-end depolymerization have, thus far, focused exclusively on aged ADP-actin filaments. Using microfluidics-assisted Total Internal Reflection Fluorescence (mf-TIRF) microscopy, we reveal that, similar to their effects on ADP filaments, cofilin and cyclase-associated protein (CAP) also promote pointed-end depolymerization of ADP-Pi filaments. Interestingly, the maximal rates of ADP-Pi filament depolymerization by CAP and cofilin together remain approximately 20-40 times lower than for ADP filaments. Further, we find that the promotion of ADP-Pi pointed-end depolymerization is conserved for all three mammalian cofilin isoforms. Taken together, the mechanisms presented here open the possibility of newly-assembled actin filaments being directly disassembled from their pointed-ends, thus bypassing the slow step of Pi release in the aging process.
Collapse
Affiliation(s)
- Ekram M. Towsif
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322
| | - Blake Andrew Miller
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322
| | - Heidi Ulrichs
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322
| | - Shashank Shekhar
- Departments of Physics, Cell biology and Biochemistry, Emory University, Atlanta, GA 30322
| |
Collapse
|
4
|
Ikawa K, Hiro S, Kondo S, Ohsawa S, Sugimura K. Coronin-1 promotes directional cell rearrangement in Drosophila wing epithelium. Cell Struct Funct 2023; 48:251-257. [PMID: 38030242 PMCID: PMC11496784 DOI: 10.1247/csf.23049] [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: 07/16/2023] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
Directional cell rearrangement is a critical process underlying correct tissue deformation during morphogenesis. Although the involvement of F-actin regulation in cell rearrangement has been established, the role and regulation of actin binding proteins (ABPs) in this process are not well understood. In this study, we investigated the function of Coronin-1, a WD-repeat actin-binding protein, in controlling directional cell rearrangement in the Drosophila pupal wing. Transgenic flies expressing Coronin-1-EGFP were generated using CRISPR-Cas9. We observed that Coronin-1 localizes at the reconnecting junction during cell rearrangement, which is dependent on actin interacting protein 1 (AIP1) and cofilin, actin disassemblers and known regulators of wing cell rearrangement. Loss of Coronin-1 function reduces cell rearrangement directionality and hexagonal cell fraction. These results suggest that Coronin-1 promotes directional cell rearrangement via its interaction with AIP1 and cofilin, highlighting the role of ABPs in the complex process of morphogenesis.Key words: morphogenesis, cell rearrangement, actin binding proteins (ABPs).
Collapse
Affiliation(s)
- Keisuke Ikawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Souta Hiro
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Shu Kondo
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Tokyo 162-8601, Japan
- Invertebrate Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Shizue Ohsawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Kaoru Sugimura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
- Universal Biology Institute, The University of Tokyo, Tokyo 113-0033, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| |
Collapse
|
5
|
Goode BL, Eskin J, Shekhar S. Mechanisms of actin disassembly and turnover. J Cell Biol 2023; 222:e202309021. [PMID: 37948068 PMCID: PMC10638096 DOI: 10.1083/jcb.202309021] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Cellular actin networks exhibit a wide range of sizes, shapes, and architectures tailored to their biological roles. Once assembled, these filamentous networks are either maintained in a state of polarized turnover or induced to undergo net disassembly. Further, the rates at which the networks are turned over and/or dismantled can vary greatly, from seconds to minutes to hours or even days. Here, we review the molecular machinery and mechanisms employed in cells to drive the disassembly and turnover of actin networks. In particular, we highlight recent discoveries showing that specific combinations of conserved actin disassembly-promoting proteins (cofilin, GMF, twinfilin, Srv2/CAP, coronin, AIP1, capping protein, and profilin) work in concert to debranch, sever, cap, and depolymerize actin filaments, and to recharge actin monomers for new rounds of assembly.
Collapse
Affiliation(s)
- Bruce L. Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Julian Eskin
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Shashank Shekhar
- Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA, USA
| |
Collapse
|
6
|
Alimov N, Hoeprich GJ, Padrick SB, Goode BL. Cyclase-associated protein interacts with actin filament barbed ends to promote depolymerization and formin displacement. J Biol Chem 2023; 299:105367. [PMID: 37863260 PMCID: PMC10692737 DOI: 10.1016/j.jbc.2023.105367] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/04/2023] [Accepted: 10/12/2023] [Indexed: 10/22/2023] Open
Abstract
Cyclase-associated protein (CAP) has emerged as a central player in cellular actin turnover, but its molecular mechanisms of action are not yet fully understood. Recent studies revealed that the N terminus of CAP interacts with the pointed ends of actin filaments to accelerate depolymerization in conjunction with cofilin. Here, we use in vitro microfluidics-assisted TIRF microscopy to show that the C terminus of CAP promotes depolymerization at the opposite (barbed) ends of actin filaments. In the absence of actin monomers, full-length mouse CAP1 and C-terminal halves of CAP1 (C-CAP1) and CAP2 (C-CAP2) accelerate barbed end depolymerization. Using mutagenesis and structural modeling, we show that these activities are mediated by the WH2 and CARP domains of CAP. In addition, we observe that CAP collaborates with profilin to accelerate barbed end depolymerization and that these effects depend on their direct interaction, providing the first known example of CAP-profilin collaborative effects in regulating actin. In the presence of actin monomers, CAP1 attenuates barbed end growth and promotes formin dissociation. Overall, these findings demonstrate that CAP uses distinct domains and mechanisms to interact with opposite ends of actin filaments and drive turnover. Further, they contribute to the emerging view of actin barbed ends as sites of dynamic molecular regulation, where numerous proteins compete and cooperate with each other to tune polymer dynamics, similar to the rich complexity seen at microtubule ends.
Collapse
Affiliation(s)
- Nikita Alimov
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Gregory J Hoeprich
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Shae B Padrick
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA.
| |
Collapse
|
7
|
Kandiyoth FB, Michelot A. Reconstitution of actin-based cellular processes: Why encapsulation changes the rules. Eur J Cell Biol 2023; 102:151368. [PMID: 37922812 DOI: 10.1016/j.ejcb.2023.151368] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/02/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023] Open
Abstract
While in vitro reconstitution of cellular processes is progressing rapidly, the encapsulation of biomimetic systems to reproduce the cellular environment is a major challenge. Here we review the difficulties, using reconstitution of processes dependent on actin polymerization as an example. Some of the problems are purely technical, due to the need for engineering strategies to encapsulate concentrated solutions in micrometer-sized compartments. However, other significant issues arise from the reduction of experimental volumes, which alters the chemical evolution of these non-equilibrium systems. Important parameters to consider for successful reconstitutions are the amount of each component, their consumption and renewal rates to guarantee their continuous availability.
Collapse
Affiliation(s)
| | - Alphée Michelot
- Aix Marseille Univ, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France.
| |
Collapse
|
8
|
Lewis M, Ono K, Qin Z, Johnsen RC, Baillie DL, Ono S. The α-arrestin SUP-13/ARRD-15 promotes isoform turnover of actin-interacting protein 1 in Caenorhabditis elegans striated muscle. PNAS NEXUS 2023; 2:pgad330. [PMID: 37869480 PMCID: PMC10590129 DOI: 10.1093/pnasnexus/pgad330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/02/2023] [Indexed: 10/24/2023]
Abstract
Precise arrangement of actin, myosin, and other regulatory components in a sarcomeric pattern is critical for producing contractile forces in striated muscles. Actin-interacting protein 1 (AIP1), also known as WD-repeat protein 1 (WDR1), is one of essential factors that regulate sarcomeric assembly of actin filaments. In the nematode Caenorhabditis elegans, mutation in unc-78, encoding one of the two AIP1 isoforms, causes severe disorganization of sarcomeric actin filaments and near paralysis, but mutation in sup-13 suppresses the unc-78-mutant phenotypes to restore nearly normal sarcomeric actin organization and worm motility. Here, we identified that sup-13 is a nonsense allele of arrd-15 encoding an α-arrestin. The sup-13/arrd-15 mutation suppressed the phenotypes of unc-78 null mutant but required aipl-1 that encodes a second AIP1 isoform. aipl-1 was normally expressed highly in embryos and downregulated in mature muscle. However, in the sup-13/arrd-15 mutant, the AIPL-1 protein was maintained at high levels in adult muscle to compensate for the absence of the UNC-78 protein. The sup-13/arrd-15 mutation caused accumulation of ubiquitinated AIPL-1 protein, suggesting that a normal function of sup-13/arrd-15 is to enhance degradation of ubiquitinated AIPL-1, thereby promoting transition of AIP1 isoforms from AIPL-1 to UNC-78 in developing muscle. These results suggest that α-arrestin is a novel factor to promote isoform turnover by enhancing protein degradation.
Collapse
Affiliation(s)
- Mario Lewis
- Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Kanako Ono
- Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zhaozhao Qin
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Robert C Johnsen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - David L Baillie
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Shoichiro Ono
- Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
| |
Collapse
|
9
|
Weng W, Gu X, Yang Y, Zhang Q, Deng Q, Zhou J, Cheng J, Zhu MX, Feng J, Huang O, Li Y. N-terminal α-amino SUMOylation of cofilin-1 is critical for its regulation of actin depolymerization. Nat Commun 2023; 14:5688. [PMID: 37709794 PMCID: PMC10502023 DOI: 10.1038/s41467-023-41520-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
Small ubiquitin-like modifier (SUMO) typically conjugates to target proteins through isopeptide linkage to the ε-amino group of lysine residues. This posttranslational modification (PTM) plays pivotal roles in modulating protein function. Cofilins are key regulators of actin cytoskeleton dynamics and are well-known to undergo several different PTMs. Here, we show that cofilin-1 is conjugated by SUMO1 both in vitro and in vivo. Using mass spectrometry and biochemical and genetic approaches, we identify the N-terminal α-amino group as the SUMO-conjugation site of cofilin-1. Common to conventional SUMOylation is that the N-α-SUMOylation of cofilin-1 is also mediated by SUMO activating (E1), conjugating (E2), and ligating (E3) enzymes and reversed by the SUMO deconjugating enzyme, SENP1. Specific to the N-α-SUMOylation is the physical association of the E1 enzyme to the substrate, cofilin-1. Using F-actin co-sedimentation and actin depolymerization assays in vitro and fluorescence staining of actin filaments in cells, we show that the N-α-SUMOylation promotes cofilin-1 binding to F-actin and cofilin-induced actin depolymerization. This covalent conjugation by SUMO at the N-α amino group of cofilin-1, rather than at an internal lysine(s), serves as an essential PTM to tune cofilin-1 function during regulation of actin dynamics.
