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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] [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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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. 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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3
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Kuhn TB, Minamide LS, Tahtamouni LH, Alderfer SA, Walsh KP, Shaw AE, Yanouri O, Haigler HJ, Ruff MR, Bamburg JR. Chemokine Receptor Antagonists Prevent and Reverse Cofilin-Actin Rod Pathology and Protect Synapses in Cultured Rodent and Human iPSC-Derived Neurons. Biomedicines 2024; 12:93. [PMID: 38255199 PMCID: PMC10813319 DOI: 10.3390/biomedicines12010093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/20/2023] [Accepted: 12/26/2023] [Indexed: 01/24/2024] Open
Abstract
Synapse loss is the principal cause of cognitive decline in Alzheimer's disease (AD) and related disorders (ADRD). Synapse development depends on the intricate dynamics of the neuronal cytoskeleton. Cofilin, the major protein regulating actin dynamics, can be sequestered into cofilactin rods, intra-neurite bundles of cofilin-saturated actin filaments that can disrupt vesicular trafficking and cause synaptic loss. Rods are a brain pathology in human AD and mouse models of AD and ADRD. Eliminating rods is the focus of this paper. One pathway for rod formation is triggered in ~20% of rodent hippocampal neurons by disease-related factors (e.g., soluble oligomers of Amyloid-β (Aβ)) and requires cellular prion protein (PrPC), active NADPH oxidase (NOX), and cytokine/chemokine receptors (CCRs). FDA-approved antagonists of CXCR4 and CCR5 inhibit Aβ-induced rods in both rodent and human neurons with effective concentrations for 50% rod reduction (EC50) of 1-10 nM. Remarkably, two D-amino acid receptor-active peptides (RAP-103 and RAP-310) inhibit Aβ-induced rods with an EC50 of ~1 pM in mouse neurons and ~0.1 pM in human neurons. These peptides are analogs of D-Ala-Peptide T-Amide (DAPTA) and share a pentapeptide sequence (TTNYT) antagonistic to several CCR-dependent responses. RAP-103 does not inhibit neuritogenesis or outgrowth even at 1 µM, >106-fold above its EC50. N-terminal methylation, or D-Thr to D-Ser substitution, decreases the rod-inhibiting potency of RAP-103 by 103-fold, suggesting high target specificity. Neither RAP peptide inhibits neuronal rod formation induced by excitotoxic glutamate, but both inhibit rods induced in human neurons by several PrPC/NOX pathway activators (Aβ, HIV-gp120 protein, and IL-6). Significantly, RAP-103 completely protects against Aβ-induced loss of mature and developing synapses and, at 0.1 nM, reverses rods in both rodent and human neurons (T½ ~ 3 h) even in the continuous presence of Aβ. Thus, this orally available, brain-permeable peptide should be highly effective in reducing rod pathology in multifactorial neurological diseases with mixed proteinopathies acting through PrPC/NOX.
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Affiliation(s)
- Thomas B. Kuhn
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Laurie S. Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Lubna H. Tahtamouni
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
- Department of Biology and Biotechnology, Faculty of Science, The Hashemite University, Zarqa 13133, Jordan
| | - Sydney A. Alderfer
- Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Keifer P. Walsh
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Alisa E. Shaw
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Omar Yanouri
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523, USA;
| | - Henry J. Haigler
- Creative Bio-Peptides, Inc., 10319 Glen Road, Suite 100, Potomac, MD 20854, USA; (H.J.H.); (M.R.R.)
| | - Michael R. Ruff
- Creative Bio-Peptides, Inc., 10319 Glen Road, Suite 100, Potomac, MD 20854, USA; (H.J.H.); (M.R.R.)
| | - James R. Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523, USA;
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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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Towsif EM, Shekhar S. Cyclase-associated protein is a pro-formin anti-capping processive depolymerase of actin barbed and pointed ends. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569482. [PMID: 38076850 PMCID: PMC10705416 DOI: 10.1101/2023.11.30.569482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Cellular actin networks display distinct assembly and disassembly dynamics resulting from multicomponent reactions occurring primarily at the two ends and the sides of actin filaments [1-3]. While barbed ends are considered the hotspot of actin assembly [4], disassembly is thought to primarily occur via reactions on filament sides and pointed ends [3, 5-11]. Cyclase-associated protein (CAP) has emerged as the main protagonist of actin disassembly and remodeling - it collaborates with cofilin to increase pointed-end depolymerization by 300-fold [6, 7], promotes filament "coalescence" in presence of Abp1 [12], and accelerates nucleotide exchange to regenerate monomers for new rounds of assembly [13-15]. CAP has also been reported to enhance cofilin-mediated severing [16, 17], but these claims have since been challenged [7]. Using microfluidics-assisted three-color single-molecule imaging, we now reveal that CAP also has important functions at filament barbed ends. We reveal that CAP is a processive barbed-end depolymerase capable of tracking both ends of the filament. Each CAP binding event leads to removal of about 5,175 and 620 subunits from the barbed and pointed ends respectively. We find that the WH2 domain is essential, and the CARP domain is dispensable for barbed-end depolymerization. We show that CAP co-localizes with barbed-end bound formin and capping protein, in the process increasing residence time of formin by 10-fold and promoting dissociation of CP by 4-fold. Our barbed-end observations combined with previously reported activities of CAP at pointed ends and sides, firmly establish CAP as a key player in actin dynamics.
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Affiliation(s)
- Ekram M. Towsif
- 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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6
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Heinze A, Rust MB. Loss of the actin regulator cyclase-associated protein 1 (CAP1) modestly affects dendritic spine remodeling during synaptic plasticity. Eur J Cell Biol 2023; 102:151357. [PMID: 37634312 DOI: 10.1016/j.ejcb.2023.151357] [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: 05/16/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 08/29/2023] Open
Abstract
Dendritic spines form the postsynaptic compartment of most excitatory synapses in the vertebrate brain. Morphological changes of dendritic spines contribute to major forms of synaptic plasticity such as long-term potentiation (LTP) or depression (LTD). Synaptic plasticity underlies learning and memory, and defects in synaptic plasticity contribute to the pathogeneses of human brain disorders. Hence, deciphering the molecules that drive spine remodeling during synaptic plasticity is critical for understanding the neuronal basis of physiological and pathological brain function. Since actin filaments (F-actin) define dendritic spine morphology, actin-binding proteins (ABP) that accelerate dis-/assembly of F-actin moved into the focus as critical regulators of synaptic plasticity. We recently identified cyclase-associated protein 1 (CAP1) as a novel actin regulator in neurons that cooperates with cofilin1, an ABP relevant for synaptic plasticity. We therefore hypothesized a crucial role for CAP1 in structural synaptic plasticity. By exploiting mouse hippocampal neurons, we tested this hypothesis in the present study. We found that induction of both forms of synaptic plasticity oppositely altered concentration of exogenous, myc-tagged CAP1 in dendritic spines, with chemical LTP (cLTP) decreasing and chemical LTD (cLTD) increasing it. cLTP induced spine enlargement in CAP1-deficient neurons. However, it did not increase the density of large spines, different from control neurons. cLTD induced spine retraction and spine size reduction in control neurons, but not in CAP1-KO neurons. Together, we report that postsynaptic myc-CAP1 concentration oppositely changed during cLTP and cTLD and that CAP1 inactivation modestly affected structural plasticity.
