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G. V. Kopylova - One of the best experts on this subject based on the ideXlab platform.
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cardiomyopathy associated mutations in tropoMyosin differently affect Actin Myosin Interaction at single molecule and ensemble levels
Journal of Muscle Research and Cell Motility, 2019Co-Authors: G. V. Kopylova, D. V. Shchepkin, Alexander M Matyushenko, Dmitrii I Levitsky, S R Nabiev, Natalia A Koubassova, Sergey Y. BershitskyAbstract:In the heart, mutations in the TPM1 gene encoding the α-isoform of tropoMyosin lead, in particular, to the development of hypertrophic and dilated cardiomyopathies. We compared the effects of hypertrophic, D175N and E180G, and dilated, E40K and E54K, cardiomyopathy mutations in TPM1 gene on the properties of single Actin-Myosin Interactions and the characteristics of the calcium regulation in an ensemble of Myosin molecules immobilised on a glass surface and interActing with regulated thin filaments. Previously, we showed that at saturating Ca2+ concentration the presence of Tpm on the Actin filament increases the duration of the Interaction. Here, we found that the studied Tpm mutations differently affected the duration: the D175N mutation reduced it compared to WT Tpm, while the E180G mutation increased it. Both dilated mutations made the duration of the Interaction even shorter than with F-Actin. The duration of the attached state of Myosin to the thin filament in the optical trap did not correlate to the sliding velocity of thin filaments and its calcium sensitivity in the in vitro motility assay. We suppose that at the level of the molecular ensemble, the cooperative mechanisms prevail in the manifestation of the effects of cardiomyopathy-associated mutations in Tpm.
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the effect of cardiac Myosin binding protein c on calcium regulation of the Actin Myosin Interaction depends on Myosin light chain isoforms
Biophysics, 2019Co-Authors: S R Nabiev, G. V. Kopylova, D. V. ShchepkinAbstract:Abstract—In addition to troponin and tropoMyosin, cardiac Myosin-binding protein C (cMyBP-C), which has an effect on the function of Myosin and thin filament activation, is involved in regulation of the Actin–Myosin Interaction in the myocardium. The β-isoform of Myosin heavy chain expressed in slow skeletal muscles is identical to that in the myocardium; however, Myosin isoforms in slow skeletal muscles and in cardiac muscle differ in the composition of the Myosin light chain isoforms. We investigated the effect of cMyBP-C on the calcium regulation of the Interaction of the Myosin of slow skeletal muscle (m. soleus) with Actin, using an in vitro motility assay and an optical trap. It was found that the physiological concentration of cMyBP-C resulted in increased calcium sensitivity of the sliding velocity of regulated thin filaments over Myosin extracted from the slow soleus muscle and increased the velocity of thin filaments, as opposed to cardiac Myosin. In the optical trap, cMyBP-C did not affect the step size of Myosin but reduced the duration of a single Actin–Myosin Interaction, thus explaining the increase in the velocity of filaments in the in vitro motility assay. Thus, the regulatory properties of cMyBP-C are exhibited in different ways depending on the composition of Myosin light chain isoforms.
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effect of interchain disulfide crosslinking in the tropoMyosin molecule on Actin Myosin Interaction in the atrial myocardium
Bulletin of Experimental Biology and Medicine, 2019Co-Authors: D. V. Shchepkin, Sergey Y. Bershitsky, Alexander M Matyushenko, G. V. KopylovaAbstract:TropoMyosin (Tpm) is one of the main regulatory proteins in the myocardium. In some heart pathologies, interchain disulfide crosslinking in the Tpm molecule occurs. In the ventricle, this change in the structural properties of the Tpm molecule affects calcium regulation of the Actin-Myosin Interaction. Using an in vitro motility assay, we found that Tpm crosslinking does not affect the Actin-Myosin Interaction in the atria. We assume that the intramolecular crosslinking of Tpm in the atrium does not play such a crucial role in the pathogenesis of heart failure as it plays in the heart ventricles.
