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Wang L, Yang Z, Satoshi F, Prasanna X, Yan Z, Vihinen H, Chen Y, Zhao Y, He X, Bu Q, Li H, Zhao Y, Jiang L, Qin F, Dai Y, Zhang N, Qin M, Kuang W, Zhao Y, Jokitalo E, Vattulainen I, Kajander T, Zhao H, Cen X. Membrane remodeling by FAM92A1 during brain development regulates neuronal morphology, synaptic function, and cognition. Nat Commun 2024; 15:6209. [PMID: 39043703 PMCID: PMC11266426 DOI: 10.1038/s41467-024-50565-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 07/12/2024] [Indexed: 07/25/2024] Open
Abstract
The Bin/Amphiphysin/Rvs (BAR) domain protein FAM92A1 is a multifunctional protein engaged in regulating mitochondrial ultrastructure and ciliogenesis, but its physiological role in the brain remains unclear. Here, we show that FAM92A1 is expressed in neurons starting from embryonic development. FAM92A1 knockout in mice results in altered brain morphology and age-associated cognitive deficits, potentially due to neuronal degeneration and disrupted synaptic plasticity. Specifically, FAM92A1 deficiency impairs diverse neuronal membrane morphology, including the mitochondrial inner membrane, myelin sheath, and synapses, indicating its roles in membrane remodeling and maintenance. By determining the crystal structure of the FAM92A1 BAR domain, combined with atomistic molecular dynamics simulations, we uncover that FAM92A1 interacts with phosphoinositide- and cardiolipin-containing membranes to induce lipid-clustering and membrane curvature. Altogether, these findings reveal the physiological role of FAM92A1 in the brain, highlighting its impact on synaptic plasticity and neural function through the regulation of membrane remodeling and endocytic processes.
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Affiliation(s)
- Liang Wang
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
| | - Ziyun Yang
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Fudo Satoshi
- Helsinki Institute of Life Science - Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Xavier Prasanna
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Ziyi Yan
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
| | - Helena Vihinen
- Helsinki Institute of Life Science (HiLIFE) - Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Yaxing Chen
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yue Zhao
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Xiumei He
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
- School of Life Sciences, Guangxi Normal University, Guilin, China
- Guangxi Universities Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, 541004, China
| | - Qian Bu
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Hongchun Li
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Ying Zhao
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Linhong Jiang
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Feng Qin
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yanping Dai
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Ni Zhang
- Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Meng Qin
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Weihong Kuang
- Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Yinglan Zhao
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Eija Jokitalo
- Helsinki Institute of Life Science (HiLIFE) - Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Tommi Kajander
- Helsinki Institute of Life Science - Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hongxia Zhao
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland.
- School of Life Sciences, Guangxi Normal University, Guilin, China.
- Guangxi Universities Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, 541004, China.
| | - Xiaobo Cen
- Mental Health Center and National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, China.
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2
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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 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.
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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.
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3
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Ma Q, Surya W, He D, Yang H, Han X, Nai MH, Lim CT, Torres J, Miao Y. Spa2 remodels ADP-actin via molecular condensation under glucose starvation. Nat Commun 2024; 15:4491. [PMID: 38802374 PMCID: PMC11130202 DOI: 10.1038/s41467-024-48863-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/15/2024] [Indexed: 05/29/2024] Open
Abstract
Actin nucleotide-dependent actin remodeling is essential to orchestrate signal transduction and cell adaptation. Rapid energy starvation requires accurate and timely reorganization of the actin network. Despite distinct treadmilling mechanisms of ADP- and ATP-actin filaments, their filament structures are nearly identical. How other actin-binding proteins regulate ADP-actin filament assembly is unclear. Here, we show that Spa2 which is the polarisome scaffold protein specifically remodels ADP-actin upon energy starvation in budding yeast. Spa2 triggers ADP-actin monomer nucleation rapidly through a dimeric core of Spa2 (aa 281-535). Concurrently, the intrinsically disordered region (IDR, aa 1-281) guides Spa2 undergoing phase separation and wetting on the surface of ADP-G-actin-derived F-actin and bundles the filaments. Both ADP-actin-specific nucleation and bundling activities of Spa2 are actin D-loop dependent. The IDR and nucleation core of Spa2 are evolutionarily conserved by coexistence in the fungus kingdom, suggesting a universal adaptation mechanism in the fungal kingdom in response to glucose starvation, regulating ADP-G-actin and ADP-F-actin with high nucleotide homogeneity.
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Affiliation(s)
- Qianqian Ma
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Danxia He
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Hanmeng Yang
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Mui Hoon Nai
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore, Singapore
| | - Chwee Teck Lim
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore, Singapore
- Institute for Health Innovation and Technology (iHealthtech), National University of Singapore, 119276, Singapore, Singapore
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore.
- Institute for Digital Molecular Analytics and Science, Nanyang Technological University, 636921, Singapore, Singapore.
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4
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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.
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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
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5
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Kyheröinen S, Prajapati B, Sokolova M, Schmitz M, Viita T, Geyer M, Vartiainen MK. Actin associates with actively elongating genes and binds directly to the Cdk9 subunit of P-TEFb. J Biol Chem 2024; 300:105698. [PMID: 38301887 PMCID: PMC10891344 DOI: 10.1016/j.jbc.2024.105698] [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: 11/15/2023] [Revised: 01/08/2024] [Accepted: 01/21/2024] [Indexed: 02/03/2024] Open
Abstract
Nuclear actin has been demonstrated to be essential for optimal transcription, but the molecular mechanisms and direct binding partner for actin in the RNA polymerase complex have remained unknown. By using purified proteins in a variety of biochemical assays, we demonstrate a direct and specific interaction between monomeric actin and Cdk9, the kinase subunit of the positive transcription elongation factor b required for RNA polymerase II pause-release. This interaction efficiently prevents actin polymerization, is not dependent on kinase activity of Cdk9, and is not involved with releasing positive transcription elongation factor b from its inhibitor 7SK snRNP complex. Supporting the specific role for actin in the elongation phase of transcription, chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) reveals that actin interacts with genes only upon their active transcription elongation. This study therefore provides novel insights into the mechanisms by which actin facilitates the transcription process.
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Affiliation(s)
- Salla Kyheröinen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Bina Prajapati
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Maria Sokolova
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | | | - Tiina Viita
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Bonn, Germany
| | - Maria K Vartiainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.
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6
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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: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [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.
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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
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7
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Gonzalez Rodriguez S, Wirshing AC, Goodman AL, Goode BL. Cytosolic concentrations of actin binding proteins and the implications for in vivo F-actin turnover. J Cell Biol 2023; 222:e202306036. [PMID: 37801069 PMCID: PMC10558290 DOI: 10.1083/jcb.202306036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/31/2023] [Accepted: 09/21/2023] [Indexed: 10/07/2023] Open
Abstract
Understanding how numerous actin-binding proteins (ABPs) work in concert to control the assembly, organization, and turnover of the actin cytoskeleton requires quantitative information about the levels of each component. Here, we measured the cellular concentrations of actin and the majority of the conserved ABPs in Saccharomyces cerevisiae, as well as the free (cytosolic) fractions of each ABP. The cellular concentration of actin is estimated to be 13.2 µM, with approximately two-thirds in the F-actin form and one-third in the G-actin form. Cellular concentrations of ABPs range from 12.4 to 0.85 µM (Tpm1> Pfy1> Cof1> Abp1> Srv2> Abp140> Tpm2> Aip1> Cap1/2> Crn1> Sac6> Twf1> Arp2/3> Scp1). The cytosolic fractions of all ABPs are unexpectedly high (0.6-0.9) and remain so throughout the cell cycle. Based on these numbers, we speculate that F-actin binding sites are limited in vivo, which leads to high cytosolic levels of ABPs, and in turn helps drive the rapid assembly and turnover of cellular F-actin structures.
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Affiliation(s)
- Sofia Gonzalez Rodriguez
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Alison C.E. Wirshing
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Anya L. Goodman
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
- Department of Chemistry and Biochemistry, California Polytechnic State University SLO, San Luis Obispo, CA, USA
| | - Bruce L. Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
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8
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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: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [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.
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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.
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9
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Guo S, Hoeprich GJ, Magliozzi JO, Gelles J, Goode BL. Dynamic remodeling of actin networks by cyclase-associated protein and CAP-Abp1 complexes. Curr Biol 2023; 33:4484-4495.e5. [PMID: 37797614 DOI: 10.1016/j.cub.2023.09.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 07/20/2023] [Accepted: 09/13/2023] [Indexed: 10/07/2023]
Abstract
How actin filaments are spatially organized and remodeled into diverse higher-order networks in vivo is still not well understood. Here, we report an unexpected F-actin "coalescence" activity driven by cyclase-associated protein (CAP) and enhanced by its interactions with actin-binding protein 1 (Abp1). We directly observe S. cerevisiae CAP and Abp1 rapidly transforming branched or linear actin networks by bundling and sliding filaments past each other, maximizing filament overlap, and promoting compaction into bundles. This activity does not require ATP and is conserved, as similar behaviors are observed for the mammalian homologs of CAP and Abp1. Coalescence depends on the CAP oligomerization domain but not the helical folded domain (HFD) that mediates its functions in F-actin severing and depolymerization. Coalescence by CAP-Abp1 further depends on interactions between CAP and Abp1 and interactions between Abp1 and F-actin. Our results are consistent with a mechanism in which the formation of energetically favorable sliding CAP and CAP-Abp1 crosslinks drives F-actin bundle compaction. Roles for CAP and CAP-Abp1 in actin remodeling in vivo are supported by strong phenotypes arising from deletion of the CAP oligomerization domain and by genetic interactions between sac6Δ and an srv2-301 mutant that does not bind Abp1. Together, these observations identify a new actin filament remodeling function for CAP, which is further enhanced by its direct interactions with Abp1.