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Affiliation(s)
- Anika Heinze
- 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
| | - 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.
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7
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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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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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Jin D, Li X, Cong H, You B, Ma Y, Hu Y, Zhang J. Role of serum CAP1 protein in the diagnosis of patients with first-time acute myocardial infarction. Medicine (Baltimore) 2023; 102:e34700. [PMID: 37773847 PMCID: PMC10545083 DOI: 10.1097/md.0000000000034700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 07/20/2023] [Indexed: 10/01/2023] Open
Abstract
The dysregulation of adenylate cyclase-associated protein 1 (CAP1) is associated with a variety of inflammatory conditions. Here, we aimed to assess the role of serum CAP1 protein in predicting acute myocardial infarction (AMI), and to explore its effect and mechanism in vascular endothelial cells injury. ELISA was utilized to detected CAP1 protein expression in serum from 70 patients with first-time AMI at 0, 6, 12, 24, 48 hours and 7 days of the onset of chest pain. Receiver operating characteristic (ROC) curve analysis was administered to analyze the diagnostic power of CAP1 for AMI. The CCK-8 and 5-BrdU assays were applied to measure cell proliferation and inflammation in a model of oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cells (HUVEC). Luciferase reporter gene assay and Western blotting were used to assess the activity of NF-κB pathway. Results showed that serum CAP1 protein expression was upregulated in patients with first-time AMI, its expression was highest at 12 hours of the onset of chest pain. CAP1 protein was positively associated with the levels of cTnI and ox-LDL. CAP1 showed a relatively high diagnostic accuracy in patients with first-time AMI compared with cTnI, and CAP1 combined with cTnI had superior diagnostic value than CAP1 and cTnI alone. The expression of CAP1 protein was increased in supernatants of ox-LDL induced HUVEC in a dose- and time-dependent manner. CAP1 inhibited cell proliferation but promoted inflammation, and induced the activation of NF-κB pathway in vitro. To sum up, increased serum CAP1 expression might serve as a novel diagnostic biomarker for patients with first-time AMI, the mechanism might be related to its induction of NF-κB pathway activation causing abnormal proliferation and inflammation and thus mediating vascular endothelial cell injury.
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Affiliation(s)
- Dongxia Jin
- Clinical School of Thoracic, Tianjin Medical University, Tianjin, P.R. China
- Department of Cardiology, Chest Hospital of Tianjin University, Tianjin, P.R. China
- Tianjin Key Laboratory of Cardiovascular Emergency and Critical Care, Tianjin, P.R. China
| | - Ximing Li
- Department of Cardiology, Chest Hospital of Tianjin University, Tianjin, P.R. China
- Tianjin Key Laboratory of Cardiovascular Emergency and Critical Care, Tianjin, P.R. China
| | - Hongliang Cong
- Department of Cardiology, Chest Hospital of Tianjin University, Tianjin, P.R. China
- Tianjin Key Laboratory of Cardiovascular Emergency and Critical Care, Tianjin, P.R. China
| | - Bingchen You
- Clinical School of Thoracic, Tianjin Medical University, Tianjin, P.R. China
| | - Yue Ma
- Department of Cardiology, Chest Hospital of Tianjin University, Tianjin, P.R. China
| | - Yuecheng Hu
- Department of Cardiology, Chest Hospital of Tianjin University, Tianjin, P.R. China
| | - Jingxia Zhang
- Department of Cardiology, Chest Hospital of Tianjin University, Tianjin, P.R. China
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Ramsey A, Akana L, Miyajima E, Douglas S, Gray J, Rowland A, Sharma KD, Xu J, Xie JY, Zhou GL. CAP1 (cyclase-associated protein 1) mediates the cyclic AMP signals that activate Rap1 in stimulating matrix adhesion of colon cancer cells. Cell Signal 2023; 104:110589. [PMID: 36621727 PMCID: PMC9908859 DOI: 10.1016/j.cellsig.2023.110589] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 12/12/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
We previously reported that CAP1 (Cyclase-Associated Protein 1) regulates matrix adhesion in mammalian cells through FAK (Focal Adhesion Kinase). More recently, we discovered a phosphor-regulation mechanism for CAP1 through the Ser307/Ser309 tandem site that is of critical importance for all CAP1 functions. However, molecular mechanisms underlying the CAP1 function in adhesion and its regulation remain largely unknown. Here we report that Rap1 also facilitates the CAP1 function in adhesion, and more importantly, we identify a novel signaling pathway where CAP1 mediates the cAMP signals, through the cAMP effectors Epac (Exchange proteins directly activated by cAMP) and PKA (Protein Kinase A), to activate Rap1 in stimulating matrix adhesion in colon cancer cells. Knockdown of CAP1 led to opposite adhesion phenotypes in SW480 and HCT116 colon cancer cells, with reduced matrix adhesion and reduced FAK and Rap1 activities in SW480 cells while it stimulated matrix adhesion as well as FAK and Rap1 activities in HCT116 cells. Importantly, depletion of CAP1 abolished the stimulatory effects of the cAMP activators forskolin and isoproterenol, as well as that of Epac and PKA, on matrix adhesion in both cell types. Our results consistently support a required role for CAP1 in the cAMP activation of Rap1. Identification of the key role for CAP1 in linking the major second messenger cAMP to activation of Rap1 in stimulating adhesion, which may potentially also regulate proliferation in other cell types, not only vertically extends our knowledge on CAP biology, but also carries important translational potential for targeting CAP1 in cancer therapeutics.
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Affiliation(s)
- Auburn Ramsey
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
| | - Lokesh Akana
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
| | - Erina Miyajima
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
| | - Spencer Douglas
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
| | - Joshua Gray
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
| | - Alyssa Rowland
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
| | - Krishna Deo Sharma
- Molecular Biosciences Graduate Program, Arkansas State University, State University, AR 72467, USA
| | - Jianfeng Xu
- Molecular Biosciences Graduate Program, Arkansas State University, State University, AR 72467, USA; Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA; College of Agriculture, Arkansas State University, State University, AR 72467, USA
| | - Jennifer Y Xie
- Molecular Biosciences Graduate Program, Arkansas State University, State University, AR 72467, USA; Department of Basic Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
| | - Guo-Lei Zhou
- Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA; Molecular Biosciences Graduate Program, Arkansas State University, State University, AR 72467, USA.
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Abstract
One of the major challenges of bottom-up synthetic biology is rebuilding a minimal cell division machinery. From a reconstitution perspective, the animal cell division apparatus is mechanically the simplest and therefore attractive to rebuild. An actin-based ring produces contractile force to constrict the membrane. By contrast, microbes and plant cells have a cell wall, so division requires concerted membrane constriction and cell wall synthesis. Furthermore, reconstitution of the actin division machinery helps in understanding the physical and molecular mechanisms of cytokinesis in animal cells and thus our own cells. In this review, we describe the state-of-the-art research on reconstitution of minimal actin-mediated cytokinetic machineries. Based on the conceptual requirements that we obtained from the physics of the shape changes involved in cell division, we propose two major routes for building a minimal actin apparatus capable of division. Importantly, we acknowledge both the passive and active roles that the confining lipid membrane can play in synthetic cytokinesis. We conclude this review by identifying the most pressing challenges for future reconstitution work, thereby laying out a roadmap for building a synthetic cell equipped with a minimal actin division machinery.