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the effect of experimental hyperthyroidism on characteristics of Actin Myosin Interaction in fast and slow skeletal muscles
Biochemistry, 2018Co-Authors: G. V. Kopylova, D. V. Shchepkin, Sergey Y. BershitskyAbstract:The molecular mechanism of the failure of contractile function of skeletal muscles caused by oxidative damage to Myosin in hyperthyroidism is not fully understood. Using an in vitro motility assay, we studied the effect of Myosin damage caused by oxidative stress in experimental hyperthyroidism on the Actin-Myosin Interaction and its regulation by calcium. We found that hyperthyroidism-induced oxidation of Myosin is accompanied by a decrease in the sliding velocity of the regulated thin filaments in the in vitro motility assay, and this effect is increased with the duration of the pathological process.
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The isoforms of α-Actin and Myosin affect the Ca2+ regulation of the Actin-Myosin Interaction in the heart.
Biochemical and biophysical research communications, 2017Co-Authors: D. V. Shchepkin, Larisa V. Nikitina, Sergey Y. Bershitsky, G. V. KopylovaAbstract:Myocardium of mammals contains a wide range of isoforms of proteins that provides contractile function of the heart. These are two isoforms of ventricular and two of atrial Myosin, α- and β-tropoMyosin, and two isoforms of α-Actin: cardiac and skeletal. We believe that the difference in the amino acid sequence of α-Actin can affect the calcium regulation of the Actin-Myosin Interaction. To test this hypothesis, we investigated effects of the isoforms of α-Actin, cardiac and skeletal, and the isoforms of cardiac Myosin on the calcium regulation of the Actin-Myosin Interaction in an in vitro motility assay using reconstructed regulated thin filaments. The results show that isoforms of α-Actin and the ratio of α/β-chains of Tpm differently affect the calcium regulation of the Actin-Myosin Interaction in myocardium in dependence on cardiac Myosin isoforms.
D. V. Shchepkin - One of the best experts on this subject based on the ideXlab platform.
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cardiomyopathy associated mutations in tropoMyosin differently affect Actin Myosin Interaction at single molecule and ensemble levels
Journal of Muscle Research and Cell Motility, 2019Co-Authors: G. V. Kopylova, D. V. Shchepkin, Alexander M Matyushenko, Dmitrii I Levitsky, S R Nabiev, Natalia A Koubassova, Sergey Y. BershitskyAbstract:In the heart, mutations in the TPM1 gene encoding the α-isoform of tropoMyosin lead, in particular, to the development of hypertrophic and dilated cardiomyopathies. We compared the effects of hypertrophic, D175N and E180G, and dilated, E40K and E54K, cardiomyopathy mutations in TPM1 gene on the properties of single Actin-Myosin Interactions and the characteristics of the calcium regulation in an ensemble of Myosin molecules immobilised on a glass surface and interActing with regulated thin filaments. Previously, we showed that at saturating Ca2+ concentration the presence of Tpm on the Actin filament increases the duration of the Interaction. Here, we found that the studied Tpm mutations differently affected the duration: the D175N mutation reduced it compared to WT Tpm, while the E180G mutation increased it. Both dilated mutations made the duration of the Interaction even shorter than with F-Actin. The duration of the attached state of Myosin to the thin filament in the optical trap did not correlate to the sliding velocity of thin filaments and its calcium sensitivity in the in vitro motility assay. We suppose that at the level of the molecular ensemble, the cooperative mechanisms prevail in the manifestation of the effects of cardiomyopathy-associated mutations in Tpm.