Collapse
Affiliation(s)
- Weiji Weng
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiaokun Gu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yang Yang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qiao Zhang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qi Deng
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jie Zhou
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jinke Cheng
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Junfeng Feng
- Brain Injury Centre, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
- Shanghai Institute of Head Trauma, Shanghai, 200127, China.
| | - Ou Huang
- Department of General Surgery, Comprehensive Breast Health Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Yong Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| |
Collapse
|
10
|
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: 141] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 12/30/2022]
Abstract
Polymerization of actin filaments against membranes produces force for numerous cellular processes, such as migration, morphogenesis, endocytosis, phagocytosis and organelle dynamics. Consequently, aberrant actin cytoskeleton dynamics are linked to various diseases, including cancer, as well as immunological and neurological disorders. Understanding how actin filaments generate forces in cells, how force production is regulated by the interplay between actin-binding proteins and how the actin-regulatory machinery responds to mechanical load are at the heart of many cellular, developmental and pathological processes. During the past few years, our understanding of the mechanisms controlling actin filament assembly and disassembly has evolved substantially. It has also become evident that the activities of key actin-binding proteins are not regulated solely by biochemical signalling pathways, as mechanical regulation is critical for these proteins. Indeed, the architecture and dynamics of the actin cytoskeleton are directly tuned by mechanical load. Here we discuss the general mechanisms by which key actin regulators, often in synergy with each other, control actin filament assembly, disassembly, and monomer recycling. By using an updated view of actin dynamics as a framework, we discuss how the mechanics and geometry of actin networks control actin-binding proteins, and how this translates into force production in endocytosis and mesenchymal cell migration.
Collapse
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
| | | |
Collapse
|
11
|
Takayama K, Matsuda K, Abe H. Formation of actin-cofilin rods by depletion forces. Biochem Biophys Res Commun 2022; 626:200-204. [PMID: 35994830 DOI: 10.1016/j.bbrc.2022.08.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 11/02/2022]
Abstract
Various stress conditions induce the formation of actin-cofilin rods in either the nucleus or the cytoplasm, although the mechanism of rod formation is unclear. In this study, we constituted actin-cofilin rods using purified actin, cofilin and actin interacting protein 1 (AIP1) in the presence of a physiological buffer containing a crowding agent, 0.8% methylcellulose (MC), which led to bundled actin filaments formed by depletion forces. Most of the F-actin bundles formed with methylcellulose were linear, whereas cofilin-bound F-actin bundles often had bent, looped, and often ring-like shapes. Increasing the amount of AIP1 shortened actin-cofilin bundles into rod-like bundles with tapering at both ends. As much shorter actin-cofilin filaments were formed in the presence of AIP1 before MC was added to the mixture, the rod-like bundle might be a mass of those short filaments. Furthermore, the small rods fused with each other to become larger rods, indicating that these rods were anisotropic liquid droplets. Several minutes after the addition of MC to the F-actin-cofilin-AIP1 mixture, we observed some long bundles in which the thick and thin parts appear alternately, reminiscent of a Plateau-Rayleigh instability observed in fluid columns. Simultaneously, we found images in which thin parts were interrupted, but the thick parts were arranged in a row in the longitudinal direction. These structures were also observed in cytoplasmic actin-cofilin rods in cells overexpressing cofilin-GFP, suggesting that cytoplasmic actin-cofilin rods have the same structure formation process as the rods reconstituted in vitro.
Collapse
Affiliation(s)
- Kohki Takayama
- Department of Biology, Graduate School of Science and Engineering, Chiba University, Chiba, 263-8522, Japan
| | - Kota Matsuda
- Department of Biology, Graduate School of Science and Engineering, Chiba University, Chiba, 263-8522, Japan
| | - Hiroshi Abe
- Department of Biology, Graduate School of Science and Engineering, Chiba University, Chiba, 263-8522, Japan; Department of Biology, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan.
| |
Collapse
|
12
|
Sun J, Zhong X, Fu X, Miller H, Lee P, Yu B, Liu C. The Actin Regulators Involved in the Function and Related Diseases of Lymphocytes. Front Immunol 2022; 13:799309. [PMID: 35371070 PMCID: PMC8965893 DOI: 10.3389/fimmu.2022.799309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/01/2022] [Indexed: 11/21/2022] Open
Abstract
Actin is an important cytoskeletal protein involved in signal transduction, cell structure and motility. Actin regulators include actin-monomer-binding proteins, Wiskott-Aldrich syndrome (WAS) family of proteins, nucleation proteins, actin filament polymerases and severing proteins. This group of proteins regulate the dynamic changes in actin assembly/disassembly, thus playing an important role in cell motility, intracellular transport, cell division and other basic cellular activities. Lymphocytes are important components of the human immune system, consisting of T-lymphocytes (T cells), B-lymphocytes (B cells) and natural killer cells (NK cells). Lymphocytes are indispensable for both innate and adaptive immunity and cannot function normally without various actin regulators. In this review, we first briefly introduce the structure and fundamental functions of a variety of well-known and newly discovered actin regulators, then we highlight the role of actin regulators in T cell, B cell and NK cell, and finally provide a landscape of various diseases associated with them. This review provides new directions in exploring actin regulators and promotes more precise and effective treatments for related diseases.
Collapse
Affiliation(s)
- Jianxuan Sun
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department and Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xingyu Zhong
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyu Fu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heather Miller
- Cytek Biosciences, R&D Clinical Reagents, Fremont, CA, United States
| | - Pamela Lee
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Bing Yu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chaohong Liu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
13
|
Abstract
The precise assembly and disassembly of actin filaments is required for several cellular processes, and their regulation has been scrutinized for decades. Twenty years ago, a handful of studies marked the advent of a new type of experiment to study actin dynamics: using optical microscopy to look at individual events, taking place on individual filaments in real time. Here, we summarize the main characteristics of this approach and how it has changed our ability to understand actin assembly dynamics. We also highlight some of its caveats and reflect on what we have learned over the past 20 years, leading us to propose a set of guidelines, which we hope will contribute to a better exploitation of this powerful tool.
Collapse
|
14
|
Ishikawa-Ankerhold HC, Kurzbach S, Kinali AS, Müller-Taubenberger A. Formation of Cytoplasmic Actin-Cofilin Rods is Triggered by Metabolic Stress and Changes in Cellular pH. Front Cell Dev Biol 2021; 9:742310. [PMID: 34869330 PMCID: PMC8635511 DOI: 10.3389/fcell.2021.742310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/27/2021] [Indexed: 11/13/2022] Open
Abstract
Actin dynamics plays a crucial role in regulating essential cell functions and thereby is largely responsible to a considerable extent for cellular energy consumption. Certain pathological conditions in humans, like neurological disorders such as Alzheimer’s disease or amyotrophic lateral sclerosis (ALS) as well as variants of nemaline myopathy are associated with cytoskeletal abnormalities, so-called actin-cofilin rods. Actin-cofilin rods are aggregates consisting mainly of actin and cofilin, which are formed as a result of cellular stress and thereby help to ensure the survival of cells under unfavorable conditions. We have used Dictyostelium discoideum, an established model system for cytoskeletal research to study formation and principles of cytoplasmic actin rod assembly in response to energy depletion. Experimentally, depletion of ATP was provoked by addition of either sodium azide, dinitrophenol, or 2-deoxy-glucose, and the formation of rod assembly was recorded by live-cell imaging. Furthermore, we show that hyperosmotic shock induces actin-cofilin rods, and that a drop in the intracellular pH accompanies this condition. Our data reveal that acidification of the cytoplasm can induce the formation of actin-cofilin rods to varying degrees and suggest that a local reduction in cellular pH may be a cause for the formation of cytoplasmic rods. We hypothesize that local phase separation mechanistically triggers the assembly of actin-cofilin rods and thereby influences the material properties of actin structures.
Collapse
Affiliation(s)
- Hellen C Ishikawa-Ankerhold
- Department of Internal Medicine I, University Hospital, LMU Munich, Munich, Germany.,Walter Brendel Centre of Experimental Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Sophie Kurzbach
- Department of Cell Biology (Anatomy III), Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Arzu S Kinali
- Walter Brendel Centre of Experimental Medicine, University Hospital, LMU Munich, Munich, Germany
| | | |
Collapse
|
15
|
Ullo MF, Logue JS. ADF and cofilin-1 collaborate to promote cortical actin flow and the leader bleb-based migration of confined cells. eLife 2021; 10:67856. [PMID: 34169836 PMCID: PMC8253594 DOI: 10.7554/elife.67856] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/22/2021] [Indexed: 01/16/2023] Open
Abstract
Melanoma cells have been shown to undergo fast amoeboid (leader bleb-based) migration, requiring a single large bleb for migration. In leader blebs, is a rapid flow of cortical actin that drives the cell forward. Using RNAi, we find that co-depleting cofilin-1 and actin depolymerizing factor (ADF) led to a large increase in cortical actin, suggesting that both proteins regulate cortical actin. Furthermore, severing factors can promote contractility through the regulation of actin architecture. However, RNAi of cofilin-1 but not ADF led to a significant decrease in cell stiffness. We found cofilin-1 to be enriched at leader bleb necks, whereas RNAi of cofilin-1 and ADF reduced bleb sizes and the frequency of motile cells. Strikingly, cells without cofilin-1 and ADF had blebs with abnormally long necks. Many of these blebs failed to retract and displayed slow actin turnover. Collectively, our data identifies cofilin-1 and ADF as actin remodeling factors required for fast amoeboid migration.
Collapse
Affiliation(s)
- Maria F Ullo
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, United States
| | - Jeremy S Logue
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, United States
| |
Collapse
|
16
|
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: 1.8] [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.
