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Liu X, Shu S. Suggesting Dictyostelium as a Model for Disease-Related Protein Studies through Myosin II Polymerization Pathway. Cells 2024; 13:263. [PMID: 38334655 PMCID: PMC10854627 DOI: 10.3390/cells13030263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/23/2024] [Accepted: 01/27/2024] [Indexed: 02/10/2024] Open
Abstract
Dictyostelium myosin II displays remarkable dynamism within the cell, continually undergoing polymerization and depolymerization processes. Under low-ion conditions, it assumes a folded structure like muscle myosins and forms thick filaments through polymerization. In our study, we presented intermediate structures observed during the early stages of polymerization of purified myosin via negative staining electron microscopy, immediately crosslinked with glutaraldehyde at the onset of polymerization. We identified folded monomers, dimers, and tetramers in the process. Our findings suggest that Dictyostelium myosin II follows a polymerization pathway in vitro akin to muscle myosin, with folded monomers forming folded parallel and antiparallel dimers that subsequently associate to create folded tetramers. These folded tetramers eventually unfold and associate with other tetramers to produce long filaments. Furthermore, our research revealed that ATP influences filament size, reducing it regardless of the status of RLC phosphorylation while significantly increasing the critical polymerization concentrations from 0.2 to 9 nM. In addition, we demonstrate the morphology of fully matured Dictyostelium myosin II filaments.
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Discovery of ultrafast myosin, its amino acid sequence, and structural features. Proc Natl Acad Sci U S A 2022; 119:2120962119. [PMID: 35173046 PMCID: PMC8872768 DOI: 10.1073/pnas.2120962119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2022] [Indexed: 11/18/2022] Open
Abstract
Cytoplasmic streaming with extremely high velocity (∼70 μm s-1) occurs in cells of the characean algae (Chara). Because cytoplasmic streaming is caused by myosin XI, it has been suggested that a myosin XI with a velocity of 70 μm s-1, the fastest myosin measured so far, exists in Chara cells. However, the velocity of the previously cloned Chara corallina myosin XI (CcXI) was about 20 μm s-1, one-third of the cytoplasmic streaming velocity in Chara Recently, the genome sequence of Chara braunii has been published, revealing that this alga has four myosin XI genes. We cloned these four myosin XI (CbXI-1, 2, 3, and 4) and measured their velocities. While the velocities of CbXI-3 and CbXI-4 motor domains (MDs) were similar to that of CcXI MD, the velocities of CbXI-1 and CbXI-2 MDs were 3.2 times and 2.8 times faster than that of CcXI MD, respectively. The velocity of chimeric CbXI-1, a functional, full-length CbXI-1 construct, was 60 μm s-1 These results suggest that CbXI-1 and CbXI-2 would be the main contributors to cytoplasmic streaming in Chara cells and show that these myosins are ultrafast myosins with a velocity 10 times faster than fast skeletal muscle myosins in animals. We also report an atomic structure (2.8-Å resolution) of myosin XI using X-ray crystallography. Based on this crystal structure and the recently published cryo-electron microscopy structure of acto-myosin XI at low resolution (4.3-Å), it appears that the actin-binding region contributes to the fast movement of Chara myosin XI. Mutation experiments of actin-binding surface loops support this hypothesis.
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Kronert WA, Melkani GC, Melkani A, Bernstein SI. A Failure to Communicate: MYOSIN RESIDUES INVOLVED IN HYPERTROPHIC CARDIOMYOPATHY AFFECT INTER-DOMAIN INTERACTION. J Biol Chem 2015; 290:29270-80. [PMID: 26446785 PMCID: PMC4705933 DOI: 10.1074/jbc.m115.681874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/01/2015] [Indexed: 11/06/2022] Open
Abstract
Our molecular modeling studies suggest a charge-dependent interaction between residues Glu-497 in the relay domain and Arg-712 in the converter domain of human β-cardiac myosin. To test the significance of this putative interaction, we generated transgenic Drosophila expressing indirect flight muscle myosin with charge reversal mutations in the relay (E496R) or converter (R713E). Each mutation yielded dramatic reductions in myosin Ca-ATPase activity (~80%) as well as in basal (~67%) and actin-activated (~84%) Mg-ATPase activity. E496R myosin-induced in vitro actin-sliding velocity was reduced by 71% and R713E myosin permitted no actin motility. Indirect flight muscles of late pupae from each mutant displayed disrupted myofibril assembly, with adults having severely abnormal myofibrils and no flight ability. To understand the molecular basis of these defects, we constructed a putative compensatory mutant that expresses myosin with both E496R and R713E. Intriguingly, ATPase values were restored to ~73% of wild-type and actin-sliding velocity increased to 40%. The double mutation suppresses myofibril assembly defects in pupal indirect flight muscles and dramatically reduces myofibril disruption in young adults. Although sarcomere organization is not sustained in older flies and flight ability is not restored in homozygotes, young heterozygotes fly well. Our results indicate that this charge-dependent interaction between the myosin relay and converter domains is essential to the mechanochemical cycle and sarcomere assembly. Furthermore, the same inter-domain interaction is disrupted when modeling human β-cardiac myosin heavy chain cardiomyopathy mutations E497D or R712L, implying that abolishing this salt bridge is one cause of the human disease.