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Heinze A, Schuldt C, Khudayberdiev S, van Bommel B, Hacker D, Schulz TG, Stringhi R, Marcello E, Mikhaylova M, Rust MB. Functional interdependence of the actin regulators CAP1 and cofilin1 in control of dendritic spine morphology. Cell Mol Life Sci 2022; 79:558. [PMID: 36264429 PMCID: PMC9585016 DOI: 10.1007/s00018-022-04593-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 12/01/2022]
Abstract
The vast majority of excitatory synapses are formed on small dendritic protrusions termed dendritic spines. Dendritic spines vary in size and density that are crucial determinants of excitatory synaptic transmission. Aberrations in spine morphogenesis can compromise brain function and have been associated with neuropsychiatric disorders. Actin filaments (F-actin) are the major structural component of dendritic spines, and therefore, actin-binding proteins (ABP) that control F-actin dis-/assembly moved into the focus as critical regulators of brain function. Studies of the past decade identified the ABP cofilin1 as a key regulator of spine morphology, synaptic transmission, and behavior, and they emphasized the necessity for a tight control of cofilin1 to ensure proper brain function. Here, we report spine enrichment of cyclase-associated protein 1 (CAP1), a conserved multidomain protein with largely unknown physiological functions. Super-resolution microscopy and live cell imaging of CAP1-deficient hippocampal neurons revealed impaired synaptic F-actin organization and dynamics associated with alterations in spine morphology. Mechanistically, we found that CAP1 cooperates with cofilin1 in spines and that its helical folded domain is relevant for this interaction. Moreover, our data proved functional interdependence of CAP1 and cofilin1 in control of spine morphology. In summary, we identified CAP1 as a novel regulator of the postsynaptic actin cytoskeleton that is essential for synaptic cofilin1 activity.
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Affiliation(s)
- Anika Heinze
- 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
| | - Cara Schuldt
- 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
| | - Sharof Khudayberdiev
- 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
| | - Bas van Bommel
- AG Optobiology, Institute of Biology, Humboldt-University, 10115, Berlin, Germany
- Institute of Chemistry and Biochemistry, Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, 14195, Berlin, Germany
| | - Daniela Hacker
- AG Optobiology, Institute of Biology, Humboldt-University, 10115, Berlin, Germany
- Guest Group 'Neuronal Protein Transport', Institute for Molecular Neurogenetics, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20251, Hamburg, Germany
| | - Toni G Schulz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Ramona Stringhi
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133, Milan, Italy
| | - Marina Mikhaylova
- AG Optobiology, Institute of Biology, Humboldt-University, 10115, Berlin, Germany
- Guest Group 'Neuronal Protein Transport', Institute for Molecular Neurogenetics, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20251, Hamburg, Germany
| | - 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.
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13
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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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14
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Bamburg JR, Minamide LS, Wiggan O, Tahtamouni LH, Kuhn TB. Cofilin and Actin Dynamics: Multiple Modes of Regulation and Their Impacts in Neuronal Development and Degeneration. Cells 2021; 10:cells10102726. [PMID: 34685706 PMCID: PMC8534876 DOI: 10.3390/cells10102726] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 02/06/2023] Open
Abstract
Proteins of the actin depolymerizing factor (ADF)/cofilin family are ubiquitous among eukaryotes and are essential regulators of actin dynamics and function. Mammalian neurons express cofilin-1 as the major isoform, but ADF and cofilin-2 are also expressed. All isoforms bind preferentially and cooperatively along ADP-subunits in F-actin, affecting the filament helical rotation, and when either alone or when enhanced by other proteins, promotes filament severing and subunit turnover. Although self-regulating cofilin-mediated actin dynamics can drive motility without post-translational regulation, cells utilize many mechanisms to locally control cofilin, including cooperation/competition with other proteins. Newly identified post-translational modifications function with or are independent from the well-established phosphorylation of serine 3 and provide unexplored avenues for isoform specific regulation. Cofilin modulates actin transport and function in the nucleus as well as actin organization associated with mitochondrial fission and mitophagy. Under neuronal stress conditions, cofilin-saturated F-actin fragments can undergo oxidative cross-linking and bundle together to form cofilin-actin rods. Rods form in abundance within neurons around brain ischemic lesions and can be rapidly induced in neurites of most hippocampal and cortical neurons through energy depletion or glutamate-induced excitotoxicity. In ~20% of rodent hippocampal neurons, rods form more slowly in a receptor-mediated process triggered by factors intimately connected to disease-related dementias, e.g., amyloid-β in Alzheimer’s disease. This rod-inducing pathway requires a cellular prion protein, NADPH oxidase, and G-protein coupled receptors, e.g., CXCR4 and CCR5. Here, we will review many aspects of cofilin regulation and its contribution to synaptic loss and pathology of neurodegenerative diseases.
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Affiliation(s)
- James R. Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (L.S.M.); (O.W.); (L.H.T.); (T.B.K.)
- Correspondence: ; Tel.: +1-970-988-9120; Fax: +1-970-491-0494
| | - Laurie S. Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (L.S.M.); (O.W.); (L.H.T.); (T.B.K.)
| | - O’Neil Wiggan
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (L.S.M.); (O.W.); (L.H.T.); (T.B.K.)
| | - Lubna H. Tahtamouni
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (L.S.M.); (O.W.); (L.H.T.); (T.B.K.)
- Department of Biology and Biotechnology, The Hashemite University, Zarqa 13115, Jordan
| | - Thomas B. Kuhn
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (L.S.M.); (O.W.); (L.H.T.); (T.B.K.)
- Department of Chemistry and Biochemistry, University of Alaska, Fairbanks, AK 99775, USA
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15
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Abstract
CAP1 (Cyclase-Associated Protein 1) is highly conserved in evolution. Originally identified in yeast as a bifunctional protein involved in Ras-adenylyl cyclase and F-actin dynamics regulation, the adenylyl cyclase component seems to be lost in mammalian cells. Prompted by our recent identification of the Ras-like small GTPase Rap1 as a GTP-independent but geranylgeranyl-specific partner for CAP1, we hypothesized that CAP1-Rap1, similar to CAP-Ras-cyclase in yeast, might play a critical role in cAMP dynamics in mammalian cells. In this study, we report that CAP1 binds and activates mammalian adenylyl cyclase in vitro, modulates cAMP in live cells in a Rap1-dependent manner, and affects cAMP-dependent proliferation. Utilizing deletion and mutagenesis approaches, we mapped the interaction of CAP1-cyclase with CAP's N-terminal domain involving critical leucine residues in the conserved RLE motifs and adenylyl cyclase's conserved catalytic loops (e.g., C1a and/or C2a). When combined with a FRET-based cAMP sensor, CAP1 overexpression-knockdown strategies, and the use of constitutively active and negative regulators of Rap1, our studies highlight a critical role for CAP1-Rap1 in adenylyl cyclase regulation in live cells. Similarly, we show that CAP1 modulation significantly affected cAMP-mediated proliferation in an RLE motif-dependent manner. The combined study indicates that CAP1-cyclase-Rap1 represents a regulatory unit in cAMP dynamics and biology. Since Rap1 is an established downstream effector of cAMP, we advance the hypothesis that CAP1-cyclase-Rap1 represents a positive feedback loop that might be involved in cAMP microdomain establishment and localized signaling.