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Affiliation(s)
- Siyang Guo
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Gregory J Hoeprich
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Joseph O Magliozzi
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
| | - Bruce L Goode
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
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10
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Rust MB, Marcello E. Disease association of cyclase-associated protein (CAP): Lessons from gene-targeted mice and human genetic studies. Eur J Cell Biol 2022; 101:151207. [PMID: 35150966 DOI: 10.1016/j.ejcb.2022.151207] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 11/03/2022] Open
Abstract
Cyclase-associated protein (CAP) is an actin binding protein that has been initially described as partner of the adenylyl cyclase in yeast. In all vertebrates and some invertebrate species, two orthologs, named CAP1 and CAP2, have been described. CAP1 and CAP2 are characterized by a similar multidomain structure, but different expression patterns. Several molecular studies clarified the biological function of the different CAP domains, and they shed light onto the mechanisms underlying CAP-dependent regulation of actin treadmilling. However, CAPs are crucial elements not only for the regulation of actin dynamics, but also for signal transduction pathways. During recent years, human genetic studies and the analysis of gene-targeted mice provided important novel insights into the physiological roles of CAPs and their involvement in the pathogenesis of several diseases. In the present review, we summarize and discuss recent progress in our understanding of CAPs' physiological functions, focusing on heart, skeletal muscle and central nervous system as well as their involvement in the mechanisms controlling metabolism. Remarkably, loss of CAPs or impairment of CAPs-dependent pathways can contribute to the pathogenesis of different diseases. Overall, these studies unraveled CAPs complexity highlighting their capability to orchestrate structural and signaling pathways in the cells.
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Affiliation(s)
- Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany.
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milan, Italy.
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11
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Schneider F, Duong TA, Metz I, Winkelmeier J, Hübner CA, Endesfelder U, Rust MB. Mutual functional dependence of cyclase-associated protein 1 (CAP1) and cofilin1 in neuronal actin dynamics and growth cone function. Prog Neurobiol 2021; 202:102050. [PMID: 33845164 DOI: 10.1016/j.pneurobio.2021.102050] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/14/2021] [Accepted: 04/07/2021] [Indexed: 01/20/2023]
Abstract
Neuron connectivity depends on growth cones that navigate axons through the developing brain. Growth cones protrude and retract actin-rich structures to sense guidance cues. These cues control local actin dynamics and steer growth cones towards attractants and away from repellents, thereby directing axon outgrowth. Hence, actin binding proteins (ABPs) moved into the focus as critical regulators of neuron connectivity. We found cyclase-associated protein 1 (CAP1), an ABP with unknown brain function, abundant in growth cones. Super-resolution microscopy and live cell imaging combined with pharmacological approaches on hippocampal neurons from gene-targeted mice revealed a crucial role for CAP1 in actin dynamics that is critical for growth cone morphology and function. Growth cone defects in CAP1 knockout (KO) neurons compromised neuron differentiation and was associated with impaired neuron connectivity in CAP1-KO brains. Mechanistically, by rescue experiments in double KO neurons lacking CAP1 and the key actin regulator cofilin1, we demonstrated that CAP1 was essential for cofilin1 function in growth cone actin dynamics and morphology and vice versa. Together, we identified CAP1 as a novel actin regulator in growth cones that was relevant for neuron connectivity, and we demonstrated functional interdependence of CAP1 and cofilin1 in neuronal actin dynamics and growth cone function.
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Affiliation(s)
- Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany; DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Thuy-An Duong
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany
| | - Isabell Metz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany
| | - Jannik Winkelmeier
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043, Marburg, Germany; Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, USA
| | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, 07743, Jena, Germany
| | - Ulrike Endesfelder
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043, Marburg, Germany; Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, USA
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany; DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany.
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12
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Kodera N, Abe H, Nguyen PDN, Ono S. Native cyclase-associated protein and actin from Xenopus laevis oocytes form a unique 4:4 complex with a tripartite structure. J Biol Chem 2021; 296:100649. [PMID: 33839148 PMCID: PMC8113726 DOI: 10.1016/j.jbc.2021.100649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 11/26/2022] Open
Abstract
Cyclase-associated protein (CAP) is a conserved actin-binding protein that regulates multiple aspects of actin dynamics, including polymerization, depolymerization, filament severing, and nucleotide exchange. CAP has been isolated from different cells and tissues in an equimolar complex with actin, and previous studies have shown that a CAP–actin complex contains six molecules each of CAP and actin. Intriguingly, here, we successfully isolated a complex of Xenopus cyclase-associated protein 1 (XCAP1) with actin from oocyte extracts, which contained only four molecules each of XCAP1 and actin. This XCAP1–actin complex remained stable as a single population of 340 kDa species during hydrodynamic analyses using gel filtration or analytical ultracentrifugation. Examination of the XCAP1–actin complex by high-speed atomic force microscopy revealed a tripartite structure: one middle globular domain and two globular arms. The two arms were observed in high and low states. The arms at the high state were spontaneously converted to the low state by dissociation of actin from the complex. However, when extra G-actin was added, the arms at the low state were converted to the high state. Based on the known structures of the N-terminal helical-folded domain and C-terminal CARP domain, we hypothesize that the middle globular domain corresponds to a tetramer of the N-terminal helical-folded domain of XCAP1 and that each arm in the high state corresponds to a heterotetramer containing a dimer of the C-terminal CARP domain of XCAP1 and two G-actin molecules. This novel configuration of a CAP–actin complex should help to understand how CAP promotes actin filament disassembly.
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Affiliation(s)
- Noriyuki Kodera
- WPI-Nano Life Science Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hiroshi Abe
- Department of Biology, Graduate School of Science, Chiba University, Chiba, Japan
| | | | - Shoichiro Ono
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA; Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA.
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13
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Rust MB, Khudayberdiev S, Pelucchi S, Marcello E. CAPt'n of Actin Dynamics: Recent Advances in the Molecular, Developmental and Physiological Functions of Cyclase-Associated Protein (CAP). Front Cell Dev Biol 2020; 8:586631. [PMID: 33072768 PMCID: PMC7543520 DOI: 10.3389/fcell.2020.586631] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/26/2020] [Indexed: 12/11/2022] Open
Abstract
Cyclase-associated protein (CAP) has been discovered three decades ago in budding yeast as a protein that associates with the cyclic adenosine monophosphate (cAMP)-producing adenylyl cyclase and that suppresses a hyperactive RAS2 variant. Since that time, CAP has been identified in all eukaryotic species examined and it became evident that the activity in RAS-cAMP signaling is restricted to a limited number of species. Instead, its actin binding activity is conserved among eukaryotes and actin cytoskeleton regulation emerged as its primary function. However, for many years, the molecular functions as well as the developmental and physiological relevance of CAP remained unknown. In the present article, we will compile important recent progress on its molecular functions that identified CAP as a novel key regulator of actin dynamics, i.e., the spatiotemporally controlled assembly and disassembly of actin filaments (F-actin). These studies unraveled a cooperation with ADF/Cofilin and Twinfilin in F-actin disassembly, a nucleotide exchange activity on globular actin monomers (G-actin) that is required for F-actin assembly and an inhibitory function towards the F-actin assembly factor INF2. Moreover, by focusing on selected model organisms, we will review current literature on its developmental and physiological functions, and we will present studies implicating CAP in human pathologies. Together, this review article summarizes and discusses recent achievements in understanding the molecular, developmental and physiological functions of CAP, which led this protein emerge as a novel CAPt'n of actin dynamics.
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Affiliation(s)
- Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, Marburg, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior, University of Marburg and Justus-Liebig-University Giessen, Giessen, Germany
| | - Sharof Khudayberdiev
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, Marburg, Germany
| | - Silvia Pelucchi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
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14
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Saker Z, Bahmad HF, Fares Y, Al Najjar Z, Saad M, Harati H, Nabha S. Prognostic impact of adenylyl cyclase-associated protein 2 (CAP2) in glioma: A clinicopathological study. Heliyon 2020; 6:e03236. [PMID: 32042970 PMCID: PMC7002826 DOI: 10.1016/j.heliyon.2020.e03236] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/05/2019] [Accepted: 01/13/2020] [Indexed: 12/21/2022] Open
Abstract
Background Gliomas are a group of diseases arising from intracranial neoplastic tissues that produce a wide spectrum of clinicopathological features and morphological changes. Key questions that intrigue neuro-oncology researchers include defining novel oncophenotypic signatures relevant to diagnosing such tumors and predicting prognoses among patients. One of the key regulators of the cellular actin dynamics is adenylyl cyclase-associated protein 2 (CAP2), a protein that has been studied before in the milieu of cancer and shown to be associated with tumor progression; yet, its expression levels in the context of gliomas have not been assessed. Hence, we were interested in investigating CAP2 expression in gliomas and evaluating its clinicopathological and prognostic significance. Materials and methods CAP2 expression at the protein level was analyzed in 47 human paraffin-embedded gliomas and normal brain tissues by automated immunohistochemical analysis. Statistical analysis was also performed to assess CAP2 expression level in normal and tumor tissues, and to evaluate its clinicopathological and prognostic significance. Results Our results revealed high expression of CAP2 protein in tumors of gliomas compared to normal tissues and normal areas adjacent to tumors. High expression of CAP2 was also associated with advanced tumor grades among gliomas. Kaplan-Meier analysis revealed that high CAP2 expression was associated with poor prognosis of patients with glioma (P < 0.05). In Cox regression analysis, CAP2 expression was indicated as an independent prognostic factor for overall survival (hazard ratio (HR) = 1.843, 95% confidence interval (CI), 1.252-2.714; P < 0.005). Conclusion CAP2 is overexpressed in glioma and it is proposed as a potential prognostic biomarker for patients with gliomas. CAP2 expression level may serve as a promising target for diagnosis and treatment of glioma.
