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Elkrief D, Matusovsky O, Cheng YS, Rassier DE. From amino-acid to disease: the effects of oxidation on actin-myosin interactions in muscle. J Muscle Res Cell Motil 2023; 44:225-254. [PMID: 37805961 DOI: 10.1007/s10974-023-09658-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/15/2023] [Indexed: 10/10/2023]
Abstract
Actin-myosin interactions form the basis of the force-producing contraction cycle within the sarcomere, serving as the primary mechanism for muscle contraction. Post-translational modifications, such as oxidation, have a considerable impact on the mechanics of these interactions. Considering their widespread occurrence, the explicit contributions of these modifications to muscle function remain an active field of research. In this review, we aim to provide a comprehensive overview of the basic mechanics of the actin-myosin complex and elucidate the extent to which oxidation influences the contractile cycle and various mechanical characteristics of this complex at the single-molecule, myofibrillar and whole-muscle levels. We place particular focus on amino acids shown to be vulnerable to oxidation in actin, myosin, and some of their binding partners. Additionally, we highlight the differences between in vitro environments, where oxidation is controlled and limited to actin and myosin and myofibrillar or whole muscle environments, to foster a better understanding of oxidative modification in muscle. Thus, this review seeks to encompass a broad range of studies, aiming to lay out the multi layered effects of oxidation in in vitro and in vivo environments, with brief mention of clinical muscular disorders associated with oxidative stress.
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Affiliation(s)
- Daren Elkrief
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Oleg Matusovsky
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Yu-Shu Cheng
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada
| | - Dilson E Rassier
- Department of Physiology, McGill University, Montreal, QC, Canada.
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC, Canada.
- Simon Fraser University, Burnaby, BC, Canada.
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2
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Yampolskaya DS, Kopylova GV, Shchepkin DV, Nabiev SR, Nikitina LV, Walklate J, Ziganshin RH, Bershitsky SY, Geeves MA, Matyushenko AM, Levitsky DI. Pseudo-phosphorylation of essential light chains affects the functioning of skeletal muscle myosin. Biophys Chem 2023; 292:106936. [PMID: 36436358 DOI: 10.1016/j.bpc.2022.106936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/10/2022] [Accepted: 11/18/2022] [Indexed: 11/21/2022]
Abstract
The work aimed to investigate how the phosphorylation of the myosin essential light chain of fast skeletal myosin (LC1) affects the functional properties of the myosin molecule. Using mass-spectrometry, we revealed phosphorylated peptides of LC1 in myosin from different fast skeletal muscles. Mutations S193D and T65D that mimic natural phosphorylation of LC1 were produced, and their effects on functional properties of the entire myosin molecule and isolated myosin head (S1) were studied. We have shown that T65D mutation drastically decreased the sliding velocity of thin filaments in an in vitro motility assay and strongly increased the duration of actin-myosin interaction in optical trap experiments. These effects of T65D mutation in LC1 observed only with the whole myosin but not with S1 were prevented by double T65D/S193D mutation. The T65D and T65D/S193D mutations increased actin-activated ATPase activity of S1 and decreased ADP affinity for the actin-S1 complex. The results indicate that pseudo-phosphorylation of LC1 differently affects the properties of the whole myosin molecule and its isolated head. Also, the results show that phosphorylation of LC1 of skeletal myosin could be one more mechanism of regulation of actin-myosin interaction that needs further investigation.
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Affiliation(s)
- Daria S Yampolskaya
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky prosp. 33, Moscow 119071, Russia
| | - Galina V Kopylova
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg 620049, Russia
| | - Daniil V Shchepkin
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg 620049, Russia
| | - Salavat R Nabiev
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg 620049, Russia
| | - Larisa V Nikitina
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg 620049, Russia
| | - Jonathan Walklate
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Sergey Y Bershitsky
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg 620049, Russia
| | - Michael A Geeves
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
| | - Alexander M Matyushenko
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky prosp. 33, Moscow 119071, Russia
| | - Dmitrii I Levitsky
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky prosp. 33, Moscow 119071, Russia.