Collapse
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
| |
Collapse
|
17
|
Shekhar S, Hoeprich GJ, Gelles J, Goode BL. Twinfilin bypasses assembly conditions and actin filament aging to drive barbed end depolymerization. J Cell Biol 2021; 220:e202006022. [PMID: 33226418 PMCID: PMC7686915 DOI: 10.1083/jcb.202006022] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 10/06/2020] [Accepted: 10/29/2020] [Indexed: 01/15/2023] Open
Abstract
Cellular actin networks grow by ATP-actin addition at filament barbed ends and have long been presumed to depolymerize at their pointed ends, primarily after filaments undergo "aging" (ATP hydrolysis and Pi release). The cytosol contains high levels of actin monomers, which favors assembly over disassembly, and barbed ends are enriched in ADP-Pi actin. For these reasons, the potential for a barbed end depolymerization mechanism in cells has received little attention. Here, using microfluidics-assisted TIRF microscopy, we show that mouse twinfilin, a member of the ADF-homology family, induces depolymerization of ADP-Pi barbed ends even under assembly-promoting conditions. Indeed, we observe in single reactions containing micromolar concentrations of actin monomers the simultaneous rapid elongation of formin-bound barbed ends and twinfilin-induced depolymerization of free barbed ends. The data show that twinfilin catalyzes dissociation of subunits from ADP-Pi barbed ends and thereby bypasses filament aging prerequisites to disassemble newly polymerized actin filaments.
Collapse
Affiliation(s)
- Shashank Shekhar
- Department of Biology, Brandeis University, Waltham, MA
- Department of Biochemistry, Brandeis University, Waltham, MA
| | | | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA
| | | |
Collapse
|
18
|
Kang DE, Woo JA. Cofilin, a Master Node Regulating Cytoskeletal Pathogenesis in Alzheimer's Disease. J Alzheimers Dis 2020; 72:S131-S144. [PMID: 31594228 PMCID: PMC6971827 DOI: 10.3233/jad-190585] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The defining pathological hallmarks of Alzheimer’s disease (AD) are proteinopathies marked by the amyloid-β (Aβ) peptide and hyperphosphorylated tau. In addition, Hirano bodies and cofilin-actin rods are extensively found in AD brains, both of which are associated with the actin cytoskeleton. The actin-binding protein cofilin known for its actin filament severing, depolymerizing, nucleating, and bundling activities has emerged as a significant player in AD pathogenesis. In this review, we discuss the regulation of cofilin by multiple signaling events impinging on LIM kinase-1 (LIMK1) and/or Slingshot homolog-1 (SSH1) downstream of Aβ. Such pathophysiological signaling pathways impact actin dynamics to regulate synaptic integrity, mitochondrial translocation of cofilin to promote neurotoxicity, and formation of cofilin-actin pathology. Other intracellular signaling proteins, such as β-arrestin, RanBP9, Chronophin, PLD1, and 14-3-3 also impinge on the regulation of cofilin downstream of Aβ. Finally, we discuss the role of activated cofilin as a bridge between actin and microtubule dynamics by displacing tau from microtubules, thereby destabilizing tau-induced microtubule assembly, missorting tau, and promoting tauopathy.
Collapse
Affiliation(s)
- David E Kang
- Byrd Institute and Alzheimer's Center, USF Health Morsani College of Medicine, Tampa, FL, USA.,Department of Molecular Medicine, USF Health Morsani College of Medicine, Tampa, FL, USA.,Division of Research, James A. Haley VA Hospital, Tampa, FL, USA
| | - Jung A Woo
- Byrd Institute and Alzheimer's Center, USF Health Morsani College of Medicine, Tampa, FL, USA.,Department of Molecular Pharmacology and Physiology, USF Health Morsani College of Medicine, Tampa, FL, USA
| |
Collapse
|
19
|
Tang VW, Nadkarni AV, Brieher WM. Catastrophic actin filament bursting by cofilin, Aip1, and coronin. J Biol Chem 2020; 295:13299-13313. [PMID: 32723865 DOI: 10.1074/jbc.ra120.015018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/24/2020] [Indexed: 11/06/2022] Open
Abstract
Cofilin is an actin filament severing protein necessary for fast actin turnover dynamics. Coronin and Aip1 promote cofilin-mediated actin filament disassembly, but the mechanism is somewhat controversial. An early model proposed that the combination of cofilin, coronin, and Aip1 disassembled filaments in bursts. A subsequent study only reported severing. Here, we used EM to show that actin filaments convert directly into globular material. A monomer trap assay also shows that the combination of all three factors produces actin monomers faster than any two factors alone. We show that coronin accelerates the release of Pi from actin filaments and promotes highly cooperative cofilin binding to actin to create long stretches of polymer with a hypertwisted morphology. Aip1 attacks these hypertwisted regions along their sides, disintegrating them into monomers or short oligomers. The results are consistent with a catastrophic mode of disassembly, not enhanced severing alone.
Collapse
Affiliation(s)
- Vivian W Tang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA
| | - Ambika V Nadkarni
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA.
| |
Collapse
|
20
|
Wang Y, Brieher WM. CD2AP links actin to PI3 kinase activity to extend epithelial cell height and constrain cell area. J Cell Biol 2020; 219:jcb.201812087. [PMID: 31723006 PMCID: PMC7039212 DOI: 10.1083/jcb.201812087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 08/26/2019] [Accepted: 10/21/2019] [Indexed: 01/03/2023] Open
Abstract
Epithelial cells are categorized as cuboidal versus squamous based on the height of the lateral membrane. Wang and Brieher show that CD2AP links PI3K activity to actin assembly to extend the height of the lateral membrane. Maintaining the correct ratio of apical, basal, and lateral membrane domains is important for epithelial physiology. Here, we show that CD2AP is a critical determinant of epithelial membrane proportions. Depletion of CD2AP or phosphoinositide 3-kinase (PI3K) inhibition results in loss of F-actin and expansion of apical–basal domains, which comes at the expense of lateral membrane height in MDCK cells. We demonstrate that the SH3 domains of CD2AP bind to PI3K and are necessary for PI3K activity along lateral membranes and constraining cell area. Tethering the SH3 domains of CD2AP or p110γ to the membrane is sufficient to rescue CD2AP-knockdown phenotypes. CD2AP and PI3K are both upstream and downstream of actin polymerization. Since CD2AP binds to both actin filaments and PI3K, CD2AP might bridge actin assembly to PI3K activation to form a positive feedback loop to support lateral membrane extension. Our results provide insight into the squamous to cuboidal to columnar epithelial transitions seen in complex epithelial tissues in vivo.
Collapse
Affiliation(s)
- Yuou Wang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, IL
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, IL
| |
Collapse
|
21
|
Jin ZL, Yao XR, Wen L, Hao G, Kwon JW, Hao J, Kim NH. AIP1 and Cofilin control the actin dynamics to modulate the asymmetric division and cytokinesis in mouse oocytes. FASEB J 2020; 34:11292-11306. [PMID: 32602619 DOI: 10.1096/fj.202000093r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/17/2020] [Accepted: 04/26/2020] [Indexed: 11/11/2022]
Abstract
Actin-interacting protein 1 (AIP1), also known as WD repeat-containing protein 1 (WDR1), is ubiquitous in eukaryotic organisms, and it plays critical roles in the dynamic reorganization of the actin cytoskeleton. However, the biological function and mechanism of AIP1 in mammalian oocyte maturation is still largely unclear. In this study, we demonstrated that AIP1 boosts ADF/Cofilin activity in mouse oocytes. AIP1 is primarily distributed around the spindle region during oocyte maturation, and its depletion impairs meiotic spindle migration and asymmetric division. The knockdown of AIP1 resulted in the gathering of a large number of actin-positive patches around the spindle region. This effect was reduced by human AIP1 (hAIP1) or Cofilin (S3A) expression. AIP1 knockdown also reduced the phosphorylation of Cofilin near the spindle, indicating that AIP1 interacts with ADF/Cofilin-decorated actin filaments and enhances filament disassembly. Moreover, the deletion of AIP1 disrupts Cofilin localization in metaphase I (MI) and induces cytokinesis defects in metaphase II (MII). Taken together, our results provide evidence that AIP1 promotes actin dynamics and cytokinesis via Cofilin in the gametes of female mice.
Collapse
Affiliation(s)
- Zhe-Long Jin
- School of Biotechnology and Healthcare, Wuyi University, Jiangmen, China.,Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
| | - Xue-Rui Yao
- School of Biotechnology and Healthcare, Wuyi University, Jiangmen, China.,Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
| | - Liu Wen
- School of Biotechnology and Healthcare, Wuyi University, Jiangmen, China
| | - Guo Hao
- School of Biotechnology and Healthcare, Wuyi University, Jiangmen, China.,Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
| | - Jeong-Woo Kwon
- School of Biotechnology and Healthcare, Wuyi University, Jiangmen, China
| | - Jiang Hao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, China
| | - Nam-Hyung Kim
- School of Biotechnology and Healthcare, Wuyi University, Jiangmen, China.,Department of Animal Sciences, Chungbuk National University, Cheongju, Korea
| |
Collapse
|
22
|
Abstract
Cell migration is an essential process, both in unicellular organisms such as amoeba and as individual or collective motility in highly developed multicellular organisms like mammals. It is controlled by a variety of activities combining protrusive and contractile forces, normally generated by actin filaments. Here, we summarize actin filament assembly and turnover processes, and how respective biochemical activities translate into different protrusion types engaged in migration. These actin-based plasma membrane protrusions include actin-related protein 2/3 complex-dependent structures such as lamellipodia and membrane ruffles, filopodia as well as plasma membrane blebs. We also address observed antagonisms between these protrusion types, and propose a model - also inspired by previous literature - in which a complex balance between specific Rho GTPase signaling pathways dictates the protrusion mechanism employed by cells. Furthermore, we revisit published work regarding the fascinating antagonism between Rac and Rho GTPases, and how this intricate signaling network can define cell behavior and modes of migration. Finally, we discuss how the assembly of actin filament networks can feed back onto their regulators, as exemplified for the lamellipodial factor WAVE regulatory complex, tightly controlling accumulation of this complex at specific subcellular locations as well as its turnover.