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Affiliation(s)
- Zahraa Saker
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Hisham F Bahmad
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon.,Department of Anatomy, Cell Biology, and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Faculty of Medicine, Beirut Arab University, Beirut, Lebanon
| | - Youssef Fares
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon.,Department of Neurosurgery, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Zahraa Al Najjar
- Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Mohamad Saad
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon.,Qatar Computing Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Hayat Harati
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
| | - Sanaa Nabha
- Neuroscience Research Center, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon
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15
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Regulation of INF2-mediated actin polymerization through site-specific lysine acetylation of actin itself. Proc Natl Acad Sci U S A 2019; 117:439-447. [PMID: 31871199 DOI: 10.1073/pnas.1914072117] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
INF2 is a formin protein that accelerates actin polymerization. A common mechanism for formin regulation is autoinhibition, through interaction between the N-terminal diaphanous inhibitory domain (DID) and C-terminal diaphanous autoregulatory domain (DAD). We recently showed that INF2 uses a variant of this mechanism that we term "facilitated autoinhibition," whereby a complex consisting of cyclase-associated protein (CAP) bound to lysine-acetylated actin (KAc-actin) is required for INF2 inhibition, in a manner requiring INF2-DID. Deacetylation of actin in the CAP/KAc-actin complex activates INF2. Here we use lysine-to-glutamine mutations as acetylmimetics to map the relevant lysines on actin for INF2 regulation, focusing on K50, K61, and K328. Biochemically, K50Q- and K61Q-actin, when bound to CAP2, inhibit full-length INF2 but not INF2 lacking DID. When not bound to CAP, these mutant actins polymerize similarly to WT-actin in the presence or absence of INF2, suggesting that the effect of the mutation is directly on INF2 regulation. In U2OS cells, K50Q- and K61Q-actin inhibit INF2-mediated actin polymerization when expressed at low levels. Direct-binding studies show that the CAP WH2 domain binds INF2-DID with submicromolar affinity but has weak affinity for actin monomers, while INF2-DAD binds CAP/K50Q-actin 5-fold better than CAP/WT-actin. Actin in complex with full-length CAP2 is predominately ATP-bound. These interactions suggest an inhibition model whereby CAP/KAc-actin serves as a bridge between INF2 DID and DAD. In U2OS cells, INF2 is 90-fold and 5-fold less abundant than CAP1 and CAP2, respectively, suggesting that there is sufficient CAP for full INF2 inhibition.
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16
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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.
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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
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17
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Mechanism of synergistic actin filament pointed end depolymerization by cyclase-associated protein and cofilin. Nat Commun 2019; 10:5320. [PMID: 31757941 PMCID: PMC6876575 DOI: 10.1038/s41467-019-13213-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/25/2019] [Indexed: 12/02/2022] Open
Abstract
The ability of cells to generate forces through actin filament turnover was an early adaptation in evolution. While much is known about how actin filaments grow, mechanisms of their disassembly are incompletely understood. The best-characterized actin disassembly factors are the cofilin family proteins, which increase cytoskeletal dynamics by severing actin filaments. However, the mechanism by which severed actin filaments are recycled back to monomeric form has remained enigmatic. We report that cyclase-associated-protein (CAP) works in synergy with cofilin to accelerate actin filament depolymerization by nearly 100-fold. Structural work uncovers the molecular mechanism by which CAP interacts with actin filament pointed end to destabilize the interface between terminal actin subunits, and subsequently recycles the newly-depolymerized actin monomer for the next round of filament assembly. These findings establish CAP as a molecular machine promoting rapid actin filament depolymerization and monomer recycling, and explain why CAP is critical for actin-dependent processes in all eukaryotes. The cofilin family proteins are actin disassembly factors but the disassembly mechanism is poorly understood. Here authors show that cyclase-associated-protein (CAP) works in synergy with cofilin to accelerate actin filament depolymerization by nearly 100-fold and reveal how CAP destabilizes the interface between terminal actin subunits.
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18
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Shekhar S, Chung J, Kondev J, Gelles J, Goode BL. Synergy between Cyclase-associated protein and Cofilin accelerates actin filament depolymerization by two orders of magnitude. Nat Commun 2019; 10:5319. [PMID: 31757952 PMCID: PMC6876572 DOI: 10.1038/s41467-019-13268-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/29/2019] [Indexed: 11/29/2022] Open
Abstract
Cellular actin networks can be rapidly disassembled and remodeled in a few seconds, yet in vitro actin filaments depolymerize slowly over minutes. The cellular mechanisms enabling actin to depolymerize this fast have so far remained obscure. Using microfluidics-assisted TIRF, we show that Cyclase-associated protein (CAP) and Cofilin synergize to processively depolymerize actin filament pointed ends at a rate 330-fold faster than spontaneous depolymerization. Single molecule imaging further reveals that hexameric CAP molecules interact with the pointed ends of Cofilin-decorated filaments for several seconds at a time, removing approximately 100 actin subunits per binding event. These findings establish a paradigm, in which a filament end-binding protein and a side-binding protein work in concert to control actin dynamics, and help explain how rapid actin network depolymerization is achieved in cells.
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Affiliation(s)
- Shashank Shekhar
- Department of Biology, Brandeis University, Waltham, MA, 02454, USA
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
- Department of Biochemistry, Brandeis University, Waltham, MA, 02454, USA
| | - Johnson Chung
- Department of Biochemistry, Brandeis University, Waltham, MA, 02454, USA
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA, 02454, USA.
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA, 02454, USA.
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19
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Purde V, Busch F, Kudryashova E, Wysocki VH, Kudryashov DS. Oligomerization Affects the Ability of Human Cyclase-Associated Proteins 1 and 2 to Promote Actin Severing by Cofilins. Int J Mol Sci 2019; 20:E5647. [PMID: 31718088 PMCID: PMC6888645 DOI: 10.3390/ijms20225647] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 02/03/2023] Open
Abstract
Actin-depolymerizing factor (ADF)/cofilins accelerate actin turnover by severing aged actin filaments and promoting the dissociation of actin subunits. In the cell, ADF/cofilins are assisted by other proteins, among which cyclase-associated proteins 1 and 2 (CAP1,2) are particularly important. The N-terminal half of CAP has been shown to promote actin filament dynamics by enhancing ADF-/cofilin-mediated actin severing, while the central and C-terminal domains are involved in recharging the depolymerized ADP-G-actin/cofilin complexes with ATP and profilin. We analyzed the ability of the N-terminal fragments of human CAP1 and CAP2 to assist human isoforms of "muscle" (CFL2) and "non-muscle" (CFL1) cofilins in accelerating actin dynamics. By conducting bulk actin depolymerization assays and monitoring single-filament severing by total internal reflection fluorescence (TIRF) microscopy, we found that the N-terminal domains of both isoforms enhanced cofilin-mediated severing and depolymerization at similar rates. According to our analytical sedimentation and native mass spectrometry data, the N-terminal recombinant fragments of both human CAP isoforms form tetramers. Replacement of the original oligomerization domain of CAPs with artificial coiled-coil sequences of known oligomerization patterns showed that the activity of the proteins is directly proportional to the stoichiometry of their oligomerization; i.e., tetramers and trimers are more potent than dimers, which are more effective than monomers. Along with higher binding affinities of the higher-order oligomers to actin, this observation suggests that the mechanism of actin severing and depolymerization involves simultaneous or consequent and coordinated binding of more than one N-CAP domain to F-actin/cofilin complexes.
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Affiliation(s)
- Vedud Purde
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Florian Busch
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
| | - Vicki H. Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Resource for Native MS-Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
- Campus Chemical Instrument Center, Mass Spectrometry and Proteomics, The Ohio State University, Columbus, OH 43210, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (V.P.); (F.B.); (E.K.); (V.H.W.)
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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20
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Hunt A, Russell MRG, Wagener J, Kent R, Carmeille R, Peddie CJ, Collinson L, Heaslip A, Ward GE, Treeck M. Differential requirements for cyclase-associated protein (CAP) in actin-dependent processes of Toxoplasma gondii. eLife 2019; 8:e50598. [PMID: 31577230 PMCID: PMC6785269 DOI: 10.7554/elife.50598] [Citation(s) in RCA: 25] [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: 07/30/2019] [Accepted: 09/26/2019] [Indexed: 12/26/2022] Open
Abstract
Toxoplasma gondii contains a limited subset of actin binding proteins. Here we show that the putative actin regulator cyclase-associated protein (CAP) is present in two different isoforms and its deletion leads to significant defects in some but not all actin dependent processes. We observe defects in cell-cell communication, daughter cell orientation and the juxtanuclear accumulation of actin, but only modest defects in synchronicity of division and no defect in the replication of the apicoplast. 3D electron microscopy reveals that loss of CAP results in a defect in formation of a normal central residual body, but parasites remain connected within the vacuole. This dissociates synchronicity of division and parasite rosetting and reveals that establishment and maintenance of the residual body may be more complex than previously thought. These results highlight the different spatial requirements for F-actin regulation in Toxoplasma which appear to be achieved by partially overlapping functions of actin regulators.