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3
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Wawro B, Nieznanska H, Nieznanski K, Gruszczynska-Biegala J, Stepkowski D, Strzelecka-Golaszewska H. Mechanisms of the modulation of actin-myosin interactions by A1-type myosin light chains. Biochim Biophys Acta Gen Subj 2022;:130132. [PMID: 35307509 DOI: 10.1016/j.bbagen.2022.130132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 03/04/2022] [Accepted: 03/13/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND The interaction of N-terminal extension of the myosin A1 essential light chain (A1 ELC) with actin is receiving increasing attention as a target in utilizing synthetic A1 ELC N-terminal-derived peptides in cardiac dysfunction therapy. METHODS To elucidate the mechanism by which these peptides regulate actin-myosin interaction, here we have investigated their effects on the myosin subfragment 1 (S1)-induced polymerization of G-actin. RESULTS The MLCFpep and MLCSpep peptides spanning the 3-12 of A1 ELC sequences from fast and slow skeletal muscle, respectively, increased the rate of actin polymerization not only by S1(A2) but also the rate of S1(A1)-induced actin polymerization, suggesting that they did not interfere with the direct binding of A1 ELC with actin. The efficiency of actin polymerization in the presence of the N-terminal ELC peptides depended on their sequence. Substitution of aspartic acid for neutral asparagine at position 5 of MLCFpep dramatically enhanced its ability to stimulate S1-induced polymerization and enabled it to initiate polymerization of G-actin in the absence of S1. CONCLUSIONS These and other results presented in this work suggest that the modulation of myosin motor activity by N-terminal ELC peptides is exerted through a change in actin filament conformation rather than through blocking the A1 ELC-actin interaction. GENERAL SIGNIFICANCE The results imply the possibility of enhancing therapeutic effects of these peptides by modifications of their sequence.
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Kopylova GV, Berg VY, Kochurova AM, Matyushenko AM, Bershitsky SY, Shchepkin DV. The effects of the tropomyosin cardiomyopathy mutations on the calcium regulation of actin-myosin interaction in the atrium and ventricle differ. Biochem Biophys Res Commun 2021; 588:29-33. [PMID: 34942531 DOI: 10.1016/j.bbrc.2021.12.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/15/2021] [Indexed: 12/17/2022]
Abstract
The molecular mechanisms of pathogenesis of atrial myopathy associated with hypertrophic (HCM) and dilated (DCM) mutations of sarcomeric proteins are still poorly understood. For this, one needs to investigate the effects of the mutations on actin-myosin interaction in the atria separately from ventricles. We compared the impact of the HCM and DCM mutations of tropomyosin (Tpm) on the calcium regulation of the thin filament interaction with atrial and ventricular myosin using an in vitro motility assay. We found that the mutations differently affect the calcium regulation of actin-myosin interaction in the atria and ventricles. The DCM E40K Tpm mutation significantly reduced the maximum sliding velocity of thin filaments with ventricular myosin and its Ca2+-sensitivity. With atrial myosin, its effects were less pronounced. The HCM I172T mutation reduced the Ca2+-sensitivity of the sliding velocity of filaments with ventricular myosin but increased it with the atrial one. The HCM L185R mutation did not affect actin-myosin interaction in the atria. The results indicate that the difference in the effects of Tpm mutations on the actin-myosin interaction in the atria and ventricles may be responsible for the difference in pathological changes in the atrial and ventricular myocardium.
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Affiliation(s)
- Galina V Kopylova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia
| | - Valentina Y Berg
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia
| | - Anastasia M Kochurova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia
| | - Alexander M Matyushenko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Sergey Y Bershitsky
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia
| | - Daniil V Shchepkin
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, Russia.