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16
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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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17
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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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18
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Kepser LJ, Khudayberdiev S, Hinojosa LS, Macchi C, Ruscica M, Marcello E, Culmsee C, Grosse R, Rust MB. Cyclase-associated protein 2 (CAP2) controls MRTF-A localization and SRF activity in mouse embryonic fibroblasts. Sci Rep 2021; 11:4789. [PMID: 33637797 PMCID: PMC7910472 DOI: 10.1038/s41598-021-84213-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 02/12/2021] [Indexed: 01/09/2023] Open
Abstract
Recent studies identified cyclase-associated proteins (CAPs) as important regulators of actin dynamics that control assembly and disassembly of actin filaments (F-actin). While these studies significantly advanced our knowledge of their molecular functions, the physiological relevance of CAPs largely remained elusive. Gene targeting in mice implicated CAP2 in heart physiology and skeletal muscle development. Heart defects in CAP2 mutant mice were associated with altered activity of serum response factor (SRF), a transcription factor involved in multiple biological processes including heart function, but also skeletal muscle development. By exploiting mouse embryonic fibroblasts (MEFs) from CAP2 mutant mice, we aimed at deciphering the CAP2-dependent mechanism relevant for SRF activity. Reporter assays and mRNA quantification by qPCR revealed reduced SRF-dependent gene expression in mutant MEFs. Reduced SRF activity in CAP2 mutant MEFs was associated with altered actin turnover, a shift in the actin equilibrium towards monomeric actin (G-actin) as well as and reduced nuclear levels of myocardin-related transcription factor A (MRTF-A), a transcriptional SRF coactivator that is shuttled out of the nucleus and, hence, inhibited upon G-actin binding. Moreover, pharmacological actin manipulation with jasplakinolide restored MRTF-A distribution in mutant MEFs. Our data are in line with a model in which CAP2 controls the MRTF-SRF pathway in an actin-dependent manner. While MRTF-A localization and SRF activity was impaired under basal conditions, serum stimulation induced nuclear MRTF-A translocation and SRF activity in mutant MEFs similar to controls. In summary, our data revealed that in MEFs CAP2 controls basal MRTF-A localization and SRF activity, while it was dispensable for serum-induced nuclear MRTF-A translocation and SRF stimulation.
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Affiliation(s)
- Lara-Jane Kepser
- Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Sharof Khudayberdiev
- Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Laura Soto Hinojosa
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
- Institute of Pharmacology, University of Marburg, 35032, Marburg, Germany
| | - Chiara Macchi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Massimiliano Ruscica
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35032, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032, Marburg, Germany
| | - Robert Grosse
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
- Institute of Pharmacology, University of Marburg, 35032, Marburg, Germany
| | - Marco B Rust
- Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany.
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany.
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032, Marburg, Germany.
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19
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Huang X, Chao R, Zhang Y, Wang P, Gong X, Liang D, Wang Y. CAP1, a target of miR-144/451, negatively regulates erythroid differentiation and enucleation. J Cell Mol Med 2021; 25:2377-2389. [PMID: 33496386 PMCID: PMC7933962 DOI: 10.1111/jcmm.16067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 02/06/2023] Open
Abstract
The exact molecular mechanism underlying erythroblast enucleation has been a fundamental biological question for decades. In this study, we found that miR-144/451 critically regulated erythroid differentiation and enucleation. We further identified CAP1, a G-actin-binding protein, as a direct target of miR-144/451 in these processes. During terminal erythropoiesis, CAP1 expression declines along with gradually increased miR-144/451 levels. Enforced CAP1 up-regulation inhibits the formation of contractile actin rings in erythroblasts and prevents their terminal differentiation and enucleation. Our findings reveal a negative regulatory role of CAP1 in miR-144/451-mediated erythropoiesis and thus shed light on how microRNAs fine-tune terminal erythroid development through regulating actin dynamics.
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Affiliation(s)
- Xiaoli Huang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Ruihua Chao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yanyang Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Pengxiang Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Xueping Gong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Dongli Liang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China
| | - Yuan Wang
- Department of Animal Sciences, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI, USA
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20
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Shekhar S, Hoeprich GJ, Gelles J, Goode BL. Twinfilin bypasses assembly conditions and actin filament aging to drive barbed end depolymerization. J Cell Biol 2021; 220:e202006022. [PMID: 33226418 PMCID: PMC7686915 DOI: 10.1083/jcb.202006022] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 10/06/2020] [Accepted: 10/29/2020] [Indexed: 01/15/2023] Open
Abstract
Cellular actin networks grow by ATP-actin addition at filament barbed ends and have long been presumed to depolymerize at their pointed ends, primarily after filaments undergo "aging" (ATP hydrolysis and Pi release). The cytosol contains high levels of actin monomers, which favors assembly over disassembly, and barbed ends are enriched in ADP-Pi actin. For these reasons, the potential for a barbed end depolymerization mechanism in cells has received little attention. Here, using microfluidics-assisted TIRF microscopy, we show that mouse twinfilin, a member of the ADF-homology family, induces depolymerization of ADP-Pi barbed ends even under assembly-promoting conditions. Indeed, we observe in single reactions containing micromolar concentrations of actin monomers the simultaneous rapid elongation of formin-bound barbed ends and twinfilin-induced depolymerization of free barbed ends. The data show that twinfilin catalyzes dissociation of subunits from ADP-Pi barbed ends and thereby bypasses filament aging prerequisites to disassemble newly polymerized actin filaments.
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Affiliation(s)
- Shashank Shekhar
- Department of Biology, Brandeis University, Waltham, MA
- Department of Biochemistry, Brandeis University, Waltham, MA
| | | | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA
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21
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Ben Zablah Y, Merovitch N, Jia Z. The Role of ADF/Cofilin in Synaptic Physiology and Alzheimer's Disease. Front Cell Dev Biol 2020; 8:594998. [PMID: 33282872 PMCID: PMC7688896 DOI: 10.3389/fcell.2020.594998] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/23/2020] [Indexed: 12/21/2022] Open
Abstract
Actin-depolymerization factor (ADF)/cofilin, a family of actin-binding proteins, are critical for the regulation of actin reorganization in response to various signals. Accumulating evidence indicates that ADF/cofilin also play important roles in neuronal structure and function, including long-term potentiation and depression. These are the most extensively studied forms of long-lasting synaptic plasticity and are widely regarded as cellular mechanisms underlying learning and memory. ADF/cofilin regulate synaptic function through their effects on dendritic spines and the trafficking of glutamate receptors, the principal mediator of excitatory synaptic transmission in vertebrates. Regulation of ADF/cofilin involves various signaling pathways converging on LIM domain kinases and slingshot phosphatases, which phosphorylate/inactivate and dephosphorylate/activate ADF/cofilin, respectively. Actin-depolymerization factor/cofilin activity is also regulated by other actin-binding proteins, activity-dependent subcellular distribution and protein translation. Abnormalities in ADF/cofilin have been associated with several neurodegenerative disorders such as Alzheimer’s disease. Therefore, investigating the roles of ADF/cofilin in the brain is not only important for understanding the fundamental processes governing neuronal structure and function, but also may provide potential therapeutic strategies to treat brain disorders.