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Affiliation(s)
- Alex Hunt
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | | | - Jeanette Wagener
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Robyn Kent
- Department of Microbiology and Molecular GeneticsUniversity of Vermont Larner College of MedicineBurlingtonUnited States
| | - Romain Carmeille
- Department of Molecular and Cell BiologyUniversity of ConnecticutStorrsUnited States
| | - Christopher J Peddie
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick InstituteLondonUnited Kingdom
| | - Aoife Heaslip
- Department of Molecular and Cell BiologyUniversity of ConnecticutStorrsUnited States
| | - Gary E Ward
- Department of Microbiology and Molecular GeneticsUniversity of Vermont Larner College of MedicineBurlingtonUnited States
| | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick InstituteLondonUnited Kingdom
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21
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Oda T, Takeda S, Narita A, Maéda Y. Structural Polymorphism of Actin. J Mol Biol 2019; 431:3217-3228. [DOI: 10.1016/j.jmb.2019.05.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/17/2019] [Accepted: 05/30/2019] [Indexed: 12/18/2022]
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22
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Mechanism of CAP1-mediated apical actin polymerization in pollen tubes. Proc Natl Acad Sci U S A 2019; 116:12084-12093. [PMID: 31123151 DOI: 10.1073/pnas.1821639116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Srv2p/CAP1 is an essential regulator of actin turnover, but its exact function in regulating actin polymerization, particularly the contribution of its actin nucleotide exchange activity, remains incompletely understood. We found that, although Arabidopsis CAP1 is distributed uniformly in the cytoplasm, its loss of function has differential effects on the actin cytoskeleton within different regions of the pollen tube. Specifically, the F-actin level increases in the shank but decreases in the apical region of cap1 pollen tubes. The reduction in apical F-actin results mainly from impaired polymerization of membrane-originated actin within cap1 pollen tubes. The actin nucleotide exchange activity of CAP1 is involved in apical actin polymerization. CAP1 acts synergistically with pollen ADF and profilin to promote actin turnover in vitro, and it can overcome the inhibitory effects of ADF and synergize with profilin to promote actin nucleotide exchange. Consistent with its role as a shuttle molecule between ADF and profilin, the cytosolic concentration of CAP1 is much lower than that of ADF and profilin in pollen. Thus, CAP1 synergizes with ADF and profilin to drive actin turnover in pollen and promote apical actin polymerization in pollen tubes in a manner that involves its actin nucleotide exchange activity.
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23
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24
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Li L, Zhang S, Liu X, Yu R, Li X, Liu M, Zhang H, Zheng X, Wang P, Zhang Z. Magnaporthe oryzae Abp1, a MoArk1 Kinase-Interacting Actin Binding Protein, Links Actin Cytoskeleton Regulation to Growth, Endocytosis, and Pathogenesis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:437-451. [PMID: 30451565 DOI: 10.1094/mpmi-10-18-0281-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The actin cytoskeleton and actin-coupled endocytosis are conserved cellular processes required for the normal growth and pathogenesis of the rice blast fungus Magnaporthe oryzae. We have previously shown that actin regulating kinase MoArk1 regulates actin dynamics and endocytosis to play a key role in virulence of the fungus. To understand the underlying mechanism, we have characterized the actin-binding protein MoAbp1 that interacts with MoArk1 from M. oryzae. The ΔMoabp1 mutant exhibited delayed endocytosis and defects in growth, host penetration, and invasive growth. Consistent with its putative function associated with actin-binding, MoAbp1 regulates the localization of actin patches and plays a role in MoArk1 phosphorylation. In addition, MoAbp1 interacts with MoCap (adenylyl cyclase-associated protein) affecting its normal patch localization pattern and the actin protein MoAct1 through its conserved domains. Taken together, our results support a notion that MoAbp1 functions as a protein scaffold linking MoArk1, MoCap1, and MoAct1 to regulate actin cytoskeleton dynamics critical in growth and pathogenicity of the blast fungus.
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Affiliation(s)
- Lianwei Li
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Shengpei Zhang
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Xinyu Liu
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Rui Yu
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Xinrui Li
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Muxing Liu
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Haifeng Zhang
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Xiaobo Zheng
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
| | - Ping Wang
- 2 Departments of Pediatrics, and Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, U.S.A
| | - Zhengguang Zhang
- 1 Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China; and
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25
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Chae CW, Kwon YW. Cell signaling and biological pathway in cardiovascular diseases. Arch Pharm Res 2019; 42:195-205. [PMID: 30877558 DOI: 10.1007/s12272-019-01141-0] [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: 11/30/2018] [Accepted: 03/04/2019] [Indexed: 12/12/2022]
Abstract
Currently, coronary artery disease accounts for a large proportion of deaths occurring worldwide. Damage to the heart muscle over a short period of time leads to myocardial infarction (MI). The biological mechanisms of atherosclerosis, one of the causes of MI, have been well studied. Resistin, a type of adipokine, is closely associated with intravascular level of low-density lipoprotein cholesterol and augmentation of the expression of adhesion molecules in endothelial cells. Therefore, resistin, which is highly associated with inflammation, can progress into coronary artery disease. Adenylyl cyclase associated protein 1, a binding partner of resistin, also plays an important role in inducing pro-inflammatory cytokines. The induction of these cytokines can aggravate atherosclerosis by promoting severe plaque rupture of the lesion site. Recently, drugs, such as statins that can inhibit inflammation have been extensively studied. The development of effective new drugs that can directly or indirectly block pro-inflammatory cytokines may have a great potential in the treatment of coronary artery disease in the future.
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Affiliation(s)
- Cheong-Whan Chae
- National Research Laboratory for Stem Cell Niche, Center for Medical Innovation, Seoul National University Hospital, Seoul, 110-744, Republic of Korea
| | - Yoo-Wook Kwon
- National Research Laboratory for Stem Cell Niche, Center for Medical Innovation, Seoul National University Hospital, Seoul, 110-744, Republic of Korea. .,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea. .,Department of Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
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Srv2 Is a Pro-fission Factor that Modulates Yeast Mitochondrial Morphology and Respiration by Regulating Actin Assembly. iScience 2018; 11:305-317. [PMID: 30639852 PMCID: PMC6327880 DOI: 10.1016/j.isci.2018.12.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 09/16/2018] [Accepted: 12/20/2018] [Indexed: 01/04/2023] Open
Abstract
Dynamic processes such as fusion, fission, and trafficking are important in the regulation of cellular organelles, with an abundant literature focused on mitochondria. Mitochondrial dynamics not only help shape its network within cells but also are involved in the modulation of respiration and integrity. Disruptions of mitochondrial dynamics are associated with neurodegenerative disorders. Although proteins that directly bind mitochondria to promote membrane fusion/fission have been studied intensively, machineries that regulate dynamic mitochondrial processes remain to be explored. We have identified an interaction between the mitochondrial fission GTPase Dnm1/DRP1 and the actin-regulatory protein Srv2/CAP at mitochondria. Deletion of Srv2 causes elongated-hyperfused mitochondria and reduces the reserved respiration capacity in yeast cells. Our results further demonstrate that the irregular network morphology in Δsrv2 cells derives from disrupted actin assembly at mitochondria. We suggest that Srv2 functions as a pro-fission factor in shaping mitochondrial dynamics and regulating activity through its actin-regulatory effects. Srv2 interacts with fission protein Dnm1 on mitochondria in yeast cells Srv2 deletion causes an irregular, hyperfused-elongated mitochondrial network The irregular network derives from loss of Srv2-mediated actin assembly at mitochondria Srv2 modulates both mitochondrial dynamics and activity
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27
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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.
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Affiliation(s)
- Henry N. Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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28
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Kotila T, Kogan K, Enkavi G, Guo S, Vattulainen I, Goode BL, Lappalainen P. Structural basis of actin monomer re-charging by cyclase-associated protein. Nat Commun 2018; 9:1892. [PMID: 29760438 PMCID: PMC5951797 DOI: 10.1038/s41467-018-04231-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/13/2018] [Indexed: 11/10/2022] Open
Abstract
Actin polymerization powers key cellular processes, including motility, morphogenesis, and endocytosis. The actin turnover cycle depends critically on "re-charging" of ADP-actin monomers with ATP, but whether this reaction requires dedicated proteins in cells, and the underlying mechanism, have remained elusive. Here we report that nucleotide exchange catalyzed by the ubiquitous cytoskeletal regulator cyclase-associated protein (CAP) is critical for actin-based processes in vivo. We determine the structure of the CAP-actin complex, which reveals that nucleotide exchange occurs in a compact, sandwich-like complex formed between the dimeric actin-binding domain of CAP and two ADP-actin monomers. In the crystal structure, the C-terminal tail of CAP associates with the nucleotide-sensing region of actin, and this interaction is required for rapid re-charging of actin by both yeast and mammalian CAPs. These data uncover the conserved structural basis and biological role of protein-catalyzed re-charging of actin monomers.