Collapse
|
23
|
Dendritic Spines in Alzheimer's Disease: How the Actin Cytoskeleton Contributes to Synaptic Failure. Int J Mol Sci 2020; 21:ijms21030908. [PMID: 32019166 PMCID: PMC7036943 DOI: 10.3390/ijms21030908] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/24/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by Aβ-driven synaptic dysfunction in the early phases of pathogenesis. In the synaptic context, the actin cytoskeleton is a crucial element to maintain the dendritic spine architecture and to orchestrate the spine’s morphology remodeling driven by synaptic activity. Indeed, spine shape and synaptic strength are strictly correlated and precisely governed during plasticity phenomena in order to convert short-term alterations of synaptic strength into long-lasting changes that are embedded in stable structural modification. These functional and structural modifications are considered the biological basis of learning and memory processes. In this review we discussed the existing evidence regarding the role of the spine actin cytoskeleton in AD synaptic failure. We revised the physiological function of the actin cytoskeleton in the spine shaping and the contribution of actin dynamics in the endocytosis mechanism. The internalization process is implicated in different aspects of AD since it controls both glutamate receptor membrane levels and amyloid generation. The detailed understanding of the mechanisms controlling the actin cytoskeleton in a unique biological context as the dendritic spine could pave the way to the development of innovative synapse-tailored therapeutic interventions and to the identification of novel biomarkers to monitor synaptic loss in AD.
Collapse
|
24
|
Abstract
Actin polymerization is essential for cells to migrate, as well as for various cell biological processes such as cytokinesis and vesicle traffic. This brief review describes the mechanisms underlying its different roles and recent advances in our understanding. Actin usually requires "nuclei"-preformed actin filaments-to start polymerizing, but, once initiated, polymerization continues constitutively. The field therefore has a strong focus on nucleators, in particular the Arp2/3 complex and formins. These have different functions, are controlled by contrasting mechanisms, and generate alternate geometries of actin networks. The Arp2/3 complex functions only when activated by nucleation-promoting factors such as WASP, Scar/WAVE, WASH, and WHAMM and when binding to a pre-existing filament. Formins can be individually active but are usually autoinhibited. Each is controlled by different mechanisms and is involved in different biological roles. We also describe the processes leading to actin disassembly and their regulation and conclude with four questions whose answers are important for understanding actin dynamics but are currently unanswered.
Collapse
Affiliation(s)
- Simona Buracco
- Institute of Cancer Sciences, University of Glasgow, Bearsden, G61 1BD, UK
| | - Sophie Claydon
- Institute of Cancer Sciences, University of Glasgow, Bearsden, G61 1BD, UK
| | - Robert Insall
- Institute of Cancer Sciences, University of Glasgow, Bearsden, G61 1BD, UK
| |
Collapse
|
25
|
Bowes C, Redd M, Yousfi M, Tauzin M, Murayama E, Herbomel P. Coronin 1A depletion restores the nuclear stability and viability of Aip1/Wdr1-deficient neutrophils. J Cell Biol 2019; 218:3258-3271. [PMID: 31471458 PMCID: PMC6781450 DOI: 10.1083/jcb.201901024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 06/20/2019] [Accepted: 07/01/2019] [Indexed: 12/21/2022] Open
Abstract
Bowes et al. show that in zebrafish embryos deficient in the cofilin cofactor AIP1/Wdr1, neutrophils display F-actin as cytoplasmic aggregates, spatially uncoupled from active myosin, then undergo a progressive unwinding of their nucleus followed by eruptive cell death. This adverse phenotype is fully rescued by depletion of another cofilin cofactor, coronin 1A. Actin dynamics is central for cells, and especially for the fast-moving leukocytes. The severing of actin filaments is mainly achieved by cofilin, assisted by Aip1/Wdr1 and coronins. We found that in Wdr1-deficient zebrafish embryos, neutrophils display F-actin cytoplasmic aggregates and a complete spatial uncoupling of phospho-myosin from F-actin. They then undergo an unprecedented gradual disorganization of their nucleus followed by eruptive cell death. Their cofilin is mostly unphosphorylated and associated with F-actin, thus likely outcompeting myosin for F-actin binding. Myosin inhibition reproduces in WT embryos the nuclear instability and eruptive death of neutrophils seen in Wdr1-deficient embryos. Strikingly, depletion of the main coronin of leukocytes, coronin 1A, fully restores the cortical location of F-actin, nuclear integrity, viability, and mobility of Wdr1-deficient neutrophils in vivo. Our study points to an essential role of actomyosin contractility in maintaining the integrity of the nucleus of neutrophils and a new twist in the interplay of cofilin, Wdr1, and coronin in regulating F-actin dynamics.
Collapse
Affiliation(s)
- Charnese Bowes
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Paris, France.,Centre National de la Recherche Scientifique, UMR3738, Paris, France
| | - Michael Redd
- University of Utah, Huntsman Cancer Institute, Salt Lake City, UT
| | - Malika Yousfi
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Paris, France.,Centre National de la Recherche Scientifique, UMR3738, Paris, France
| | - Muriel Tauzin
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Paris, France.,Centre National de la Recherche Scientifique, UMR3738, Paris, France
| | - Emi Murayama
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Paris, France.,Centre National de la Recherche Scientifique, UMR3738, Paris, France
| | - Philippe Herbomel
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Paris, France .,Centre National de la Recherche Scientifique, UMR3738, Paris, France
| |
Collapse
|
26
|
Qin Y, Li W, Long Y, Zhan Z. Relationship between p-cofilin and cisplatin resistance in patients with ovarian cancer and the role of p-cofilin in prognosis. Cancer Biomark 2019; 24:469-475. [PMID: 30932883 DOI: 10.3233/cbm-182209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE This study aims to determine the correlation between p-cofilin expression and cisplatin resistance in patients with ovarian cancer, and also to investigate the role of p-cofilin in prognosis. PATIENTS AND METHODS The ovarian cancer cell line A2780/DDP resistant to cisplatin was prepared. The cell resistance to cisplatin was measured via MTT assay. The cell invasion capacity was identified via Transwell assay. The mRNA expression and protein level was evaluated via semi-quantitative PCR and Western blot, respectively. The tumor tissues of patients with cisplatin-resistant ovarian cancer were collected. The relationship between prognosis and p-cofilin expression was analyzed. RESULTS The growth rate of A2780 was similar to that of A2780/DDP. The sensitivity of A2780 to cisplatin was significantly higher than that of A2780/DDP (p< 0.01). The migration capacity of A2780/DDP was significantly increased compared to that of A2780 (p< 0.01), indicating that the cisplatin-resistant cell lines were successfully constructed. Both CFL1 mRNA level and p-cofilin level in A2780/DDP was significantly higher than that in A2780 (p< 0.01). The p-cofilin level in cancer tissues in patients with cisplatin-resistant ovarian cancer was significantly higher than that in patients with cisplatin-sensitive ovarian cancer (p< 0.01). The cisplatin resistance was positively correlated with the p-cofilin expression level (r= 0.802, p= 0.023). The survival time of patients with normal or low level of p-cofilin was significantly longer than that of patients with high expression. CONCLUSION The cisplatin resistance of ovarian cancer is closely related to the expression level of p-cofilin, which affects the prognosis of patients with ovarian cancer.
Collapse
|
27
|
Sizes of actin networks sharing a common environment are determined by the relative rates of assembly. PLoS Biol 2019; 17:e3000317. [PMID: 31181075 PMCID: PMC6586355 DOI: 10.1371/journal.pbio.3000317] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 06/20/2019] [Accepted: 05/28/2019] [Indexed: 12/31/2022] Open
Abstract
Within the cytoplasm of a single cell, several actin networks can coexist with distinct sizes, geometries, and protein compositions. These actin networks assemble in competition for a limited pool of proteins present in a common cellular environment. To predict how two distinct networks of actin filaments control this balance, the simultaneous assembly of actin-related protein 2/3 (Arp2/3)-branched networks and formin-linear networks of actin filaments around polystyrene microbeads was investigated with a range of actin accessory proteins (profilin, capping protein, actin-depolymerizing factor [ADF]/cofilin, and tropomyosin). Accessory proteins generally affected actin assembly rates for the distinct networks differently. These effects at the scale of individual actin networks were surprisingly not always correlated with corresponding loss-of-function phenotypes in cells. However, our observations agreed with a global interpretation, which compared relative actin assembly rates of individual actin networks. This work supports a general model in which the size of distinct actin networks is determined by their relative capacity to assemble in a common and competing environment. A biomimetic assay using polystyrene beads compares the rates of actin assembly on linear and branched networks, revealing how the size of rival actin networks in cells is regulated by their relative capacity to assemble in a common environment.
Collapse
|
28
|
Duda M, Kirkland NJ, Khalilgharibi N, Tozluoglu M, Yuen AC, Carpi N, Bove A, Piel M, Charras G, Baum B, Mao Y. Polarization of Myosin II Refines Tissue Material Properties to Buffer Mechanical Stress. Dev Cell 2019; 48:245-260.e7. [PMID: 30695698 PMCID: PMC6353629 DOI: 10.1016/j.devcel.2018.12.020] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 11/26/2018] [Accepted: 12/21/2018] [Indexed: 11/06/2022]
Abstract
As tissues develop, they are subjected to a variety of mechanical forces. Some of these forces are instrumental in the development of tissues, while others can result in tissue damage. Despite our extensive understanding of force-guided morphogenesis, we have only a limited understanding of how tissues prevent further morphogenesis once the shape is determined after development. Here, through the development of a tissue-stretching device, we uncover a mechanosensitive pathway that regulates tissue responses to mechanical stress through the polarization of actomyosin across the tissue. We show that stretch induces the formation of linear multicellular actomyosin cables, which depend on Diaphanous for their nucleation. These stiffen the epithelium, limiting further changes in shape, and prevent fractures from propagating across the tissue. Overall, this mechanism of force-induced changes in tissue mechanical properties provides a general model of force buffering that serves to preserve the shape of tissues under conditions of mechanical stress.