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Affiliation(s)
- Youssif Ben Zablah
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Neil Merovitch
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhengping Jia
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada.,Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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22
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Somboon P, Soontorngun N. An actin depolymerizing agent 19,20-epoxycytochalasin Q of Xylaria sp. BCC 1067 enhanced antifungal action of azole drugs through ROS-mediated cell death in yeast. Microbiol Res 2020; 243:126646. [PMID: 33227681 DOI: 10.1016/j.micres.2020.126646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/30/2020] [Accepted: 11/06/2020] [Indexed: 01/21/2023]
Abstract
Multidrug resistance is a highly conserved phenomenon among all living organisms and a major veritable public health problem worldwide. Repetitive uses of antibiotics lead to antimicrobial drug resistance. Here, 19,20-epoxycytochalasin Q (ECQ) was isolated from endophytic fungus Xylaria sp. BCC 1067 and, its chemical structure was determined via chromatographic and spectral methods. ECQ displayed an antifungal activity with low MIC50 of 410 and 55 mg/l in the model yeast Saccharomyces cerevisiae wild-type and ScΔpdr5 strains, respectively. ECQ was a new inducer and potential substrate of key multi-drug efflux pumps S. cerevisiae ScPdr5 and Candida albicans CaCdr1. ECQ targeted actin filament, disrupting actin dynamics of yeast cells. ECQ also sensitized the ScΔsrv2 mutant, lacking suppressor of RasVal19. Overexpression of ScPDR5 or CaCDR1 genes prevented aggregation of actin and alleviated antifungal effect of ECQ. Additionally, ECQ induced high accumulation of reactive oxygen species, caused plasma membrane leakage and decreased yeast cell survival. Importantly, a discovery of ECQ implied a cellular connection between multi-drug resistance and actin stability, an important determinant of transporter mediated-drug resistance mechanism. Combination of ECQ and antifungal azoles displayed promising drug synergy against S. cerevisiae strains expressing multi-drug transporters, thereby providing potential solution for antifungal therapy and chemotherapeutic application.
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Affiliation(s)
- Pichayada Somboon
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Nitnipa Soontorngun
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand.
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23
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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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24
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Adachi M, Masugi Y, Yamazaki K, Emoto K, Kobayashi Y, Tominaga E, Banno K, Aoki D, Sakamoto M. Upregulation of cyclase-associated actin cytoskeleton regulatory protein 2 in epithelial ovarian cancer correlates with aggressive histologic types and worse outcomes. Jpn J Clin Oncol 2020; 50:643-652. [PMID: 32211793 DOI: 10.1093/jjco/hyaa026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 01/22/2020] [Accepted: 02/08/2020] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE Cyclase-associated actin cytoskeleton regulatory protein 2 (CAP2) regulates actin dynamics to control cell cycles and cell migration. CAP2 overexpression contributes to cancer progression in several tumor types; however, the role of CAP2 expression in ovarian cancer remains unclear. This study aimed to clarify the significance of CAP2 expression in epithelial ovarian tumor. METHODS We evaluated CAP2 expression in ovarian cancer cell lines using quantitative real-time polymerase chain reaction, western blotting and immunocytochemistry and examined the effect of CAP2 silencing in migration and proliferation assays. CAP2 immunohistochemistry was conducted using tissue specimens from 432 ovarian carcinoma patients; a further 55 borderline and benign 65 lesions were analyzed. CAP2 expression levels were defined as low, intermediate or high, for correlation analysis with clinicopathological factors. RESULTS CAP2 expression was significantly higher in cell lines from Type II ovarian cancer than in those in Type I, and knockdown of CAP2 showed decreased migration and proliferation. Higher levels of CAP2 expression in human tissues were associated with Type II histology, residual lesion, lymph node metastasis, ascites cytology and higher clinical stage. High CAP2 expression levels were observed in 26 (23.4%) of 111 Type II ovarian cancers and in 16 (5.0%) of 321 Type I cancers but not in any borderline or benign lesions. Multivariate analyses showed that CAP2 expression in ovarian cancer is an independent prognostic factor for recurrence-free survival (P = 0.019). CONCLUSION CAP2 expression is upregulated in aggressive histologic types of epithelial ovarian cancer and serves as a novel prognostic biomarker for patient survival.
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Affiliation(s)
- Masataka Adachi
- Department of Pathology, Keio University School of Medicine, Tokyo, Japan.,Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Yohei Masugi
- Department of Pathology, Keio University School of Medicine, Tokyo, Japan
| | - Ken Yamazaki
- Department of Pathology, Keio University School of Medicine, Tokyo, Japan
| | - Katsura Emoto
- Department of Pathology, Keio University School of Medicine, Tokyo, Japan
| | - Yusuke Kobayashi
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Eiichiro Tominaga
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Kouji Banno
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Daisuke Aoki
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Michiie Sakamoto
- Department of Pathology, Keio University School of Medicine, Tokyo, Japan
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25
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Bleicher P, Sciortino A, Bausch AR. The dynamics of actin network turnover is self-organized by a growth-depletion feedback. Sci Rep 2020; 10:6215. [PMID: 32277095 PMCID: PMC7148320 DOI: 10.1038/s41598-020-62942-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/24/2020] [Indexed: 01/22/2023] Open
Abstract
The dynamics of actin networks is modulated by a machinery consisting of actin binding proteins that control the turnover of filaments in space and time. To study this complex orchestration, in vitro reconstitution approaches strive to project actin dynamics in ideal, minimal systems. To this extent we reconstitute a self-supplying, dense network of globally treadmilling filaments. In this system we analyze growth and intrinsic turnover by means of FRAP measurements and thereby demonstrate how the depletion of monomers and actin binding partners modulate the dynamics in active actin networks. The described effects occur only in dense networks, as single filament dynamics are unable to produce depletion effects to this extent. Furthermore, we demonstrate a synergistic relationship between the nucleators formin and Arp2/3 when branched networks and formin-induced networks are colocalized. As a result, the formin-enhanced filament turnover depletes cofilin at the surface and thus protects the dense, Arp2/3 polymerized network from debranching. Ultimately, these results may be key for understanding the maintenance of the two contradicting requirements of network stability and dynamics in cells.
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Affiliation(s)
- P Bleicher
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany
| | - A Sciortino
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany
| | - A R Bausch
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany.