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Affiliation(s)
- William A Kronert
- From the Department of Biology, Molecular Biology Institute and Heart Institute San Diego State University, San Diego, California 92182-4614
| | - Girish C Melkani
- From the Department of Biology, Molecular Biology Institute and Heart Institute San Diego State University, San Diego, California 92182-4614
| | - Anju Melkani
- From the Department of Biology, Molecular Biology Institute and Heart Institute San Diego State University, San Diego, California 92182-4614
| | - Sanford I Bernstein
- From the Department of Biology, Molecular Biology Institute and Heart Institute San Diego State University, San Diego, California 92182-4614
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4
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How actin initiates the motor activity of Myosin. Dev Cell 2015; 33:401-12. [PMID: 25936506 DOI: 10.1016/j.devcel.2015.03.025] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 02/23/2015] [Accepted: 03/30/2015] [Indexed: 11/22/2022]
Abstract
Fundamental to cellular processes are directional movements driven by molecular motors. A common theme for these and other molecular machines driven by ATP is that controlled release of hydrolysis products is essential for using the chemical energy efficiently. Mechanochemical transduction by myosin motors on actin is coupled to unknown structural changes that result in the sequential release of inorganic phosphate (Pi) and MgADP. We present here a myosin structure possessing an actin-binding interface and a tunnel (back door) that creates an escape route for Pi with a minimal rotation of the myosin lever arm that drives movements. We propose that this state represents the beginning of the powerstroke on actin and that Pi translocation from the nucleotide pocket triggered by actin binding initiates myosin force generation. This elucidates how actin initiates force generation and movement and may represent a strategy common to many molecular machines.
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Witjas-Paalberends ER, Ferrara C, Scellini B, Piroddi N, Montag J, Tesi C, Stienen GJM, Michels M, Ho CY, Kraft T, Poggesi C, van der Velden J. Faster cross-bridge detachment and increased tension cost in human hypertrophic cardiomyopathy with the R403Q MYH7 mutation. J Physiol 2014; 592:3257-72. [PMID: 24928957 DOI: 10.1113/jphysiol.2014.274571] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The first mutation associated with hypertrophic cardiomyopathy (HCM) is the R403Q mutation in the gene encoding β-myosin heavy chain (β-MyHC). R403Q locates in the globular head of myosin (S1), responsible for interaction with actin, and thus motor function of myosin. Increased cross-bridge relaxation kinetics caused by the R403Q mutation might underlie increased energetic cost of tension generation; however, direct evidence is absent. Here we studied to what extent cross-bridge kinetics and energetics are related in single cardiac myofibrils and multicellular cardiac muscle strips of three HCM patients with the R403Q mutation and nine sarcomere mutation-negative HCM patients (HCMsmn). Expression of R403Q was on average 41 ± 4% of total MYH7 mRNA. Cross-bridge slow relaxation kinetics in single R403Q myofibrils was significantly higher (P < 0.0001) than in HCMsmn myofibrils (0.47 ± 0.02 and 0.30 ± 0.02 s(-1), respectively). Moreover, compared to HCMsmn, tension cost was significantly higher in the muscle strips of the three R403Q patients (2.93 ± 0.25 and 1.78 ± 0.10 μmol l(-1) s(-1) kN(-1) m(-2), respectively) which showed a positive linear correlation with relaxation kinetics in the corresponding myofibril preparations. This correlation suggests that faster cross-bridge relaxation kinetics results in an increase in energetic cost of tension generation in human HCM with the R403Q mutation compared to HCMsmn. Therefore, increased tension cost might contribute to HCM disease in patients carrying the R403Q mutation.