Collapse
Affiliation(s)
- Maria Duda
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Natalie J Kirkland
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Nargess Khalilgharibi
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; London Centre for Nanotechnology, University College London, London WC1E 6BT, UK; Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London WC1E 6BT, UK
| | - Melda Tozluoglu
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Alice C Yuen
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Nicolas Carpi
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris 75005, France
| | - Anna Bove
- London Centre for Nanotechnology, University College London, London WC1E 6BT, UK; Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Matthieu Piel
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris 75005, France
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK; Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK; College of Information and Control, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
| |
Collapse
|
29
|
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: 69] [Impact Index Per Article: 11.5] [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.
Collapse
|
30
|
Jansen S, Goode BL. Tropomyosin isoforms differentially tune actin filament length and disassembly. Mol Biol Cell 2019; 30:671-679. [PMID: 30650006 PMCID: PMC6589703 DOI: 10.1091/mbc.e18-12-0815] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cellular actin networks exhibit diverse filamentous architectures and turnover dynamics, but how these differences are specified remains poorly understood. Here, we used multicolor total internal reflection fluorescence microscopy to ask how decoration of actin filaments by five biologically prominent Tropomyosin (TPM) isoforms influences disassembly induced by Cofilin alone, or by the collaborative effects of Cofilin, Coronin, and AIP1 (CCA). TPM decoration restricted Cofilin binding to pointed ends, while not interfering with Coronin binding to filament sides. Different isoforms of TPM provided variable levels of protection against disassembly, with the strongest protection by Tpm3.1 and the weakest by Tpm1.6. In biomimetic assays in which filaments were simultaneously assembled by formins and disassembled by CCA, these TPM isoform-specific effects persisted, giving rise to filaments with different lengths and treadmilling behavior. Together, our data reveal that TPM isoforms have quantitatively distinct abilities to tune actin filament length and turnover.
Collapse
Affiliation(s)
- Silvia Jansen
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO 63110
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454
| |
Collapse
|
31
|
Higgs HN. A fruitful tree: developing the dendritic nucleation model of actin-based cell motility. Mol Biol Cell 2018. [PMCID: PMC6333179 DOI: 10.1091/mbc.e18-07-0426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A fundamental question in cell biology concerns how cells move, and this has been the subject of intense research for decades. In the 1990s, a major leap forward was made in our understanding of cell motility, with the proposal of the dendritic nucleation model. This essay describes the events leading to the development of the model, including findings from many laboratories and scientific disciplines. The story is an excellent example of the scientific process in action, with the combination of multiple perspectives leading to robust conclusions.
Collapse
Affiliation(s)
- Henry N. Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| |
Collapse
|
32
|
Hayakawa K, Sekiguchi C, Sokabe M, Ono S, Tatsumi H. Real-Time Single-Molecule Kinetic Analyses of AIP1-Enhanced Actin Filament Severing in the Presence of Cofilin. J Mol Biol 2018; 431:308-322. [PMID: 30439520 DOI: 10.1016/j.jmb.2018.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 11/08/2018] [Accepted: 11/08/2018] [Indexed: 11/17/2022]
Abstract
Rearrangement of actin filaments by polymerization, depolymerization, and severing is important for cell locomotion, membrane trafficking, and many other cellular functions. Cofilin and actin-interacting protein 1 (AIP1; also known as WDR1) are evolutionally conserved proteins that cooperatively sever actin filaments. However, little is known about the biophysical basis of the actin filament severing by these proteins. Here, we performed single-molecule kinetic analyses of fluorescently labeled AIP1 during the severing process of cofilin-decorated actin filaments. Results demonstrated that binding of a single AIP molecule was sufficient to enhance filament severing. After AIP1 binding to a filament, severing occurred with a delay of 0.7 s. Kinetics of binding and dissociation of a single AIP1 molecule to/from actin filaments followed a second-order and a first-order kinetics scheme, respectively. AIP1 binding and severing were detected preferentially at the boundary between the cofilin-decorated and bare regions on actin filaments. Based on the kinetic parameters explored in this study, we propose a possible mechanism behind the enhanced severing by AIP1.
Collapse
Affiliation(s)
- Kimihide Hayakawa
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya 466-8550, Japan
| | - Carina Sekiguchi
- Department of Physiology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya 466-8550, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya 466-8550, Japan
| | - Shoichiro Ono
- Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hitoshi Tatsumi
- Department of Applied Bioscience, Kanazawa Institute of Technology (KIT), Ishikawa 924-0838, Japan.
| |
Collapse
|
33
|
Watanabe N, Tohyama K, Yamashiro S. Mechanostress resistance involving formin homology proteins: G- and F-actin homeostasis-driven filament nucleation and helical polymerization-mediated actin polymer stabilization. Biochem Biophys Res Commun 2018; 506:323-329. [PMID: 30309655 DOI: 10.1016/j.bbrc.2018.09.189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 09/30/2018] [Indexed: 01/28/2023]
Abstract
The actin cytoskeleton has two faces. One side provides the relatively stable scaffold to maintain the shape of cell cortex fit to the organs. The other side rapidly changes morphology in response to extracellular stimuli including chemical signal and physical strain. Our series of studies employing single-molecule speckle analysis of actin have revealed diverse F-actin lifetimes spanning a range of seconds to minutes in live cells. The dynamic part of the actin turnover is tightly coupled with actin nucleation activities of formin homology proteins (formins), which serve as rapid and efficient F-actin restoration mechanisms in cells under physical stress. More recently, our two studies revealed stabilization of F-actin either by actomyosin contractile force or by helical rotation of processively-actin polymerizing diaphanous-related formin mDia1. These findings quantitatively explain our proposed anti-mechanostress cascade in that G-actin released from F-actin upon loss of tension triggers frequent nucleation and subsequent fast elongation of F-actin by formins. This formin-restored F-actin may become specifically stabilized over long distance by helical polymerization-mediated filament untwisting. In this review, we discuss how and to what extent formins-mediated F-actin restoration might confer mechanostress resistance to the cell. We also give thought to the possible involvement of helical polymerization-mediated filament untwisting in the formation of diverse actin architectures including chirality control.
Collapse
Affiliation(s)
- Naoki Watanabe
- Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Biostudies, Japan; Department of Pharmacology, Kyoto University Graduate School of Medicine, Japan.
| | - Kiyoshi Tohyama
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Japan
| | - Sawako Yamashiro
- Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Biostudies, Japan
| |
Collapse
|
34
|
AIP1 and cofilin ensure a resistance to tissue tension and promote directional cell rearrangement. Nat Commun 2018; 9:3295. [PMID: 30202062 PMCID: PMC6131156 DOI: 10.1038/s41467-018-05605-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 07/14/2018] [Indexed: 01/30/2023] Open
Abstract
In order to understand how tissue mechanics shapes animal body, it is critical to clarify how cells respond to and resist tissue stress when undergoing morphogenetic processes, such as cell rearrangement. Here, we address the question in the Drosophila wing epithelium, where anisotropic tissue tension orients cell rearrangements. We found that anisotropic tissue tension localizes actin interacting protein 1 (AIP1), a cofactor of cofilin, on the remodeling junction via cooperative binding of cofilin to F-actin. AIP1 and cofilin promote actin turnover and locally regulate the Canoe-mediated linkage between actomyosin and the junction. This mechanism is essential for cells to resist the mechanical load imposed on the remodeling junction perpendicular to the direction of tissue stretching. Thus, the present study delineates how AIP1 and cofilin achieve an optimal balance between resistance to tissue tension and morphogenesis.
Collapse
|
35
|
Kemp JP, Brieher WM. The actin filament bundling protein α-actinin-4 actually suppresses actin stress fibers by permitting actin turnover. J Biol Chem 2018; 293:14520-14533. [PMID: 30049798 DOI: 10.1074/jbc.ra118.004345] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/21/2018] [Indexed: 01/07/2023] Open
Abstract
Cells organize actin filaments into contractile bundles known as stress fibers that resist mechanical stress, increase cell adhesion, remodel the extracellular matrix, and maintain tissue integrity. α-actinin is an actin filament bundling protein that is thought to be essential for stress fiber formation and stability. However, previous studies have also suggested that α-actinin might disrupt fibers, making the true function of this biomolecule unclear. Here we use fluorescence imaging to show that kidney epithelial cells depleted of α-actinin-4 via shRNA or CRISPR/Cas9, or expressing a disruptive mutant make more massive stress fibers that are less dynamic than those in WT cells, leading to defects in cell motility and wound healing. The increase in stress fiber mass and stability can be explained, in part, by increased loading of the filament component tropomyosin onto stress fibers in the absence of α-actinin, as monitored via immunofluorescence. We show using imaging and cosedimentation that α-actinin and tropomyosin compete for binding to F-actin and that tropomyosin shields actin filaments from cofilin-mediated disassembly in vitro and in cells. Perturbing tropomyosin in cells lacking α-actinin-4 results in a complete loss of stress fibers. Our results with α-actinin-4 on stress fiber organization are the opposite of what might have been predicted from previous in vitro biochemistry and further highlight how the complex interactions of multiple proteins competing for filament binding lead to unexpected functions for actin-binding proteins in cells.
Collapse
Affiliation(s)
| | - William M Brieher
- From the Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801
| |
Collapse
|
36
|
Borovac J, Bosch M, Okamoto K. Regulation of actin dynamics during structural plasticity of dendritic spines: Signaling messengers and actin-binding proteins. Mol Cell Neurosci 2018; 91:122-130. [PMID: 30004015 DOI: 10.1016/j.mcn.2018.07.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 06/25/2018] [Accepted: 07/06/2018] [Indexed: 12/17/2022] Open
Abstract
Activity-dependent plasticity of synaptic structure and function plays an essential role in neuronal development and in cognitive functions including learning and memory. The formation, maintenance and modulation of dendritic spines are mainly controlled by the dynamics of actin filaments (F-actin) through interaction with various actin-binding proteins (ABPs) and postsynaptic signaling messengers. Induction of long-term potentiation (LTP) triggers a cascade of events involving Ca2+ signaling, intracellular pathways such as cAMP and cGMP, and regulation of ABPs such as CaMKII, Cofilin, Aip1, Arp2/3, α-actinin, Profilin and Drebrin. We review here how these ABPs modulate the rate of assembly, disassembly, stabilization and bundling of F-actin during LTP induction. We highlight the crucial role that CaMKII exerts in both functional and structural plasticity by directly coupling Ca2+ signaling with F-actin dynamics through the β subunit. Moreover, we show how cAMP and cGMP second messengers regulate postsynaptic structural potentiation. Brain disorders such as Alzheimer's disease, schizophrenia or autism, are associated with alterations in the regulation of F-actin dynamics by these ABPs and signaling messengers. Thus, a better understanding of the molecular mechanisms controlling actin cytoskeleton can provide cues for the treatment of these disorders.