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Dynamic Phosphorylation and Dephosphorylation of Cyclase-Associated Protein 1 by Antagonistic Signaling through Cyclin-Dependent Kinase 5 and cAMP Are Critical for the Protein Functions in Actin Filament Disassembly and Cell Adhesion. Mol Cell Biol 2020; 40:MCB.00282-19. [PMID: 31791978 DOI: 10.1128/mcb.00282-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/25/2019] [Indexed: 12/15/2022] Open
Abstract
Cyclase-associated protein 1 (CAP1) is a conserved actin-regulating protein that enhances actin filament dynamics and also regulates adhesion in mammalian cells. We previously found that phosphorylation at the Ser307/Ser309 tandem site controls its association with cofilin and actin and is important for CAP1 to regulate the actin cytoskeleton. Here, we report that transient Ser307/Ser309 phosphorylation is required for CAP1 function in both actin filament disassembly and cell adhesion. Both the phosphomimetic and the nonphosphorylatable CAP1 mutant, which resist transition between phosphorylated and dephosphorylated forms, had defects in rescuing the reduced rate of actin filament disassembly in the CAP1 knockdown HeLa cells. The phosphorylation mutants also had defects in alleviating the elevated focal adhesion kinase (FAK) activity and the enhanced focal adhesions in the knockdown cells. In dissecting further phosphoregulatory cell signals for CAP1, we found that cyclin-dependent kinase 5 (CDK5) phosphorylates both Ser307 and Ser309 residues, whereas cAMP signaling induces dephosphorylation at the tandem site, through its effectors protein kinase A (PKA) and exchange proteins directly activated by cAMP (Epac). No evidence supports an involvement of activated protein phosphatase in executing the dephosphorylation downstream from cAMP, whereas preventing CAP1 from accessing its kinase CDK5 appears to underlie CAP1 dephosphorylation induced by cAMP. Therefore, this study provides direct cellular evidence that transient phosphorylation is required for CAP1 functions in both actin filament turnover and adhesion, and the novel mechanistic insights substantially extend our knowledge of the cell signals that function in concert to regulate CAP1 by facilitating its transient phosphorylation.
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27
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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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28
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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: 65] [Impact Index Per Article: 13.0] [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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29
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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: 46] [Impact Index Per Article: 9.2] [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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30
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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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31
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A M, Fung TS, Kettenbach AN, Chakrabarti R, Higgs HN. A complex containing lysine-acetylated actin inhibits the formin INF2. Nat Cell Biol 2019; 21:592-602. [PMID: 30962575 PMCID: PMC6501848 DOI: 10.1038/s41556-019-0307-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 02/28/2019] [Indexed: 11/10/2022]
Abstract
Inverted formin 2 (INF2) is a member of the formin family of actin assembly factors. Dominant missense mutations in INF2 are linked to two diseases: focal segmental glomerulosclerosis, a kidney disease, and Charcot-Marie-Tooth disease, a neuropathy. All of the disease mutations map to the autoinhibitory diaphanous inhibitory domain. Interestingly, purified INF2 is not autoinhibited, suggesting the existence of other cellular inhibitors. Here, we purified an INF2 inhibitor from mouse brain tissue, and identified it as a complex of lysine-acetylated actin (KAc-actin) and cyclase-associated protein (CAP). Inhibition of INF2 by CAP-KAc-actin is dependent on the INF2 diaphanous inhibitory domain (DID). Treatment of CAP-KAc-actin-inhibited INF2 with histone deacetylase 6 releases INF2 inhibition, whereas inhibitors of histone deacetylase 6 block the activation of cellular INF2. Disease-associated INF2 mutants are poorly inhibited by CAP-KAc-actin, suggesting that focal segmental glomerulosclerosis and Charcot-Marie-Tooth disease result from reduced CAP-KAc-actin binding. These findings reveal a role for KAc-actin in the regulation of an actin assembly factor by a mechanism that we call facilitated autoinhibition.
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Affiliation(s)
- Mu A
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Tak Shun Fung
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Rajarshi Chakrabarti
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Henry N Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
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32
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Aspit L, Levitas A, Etzion S, Krymko H, Slanovic L, Zarivach R, Etzion Y, Parvari R. CAP2 mutation leads to impaired actin dynamics and associates with supraventricular tachycardia and dilated cardiomyopathy. J Med Genet 2018; 56:228-235. [DOI: 10.1136/jmedgenet-2018-105498] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 10/10/2018] [Accepted: 10/22/2018] [Indexed: 11/04/2022]
Abstract
BackgroundDilated cardiomyopathy (DCM) is a primary myocardial disease leading to contractile dysfunction, progressive heart failure and excessive risk of sudden cardiac death. Around half of DCM cases are idiopathic, and genetic factors seem to play an important role.AimWe investigated a possible genetic cause of DCM in two consanguineous children from a Bedouin family.Methods and resultsUsing exome sequencing and searching for rare homozygous variations, we identified a nucleotide change in the donor splice consensus sequence of exon 7 in CAP2 as the causative mutation. Using patient-derived fibroblasts, we demonstrated that the mutation causes skipping of exons 6 and 7. The resulting protein is missing 64 amino acids in its N-CAP domain that should prevent its correct folding. CAP2 protein level was markedly reduced without notable compensation by the homolog CAP1. However, β-actin mRNA was elevated as demonstrated by real-time qPCR. In agreement with the essential role of CAP2 in actin filament polymerization, we demonstrate that the mutation affects the kinetics of repolymerization of actin in patient fibroblasts.ConclusionsThis is the first report of a recessive deleterious mutation in CAP2 and its association with DCM in humans. The clinical phenotype recapitulates the damaging effects on the heart observed in Cap2 knockout mice including DCM and cardiac conduction disease, but not the other effects on growth, viability, wound healing and eye development. Our data underscore the importance of the proper kinetics of actin polymerization for normal function of the human heart.
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33
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Hilton DM, Aguilar RM, Johnston AB, Goode BL. Species-Specific Functions of Twinfilin in Actin Filament Depolymerization. J Mol Biol 2018; 430:3323-3336. [PMID: 29928893 DOI: 10.1016/j.jmb.2018.06.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 11/16/2022]
Abstract
Twinfilin is a highly conserved member of the actin depolymerization factor homology (ADF-H) protein superfamily, which also includes ADF/Cofilin, Abp1/Drebrin, GMF, and Coactosin. Twinfilin has a unique molecular architecture consisting of two ADF-H domains joined by a linker and followed by a C-terminal tail. Yeast Twinfilin, in conjunction with yeast cyclase-associated protein (Srv2/CAP), increases the rate of depolymerization at both the barbed and pointed ends of actin filaments. However, it has remained unclear whether these activities extend to Twinfilin homologs in other species. To address this, we purified the three mouse Twinfilin isoforms (mTwf1, mTwf2a, mTwf2b) and mouse CAP1, and used total internal reflection fluorescence microscopy assays to study their effects on filament disassembly. Our results show that all three mouse Twinfilin isoforms accelerate barbed end depolymerization similar to yeast Twinfilin, suggesting that this activity is evolutionarily conserved. In striking contrast, mouse Twinfilin isoforms and CAP1 failed to induce rapid pointed end depolymerization. Using chimeras, we show that the yeast-specific pointed end depolymerization activity is specified by the C-terminal ADF-H domain of yeast Twinfilin. In addition, Tropomyosin decoration of filaments failed to impede depolymerization by yeast and mouse Twinfilin and Srv2/CAP, but inhibited Cofilin severing. Together, our results indicate that Twinfilin has conserved functions in regulating barbed end dynamics, although its ability to drive rapid pointed end depolymerization appears to be species-specific. We discuss the implications of this work, including that pointed end depolymerization may be catalyzed by different ADF-H family members in different species.