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5
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Khokhlova A, Myachina T, Butova X, Volzhaninov D, Berg V, Kochurova A, Kuznetsov D, Mukhlynina E, Kopylova G, Shchepkin D. Differing effects of estrogen deficiency on the contractile function of atrial and ventricular myocardium. Biochem Biophys Res Commun 2021; 541:30-5. [PMID: 33461065 DOI: 10.1016/j.bbrc.2020.12.102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 12/30/2020] [Indexed: 11/20/2022]
Abstract
Estrogen deficiency has a significant influence on the excitation-contraction coupling in the ventricular myocardium but its impact on the atrial contractile function has not been studied. We have compared the effects of estrogen deficiency on the contractility and cytosolic Ca2+ transient of single cardiomyocytes isolated from the left atrium (LA) and the left ventricle (LV) of rats subjected to ovariectomy (OVX) or sham surgery (Sham). The characteristics of actin-myosin interaction were studied in an in vitro motility assay. We found that OVX decreased the contractility of LV single cardiomyocytes but increased that of LA myocytes. The disturbance of ventricular mechanical function may be explained by the acceleration of Ca2+ transient and reduced Ca2+ sensitivity of the actin-myosin interaction. The augmentation of LA contractility may be explained by accelerated cross-bridge kinetics and increased end-diastolic sarcomere length, which may lead to elevated tension in atrial cells due to the Frank-Starling mechanism.
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6
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Shchepkin DV, Nabiev SR, Nikitina LV, Kochurova AM, Berg VY, Bershitsky SY, Kopylova GV. Myosin from the ventricle is more sensitive to omecamtiv mecarbil than myosin from the atrium. Biochem Biophys Res Commun 2020; 528:658-663. [PMID: 32513536 DOI: 10.1016/j.bbrc.2020.05.108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 05/17/2020] [Indexed: 11/25/2022]
Abstract
Omecamtiv mecarbil (OM), an activator of cardiac myosin, strongly affects contractile characteristics of the ventricles and, to a much lesser extent, the characteristics of atrial contraction. We compared the molecular mechanism of action of OM on the interaction of atrial and ventricular myosin with actin using an optical trap and an in vitro motility assay. In concentrations up to 0.5 μM, OM did not affect the step size of a myosin molecule but reduced it at a higher OM level. OM substantially prolonged the interaction of both isoforms of myosin with actin. However, the interaction characteristics of ventricular myosin with actin were more sensitive to OM than those of atrial myosin. Our results, obtained at the level of isolated proteins, can explain why the impact of OM in therapeutic concentrations on the contractile function of the atrium is less significant as compared to those of the ventricle.
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Affiliation(s)
- Daniil V Shchepkin
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Salavat R Nabiev
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Larisa V Nikitina
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Anastasia M Kochurova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Valentina Y Berg
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Sergey Y Bershitsky
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Galina V Kopylova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia.
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7
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Matyushenko AM, Shchepkin DV, Kopylova GV, Bershitsky SY, Levitsky DI. Unique functional properties of slow skeletal muscle tropomyosin. Biochimie 2020; 174:1-8. [PMID: 32224097 DOI: 10.1016/j.biochi.2020.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/19/2020] [Accepted: 03/19/2020] [Indexed: 12/20/2022]
Abstract
Tropomyosin (Tpm) is an α-helical coiled-coil actin-binding protein playing an essential role in the regulation of muscle contraction. The α- (Tpm 1.1) and γ- (Tpm 3.12) Tpm isoforms are expressed in fast and slow human skeletal muscles, respectively, while β-Tpm (Tpm 2.2) is expressed in both muscle types. This results in the formation of Tpm αα- and γγ-homodimers as well as αβ- and γβ-heterodimers. The properties of αα-homodimer are well studied, whereas very little is known about the functional properties of γγ-homodimer and γβ-heterodimer. We investigated interaction characteristics of Tpm γγ-homodimer and γβ-heterodimer with actin filaments and Ca2+-regulation of actin-myosin interaction on myosin from fast and slow skeletal muscles. The results showed that complexes formed by γγ-Tpm and γβ-Tpm with F-actin are more stable than those with αα-Tpm and αβ-Tpm. The maximum sliding speed of regulated thin filaments with either γγ-Tpm or γβ-Tpm moving over skeletal myosin was significantly less than that of the filaments with αα-Tpm or αβ-Tpm. The results indicate that isoforms of Tpm along with isoforms of myosin determine of functional properties of skeletal muscles and support an idea on the combined expression of myosin and Tpm isoforms.