Collapse
Affiliation(s)
- Jelena Borovac
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Miquel Bosch
- Institute for Bioengineering of Catalonia, Barcelona 08028, Spain.
| | - Kenichi Okamoto
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1X5, Canada.
| |
Collapse
|
37
|
Attaching-and-Effacing Pathogens Exploit Junction Regulatory Activities of N-WASP and SNX9 to Disrupt the Intestinal Barrier. Cell Mol Gastroenterol Hepatol 2018. [PMID: 29675452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND & AIMS Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent pathway. METHODS We analyzed mice with intestine-specific N-WASP deletion and generated cell lines with N-WASP and SNX9 depletion for dynamic functional assays. We generated EPEC and Citrobacter rodentium strains complemented with EspF bearing point mutations abolishing N-WASP and SNX9 binding to investigate the requirement for these interactions. RESULTS Mice lacking N-WASP in the intestinal epithelium showed spontaneously increased permeability, abnormal AJC morphology, and mislocalization of occludin. N-WASP depletion in epithelial cell lines led to impaired assembly and disassembly of tight junctions in response to changes in extracellular calcium. Cells lacking N-WASP or SNX9 supported actin pedestals and type III secretion, but were resistant to EPEC-induced AJC disassembly and loss of transepithelial resistance. We found that during in vivo infection with AE pathogens, EspF must bind both N-WASP and SNX9 to disrupt AJCs and induce intestinal barrier dysfunction. CONCLUSIONS Overall, these studies show that N-WASP critically regulates AJC homeostasis, and the AE pathogen effector EspF specifically exploits both N-WASP and SNX9 to disrupt intestinal barrier integrity during infection.
Collapse
Key Words
- ADF, actin depolymerization factor
- AE, attaching-and-effacing
- AJ, adherens junction
- AJC, apical junction complex
- Arp, actin-related protein
- CR, Citrobacter rodentium
- Crb, Crumbs
- Cytoskeleton
- DBS100, David B. Schauer 100
- EHEC, enterohemorrhagic Escherichia coli
- EM, electron microscopy
- EPEC, enteropathogenic Escherichia coli
- EcoRI, E. coli RY13 I
- EspF
- EspF, early secreted antigenic target-6 (ESX)-1 secretion-associated protein F
- FITC, fluorescein isothiocyanate
- Junction Regulation
- KO, knockout
- N-WASP
- N-WASP, Neural Wiskott-Aldrich Syndrome protein
- NWKD, Neural Wiskott-Aldrich Syndrome protein knockdown
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- SNX9, sorting nexin 9
- SNX9KD, sorting nexin 9 knockdown
- TER, transepithelial electrical resistance
- TJ, tight junction
- Tir, translocated intimin receptor
- ZO-1, zonula occludens-1
- iNWKO, intestine Neural Wiskott-Aldrich Syndrome protein knockout
- shRNA, short hairpin RNA
Collapse
|
38
|
Mentel M, Ionescu AE, Puscalau-Girtu I, Helm MS, Badea RA, Rizzoli SO, Szedlacsek SE. WDR1 is a novel EYA3 substrate and its dephosphorylation induces modifications of the cellular actin cytoskeleton. Sci Rep 2018; 8:2910. [PMID: 29440662 PMCID: PMC5811557 DOI: 10.1038/s41598-018-21155-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 01/31/2018] [Indexed: 12/12/2022] Open
Abstract
Eyes absent (EYA) proteins are unusual proteins combining in a single polypeptide chain transactivation, threonine phosphatase, and tyrosine phosphatase activities. They play pivotal roles in organogenesis and are involved in a variety of physiological and pathological processes including innate immunity, DNA damage repair or cancer metastasis. The molecular targets of EYA tyrosine phosphatase activity are still elusive. Therefore, we sought to identify novel EYA substrates and also to obtain further insight into the tyrosine-dephosphorylating role of EYA proteins in various cellular processes. We show here that Src kinase phosphorylates tyrosine residues in two human EYA family members, EYA1 and EYA3. Both can autodephosphorylate these residues and their nuclear and cytoskeletal localization seems to be controlled by Src phosphorylation. Next, using a microarray of phosphotyrosine-containing peptides, we identified a phosphopeptide derived from WD-repeat-containing protein 1 (WDR1) that is dephosphorylated by EYA3. We further demonstrated that several tyrosine residues on WDR1 are phosphorylated by Src kinase, and are efficiently dephosphorylated by EYA3, but not by EYA1. The lack of phosphorylation generates major changes to the cellular actin cytoskeleton. We, therefore, conclude that WDR1 is an EYA3-specific substrate, which implies that EYA3 is a key modulator of the cytoskeletal reorganization.
Collapse
Affiliation(s)
- Mihaela Mentel
- Department of Enzymology, Institute of Biochemistry of the Romanian Academy, Spl. Independentei 296, Bucharest, 060031, Romania
| | - Aura E Ionescu
- Department of Enzymology, Institute of Biochemistry of the Romanian Academy, Spl. Independentei 296, Bucharest, 060031, Romania
| | - Ioana Puscalau-Girtu
- Department of Enzymology, Institute of Biochemistry of the Romanian Academy, Spl. Independentei 296, Bucharest, 060031, Romania
| | - Martin S Helm
- Department for Neuro- and Sensory Physiology, University Medical Center Göttingen, and Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Cluster of Excellence 171, Humboldtalle 23, Göttingen, 37073, Germany.,Max-Planck Research School Molecular Biology, Göttingen, 37077, Germany
| | - Rodica A Badea
- Department of Enzymology, Institute of Biochemistry of the Romanian Academy, Spl. Independentei 296, Bucharest, 060031, Romania
| | - Silvio O Rizzoli
- Department for Neuro- and Sensory Physiology, University Medical Center Göttingen, and Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Cluster of Excellence 171, Humboldtalle 23, Göttingen, 37073, Germany
| | - Stefan E Szedlacsek
- Department of Enzymology, Institute of Biochemistry of the Romanian Academy, Spl. Independentei 296, Bucharest, 060031, Romania.
| |
Collapse
|
39
|
Garber JJ, Mallick EM, Scanlon KM, Turner JR, Donnenberg MS, Leong JM, Snapper SB. Attaching-and-Effacing Pathogens Exploit Junction Regulatory Activities of N-WASP and SNX9 to Disrupt the Intestinal Barrier. Cell Mol Gastroenterol Hepatol 2017; 5:273-288. [PMID: 29675452 PMCID: PMC5904039 DOI: 10.1016/j.jcmgh.2017.11.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 11/28/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND & AIMS Neural Wiskott-Aldrich Syndrome protein (N-WASP) is a key regulator of the actin cytoskeleton in epithelial tissues and is poised to mediate cytoskeletal-dependent aspects of apical junction complex (AJC) homeostasis. Attaching-and-effacing (AE) pathogens disrupt this homeostasis through translocation of the effector molecule early secreted antigenic target-6 (ESX)-1 secretion-associated protein F (EspF). Although the mechanisms underlying AJC disruption by EspF are unknown, EspF contains putative binding sites for N-WASP and the endocytic regulator sorting nexin 9 (SNX9). We hypothesized that N-WASP regulates AJC integrity and AE pathogens use EspF to induce junction disassembly through an N-WASP- and SNX9-dependent pathway. METHODS We analyzed mice with intestine-specific N-WASP deletion and generated cell lines with N-WASP and SNX9 depletion for dynamic functional assays. We generated EPEC and Citrobacter rodentium strains complemented with EspF bearing point mutations abolishing N-WASP and SNX9 binding to investigate the requirement for these interactions. RESULTS Mice lacking N-WASP in the intestinal epithelium showed spontaneously increased permeability, abnormal AJC morphology, and mislocalization of occludin. N-WASP depletion in epithelial cell lines led to impaired assembly and disassembly of tight junctions in response to changes in extracellular calcium. Cells lacking N-WASP or SNX9 supported actin pedestals and type III secretion, but were resistant to EPEC-induced AJC disassembly and loss of transepithelial resistance. We found that during in vivo infection with AE pathogens, EspF must bind both N-WASP and SNX9 to disrupt AJCs and induce intestinal barrier dysfunction. CONCLUSIONS Overall, these studies show that N-WASP critically regulates AJC homeostasis, and the AE pathogen effector EspF specifically exploits both N-WASP and SNX9 to disrupt intestinal barrier integrity during infection.