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the effect of cardiac Myosin binding protein c on calcium regulation of the Actin Myosin Interaction depends on Myosin light chain isoforms
Biophysics, 2019Co-Authors: S R Nabiev, G. V. Kopylova, D. V. ShchepkinAbstract:Abstract—In addition to troponin and tropoMyosin, cardiac Myosin-binding protein C (cMyBP-C), which has an effect on the function of Myosin and thin filament activation, is involved in regulation of the Actin–Myosin Interaction in the myocardium. The β-isoform of Myosin heavy chain expressed in slow skeletal muscles is identical to that in the myocardium; however, Myosin isoforms in slow skeletal muscles and in cardiac muscle differ in the composition of the Myosin light chain isoforms. We investigated the effect of cMyBP-C on the calcium regulation of the Interaction of the Myosin of slow skeletal muscle (m. soleus) with Actin, using an in vitro motility assay and an optical trap. It was found that the physiological concentration of cMyBP-C resulted in increased calcium sensitivity of the sliding velocity of regulated thin filaments over Myosin extracted from the slow soleus muscle and increased the velocity of thin filaments, as opposed to cardiac Myosin. In the optical trap, cMyBP-C did not affect the step size of Myosin but reduced the duration of a single Actin–Myosin Interaction, thus explaining the increase in the velocity of filaments in the in vitro motility assay. Thus, the regulatory properties of cMyBP-C are exhibited in different ways depending on the composition of Myosin light chain isoforms.
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effect of interchain disulfide crosslinking in the tropoMyosin molecule on Actin Myosin Interaction in the atrial myocardium
Bulletin of Experimental Biology and Medicine, 2019Co-Authors: D. V. Shchepkin, Sergey Y. Bershitsky, Alexander M Matyushenko, G. V. KopylovaAbstract:TropoMyosin (Tpm) is one of the main regulatory proteins in the myocardium. In some heart pathologies, interchain disulfide crosslinking in the Tpm molecule occurs. In the ventricle, this change in the structural properties of the Tpm molecule affects calcium regulation of the Actin-Myosin Interaction. Using an in vitro motility assay, we found that Tpm crosslinking does not affect the Actin-Myosin Interaction in the atria. We assume that the intramolecular crosslinking of Tpm in the atrium does not play such a crucial role in the pathogenesis of heart failure as it plays in the heart ventricles.
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the effect of experimental hyperthyroidism on characteristics of Actin Myosin Interaction in fast and slow skeletal muscles
Biochemistry, 2018Co-Authors: G. V. Kopylova, D. V. Shchepkin, Sergey Y. BershitskyAbstract:The molecular mechanism of the failure of contractile function of skeletal muscles caused by oxidative damage to Myosin in hyperthyroidism is not fully understood. Using an in vitro motility assay, we studied the effect of Myosin damage caused by oxidative stress in experimental hyperthyroidism on the Actin-Myosin Interaction and its regulation by calcium. We found that hyperthyroidism-induced oxidation of Myosin is accompanied by a decrease in the sliding velocity of the regulated thin filaments in the in vitro motility assay, and this effect is increased with the duration of the pathological process.
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The isoforms of α-Actin and Myosin affect the Ca2+ regulation of the Actin-Myosin Interaction in the heart.
Biochemical and biophysical research communications, 2017Co-Authors: D. V. Shchepkin, Larisa V. Nikitina, Sergey Y. Bershitsky, G. V. KopylovaAbstract:Myocardium of mammals contains a wide range of isoforms of proteins that provides contractile function of the heart. These are two isoforms of ventricular and two of atrial Myosin, α- and β-tropoMyosin, and two isoforms of α-Actin: cardiac and skeletal. We believe that the difference in the amino acid sequence of α-Actin can affect the calcium regulation of the Actin-Myosin Interaction. To test this hypothesis, we investigated effects of the isoforms of α-Actin, cardiac and skeletal, and the isoforms of cardiac Myosin on the calcium regulation of the Actin-Myosin Interaction in an in vitro motility assay using reconstructed regulated thin filaments. The results show that isoforms of α-Actin and the ratio of α/β-chains of Tpm differently affect the calcium regulation of the Actin-Myosin Interaction in myocardium in dependence on cardiac Myosin isoforms.
Kazuhiro Kohama - One of the best experts on this subject based on the ideXlab platform.