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Affiliation(s)
- Tommi Kotila
- Institute of Biotechnology, University of Helsinki, 00014, Helsinki, Finland
| | - Konstantin Kogan
- Institute of Biotechnology, University of Helsinki, 00014, Helsinki, Finland
| | - Giray Enkavi
- Department of Physics, University of Helsinki, 00014, Helsinki, Finland
| | - Siyang Guo
- Department of Biology, Brandeis University, Waltham, MA, 02453, USA
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, 00014, Helsinki, Finland
- Laboratory of Physics, Tampere University of Technology, 33101, Tampere, Finland
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA, 02453, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, 00014, Helsinki, Finland.
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29
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Kakurina GV, Kolegova ES, Kondakova IV. Adenylyl Cyclase-Associated Protein 1: Structure, Regulation, and Participation in Cellular Processes. BIOCHEMISTRY (MOSCOW) 2018. [PMID: 29534668 DOI: 10.1134/s0006297918010066] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This review summarizes information available to date about the structural organization, regulation of functional activity of adenylyl cyclase-associated protein 1 (CAP1), and its participation in cellular processes. Numerous data are generalized on the role of CAP1 in the regulation of actin cytoskeleton and its interactions with many actin-binding proteins. Attention is drawn to the similarity of the structure of CAP1 and its contribution to the remodeling of actin filaments in prokaryotes and eukaryotes, as well as to the difference in the interaction of CAP1 with adenylyl cyclase in these cells. In addition, we discuss the participation of CAP1 in various pathological processes.
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Affiliation(s)
- G V Kakurina
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, 634050, Russia.
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30
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Iwase S, Ono S. Conserved hydrophobic residues in the CARP/β-sheet domain of cyclase-associated protein are involved in actin monomer regulation. Cytoskeleton (Hoboken) 2017; 74:343-355. [PMID: 28696540 DOI: 10.1002/cm.21385] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/05/2017] [Accepted: 07/07/2017] [Indexed: 01/12/2023]
Abstract
Cyclase-associated protein (CAP) is a multidomain protein that promotes actin filament dynamics. The C-terminal region of CAP contains a CAP and X-linked retinitis pigmentosa 2 protein (CARP) domain (or a β-sheet domain), which binds to actin monomer and is essential for enhancing exchange of actin-bound nucleotides. However, how the CARP domain binds to actin is not clearly understood. Here, we report that conserved hydrophobic residues in the CARP domain play important roles in the function of CAP to regulate actin dynamics. Single mutations of three conserved surface-exposed hydrophobic residues in the CARP domain of CAS-2, a Caenorhabditis elegans CAP, significantly reduce its binding to actin monomers and suppress its nucleotide exchange activity on actin. As a result, these mutants are weaker than wild-type to compete with ADF/cofilin to promote recycling of actin monomers for polymerization. A double mutation (V367A/I373A) eliminates these actin-regulatory functions of CAS-2. These hydrophobic residues and previously identified functional residues are scattered on a concave β-sheet of the CARP domain, suggesting that a wide area of the β-sheet is involved in binding to actin. These observations suggest that the CARP domain of CAP binds to actin in a distinct manner from other known actin-binding proteins.
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Affiliation(s)
- Shohei Iwase
- Department of Pathology, Winship Cancer Institute, Emory University, Atlanta, Georgia.,Department of Cell Biology, Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Shoichiro Ono
- Department of Pathology, Winship Cancer Institute, Emory University, Atlanta, Georgia.,Department of Cell Biology, Winship Cancer Institute, Emory University, Atlanta, Georgia
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31
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The C-terminal dimerization motif of cyclase-associated protein is essential for actin monomer regulation. Biochem J 2016; 473:4427-4441. [PMID: 27729544 DOI: 10.1042/bcj20160329] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 09/22/2016] [Accepted: 10/11/2016] [Indexed: 12/31/2022]
Abstract
Cyclase-associated protein (CAP) is a conserved actin-regulatory protein that functions together with actin depolymerizing factor (ADF)/cofilin to enhance actin filament dynamics. CAP has multiple functional domains, and the function to regulate actin monomers is carried out by its C-terminal half containing a Wiskott-Aldrich Syndrome protein homology 2 (WH2) domain, a CAP and X-linked retinitis pigmentosa 2 (CARP) domain, and a dimerization motif. WH2 and CARP are implicated in binding to actin monomers and important for enhancing filament turnover. However, the role of the dimerization motif is unknown. Here, we investigated the function of the dimerization motif of CAS-2, a CAP isoform in the nematode Caenorhabditis elegans, in actin monomer regulation. CAS-2 promotes ATP-dependent recycling of ADF/cofilin-bound actin monomers for polymerization by enhancing exchange of actin-bound nucleotides. The C-terminal half of CAS-2 (CAS-2C) has nearly as strong activity as full-length CAS-2. Maltose-binding protein (MBP)-tagged CAS-2C is a dimer. However, MBP-CAS-2C with a truncation of either one or two C-terminal β-strands is monomeric. Truncations of the dimerization motif in MBP-CAS-2C nearly completely abolish its activity to sequester actin monomers from polymerization and enhance nucleotide exchange on actin monomers. As a result, these CAS-2C variants, also in the context of full-length CAS-2, fail to compete with ADF/cofilin to release actin monomers for polymerization. CAS-2C variants lacking the dimerization motif exhibit enhanced binding to actin filaments, which is mediated by WH2. Taken together, these results suggest that the evolutionarily conserved dimerization motif of CAP is essential for its C-terminal region to exert the actin monomer-specific regulatory function.
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32
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Kumar A, Paeger L, Kosmas K, Kloppenburg P, Noegel AA, Peche VS. Neuronal Actin Dynamics, Spine Density and Neuronal Dendritic Complexity Are Regulated by CAP2. Front Cell Neurosci 2016; 10:180. [PMID: 27507934 PMCID: PMC4960234 DOI: 10.3389/fncel.2016.00180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/04/2016] [Indexed: 11/29/2022] Open
Abstract
Actin remodeling is crucial for dendritic spine development, morphology and density. CAP2 is a regulator of actin dynamics through sequestering G-actin and severing F-actin. In a mouse model, ablation of CAP2 leads to cardiovascular defects and delayed wound healing. This report investigates the role of CAP2 in the brain using Cap2gt/gt mice. Dendritic complexity, the number and morphology of dendritic spines were altered in Cap2gt/gt with increased number of excitatory synapses. This was accompanied by increased F-actin content and F-actin accumulation in cultured Cap2gt/gt neurons. Moreover, reduced surface GluA1 was observed in mutant neurons under basal condition and after induction of chemical LTP. Additionally, we show an interaction between CAP2 and n-cofilin, presumably mediated through the C-terminal domain of CAP2 and dependent on cofilin Ser3 phosphorylation. In vivo, the consequences of this interaction were altered phosphorylated cofilin levels and formation of cofilin aggregates in the neurons. Thus, our studies identify a novel role of CAP2 in neuronal development and neuronal actin dynamics.
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Affiliation(s)
- Atul Kumar
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
| | - Lars Paeger
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany; Biocenter, Institute for Zoology, University of Cologne, CologneGermany
| | - Kosmas Kosmas
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
| | - Peter Kloppenburg
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany; Biocenter, Institute for Zoology, University of Cologne, CologneGermany
| | - Angelika A Noegel
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
| | - Vivek S Peche
- Institute of Biochemistry I, Medical Faculty, University of Cologne, CologneGermany; Center for Molecular Medicine Cologne, University of Cologne, CologneGermany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, CologneGermany
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33
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Tariq N, Basharat Z, Butt S, Baig DN. Distribution analysis of profilin isoforms at transcript resolution with mRNA-seq and secondary structure in various organs of Rattus norvegicus. Gene 2016; 589:49-55. [PMID: 27185630 DOI: 10.1016/j.gene.2016.05.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 11/15/2022]
Abstract
Profilin (Pfn) is an actin binding protein, ubiquitously found in mammals and is essential for the actin polymerization in cells. In brain, it plays a pivotal role in neurogenesis and synapse formation by interacting with various proteins. Four Pfn isoforms have been identified in mammals. This study presents the identification and transcriptional expression of various Pfn isoforms (Pfn1, Pfn2, Pfn3 and Pfn4) in brain, heart, kidney, liver, and muscle and testis of Rattus norvegicus. Organs have been classified into groups based on some similarities. Group I includes brain and testis, Group II includes skeletal muscle and heart, while Group III includes kidney and liver. Pfn1 has been identified in all groups, Pfn2 and Pfn3 have been identified in group I, group III and in one organ (skeletal muscle) of group II. To the best of the authors knowledge, no report of Pfn1 and Pfn2 presence in testis, Pfn3 in brain, liver and skeletal muscle, Pfn4 in kidney and skeletal muscle exists to date. Transcriptional expression showed variations among expression level of different Pfn isoforms in various organs with respect to the control gene GADPH. We hypothesize that this could be attributed to profilin isoform specific mRNA structure and corresponding motifs, which generally contribute to similar or varied decay rates, cellular localization, post transcriptional regulation pattern and ligand binding.