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Affiliation(s)
| | - Claudia Ferrara
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Beatrice Scellini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Ger J M Stienen
- Department of Physiology, VU University Medical Centre, Amsterdam, The Netherlands Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands
| | - Michelle Michels
- Thorax Centre, Cardiology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Carolyn Y Ho
- Brigham and Women's Hospital, Cardiology, Boston, USA
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Centre, Amsterdam, The Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
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Nie QM, Sasai M, Terada TP. Conformational flexibility of loops of myosin enhances the global bias in the actin–myosin interaction landscape. Phys Chem Chem Phys 2014; 16:6441-7. [DOI: 10.1039/c3cp54464h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Shu S, Liu X, Kriebel PW, Hong MS, Daniels MP, Parent CA, Korn ED. Expression of Y53A-actin in Dictyostelium disrupts the cytoskeleton and inhibits intracellular and intercellular chemotactic signaling. J Biol Chem 2010; 285:27713-25. [PMID: 20610381 DOI: 10.1074/jbc.m110.116277] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We showed previously that phosphorylation of Tyr(53), or its mutation to Ala, inhibits actin polymerization in vitro with formation of aggregates of short filaments, and that expression of Y53A-actin in Dictyostelium blocks differentiation and development at the mound stage (Liu, X., Shu, S., Hong, M. S., Levine, R. L., and Korn, E. D. (2006) Proc. Natl. Acad. Sci. U.S.A. 103, 13694-13699; Liu, X., Shu, S., Hong, M. S., Yu, B., and Korn, E. D. (2010) J. Biol. Chem. 285, 9729-9739). We now show that expression of Y53A-actin, which does not affect cell growth, phagocytosis, or pinocytosis, inhibits the formation of head-to-tail cell streams during cAMP-induced aggregation, although individual amoebae chemotax normally. We show that expression of Y53A-actin causes a 50% reduction of cell surface cAMP receptors, and inhibits cAMP-induced increases in adenylyl cyclase A activity, phosphorylation of ERK2, and actin polymerization. Trafficking of vesicles containing adenylyl cyclase A to the rear of the cell and secretion of the ACA vesicles are also inhibited. The actin cytoskeleton of cells expressing Y53A-actin is characterized by numerous short filaments, and bundled and aggregated filaments similar to the structures formed by copolymerization of purified Y53A-actin and wild-type actin in vitro. This disorganized actin cytoskeleton may be responsible for the inhibition of intracellular and intercellular cAMP signaling in cells expressing F-Y53A-actin.
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Affiliation(s)
- Shi Shu
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA
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Liu X, Shu S, Hong MSS, Yu B, Korn ED. Mutation of actin Tyr-53 alters the conformations of the DNase I-binding loop and the nucleotide-binding cleft. J Biol Chem 2010; 285:9729-9739. [PMID: 20100837 DOI: 10.1074/jbc.m109.073452] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All but 11 of the 323 known actin sequences have Tyr at position 53, and the 11 exceptions have the conservative substitution Phe, which raises the following questions. What is the critical role(s) of Tyr-53, and, if it can be replaced by Phe, why has this happened so infrequently? We compared the properties of purified endogenous Dictyostelium actin and mutant constructs with Tyr-53 replaced by Phe, Ala, Glu, Trp, and Leu. The Y53F mutant did not differ significantly from endogenous actin in any of the properties assayed, but the Y53A and Y53E mutants differed substantially; affinity for DNase I was reduced, the rate of nucleotide exchange was increased, the critical concentration for polymerization was increased, filament elongation was inhibited, and polymerized actin was in the form of small oligomers and imperfect filaments. Growth and/or development of cells expressing these actin mutants were also inhibited. The Trp and Leu mutations had lesser but still significant effects on cell phenotype and the biochemical properties of the purified actins. We conclude that either Tyr or Phe is required to maintain the functional conformations of the DNase I-binding loop (D-loop) in both G- and F-actin, and that the conformation of the D-loop affects not only the properties that directly involve the D-loop (binding to DNase I and polymerization) but also allosterically modifies the conformation of the nucleotide-binding cleft, thus increasing the rate of nucleotide exchange. The apparent evolutionary "preference" for Tyr at position 53 may be the result of Tyr allowing dynamic modification of the D-loop conformation by phosphorylation (Baek, K., Liu, X., Ferron, F., Shu, S., Korn, E. D., and Dominguez, R. (2008) Proc. Natl. Acad. Sci. U.S.A. 105, 11748-11753) with effects similar, but not identical, to those of the Ala and Glu mutations.