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Affiliation(s)
- Alexander M Matyushenko
- A. N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Daniil V Shchepkin
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Galina V Kopylova
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Sergey Y Bershitsky
- Institute of Immunology and Physiology of the Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Dmitrii I Levitsky
- A. N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia; A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119234, Russia.
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8
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Kopylova G, Nabiev S, Shchepkin D, Bershitsky S. Carbonylation of atrial myosin prolongs its interaction with actin. Eur Biophys J 2018; 47:11-18. [PMID: 28409219 DOI: 10.1007/s00249-017-1209-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/22/2017] [Accepted: 04/07/2017] [Indexed: 11/26/2022]
Abstract
Carbonylation induced by hyperthyroidism suppresses force generation of skeletal myosin and sliding velocity of actin filaments in an in vitro motility assay. However, its effects on cardiac myosin at the molecular level have not been studied. Hyperthyroidism induces a change in expression of myosin heavy chains in ventricles, which may mask the effect of oxidation. In contrast to ventricular myosin, expression of myosin heavy chains in the atrium does not change upon hyperthyroidism and enables investigation of the effect of oxidation on cardiac myosin. We studied the influence of carbonylation, a type of protein oxidation, on the motor function of atrial myosin and Ca2+ regulation of actin-myosin interaction at the level of isolated proteins and single molecules using an in vitro motility assay and an optical trap. Carbonylation of atrial myosin prolonged its attached state on actin and decreased maximal sliding velocity of thin filaments over this myosin but did not affect the calcium sensitivity of the velocity. The results indicate that carbonylation of atrial myosin induced by hyperthyroidism can be a rate-limiting factor of atrium contractility and so participates in the genesis of heart failure in hyperthyroidism.
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Affiliation(s)
- G Kopylova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomayskaya ul. 106, Yekaterinburg, 620049, Russia.
| | - S Nabiev
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomayskaya ul. 106, Yekaterinburg, 620049, Russia
| | - D Shchepkin
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomayskaya ul. 106, Yekaterinburg, 620049, Russia
| | - S Bershitsky
- Institute of Immunology and Physiology, Russian Academy of Sciences, Pervomayskaya ul. 106, Yekaterinburg, 620049, Russia
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9
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Karpicheva OE, Sirenko VV, Rysev NA, Simonyan AO, Borys D, Moraczewska J, Borovikov YS. Deviations in conformational rearrangements of thin filaments and myosin caused by the Ala155Thr substitution in hydrophobic core of tropomyosin. Biochim Biophys Acta Proteins Proteom 2017; 1865:1790-1799. [PMID: 28939420 DOI: 10.1016/j.bbapap.2017.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/14/2017] [Accepted: 09/18/2017] [Indexed: 12/28/2022]
Abstract
Effects of the Ala155Thr substitution in hydrophobic core of tropomyosin Tpm1.1 on conformational rearrangements of the components of the contractile system (Tpm1.1, actin and myosin heads) were studied by polarized fluorimetry technique at different stages of the actomyosin ATPase cycle. The proteins were labelled by fluorescent probes and incorporated into ghost muscle fibres. The substitution violated the blocked and closed states of thin filaments stimulating abnormal displacement of tropomyosin to the inner domains of actin, switching actin on and increasing the relative number of the myosin heads in strong-binding state. Furthermore, the mutant tropomyosin disrupted the major function of troponin to alter the distribution of the different functional states of thin filaments. At low Ca2+ troponin did not effectively switch thin filament off and the myosin head lost the ability to drive the spatial arrangement of the mutant tropomyosin. The information about tropomyosin flexibility obtained from the fluorescent probes at Cys190 indicates that this tropomyosin is generally more rigid, that obviously prevents tropomyosin to bend and adopt the appropriate conformation required for proper regulation.