Collapse
Key Words
- ADF, actin depolymerization factor
- AE, attaching-and-effacing
- AJ, adherens junction
- AJC, apical junction complex
- Arp, actin-related protein
- CR, Citrobacter rodentium
- Crb, Crumbs
- Cytoskeleton
- DBS100, David B. Schauer 100
- EHEC, enterohemorrhagic Escherichia coli
- EM, electron microscopy
- EPEC, enteropathogenic Escherichia coli
- EcoRI, E. coli RY13 I
- EspF
- EspF, early secreted antigenic target-6 (ESX)-1 secretion-associated protein F
- FITC, fluorescein isothiocyanate
- Junction Regulation
- KO, knockout
- N-WASP
- N-WASP, Neural Wiskott-Aldrich Syndrome protein
- NWKD, Neural Wiskott-Aldrich Syndrome protein knockdown
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- SNX9, sorting nexin 9
- SNX9KD, sorting nexin 9 knockdown
- TER, transepithelial electrical resistance
- TJ, tight junction
- Tir, translocated intimin receptor
- ZO-1, zonula occludens-1
- iNWKO, intestine Neural Wiskott-Aldrich Syndrome protein knockout
- shRNA, short hairpin RNA
Collapse
Affiliation(s)
- John J. Garber
- Gastrointestinal Unit, Massachusetts General Hospital, Boston, Massachusetts,Division of Gastroenterology/Nutrition and Center for Inflammatory Bowel Disease Treatment and Research, Boston Children's Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Emily M. Mallick
- Department of Medicine Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Karen M. Scanlon
- Department of Medicine and Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - Jerrold R. Turner
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Michael S. Donnenberg
- Department of Medicine and Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
| | - Scott B. Snapper
- Division of Gastroenterology/Nutrition and Center for Inflammatory Bowel Disease Treatment and Research, Boston Children's Hospital, Boston, Massachusetts,Division of Gastroenterology and Hepatology, Brigham and Women's Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts,Correspondence Address correspondence to: Scott B. Snapper, MD, PhD, Division of Gastroenterology/Nutrition, Boston Children’s Hospital, Enders 676, 300 Longwood Avenue, Boston, Massachusetts 02115. fax: (617) 730-0498.
| |
Collapse
|
40
|
Functions of actin-interacting protein 1 (AIP1)/WD repeat protein 1 (WDR1) in actin filament dynamics and cytoskeletal regulation. Biochem Biophys Res Commun 2017; 506:315-322. [PMID: 29056508 DOI: 10.1016/j.bbrc.2017.10.096] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 10/18/2017] [Indexed: 02/04/2023]
Abstract
Actin-depolymerizing factor (ADF)/cofilin and actin-interacting protein 1 (AIP1), also known as WD-repeat protein 1 (WDR1), are conserved among eukaryotes and play critical roles in dynamic reorganization of the actin cytoskeleton. AIP1 preferentially promotes disassembly of ADF/cofilin-decorated actin filaments but exhibits minimal effects on bare actin filaments. Therefore, AIP1 has been often considered to be an ancillary co-factor of ADF/cofilin that merely boosts ADF/cofilin activity level. However, genetic and cell biological studies show that AIP1 deficiency often causes lethality or severe abnormalities in multiple tissues and organs including muscle, epithelia, and blood, suggesting that AIP1 is a major regulator of many biological processes that depend on actin dynamics. This review summarizes recent progress in studies on the biochemical mechanism of actin filament severing by AIP1 and in vivo functions of AIP1 in model organisms and human diseases.
Collapse
|
41
|
Wioland H, Guichard B, Senju Y, Myram S, Lappalainen P, Jégou A, Romet-Lemonne G. ADF/Cofilin Accelerates Actin Dynamics by Severing Filaments and Promoting Their Depolymerization at Both Ends. Curr Biol 2017; 27:1956-1967.e7. [PMID: 28625781 PMCID: PMC5505867 DOI: 10.1016/j.cub.2017.05.048] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/04/2017] [Accepted: 05/16/2017] [Indexed: 12/14/2022]
Abstract
Actin-depolymerizing factor (ADF)/cofilins contribute to cytoskeletal dynamics by promoting rapid actin filament disassembly. In the classical view, ADF/cofilin sever filaments, and capping proteins block filament barbed ends whereas pointed ends depolymerize, at a rate that is still debated. Here, by monitoring the activity of the three mammalian ADF/cofilin isoforms on individual skeletal muscle and cytoplasmic actin filaments, we directly quantify the reactions underpinning filament severing and depolymerization from both ends. We find that, in the absence of monomeric actin, soluble ADF/cofilin can associate with bare filament barbed ends to accelerate their depolymerization. Compared to bare filaments, ADF/cofilin-saturated filaments depolymerize faster from their pointed ends and slower from their barbed ends, resulting in similar depolymerization rates at both ends. This effect is isoform specific because depolymerization is faster for ADF- than for cofilin-saturated filaments. We also show that, unexpectedly, ADF/cofilin-saturated filaments qualitatively differ from bare filaments: their barbed ends are very difficult to cap or elongate, and consequently undergo depolymerization even in the presence of capping protein and actin monomers. Such depolymerizing ADF/cofilin-decorated barbed ends are produced during 17% of severing events. They are also the dominant fate of filament barbed ends in the presence of capping protein, because capping allows growing ADF/cofilin domains to reach the barbed ends, thereby promoting their uncapping and subsequent depolymerization. Our experiments thus reveal how ADF/cofilin, together with capping protein, control the dynamics of actin filament barbed and pointed ends. Strikingly, our results propose that significant barbed-end depolymerization may take place in cells.
Collapse
Affiliation(s)
- Hugo Wioland
- Institut Jacques Monod, CNRS, Université Paris Diderot, 75013 Paris, France
| | - Berengere Guichard
- Institut Jacques Monod, CNRS, Université Paris Diderot, 75013 Paris, France
| | - Yosuke Senju
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Sarah Myram
- Institut Jacques Monod, CNRS, Université Paris Diderot, 75013 Paris, France
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Antoine Jégou
- Institut Jacques Monod, CNRS, Université Paris Diderot, 75013 Paris, France.
| | | |
Collapse
|
42
|
Shaw AE, Bamburg JR. Peptide regulation of cofilin activity in the CNS: A novel therapeutic approach for treatment of multiple neurological disorders. Pharmacol Ther 2017; 175:17-27. [PMID: 28232023 PMCID: PMC5466456 DOI: 10.1016/j.pharmthera.2017.02.031] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cofilin is a ubiquitous protein which cooperates with many other actin-binding proteins in regulating actin dynamics. Cofilin has essential functions in nervous system development including neuritogenesis, neurite elongation, growth cone pathfinding, dendritic spine formation, and the regulation of neurotransmission and spine function, components of synaptic plasticity essential for learning and memory. Cofilin's phosphoregulation is a downstream target of many transmembrane signaling processes, and its misregulation in neurons has been linked in rodent models to many different neurodegenerative and neurological disorders including Alzheimer disease (AD), aggression due to neonatal isolation, autism, manic/bipolar disorder, and sleep deprivation. Cognitive and behavioral deficits of these rodent models have been largely abrogated by modulation of cofilin activity using viral-mediated, genetic, and/or small molecule or peptide therapeutic approaches. Neuropathic pain in rats from sciatic nerve compression has also been reduced by modulating the cofilin pathway within neurons of the dorsal root ganglia. Neuroinflammation, which occurs following cerebral ischemia/reperfusion, but which also accompanies many other neurodegenerative syndromes, is markedly reduced by peptides targeting specific chemokine receptors, which also modulate cofilin activity. Thus, peptide therapeutics offer potential for cost-effective treatment of a wide variety of neurological disorders. Here we discuss some recent results from rodent models using therapeutic peptides with a surprising ability to cross the rodent blood brain barrier and alter cofilin activity in brain. We also offer suggestions as to how neuronal-specific cofilin regulation might be achieved.
Collapse
Affiliation(s)
- Alisa E Shaw
- Department of Biochemistry and Molecular Biology, Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523-1870, United States
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523-1870, United States.
| |
Collapse
|
43
|
Shekhar S, Carlier MF. Enhanced Depolymerization of Actin Filaments by ADF/Cofilin and Monomer Funneling by Capping Protein Cooperate to Accelerate Barbed-End Growth. Curr Biol 2017. [PMID: 28625780 PMCID: PMC5505869 DOI: 10.1016/j.cub.2017.05.036] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A living cell’s ability to assemble actin filaments in intracellular motile processes is directly dependent on the availability of polymerizable actin monomers, which feed polarized filament growth [1, 2]. Continued generation of the monomer pool by filament disassembly is therefore crucial. Disassemblers like actin depolymerizing factor (ADF)/cofilin and filament cappers like capping protein (CP) are essential agonists of motility [3, 4, 5, 6, 7, 8], but the exact molecular mechanisms by which they accelerate actin polymerization at the leading edge and filament turnover has been debated for over two decades [9, 10, 11, 12]. Whereas filament fragmentation by ADF/cofilin has long been demonstrated by total internal reflection fluorescence (TIRF) [13, 14], filament depolymerization was only inferred from bulk solution assays [15]. Using microfluidics-assisted TIRF microscopy, we provide the first direct visual evidence of ADF’s simultaneous severing and rapid depolymerization of individual filaments. Using a conceptually novel assay to directly visualize ADF’s effect on a population of pre-assembled filaments, we demonstrate how ADF’s enhanced pointed-end depolymerization causes an increase in polymerizable actin monomers, thus promoting faster barbed-end growth. We further reveal that ADF-enhanced depolymerization synergizes with CP’s long-predicted “monomer funneling” [16] and leads to skyrocketing of filament growth rates, close to estimated lamellipodial rates. The “funneling model” hypothesized, on thermodynamic grounds, that at high enough extent of capping, the few non-capped filaments transiently grow much faster [15], an effect proposed to be very important for motility. We provide the first direct microscopic evidence of monomer funneling at the scale of individual filaments. These results significantly enhance our understanding of the turnover of cellular actin networks. ADF enhances barbed- and pointed-end depolymerization of actin filaments Capping protein funnels monomers from all pointed ends to the few non-capped barbed ends ADF and capping protein synergy leads to skyrocketing of filament elongation rates
Collapse
Affiliation(s)
- Shashank Shekhar
- Cytoskeleton Dynamics and Cell Motility, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris Saclay, 91198 Gif-sur-Yvette Cedex, France.
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Cell Motility, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris Saclay, 91198 Gif-sur-Yvette Cedex, France.
| |
Collapse
|
44
|
Carlier MF, Shekhar S. Global treadmilling coordinates actin turnover and controls the size of actin networks. Nat Rev Mol Cell Biol 2017. [PMID: 28248322 DOI: 10.1038/nrm.(2016)172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Various cellular processes (including cell motility) are driven by the regulated, polarized assembly of actin filaments into distinct force-producing arrays of defined size and architecture. Branched, linear, contractile and cytosolic arrays coexist in vivo, and cells intricately control the number, length and assembly rate of filaments in these arrays. Recent in vitro and in vivo studies have revealed novel molecular mechanisms that regulate the number of filament barbed and pointed ends and their respective assembly and disassembly rates, thus defining classes of dynamically different filaments, which coexist in the same cell. We propose that a global treadmilling process, in which a steady-state amount of polymerizable actin monomers is established by the dynamics of each network, is responsible for defining the size and turnover of coexisting actin networks. Furthermore, signal-induced changes in the partitioning of actin to distinct arrays (mediated by RHO GTPases) result in the establishment of various steady-state concentrations of polymerizable monomers, thereby globally influencing the growth rate of actin filaments.