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Affiliation(s)
- Xiong Liu
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Shi Shu
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Myoung-Soon S Hong
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Bin Yu
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Edward D Korn
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892.
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Liu X, Shu S, Hong MSS, Levine RL, Korn ED. Phosphorylation of actin Tyr-53 inhibits filament nucleation and elongation and destabilizes filaments. Proc Natl Acad Sci U S A 2006; 103:13694-9. [PMID: 16945900 PMCID: PMC1557634 DOI: 10.1073/pnas.0606321103] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dictyostelium actin was shown to become phosphorylated on Tyr-53 late in the developmental cycle and when cells in the amoeboid stage are subjected to stress but the phosphorylated actin had not been purified and characterized. We have separated phosphorylated and unphosphorylated actin and shown that Tyr-53 phosphorylation substantially reduces actin's ability to inactivate DNase I, increases actin's critical concentration, and greatly reduces its rate of polymerization. Tyr-53 phosphorylation substantially, if not completely, inhibits nucleation and elongation from the pointed end of actin filaments and reduces the rate of elongation from the barbed end. Negatively stained electron microscopic images of polymerized Tyr-53-phosphorylated actin show a variable mixture of small oligomers and filaments, which are converted to more typical, long filaments upon addition of myosin subfragment 1. Tyr-53-phosphorylated and unphosphorylated actin copolymerize in vitro, and phosphorylated and unphosphorylated actin colocalize in amoebae. Tyr-53 phosphorylation does not affect the ability of filamentous actin to activate myosin ATPase.
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Affiliation(s)
| | - Shi Shu
- Laboratories of *Cell Biology and
| | | | - Rodney L. Levine
- Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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Korman VL, Anderson SEB, Prochniewicz E, Titus MA, Thomas DD. Structural dynamics of the actin-myosin interface by site-directed spectroscopy. J Mol Biol 2005; 356:1107-17. [PMID: 16406406 DOI: 10.1016/j.jmb.2005.10.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 10/07/2005] [Accepted: 10/11/2005] [Indexed: 11/19/2022]
Abstract
We have used site-directed spin and fluorescence labeling to test molecular models of the actin-myosin interface. Force is generated when the actin-myosin complex undergoes a transition from a disordered weak-binding state to an ordered strong-binding state. Actomyosin interface models, in which residues are classified as contributing to either weak or strong binding, have been derived by fitting individual crystallographic structures of actin and myosin into actomyosin cryo-EM maps. Our goal is to test these models using site-directed spectroscopic probes on actin and myosin. Starting with Cys-lite constructs of both yeast actin (ActC) and the Dictyostelium myosin II motor domain (S1dC), site-directed labeling (SDL) mutants were generated by mutating residues to Cys in the proposed weak and strong-binding interfaces. This report focuses on the effects of forming the strong-binding complex on four SDL mutants, two located in the proposed weak-binding interface (ActC5 and S1dC619) and two located in the proposed strong-binding interface (ActC345 and S1dC401). Neither the mutations nor labeling prevented strong actomyosin binding or actin-activation of myosin ATPase. Formation of the strong-binding complex resulted in decreased spin and fluorescence probe mobility at all sites, but both myosin-bound probes showed remarkably high mobility even after complex formation. Complex formation decreased solvent accessibility for both actin-bound probes, but increased it for the myosin-bound probes. These results are not consistent with a simple model in which there are discrete weak and strong interfaces, with only the strong interface forming under strong-binding conditions, nor are they consistent with a model in which surface residues become rigid and inaccessible upon complex formation. We conclude that all four of these residues are involved in the strong actin-myosin interface, but this interface is remarkably dynamic, especially on the surface of myosin.
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Affiliation(s)
- Vicci L Korman
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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