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Affiliation(s)
- Naila Tariq
- Department of Biological sciences, Forman Christian College (A Chartered University), 54600 Lahore, Pakistan
| | - Zarrin Basharat
- Department of Environmental Sciences, Fatima Jinnah Women University, 46000 Rawalpindi, Pakistan
| | - Saba Butt
- Department of Biological sciences, Forman Christian College (A Chartered University), 54600 Lahore, Pakistan
| | - Deeba Noreen Baig
- Department of Biological sciences, Forman Christian College (A Chartered University), 54600 Lahore, Pakistan
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34
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Lehtimäki J, Hakala M, Lappalainen P. Actin Filament Structures in Migrating Cells. Handb Exp Pharmacol 2016; 235:123-152. [PMID: 27469496 DOI: 10.1007/164_2016_28] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell migration is necessary for several developmental processes in multicellular organisms. Furthermore, many physiological processes such as wound healing and immunological events in adult animals are dependent on cell migration. Consequently, defects in cell migration are linked to various diseases including immunological disorders as well as cancer progression and metastasis formation. Cell migration is driven by specific protrusive and contractile actin filament structures, but the types and relative contributions of these actin filament arrays vary depending on the cell type and the environment of the cell. In this chapter, we introduce the most important actin filament structures that contribute to mesenchymal and amoeboid cell migration modes and discuss the mechanisms by which the assembly and turnover of these structures are controlled by various actin-binding proteins.
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Affiliation(s)
- Jaakko Lehtimäki
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Markku Hakala
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, 56, 00014, Helsinki, Finland.
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35
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High-speed depolymerization at actin filament ends jointly catalysed by Twinfilin and Srv2/CAP. Nat Cell Biol 2015; 17:1504-11. [PMID: 26458246 PMCID: PMC4808055 DOI: 10.1038/ncb3252] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/11/2015] [Indexed: 12/16/2022]
Abstract
Purified actin filaments depolymerize slowly, and cytosolic conditions strongly favor actin assembly over disassembly, which has left our understanding of how actin filaments are rapidly turned over in vivo incomplete 1,2. One mechanism for driving filament disassembly is severing by factors such as Cofilin. However, even after severing, pointed end depolymerization remains slow and unable to fully account for observed rates of actin filament turnover in vivo. Here we describe a mechanism by which Twinfilin and Cyclase-associated protein work in concert to accelerate depolymerization of actin filaments by 3-fold and 17-fold at their barbed and pointed ends, respectively. This mechanism occurs even under assembly conditions, allowing reconstitution and direct visualization of individual filaments undergoing tunable, accelerated treadmilling. Further, we use specific mutations to demonstrate that this activity is critical for Twinfilin function in vivo. These findings fill a major gap in our knowledge of mechanisms, and suggest that depolymerization and severing may be deployed separately or together to control the dynamics and architecture of distinct actin networks.
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36
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Ydenberg CA, Johnston A, Weinstein J, Bellavance D, Jansen S, Goode BL. Combinatorial genetic analysis of a network of actin disassembly-promoting factors. Cytoskeleton (Hoboken) 2015; 72:349-61. [PMID: 26147656 PMCID: PMC5014199 DOI: 10.1002/cm.21231] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022]
Abstract
The patterning of actin cytoskeleton structures in vivo is a product of spatially and temporally regulated polymer assembly balanced by polymer disassembly. While in recent years our understanding of actin assembly mechanisms has grown immensely, our knowledge of actin disassembly machinery and mechanisms has remained comparatively sparse. Saccharomyces cerevisiae is an ideal system to tackle this problem, both because of its amenabilities to genetic manipulation and live‐cell imaging and because only a single gene encodes each of the core disassembly factors: cofilin (COF1), Srv2/CAP (SRV2), Aip1 (AIP1), GMF (GMF1/AIM7), coronin (CRN1), and twinfilin (TWF1). Among these six factors, only the functions of cofilin are essential and have been well defined. Here, we investigated the functions of the nonessential actin disassembly factors by performing genetic and live‐cell imaging analyses on a combinatorial set of isogenic single, double, triple, and quadruple mutants in S. cerevisiae. Our results show that each disassembly factor makes an important contribution to cell viability, actin organization, and endocytosis. Further, our data reveal new relationships among these factors, providing insights into how they work together to orchestrate actin turnover. Finally, we observe specific combinations of mutations that are lethal, e.g., srv2Δ aip1Δ and srv2Δ crn1Δ twf1Δ, demonstrating that while cofilin is essential, it is not sufficient in vivo, and that combinations of the other disassembly factors perform vital functions. © 2015 The Authors. Cytoskeleton Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Casey A Ydenberg
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Adam Johnston
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Jaclyn Weinstein
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Danielle Bellavance
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
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Abstract
Endocytosis, the process whereby the plasma membrane invaginates to form vesicles, is essential for bringing many substances into the cell and for membrane turnover. The mechanism driving clathrin-mediated endocytosis (CME) involves > 50 different protein components assembling at a single location on the plasma membrane in a temporally ordered and hierarchal pathway. These proteins perform precisely choreographed steps that promote receptor recognition and clustering, membrane remodeling, and force-generating actin-filament assembly and turnover to drive membrane invagination and vesicle scission. Many critical aspects of the CME mechanism are conserved from yeast to mammals and were first elucidated in yeast, demonstrating that it is a powerful system for studying endocytosis. In this review, we describe our current mechanistic understanding of each step in the process of yeast CME, and the essential roles played by actin polymerization at these sites, while providing a historical perspective of how the landscape has changed since the preceding version of the YeastBook was published 17 years ago (1997). Finally, we discuss the key unresolved issues and where future studies might be headed.
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Affiliation(s)
- Bruce L Goode
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Julian A Eskin
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Beverly Wendland
- The Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218
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38
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Jansen S, Collins A, Golden L, Sokolova O, Goode BL. Structure and mechanism of mouse cyclase-associated protein (CAP1) in regulating actin dynamics. J Biol Chem 2014; 289:30732-30742. [PMID: 25228691 DOI: 10.1074/jbc.m114.601765] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Srv2/CAP is a conserved actin-binding protein with important roles in driving cellular actin dynamics in diverse animal, fungal, and plant species. However, there have been conflicting reports about whether the activities of Srv2/CAP are conserved, particularly between yeast and mammalian homologs. Yeast Srv2 has two distinct functions in actin turnover: its hexameric N-terminal-half enhances cofilin-mediated severing of filaments, while its C-terminal-half catalyzes dissociation of cofilin from ADP-actin monomers and stimulates nucleotide exchange. Here, we dissected the structure and function of mouse CAP1 to better understand its mechanistic relationship to yeast Srv2. Although CAP1 has a shorter N-terminal oligomerization sequence compared with Srv2, we find that the N-terminal-half of CAP1 (N-CAP1) forms hexameric structures with six protrusions, similar to N-Srv2. Further, N-CAP1 autonomously binds to F-actin and decorates the sides and ends of filaments, altering F-actin structure and enhancing cofilin-mediated severing. These activities depend on conserved surface residues on the helical-folded domain. Moreover, N-CAP1 enhances yeast cofilin-mediated severing, and conversely, yeast N-Srv2 enhances human cofilin-mediated severing, highlighting the mechanistic conservation between yeast and mammals. Further, we demonstrate that the C-terminal actin-binding β-sheet domain of CAP1 is sufficient to catalyze nucleotide-exchange of ADP-actin monomers, while in the presence of cofilin this activity additionally requires the WH2 domain. Thus, the structures, activities, and mechanisms of mouse and yeast Srv2/CAP homologs are remarkably well conserved, suggesting that the same activities and mechanisms underlie many of the diverse actin-based functions ascribed to Srv2/CAP homologs in different organisms.
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Affiliation(s)
- Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454 and
| | - Agnieszka Collins
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454 and
| | - Leslie Golden
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454 and
| | - Olga Sokolova
- Faculty of Biology, Moscow State University, GSP-1, 1 Leninskie Gory, Building 12, 119991 Moscow, Russia
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454 and.
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39
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Ono S. The role of cyclase-associated protein in regulating actin filament dynamics - more than a monomer-sequestration factor. J Cell Sci 2014; 126:3249-58. [PMID: 23908377 DOI: 10.1242/jcs.128231] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dynamic reorganization of the actin cytoskeleton is fundamental to a number of cell biological events. A variety of actin-regulatory proteins modulate polymerization and depolymerization of actin and contribute to actin cytoskeletal reorganization. Cyclase-associated protein (CAP) is a conserved actin-monomer-binding protein that has been studied for over 20 years. Early studies have shown that CAP sequesters actin monomers; recent studies, however, have revealed more active roles of CAP in actin filament dynamics. CAP enhances the recharging of actin monomers with ATP antagonistically to ADF/cofilin, and also promotes the severing of actin filaments in cooperation with ADF/cofilin. Self-oligomerization and binding to other proteins regulate activities and localization of CAP. CAP has crucial roles in cell signaling, development, vesicle trafficking, cell migration and muscle sarcomere assembly. This Commentary discusses the recent advances in our understanding of the functions of CAP and its implications as an important regulator of actin cytoskeletal dynamics, which are involved in various cellular activities.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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40
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Chaudhry F, Jansen S, Little K, Suarez C, Boujemaa-Paterski R, Blanchoin L, Goode BL. Autonomous and in trans functions for the two halves of Srv2/CAP in promoting actin turnover. Cytoskeleton (Hoboken) 2014; 71:351-360. [PMID: 24616256 DOI: 10.1002/cm.21170] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 01/06/2023]
Abstract
Recent evidence has suggested that Srv2/CAP (cyclase-associated protein) has two distinct functional roles in regulating actin turnover, with its N-terminus enhancing cofilin-mediated severing of actin filaments and its C-terminus catalyzing actin monomer recycling. However, it has remained unclear to what degree these two activities are coordinated by being linked in one molecule, or whether they can function autonomously. To address this, we physically divided the protein into two separate halves, N-Srv2 and C-Srv2, and asked whether they are able to function in trans both in living cells and in reconstituted assays for F-actin turnover and actin-based motility. Remarkably, in F-actin turnover assays the stimulatory effects of N-Srv2 and C-Srv2 functioning in trans were quantitatively similar to those of intact full-length Srv2. Further, in bead motility assays and in vivo, the fragments again functioned in trans, although not with the full effectiveness of intact Srv2. From these data, we conclude that the functions of the two halves of Srv2/CAP are largely autonomous, although their linkage improves coordination of the two functions in specific settings, possibly explaining why the linkage is conserved across distant plant, animal, and fungal species.