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Affiliation(s)
- Denise M Hilton
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Rey M Aguilar
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Adam B Johnston
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA.
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34
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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] [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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35
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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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36
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Zhang X, Cao S, Barila G, Edreira MM, Hong K, Wankhede M, Naim N, Buck M, Altschuler DL. Cyclase-associated protein 1 (CAP1) is a prenyl-binding partner of Rap1 GTPase. J Biol Chem 2018; 293:7659-7673. [PMID: 29618512 DOI: 10.1074/jbc.ra118.001779] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/22/2018] [Indexed: 12/20/2022] Open
Abstract
Rap1 proteins are members of the Ras subfamily of small GTPases involved in many biological responses, including adhesion, cell proliferation, and differentiation. Like all small GTPases, they work as molecular allosteric units that are active in signaling only when associated with the proper membrane compartment. Prenylation, occurring in the cytosol, is an enzymatic posttranslational event that anchors small GTPases at the membrane, and prenyl-binding proteins are needed to mask the cytoplasm-exposed lipid during transit to the target membrane. However, several of these proteins still await discovery. In this study, we report that cyclase-associated protein 1 (CAP1) binds Rap1. We found that this binding is GTP-independent, does not involve Rap1's effector domain, and is fully contained in its C-terminal hypervariable region (HVR). Furthermore, Rap1 prenylation was required for high-affinity interactions with CAP1 in a geranylgeranyl-specific manner. The prenyl binding specifically involved CAP1's C-terminal hydrophobic β-sheet domain. We present a combination of experimental and computational approaches, yielding a model whereby the high-affinity binding between Rap1 and CAP1 involves electrostatic and nonpolar side-chain interactions between Rap1's HVR residues, lipid, and CAP1 β-sheet domain. The binding was stabilized by the lipid insertion into the β-solenoid whose interior was occupied by nonpolar side chains. This model was reminiscent of the recently solved structure of the PDEδ-K-Ras complex; accordingly, disruptors of this complex, e.g. deltarasin, blocked the Rap1-CAP1 interaction. These findings indicate that CAP1 is a geranylgeranyl-binding partner of Rap1.
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Affiliation(s)
- Xuefeng Zhang
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Shufen Cao
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44116
| | - Guillermo Barila
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Martin M Edreira
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Kyoungja Hong
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Mamta Wankhede
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Nyla Naim
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Matthias Buck
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44116
| | - Daniel L Altschuler
- From the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
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37
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Liu Y, Xiao W, Shinde M, Field J, Templeton DM. Cadmium favors F-actin depolymerization in rat renal mesangial cells by site-specific, disulfide-based dimerization of the CAP1 protein. Arch Toxicol 2018; 92:1049-1064. [PMID: 29222746 PMCID: PMC6925060 DOI: 10.1007/s00204-017-2142-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 12/05/2017] [Indexed: 12/30/2022]
Abstract
Cadmium is a toxic metal that produces oxidative stress and has been shown to disrupt the actin cytoskeleton in rat renal mesangial cells (RMC). In a survey of proteins that might undergo Cd2+-dependent disulfide crosslinking, we identified the adenylyl cyclase-associated protein, CAP1, as undergoing a dimerization in response to Cd2+ (5-40 µM) that was sensitive to disulfide reducing agents, was reproduced by the disulfide crosslinking agent diamide, and was shown by site-directed mutagenesis to involve the Cys29 residue of the protein. Reactive oxygen species are not involved in the thiol oxidation, and glutathione modulates background levels of dimer. CAP1 is known to enhance cofilin's F-actin severing activity through binding to F-actin and cofilin. F-actin sedimentation and GST-cofilin pulldown studies of CAP1 demonstrated enrichment of the CAP1 dimer's association with cofilin, and in the cofilin-F-actin pellet, suggesting that Cd2+-induced dimer increases the formation of a CAP1-cofilin-F-actin complex. Both siRNA-based silencing of CAP1 and overexpression of a CAP1 mutant lacking Cys29 (and therefore, incapable of dimerization in response to Cd2+) increased RMC viability and provided some protection of F-actin structures against Cd2+. It is concluded that Cd2+ brings about disruption of the RMC cytoskeleton in part through formation of a CAP1 dimer that increases recruitment of cofilin to F-actin filaments.
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Affiliation(s)
- Ying Liu
- Laboratory Medicine and Pathobiology 1 King's College Circle, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Weiqun Xiao
- Laboratory Medicine and Pathobiology 1 King's College Circle, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Manasi Shinde
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jeffrey Field
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Douglas M Templeton
- Laboratory Medicine and Pathobiology 1 King's College Circle, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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38
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Jin ZL, Jo YJ, Namgoong S, Kim NH. CAP1 mediated actin cycling via ADF/cofilin is essential for asymmetric division in mouse oocytes. J Cell Sci 2018; 131:jcs.222356. [DOI: 10.1242/jcs.222356] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/23/2018] [Indexed: 11/20/2022] Open
Abstract
Dynamic reorganization of the actin cytoskeleton is fundamental to a number of cellular events, and various actin-regulatory proteins modulate actin polymerization and depolymerization. Cyclase-associated proteins (CAPs), highly conserved actin monomer-binding proteins, have been known to promote actin disassembly by enhancing the actin-severing activity of ADF/cofilin. In this study, we found that CAP1 regulated actin remodeling during mouse oocyte maturation. Efficient actin disassembly during oocyte maturation is essential for asymmetric division and cytokinesis. CAP1 knockdown impaired meiotic spindle migration and asymmetric division, and it resulted in an accumulation of excessive actin filaments near the spindles. In contrast, CAP1 overexpression reduced actin mesh levels. CAP1 knockdown also rescued the decrease in cofilin overexpression-mediated actin levels, and simultaneous expression of human CAP1 (hCAP1) and cofilin synergistically decreased cytoplasmic actin levels. Overexpression of hCAP1 decreased the amount of phosphorylated cofilin, indicating that CAP1 facilitated actin depolymerization via interaction with ADF/cofilin during mouse oocyte maturation. Taken together, our results provide evidence of the importance of dynamic actin recycling by CAP1 and cofilin in the asymmetric division of mouse female gametes.