Collapse
Affiliation(s)
- Marie-France Carlier
- Institute for Integrative Biology of the Cell (I2BC), CNRS, Gif-sur-Yvette, Paris 91190, France
| | - Shashank Shekhar
- Institute for Integrative Biology of the Cell (I2BC), CNRS, Gif-sur-Yvette, Paris 91190, France
| |
Collapse
|
45
|
Christensen JR, Hocky GM, Homa KE, Morganthaler AN, Hitchcock-DeGregori SE, Voth GA, Kovar DR. Competition between Tropomyosin, Fimbrin, and ADF/Cofilin drives their sorting to distinct actin filament networks. eLife 2017; 6. [PMID: 28282023 PMCID: PMC5404920 DOI: 10.7554/elife.23152] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/09/2017] [Indexed: 12/15/2022] Open
Abstract
The fission yeast actin cytoskeleton is an ideal, simplified system to investigate fundamental mechanisms behind cellular self-organization. By focusing on the stabilizing protein tropomyosin Cdc8, bundling protein fimbrin Fim1, and severing protein coffin Adf1, we examined how their pairwise and collective interactions with actin filaments regulate their activity and segregation to functionally diverse F-actin networks. Utilizing multi-color TIRF microscopy of in vitro reconstituted F-actin networks, we observed and characterized two distinct Cdc8 cables loading and spreading cooperatively on individual actin filaments. Furthermore, Cdc8, Fim1, and Adf1 all compete for association with F-actin by different mechanisms, and their cooperative association with actin filaments affects their ability to compete. Finally, competition between Fim1 and Adf1 for F-actin synergizes their activities, promoting rapid displacement of Cdc8 from a dense F-actin network. Our findings reveal that competitive and cooperative interactions between actin binding proteins help define their associations with different F-actin networks. DOI:http://dx.doi.org/10.7554/eLife.23152.001 Cells use a protein called actin to provide shape, to generate the forces needed for cells to divide, and for many other essential processes. Inside a cell, individual actin proteins join up to form long filaments. These actin filaments are organized in different ways to make networks that have distinct properties, each tailored for a specific process. For instance, bundles of straight actin filaments help a cell to divide, whereas a network of branched actin filaments allows cells to move. The different proteins that bind to actin filaments influence how quickly actin filaments are assembled and organized into networks. Therefore, many of the properties of an actin filament network are due to the actin binding proteins that are associated with it. Two actin binding proteins called fimbrin and cofilin associate with a type of actin filament network known as the actin patch. A third actin binding protein called tropomyosin associates with a different network that forms a ring. It is not known how particular actin binding proteins choose to associate with one actin network instead of another. Christensen et al. used a fluorescence microscopy technique to study how fimbrin, cofilin and tropomyosin associate with different actin networks in a single-celled organism called fission yeast. This technique involved incubating actin and actin binding proteins together in a microscope chamber. The experiments show that some actin binding proteins, like tropomyosin, cooperate to bind to actin. Individual tropomyosin molecules find it difficult to bind actin filaments on their own, but once one tropomyosin molecule is attached to the filament, others rapidly join to coat the filament. On the other hand, some actin-binding proteins compete for binding to filaments. For example, the binding of fimbrin to actin filaments causes tropomyosin to be removed from the actin network. Further experiments revealed that fimbrin and cofilin work with each other to rapidly generate a dense actin network and displace tropomyosin. Together, the findings of Christensen et al. suggest that competitions between actin binding proteins determine which actin binding proteins are associated with an actin network. The next challenge is to understand how the most competitive actin-binding proteins are kept off actin networks where they do not belong. Further studies will shed light on how these interactions cause large changes in how the cell is organized. DOI:http://dx.doi.org/10.7554/eLife.23152.002
Collapse
Affiliation(s)
- Jenna R Christensen
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Glen M Hocky
- Department of Chemistry, The University of Chicago, Chicago, United States.,James Franck Institute, The University of Chicago, Chicago, United States
| | - Kaitlin E Homa
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Alisha N Morganthaler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Sarah E Hitchcock-DeGregori
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, United States
| | - Gregory A Voth
- Department of Chemistry, The University of Chicago, Chicago, United States.,James Franck Institute, The University of Chicago, Chicago, United States.,Computation Institute, The University of Chicago, Chicago, United States.,Institute for Biophysical Dynamics, The University of Chicago, Chicago, United States
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States.,Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States
| |
Collapse
|
46
|
Carlier MF, Shekhar S. Global treadmilling coordinates actin turnover and controls the size of actin networks. Nat Rev Mol Cell Biol 2017; 18:389-401. [DOI: 10.1038/nrm.2016.172] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
47
|
Shekhar S, Carlier MF. Single-filament kinetic studies provide novel insights into regulation of actin-based motility. Mol Biol Cell 2016; 27:1-6. [PMID: 26715420 PMCID: PMC4694749 DOI: 10.1091/mbc.e15-06-0352] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Polarized assembly of actin filaments forms the basis of actin-based motility and is regulated both spatially and temporally. Cells use a variety of mechanisms by which intrinsically slower processes are accelerated, and faster ones decelerated, to match rates observed in vivo. Here we discuss how kinetic studies of individual reactions and cycles that drive actin remodeling have provided a mechanistic and quantitative understanding of such processes. We specifically consider key barbed-end regulators such as capping protein and formins as illustrative examples. We compare and contrast different kinetic approaches, such as the traditional pyrene-polymerization bulk assays, as well as more recently developed single-filament and single-molecule imaging approaches. Recent development of novel biophysical methods for sensing and applying forces will in future allow us to address the very important relationship between mechanical stimulus and kinetics of actin-based motility.
Collapse
Affiliation(s)
- Shashank Shekhar
- Cytoskeleton Dynamics and Cell Motility, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Cell Motility, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
| |
Collapse
|
48
|
Abstract
The actin depolymerizing factor (ADF)/cofilin family comprises small actin-binding proteins with crucial roles in development, tissue homeostasis and disease. They are best known for their roles in regulating actin dynamics by promoting actin treadmilling and thereby driving membrane protrusion and cell motility. However, recent discoveries have increased our understanding of the functions of these proteins beyond their well-characterized roles. This Cell Science at a Glance article and the accompanying poster serve as an introduction to the diverse roles of the ADF/cofilin family in cells. The first part of the article summarizes their actions in actin treadmilling and the main mechanisms for their intracellular regulation; the second part aims to provide an outline of the emerging cellular roles attributed to the ADF/cofilin family, besides their actions in actin turnover. The latter part discusses an array of diverse processes, which include regulation of intracellular contractility, maintenance of nuclear integrity, transcriptional regulation, nuclear actin monomer transfer, apoptosis and lipid metabolism. Some of these could, of course, be indirect consequences of actin treadmilling functions, and this is discussed.
Collapse
Affiliation(s)
- Georgios Kanellos
- Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XR, UK
| | - Margaret C Frame
- Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XR, UK
| |
Collapse
|
49
|
Fritzsche M, Erlenkämper C, Moeendarbary E, Charras G, Kruse K. Actin kinetics shapes cortical network structure and mechanics. SCIENCE ADVANCES 2016; 2:e1501337. [PMID: 27152338 PMCID: PMC4846455 DOI: 10.1126/sciadv.1501337] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 03/30/2016] [Indexed: 05/20/2023]
Abstract
The actin cortex of animal cells is the main determinant of cellular mechanics. The continuous turnover of cortical actin filaments enables cells to quickly respond to stimuli. Recent work has shown that most of the cortical actin is generated by only two actin nucleators, the Arp2/3 complex and the formin Diaph1. However, our understanding of their interplay, their kinetics, and the length distribution of the filaments that they nucleate within living cells is poor. Such knowledge is necessary for a thorough comprehension of cellular processes and cell mechanics from basic polymer physics principles. We determined cortical assembly rates in living cells by using single-molecule fluorescence imaging in combination with stochastic simulations. We find that formin-nucleated filaments are, on average, 10 times longer than Arp2/3-nucleated filaments. Although formin-generated filaments represent less than 10% of all actin filaments, mechanical measurements indicate that they are important determinants of cortical elasticity. Tuning the activity of actin nucleators to alter filament length distribution may thus be a mechanism allowing cells to adjust their macroscopic mechanical properties to their physiological needs.
Collapse
Affiliation(s)
- Marco Fritzsche
- MRC Human Immunology Unit, Weatherall Institute for Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
- Corresponding author. E-mail: (M.F.); (K.K.); (G.C.)
| | - Christoph Erlenkämper
- Theoretische Physik, Universität des Saarlandes, 66041 Saarbrücken, Germany
- Institut Curie, 26 Rue d’Ulm, 75248 Paris Cedex 05, France
| | - Emad Moeendarbary
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Guillaume Charras
- London Centre for Nanotechnology, Institute for the Physics of Living Systems, and Department of Cell and Developmental Biology, University College London, London WC1H 0AH, UK
- Corresponding author. E-mail: (M.F.); (K.K.); (G.C.)
| | - Karsten Kruse
- Theoretische Physik, Universität des Saarlandes, 66041 Saarbrücken, Germany
- Corresponding author. E-mail: (M.F.); (K.K.); (G.C.)
| |
Collapse
|
50
|
Abstract
Actin-filament disassembly is indispensable for replenishing the pool of polymerizable actin and allows continuous dynamic remodelling of the actin cytoskeleton. A new study now reveals that ADF/cofilin preferentially dismantles branched networks and provides new insights into the collaborative work of ADF/cofilin and Aip1 on filament disassembly at the molecular level.
Collapse
Affiliation(s)
- Moritz Winterhoff
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover, Germany.
| |
Collapse
|