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Affiliation(s)
- Olga E Karpicheva
- Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Av., 194064 St Petersburg, Russia
| | - Vladimir V Sirenko
- Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Av., 194064 St Petersburg, Russia
| | - Nikita A Rysev
- Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Av., 194064 St Petersburg, Russia
| | - Armen O Simonyan
- Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Av., 194064 St Petersburg, Russia; Saint Petersburg State University, 7/9 Universitetskaya nab, 199034 St Petersburg, Russia
| | - Danuta Borys
- Department of Biochemistry and Cell Biology, Faculty of Natural Sciences, Kazimierz Wielki University in Bydgoszcz, 12 Ks. J. Poniatowski St., 85-671 Bydgoszcz, Poland
| | - Joanna Moraczewska
- Department of Biochemistry and Cell Biology, Faculty of Natural Sciences, Kazimierz Wielki University in Bydgoszcz, 12 Ks. J. Poniatowski St., 85-671 Bydgoszcz, Poland
| | - Yurii S Borovikov
- Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Av., 194064 St Petersburg, Russia.
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10
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Syomin FA, Tsaturyan AK. A simple model of cardiac muscle for multiscale simulation: Passive mechanics, crossbridge kinetics and calcium regulation. J Theor Biol 2017; 420:105-16. [PMID: 28223172 DOI: 10.1016/j.jtbi.2017.02.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 02/09/2017] [Accepted: 02/16/2017] [Indexed: 11/22/2022]
Abstract
A simple model of cardiac muscle was designed for multiscale simulation of heart mechanics. Relaxed cardiac muscle was described as a transversally isotropic hyperelastic material. Active tension caused by actin-myosin crossbridges depends on the ensemble averaged strain of myosin heads bound to actin. Calcium activation was modeled by Ca2+ binding to troponin-C. To account for the dependence of troponin affinity for Ca2+ on myosin heads strongly bound to actin, the kinetics of troponin binding to Ca2+ in the overlap zone of the thin and thick filaments and outside it were separated. The changes in the length of these zones during muscle shortening or lengthening were accounted for explicitly. Simplified version of the model contains only 5 ordinary differential equations (ODE). Model parameters were estimated from a limited set of experiments with skeletal and cardiac muscle. Simulations have shown that model reproduces qualitatively a number of experimental observations: steady-state force-velocity and stiffness-velocity relations; mechanical responses to step changes in muscle length or load; steep Ca2+-tension relationship and its dependence on sarcomere length tension (the Frank-Starling mechanism); tension, shortening and Ca2+-transients in twitch isometric and isotonic contractions, tension development and redevelopment upon fast change in Ca2+ concentration or muscle release followed by re-stretch. We believe that the model can be effectively used for modeling contraction and relaxation of the heart.
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11
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Kopylova G, Nabiev S, Nikitina L, Shchepkin D, Bershitsky S. The properties of the actin-myosin interaction in the heart muscle depend on the isoforms of myosin but not of α-actin. Biochem Biophys Res Commun 2016; 476:648-653. [PMID: 27264951 DOI: 10.1016/j.bbrc.2016.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/02/2016] [Indexed: 11/27/2022]
Abstract
In myocardium of mammals there are two isoforms of myosin heavy chains, α and β. In ventricle, together with ventricular isoforms of light chains they form two isomyosins: V1 and V3, homodimers of α- and β-heavy chains, respectively. In atria, α- and β-heavy chains together with atrial light chains form A1 (αα) and A2 (ββ) isomyosins. Besides in myocardium two isoforms of α-actin, skeletal and cardiac, are expressed. We assume that the differences in the amino acid sequence of cardiac and skeletal actin may affect its interaction with myosin. To test this hypothesis, we investigated characteristics of actin-myosin interactions of cardiac and skeletal isoforms of α-actin with the isoforms of cardiac myosin using an optical trap technique and an in vitro motility assay. It was found that the mechanical and kinetic characteristics of the interactions of the isoforms of cardiac myosin with actin depend on the isoforms of myosin not α-actin.