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Affiliation(s)
- Faisal Chaudhry
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A
| | - Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A
| | - Kristin Little
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A
| | - Cristian Suarez
- Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE
| | - Rajaa Boujemaa-Paterski
- Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE
| | - Laurent Blanchoin
- Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A
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Talman AM, Chong R, Chia J, Svitkina T, Agaisse H. Actin network disassembly powers dissemination of Listeria monocytogenes. J Cell Sci 2014; 127:240-9. [PMID: 24155331 PMCID: PMC3874788 DOI: 10.1242/jcs.140038] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 09/10/2013] [Indexed: 11/20/2022] Open
Abstract
Several bacterial pathogens hijack the actin assembly machinery and display intracellular motility in the cytosol of infected cells. At the cell cortex, intracellular motility leads to bacterial dissemination through formation of plasma membrane protrusions that resolve into vacuoles in adjacent cells. Here, we uncover a crucial role for actin network disassembly in dissemination of Listeria monocytogenes. We found that defects in the disassembly machinery decreased the rate of actin tail turnover but did not affect the velocity of the bacteria in the cytosol. By contrast, defects in the disassembly machinery had a dramatic impact on bacterial dissemination. Our results suggest a model of L. monocytogenes dissemination in which the disassembly machinery, through local recycling of the actin network in protrusions, fuels continuous actin assembly at the bacterial pole and concurrently exhausts cytoskeleton components from the network distal to the bacterium, which enables membrane apposition and resolution of protrusions into vacuoles.
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Affiliation(s)
- Arthur M. Talman
- Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06536, USA
| | - Ryan Chong
- Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06536, USA
| | - Jonathan Chia
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hervé Agaisse
- Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06536, USA
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42
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Guardians of the actin monomer. Eur J Cell Biol 2013; 92:316-32. [DOI: 10.1016/j.ejcb.2013.10.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/03/2013] [Accepted: 10/23/2013] [Indexed: 11/22/2022] Open
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ATP-dependent regulation of actin monomer-filament equilibrium by cyclase-associated protein and ADF/cofilin. Biochem J 2013; 453:249-59. [PMID: 23672398 DOI: 10.1042/bj20130491] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
CAP (cyclase-associated protein) is a conserved regulator of actin filament dynamics. In the nematode Caenorhabditis elegans, CAS-1 is an isoform of CAP that is expressed in striated muscle and regulates sarcomeric actin assembly. In the present study, we report that CAS-2, a second CAP isoform in C. elegans, attenuates the actin-monomer-sequestering effect of ADF (actin depolymerizing factor)/cofilin to increase the steady-state levels of actin filaments in an ATP-dependent manner. CAS-2 binds to actin monomers without a strong preference for either ATP- or ADP-actin. CAS-2 strongly enhances the exchange of actin-bound nucleotides even in the presence of UNC-60A, a C. elegans ADF/cofilin that inhibits nucleotide exchange. UNC-60A induces the depolymerization of actin filaments and sequesters actin monomers, whereas CAS-2 reverses the monomer-sequestering effect of UNC-60A in the presence of ATP, but not in the presence of only ADP or the absence of ATP or ADP. A 1:100 molar ratio of CAS-2 to UNC-60A is sufficient to increase actin filaments. CAS-2 has two independent actin-binding sites in its N- and C-terminal halves, and the C-terminal half is necessary and sufficient for the observed activities of the full-length CAS-2. These results suggest that CAS-2 (CAP) and UNC-60A (ADF/cofilin) are important in the ATP-dependent regulation of the actin monomer-filament equilibrium.
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Zhou GL, Zhang H, Field J. Mammalian CAP (Cyclase-associated protein) in the world of cell migration: Roles in actin filament dynamics and beyond. Cell Adh Migr 2013; 8:55-9. [PMID: 24429384 DOI: 10.4161/cam.27479] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cell migration is essential for a variety of fundamental biological processes such as embryonic development, wound healing, and immune response. Aberrant cell migration also underlies pathological conditions such as cancer metastasis, in which morphological transformation promotes spreading of cancer to new sites. Cell migration is driven by actin dynamics, which is the repeated cycling of monomeric actin (G-actin) into and out of filamentous actin (F-actin). CAP (Cyclase-associated protein, also called Srv2) is a conserved actin-regulatory protein, which is implicated in cell motility and the invasiveness of human cancers. It cooperates with another actin regulatory protein, cofilin, to accelerate actin dynamics. Hence, knockdown of CAP1 slows down actin filament turnover, which in most cells leads to reduced cell motility. However, depletion of CAP1 in HeLa cells, while causing reduction in dynamics, actually led to increased cell motility. The increases in motility are likely through activation of cell adhesion signals through an inside-out signaling. The potential to activate adhesion signaling competes with the negative effect of CAP1 depletion on actin dynamics, which would reduce cell migration. In this commentary, we provide a brief overview of the roles of mammalian CAP1 in cell migration, and highlight a likely mechanism underlying the activation of cell adhesion signaling and elevated motility caused by depletion of CAP1.
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Affiliation(s)
- Guo-Lei Zhou
- Department of Biological Sciences; Arkansas State University; State University, AR USA; Molecular Biosciences Program; Arkansas State University; State University, AR USA
| | - Haitao Zhang
- Department of Biological Sciences; Arkansas State University; State University, AR USA; Molecular Biosciences Program; Arkansas State University; State University, AR USA
| | - Jeffrey Field
- Department of Pharmacology; University of Pennsylvania Perelman School of Medicine; Philadelphia, PA USA
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Makkonen M, Bertling E, Chebotareva NA, Baum J, Lappalainen P. Mammalian and malaria parasite cyclase-associated proteins catalyze nucleotide exchange on G-actin through a conserved mechanism. J Biol Chem 2012. [PMID: 23184938 DOI: 10.1074/jbc.m112.435719] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclase-associated proteins (CAPs) are among the most highly conserved regulators of actin dynamics, being present in organisms from mammals to apicomplexan parasites. Yeast, plant, and mammalian CAPs are large multidomain proteins, which catalyze nucleotide exchange on actin monomers from ADP to ATP and recycle actin monomers from actin-depolymerizing factor (ADF)/cofilin for new rounds of filament assembly. However, the mechanism by which CAPs promote nucleotide exchange is not known. Furthermore, how apicomplexan CAPs, which lack many domains present in yeast and mammalian CAPs, contribute to actin dynamics is not understood. We show that, like yeast Srv2/CAP, mouse CAP1 interacts with ADF/cofilin and ADP-G-actin through its N-terminal α-helical and C-terminal β-strand domains, respectively. However, in the variation to yeast Srv2/CAP, mouse CAP1 has two adjacent profilin-binding sites, and it interacts with ATP-actin monomers with high affinity through its WH2 domain. Importantly, we revealed that the C-terminal β-sheet domain of mouse CAP1 is essential and sufficient for catalyzing nucleotide exchange on actin monomers, although the adjacent WH2 domain is not required for this function. Supporting these data, we show that the malaria parasite Plasmodium falciparum CAP, which is entirely composed of the β-sheet domain, efficiently promotes nucleotide exchange on actin monomers. Collectively, this study provides evidence that catalyzing nucleotide exchange on actin monomers via the β-sheet domain is the most highly conserved function of CAPs from mammals to apicomplexan parasites. Other functions, including interactions with profilin and ADF/cofilin, evolved in more complex organisms to adjust the specific role of CAPs in actin dynamics.
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Affiliation(s)
- Maarit Makkonen
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
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46
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Chaudhry F, Breitsprecher D, Little K, Sharov G, Sokolova O, Goode BL. Srv2/cyclase-associated protein forms hexameric shurikens that directly catalyze actin filament severing by cofilin. Mol Biol Cell 2012; 24:31-41. [PMID: 23135996 PMCID: PMC3530777 DOI: 10.1091/mbc.e12-08-0589] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Dual-color total internal reflection fluorescence microscopy revealed that the N-terminal half of Srv2 (N-Srv2) directly catalyzes severing of cofilin-decorated actin filaments. N-Srv2 formed novel six-bladed structures resembling ninja throwing stars (shurikens), and N-Srv2 activities were critical for actin organization in vivo and were lethal in combination with Aip1. Actin filament severing is critical for the dynamic turnover of cellular actin networks. Cofilin severs filaments, but additional factors may be required to increase severing efficiency in vivo. Srv2/cyclase-associated protein (CAP) is a widely expressed protein with a role in binding and recycling actin monomers ascribed to domains in its C-terminus (C-Srv2). In this paper, we report a new biochemical and cellular function for Srv2/CAP in directly catalyzing cofilin-mediated severing of filaments. This function is mediated by its N-terminal half (N-Srv2), and is physically and genetically separable from C-Srv2 activities. Using dual-color total internal reflection fluorescence microscopy, we determined that N-Srv2 stimulates filament disassembly by increasing the frequency of cofilin-mediated severing without affecting cofilin binding to filaments. Structural analysis shows that N-Srv2 forms novel hexameric star-shaped structures, and disrupting oligomerization impairs N-Srv2 activities and in vivo function. Further, genetic analysis shows that the combined activities of N-Srv2 and Aip1 are essential in vivo. These observations define a novel mechanism by which the combined activities of cofilin and Srv2/CAP lead to enhanced filament severing and support an emerging view that actin disassembly is controlled not by cofilin alone, but by a more complex set of factors working in concert.