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Affiliation(s)
- Zhe-Long Jin
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Korea
| | - Yu-Jin Jo
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Korea
| | - Suk Namgoong
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Korea
| | - Nam-Hyung Kim
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Korea
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39
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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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40
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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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41
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Zhao S, Jiang Y, Zhao Y, Huang S, Yuan M, Zhao Y, Guo Y. CASEIN KINASE1-LIKE PROTEIN2 Regulates Actin Filament Stability and Stomatal Closure via Phosphorylation of Actin Depolymerizing Factor. THE PLANT CELL 2016; 28:1422-39. [PMID: 27268429 PMCID: PMC4944410 DOI: 10.1105/tpc.16.00078] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/06/2016] [Indexed: 05/03/2023]
Abstract
The opening and closing of stomata are crucial for plant photosynthesis and transpiration. Actin filaments undergo dynamic reorganization during stomatal closure, but the underlying mechanism for this cytoskeletal reorganization remains largely unclear. In this study, we identified and characterized Arabidopsis thaliana casein kinase 1-like protein 2 (CKL2), which responds to abscisic acid (ABA) treatment and participates in ABA- and drought-induced stomatal closure. Although CKL2 does not bind to actin filaments directly and has no effect on actin assembly in vitro, it colocalizes with and stabilizes actin filaments in guard cells. Further investigation revealed that CKL2 physically interacts with and phosphorylates actin depolymerizing factor 4 (ADF4) and inhibits its activity in actin filament disassembly. During ABA-induced stomatal closure, deletion of CKL2 in Arabidopsis alters actin reorganization in stomata and renders stomatal closure less sensitive to ABA, whereas deletion of ADF4 impairs the disassembly of actin filaments and causes stomatal closure to be more sensitive to ABA Deletion of ADF4 in the ckl2 mutant partially recues its ABA-insensitive stomatal closure phenotype. Moreover, Arabidopsis ADFs from subclass I are targets of CKL2 in vitro. Thus, our results suggest that CKL2 regulates actin filament reorganization and stomatal closure mainly through phosphorylation of ADF.
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Affiliation(s)
- Shuangshuang Zhao
- Key Laboratory of Plant Stress, Life Science College, Shandong Normal University, Jinan 250014, China State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yuxiang Jiang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Science, Beijing 100093, China
| | - Yang Zhao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Science, Beijing 100093, China Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ming Yuan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yanxiu Zhao
- Key Laboratory of Plant Stress, Life Science College, Shandong Normal University, Jinan 250014, China
| | - Yan Guo
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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42
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Field J, Ye DZ, Shinde M, Liu F, Schillinger KJ, Lu M, Wang T, Skettini M, Xiong Y, Brice AK, Chung DC, Patel VV. CAP2 in cardiac conduction, sudden cardiac death and eye development. Sci Rep 2015; 5:17256. [PMID: 26616005 PMCID: PMC4663486 DOI: 10.1038/srep17256] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/14/2015] [Indexed: 02/03/2023] Open
Abstract
Sudden cardiac death kills 180,000 to 450,000 Americans annually, predominantly males. A locus that confers a risk for sudden cardiac death, cardiac conduction disease, and a newly described developmental disorder (6p22 syndrome) is located at 6p22. One gene at 6p22 is CAP2, which encodes a cytoskeletal protein that regulates actin dynamics. To determine the role of CAP2 in vivo, we generated knockout (KO) mice. cap2−/cap2− males were underrepresented at weaning and ~70% died by 12 weeks of age, but cap2−/cap2− females survived at close to the expected levels and lived normal life spans. CAP2 knockouts resembled patients with 6p22 syndrome in that mice were smaller and they developed microphthalmia and cardiac disease. The cardiac disease included cardiac conduction disease (CCD) and, after six months of age, dilated cardiomyopathy (DCM), most noticeably in the males. To address the mechanisms underlying these phenotypes, we used Cre-mediated recombination to knock out CAP2 in cardiomyocytes. We found that the mice developed CCD, leading to sudden cardiac death from complete heart block, but no longer developed DCM or the other phenotypes, including sex bias. These studies establish a direct role for CAP2 and actin dynamics in sudden cardiac death and cardiac conduction disease.
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Affiliation(s)
- Jeffrey Field
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Diana Z Ye
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Manasi Shinde
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Fang Liu
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Kurt J Schillinger
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA.,Section of Cardiac Electrophysiology, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - MinMin Lu
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Tao Wang
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Michelle Skettini
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Yao Xiong
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Angela K Brice
- University Laboratory Animal Resources and School of Veterinary Medicine, Department of Pathobiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel C Chung
- Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Pennsylvania 19041 USA
| | - Vickas V Patel
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA.,Section of Cardiac Electrophysiology, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
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43
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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: 89] [Impact Index Per Article: 9.9] [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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44
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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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45
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Coronin Enhances Actin Filament Severing by Recruiting Cofilin to Filament Sides and Altering F-Actin Conformation. J Mol Biol 2015; 427:3137-47. [PMID: 26299936 DOI: 10.1016/j.jmb.2015.08.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 08/12/2015] [Accepted: 08/12/2015] [Indexed: 11/23/2022]
Abstract
High rates of actin filament turnover are essential for many biological processes and require the activities of multiple actin-binding proteins working in concert. The mechanistic role of the actin filament severing protein cofilin is now firmly established; however, the contributions of other conserved disassembly-promoting factors including coronin have remained more obscure. Here, we have investigated the mechanism by which yeast coronin (Crn1) enhances F-actin turnover. Using multi-color total internal reflection fluorescence microscopy, we show that Crn1 enhances Cof1-mediated severing by accelerating Cof1 binding to actin filament sides. Further, using biochemical assays to interrogate F-actin conformation, we show that Crn1 alters longitudinal and lateral actin-actin contacts and restricts opening of the nucleotide-binding cleft in actin subunits. Moreover, Crn1 and Cof1 show opposite structural effects on F-actin yet synergize in promoting release of phalloidin from filaments, suggesting that Crn1/Cof1 co-decoration may increase local discontinuities in filament topology to enhance severing.
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46
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Jansen S, Collins A, Chin SM, Ydenberg CA, Gelles J, Goode BL. Single-molecule imaging of a three-component ordered actin disassembly mechanism. Nat Commun 2015; 6:7202. [PMID: 25995115 PMCID: PMC4443854 DOI: 10.1038/ncomms8202] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 04/17/2015] [Indexed: 12/25/2022] Open
Abstract
The mechanisms by which cells destabilize and rapidly disassemble filamentous actin networks have remained elusive; however, Coronin, Cofilin and AIP1 have been implicated in this process. Here using multi-wavelength single-molecule fluorescence imaging, we show that mammalian Cor1B, Cof1 and AIP1 work in concert through a temporally ordered pathway to induce highly efficient severing and disassembly of actin filaments. Cor1B binds to filaments first, and dramatically accelerates the subsequent binding of Cof1, leading to heavily decorated, stabilized filaments. Cof1 in turn recruits AIP1, which rapidly triggers severing and remains bound to the newly generated barbed ends. New growth at barbed ends generated by severing was blocked specifically in the presence of all three proteins. This activity enabled us to reconstitute and directly visualize single actin filaments being rapidly polymerized by formins at their barbed ends while simultanteously being stochastically severed and capped along their lengths, and disassembled from their pointed ends. The roles of Coronin, Cofilin and AIP1 in promoting actin disassembly have not been well understood. Here using single-molecule fluorescence imaging, Jansen et al. show that the three proteins act together in a coordinated, temporal pathway to induce rapid severing and disassembly of actin filaments.
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Affiliation(s)
- Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Agnieszka Collins
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Samantha M Chin
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Casey A Ydenberg
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
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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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