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Affiliation(s)
- G Kopylova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia.
| | - S Nabiev
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - L Nikitina
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - D Shchepkin
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - S Bershitsky
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
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12
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Bai F, Caster HM, Rubenstein PA, Dawson JF, Kawai M. Using baculovirus/insect cell expressed recombinant actin to study the molecular pathogenesis of HCM caused by actin mutation A331P. J Mol Cell Cardiol 2014; 74:64-75. [PMID: 24793351 DOI: 10.1016/j.yjmcc.2014.04.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 01/07/2023]
Abstract
Recombinant WT human cardiac actin (WT actin) was expressed using the baculovirus/insect cell expression system, purified, and used to reconstitute the thin-filament of bovine cardiac muscle fibers, together with bovine cardiac tropomyosin (Tm) and troponin (Tn). Effects of [Ca(2+)], [ATP], [phosphate] and [ADP] on tension and tension transients were studied at 25°C by using sinusoidal analysis, and the results were compared with those of native fibers and fibers reconstituted with purified bovine cardiac actin (BVC actin). In actin filament reconstituted fibers (without Tm/Tn), those reconstituted with WT actin showed exactly the same active tension as those reconstituted with purified BVC actin (WT: 0.75±0.06 T0, N=11; BVC: 0.73±0.07 T0, N=12, where T0 is the tension of original fibers before extraction). After Tm/Tn reconstitution, fibers reconstituted with WT actin generated 0.85±0.06 T0 (N=11) compared to 0.98±0.04 T0 (N=12) recovered by those reconstituted with BVC actin. In the presence of Tm/Tn, WT actin reconstituted fibers showed exactly the same Ca(2+) sensitivity as those of the native fibers and BVC actin reconstituted fibers (pCa50: native fibers: 5.69±0.01, N=10; WT: 5.69±0.02, N=11; BVC: 5.68±0.02, N=12). Sinusoidal analysis showed that the cross-bridge kinetics were the same among native fibers, BVC actin reconstituted fibers and WT actin reconstituted fibers, followed by reconstitution of Tm/Tn. These results demonstrate that baculovirus/insect cell expressed actin has no significant differences from tissue purified actin and can be used for thin-filament reconstitution assays. One hypertrophic cardiomyopathy (HCM) causing actin mutant A331P actin was also expressed and studied similarly, and the results were compared to those of the WT actin. In the reconstituted fibers, A331P significantly decreased the tension both in the absence of Tm/Tn (0.55±0.03 T0, N=13) and in their presence (0.65±0.02 T0, N=13) compared to those of the WT (0.75±0.06 T0 and 0.85±0.06 T0, respectively, N=11). A331P also showed decreased pCa50 (5.57±0.03, N=13) compared to that of WT (5.69±0.02, N=11). The cross-bridge kinetics and its distribution were similar between WT and A331P actin reconstituted fibers, indicating that force/cross-bridge was decreased by A331P. In conclusion, A331P causes a weakened cross-bridge force, which leads to a decreased active tension, reduces left-ventricular ejection fraction, and eventually results in the HCM phenotype.
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Affiliation(s)
- Fan Bai
- Department of Anatomy and Cell Biology, The University of Iowa, Iowa City, IA 52242-1109, USA.
| | - Hannah M Caster
- Department of Anatomy and Cell Biology, The University of Iowa, Iowa City, IA 52242-1109, USA.
| | - Peter A Rubenstein
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242-1109, USA.
| | - John F Dawson
- Department of Molecular & Cellular Biology, University of Guelph, College of Biological Science, Guelph, Ontario N1G 2 W1, Canada.
| | - Masataka Kawai
- Department of Anatomy and Cell Biology, The University of Iowa, Iowa City, IA 52242-1109, USA; Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242-1109, USA.
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