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Affiliation(s)
- Faisal Chaudhry
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
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47
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Zhou X, Zhang H, Li G, Shaw B, Xu JR. The Cyclase-associated protein Cap1 is important for proper regulation of infection-related morphogenesis in Magnaporthe oryzae. PLoS Pathog 2012; 8:e1002911. [PMID: 22969430 PMCID: PMC3435248 DOI: 10.1371/journal.ppat.1002911] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 08/02/2012] [Indexed: 12/03/2022] Open
Abstract
Surface recognition and penetration are critical steps in the infection cycle of many plant pathogenic fungi. In Magnaporthe oryzae, cAMP signaling is involved in surface recognition and pathogenesis. Deletion of the MAC1 adenylate cyclase gene affected appressorium formation and plant infection. In this study, we used the affinity purification approach to identify proteins that are associated with Mac1 in vivo. One of the Mac1-interacting proteins is the adenylate cyclase-associated protein named Cap1. CAP genes are well-conserved in phytopathogenic fungi but none of them have been functionally characterized. Deletion of CAP1 blocked the effects of a dominant RAS2 allele and resulted in defects in invasive growth and a reduced intracellular cAMP level. The Δcap1 mutant was defective in germ tube growth, appressorium formation, and formation of typical blast lesions. Cap1-GFP had an actin-like localization pattern, localizing to the apical regions in vegetative hyphae, at the periphery of developing appressoria, and in circular structures at the base of mature appressoria. Interestingly, Cap1, similar to LifeAct, did not localize to the apical regions in invasive hyphae, suggesting that the apical actin cytoskeleton differs between vegetative and invasive hyphae. Domain deletion analysis indicated that the proline-rich region P2 but not the actin-binding domain (AB) of Cap1 was responsible for its subcellular localization. Nevertheless, the AB domain of Cap1 must be important for its function because CAP1ΔAB only partially rescued the Δcap1 mutant. Furthermore, exogenous cAMP induced the formation of appressorium-like structures in non-germinated conidia in CAP1ΔAB transformants. This novel observation suggested that AB domain deletion may result in overstimulation of appressorium formation by cAMP treatment. Overall, our results indicated that CAP1 is important for the activation of adenylate cyclase, appressorium morphogenesis, and plant infection in M. oryzae. CAP1 may also play a role in feedback inhibition of Ras2 signaling when Pmk1 is activated. In Magnaporthe oryzae, cAMP signaling is known to play an important role in surface recognition and plant penetration. The Mac1 adenylate cyclase is essential for plant infection. To better understand Mac1 activation mechanisms, in this study we used the affinity purification approach to identify proteins that are associated with Mac1 in vivo. One of the Mac1-interacting protein is the adenylate cyclase associated protein (CAP) encoded by the CAP1 gene. Results from our study indicated that Cap1 is important for Mac1 activation and plant infection in M. oryzae. The Δcap1 mutant was defective in germ tube growth and appressorium formation and failed to cause typical blast lesions. Like LifeAct, Cap1 localized to apical patches in vegetative hyphae but not in invasive hyphae. The P2 proline-rich region was important for Cap1 localization but the actin-binding domain played a role in feedback inhibition of Ras signaling. To our knowledge, functional characterization of CAP genes has not been reported in filamentous fungi. Our results indicate that CAP1 is important for regulating adenylate cyclase activities, appressorium morphogenesis, and plant infection. Further characterization of CAP1 will be important to better understand the interaction between cAMP signaling and the PMK1 pathway in M. oryzae.
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Affiliation(s)
- Xiaoying Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
| | - Haifeng Zhang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
| | - Guotian Li
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
- Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shanxi, China
| | - Brian Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, United States of America
| | - Jin-Rong Xu
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
- Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shanxi, China
- * E-mail:
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48
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Normoyle KPM, Brieher WM. Cyclase-associated protein (CAP) acts directly on F-actin to accelerate cofilin-mediated actin severing across the range of physiological pH. J Biol Chem 2012; 287:35722-35732. [PMID: 22904322 DOI: 10.1074/jbc.m112.396051] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Fast actin depolymerization is necessary for cells to rapidly reorganize actin filament networks. Utilizing a Listeria fluorescent actin comet tail assay to monitor actin disassembly rates, we observed that although a mixture of actin disassembly factors (cofilin, coronin, and actin-interacting protein 1 is sufficient to disassemble actin comet tails in the presence of physiological G-actin concentrations this mixture was insufficient to disassemble actin comet tails in the presence of physiological F-actin concentrations. Using biochemical complementation, we purified cyclase-associated protein (CAP) from thymus extracts as a factor that protects against the inhibition of excess F-actin. CAP has been shown to participate in actin dynamics but has been thought to act by liberating cofilin from ADP·G-actin monomers to restore cofilin activity. However, we found that CAP augments cofilin-mediated disassembly by accelerating the rate of cofilin-mediated severing. We also demonstrated that CAP acts directly on F-actin and severs actin filaments at acidic, but not neutral, pH. At the neutral pH characteristic of cytosol in most mammalian cells, we demonstrated that neither CAP nor cofilin are capable of severing actin filaments. However, the combination of CAP and cofilin rapidly severed actin at all pH values across the physiological range. Therefore, our results reveal a new function for CAP in accelerating cofilin-mediated actin filament severing and provide a mechanism through which cells can maintain high actin turnover rates without having to alkalinize cytosol, which would affect many biochemical reactions beyond actin depolymerization.
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Affiliation(s)
- Kieran P M Normoyle
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois 61801.
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49
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Nomura K, Ono K, Ono S. CAS-1, a C. elegans cyclase-associated protein, is required for sarcomeric actin assembly in striated muscle. J Cell Sci 2012; 125:4077-89. [PMID: 22623720 DOI: 10.1242/jcs.104950] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Assembly of contractile apparatuses in striated muscle requires precisely regulated reorganization of the actin cytoskeletal proteins into sarcomeric organization. Regulation of actin filament dynamics is one of the essential processes of myofibril assembly, but the mechanism of actin regulation in striated muscle is not clearly understood. Actin depolymerizing factor (ADF)/cofilin is a key enhancer of actin filament dynamics in striated muscle in both vertebrates and nematodes. Here, we report that CAS-1, a cyclase-associated protein in Caenorhabditis elegans, promotes ADF/cofilin-dependent actin filament turnover in vitro and is required for sarcomeric actin organization in striated muscle. CAS-1 is predominantly expressed in striated muscle from embryos to adults. In vitro, CAS-1 binds to actin monomers and enhances exchange of actin-bound ATP/ADP even in the presence of UNC-60B, a muscle-specific ADF/cofilin that inhibits the nucleotide exchange. As a result, CAS-1 and UNC-60B cooperatively enhance actin filament turnover. The two proteins also cooperate to shorten actin filaments. A cas-1 mutation is homozygous lethal with defects in sarcomeric actin organization. cas-1-mutant embryos and worms have aggregates of actin in muscle cells, and UNC-60B is mislocalized to the aggregates. These results provide genetic and biochemical evidence that cyclase-associated protein is a critical regulator of sarcomeric actin organization in striated muscle.
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Affiliation(s)
- Kazumi Nomura
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
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50
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Olshina MA, Wong W, Baum J. Holding back the microfilament--structural insights into actin and the actin-monomer-binding proteins of apicomplexan parasites. IUBMB Life 2012; 64:370-7. [PMID: 22454107 DOI: 10.1002/iub.1014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 02/03/2012] [Indexed: 01/02/2023]
Abstract
Parasites from the phylum Apicomplexa are responsible for several major diseases of man, including malaria and toxoplasmosis. These highly motile protozoa use a conserved actomyosin-based mode of movement to power tissue traversal and host cell invasion. The mode termed as 'gliding motility' relies on the dynamic turnover of actin, whose polymerisation state is controlled by a markedly limited number of identifiable regulators when compared with other eukaryotic cells. Recent studies of apicomplexan actin regulator structure-in particular those of the core triad of monomer-binding proteins, actin-depolymerising factor/cofilin, cyclase-associated protein/Srv2, and profilin-have provided new insights into possible mechanisms of actin regulation in parasite cells, highlighting divergent structural features and functions to regulators from other cellular systems. Furthermore, the unusual nature of apicomplexan actin itself is increasingly coming into the spotlight. Here, we review recent advances in understanding of the structure and function of actin and its regulators in apicomplexan parasites. In particular we explore the paradox between there being an abundance of unpolymerised actin, its having a seemingly increased potential to form filaments relative to vertebrate actin, and the apparent lack of visible, stable filaments in parasite cells.
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Affiliation(s)
- Maya A Olshina
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
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