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nonkinase activity of mlck in elongated filopodia formation and chemotaxis of vascular smooth muscle cells toward sphingosylphosphorylcholine
American Journal of Physiology-heart and Circulatory Physiology, 2009Co-Authors: Honghui Wang, Akio Nakamura, Atsushi Matsumoto, Shinji Yoshiyama, Xiaoran Qin, Ce Xie, Yue Zhang, Ying Gao, Ryoki Ishikawa, Kazuhiro KohamaAbstract:The Actin-Myosin Interaction of vascular smooth muscle cells (VSMCs) is regulated by Myosin light chain kinase (MLCK), which is a fusion protein of the central catalytic domain with the N-terminal Actin-binding and C-terminal Myosin-binding domains. In addition to the regulatory role of kinase activity mediated by the catalytic domain, nonkinase activity that derives from both terminals is able to exert a regulatory role as reviewed by Nakamura et al. (32). We previously showed that nonkinase activity mediated the filopodia upon the stimulation by sphingosylphosphorylcholine (SPC) (25). To explore the regulatory role of nonkinase activity in chemotaxis, we constructed VSMCs where the expression of MLCK was totally abolished by using a lentivirus-mediated RNAi system. We hypothesized that the MLCK-downregulated VSMCs were unable to form filopodia and to migrate upon SPC stimulation and confirmed the hypothesis. We further constructed a kinase-inactive mutant from bovine cDNA coding wild-type (WT) MLCK by mutating the ATP-binding sites located in the catalytic domain, followed by confirming the presence (absence) of the kinase activity of WT (kinase-inactive mutant). We transfected WT and the mutant into MLCK-downregulated VSMCs. We expected that the transfected VSMCs will recover the ability to induce filopodia and chemotaxis toward SPC and found both constructs rescued the ability. Because they share the Actin- and Myosin-binding domains, we concluded nonkinase activity plays a major role for SPC-induced migration.
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calcium regulation of the Actin Myosin Interaction of physarum polycephalum
International Review of Cytology-a Survey of Cell Biology, 1999Co-Authors: Akio Nakamura, Kazuhiro KohamaAbstract:Plasmodia of Physarum polycephalum show vigorous cytoplasmic streaming, the motive force of which is supported by the Actin-Myosin Interaction. Calcium is not required for the Interaction but inhibits it. This calcium inhibition, a regulatory mode first discovered in Physarum, is the overwhelming mode of regulation of cytoplasmic streaming of plant cells and lower eukaryotes, and it is diametrically opposite to calcium activation of the Interaction found in muscle and nonmuscle cells of the animal kingdom. Myosin, Myosin II in Myosin superfamily, is the most important protein for Ca2+ action. Its essential light chain, called calcium-binding light chain, is the sole protein that binds Ca2+. Although phosphorylation and dephosphorylation of Myosin modify its properties, regulation of physiological significance is shown to be Ca-binding to Myosin. The Actin-binding protein of Physarum amplifies calcium inhibition when Ca2+ binds to calmodulin and other calcium-binding proteins. This review also includes characterization of this and other calcium-binding proteins of Physarum.
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Myosin light chain kinase from skeletal muscle regulates an atp dependent Interaction between Actin and Myosin by binding to Actin
Molecular and Cellular Biochemistry, 1999Co-Authors: Koichiro Fujita, Manabu Sato, Tsuyoshi Okagaki, Yukio Nagamachi, Kazuhiro KohamaAbstract:Myosin light chain kinase (MLCK) has been purified from various muscles as an enzyme to phosphorylate Myosin light chains. While the regulatory role of smooth muscle MLCK is well understood, the role of skeletal muscle MLCK in the regulation of contraction has not been fully characterized. Such characterization of skeletal muscle MLCK is difficult because skeletal muscle Myosin interacts with Actin whether or not the Myosin is phosphorylated. Taking the hint from our recent finding that smooth muscle MLCK inhibits the Actin-Myosin Interaction by binding to Actin (Kohama et al., Biochem Biophys Res Commun 184: 1204–1211, 1992), we investigated the regulatory role of the Actin-binding activity of MLCK from chicken breast muscle in the Actin-Myosin Interaction. The amount of MLCK that bound to Actin increased with increases in the concentration of MLCK. However, MLCK hardly bound to Myosin. The Actin-binding activity of MLCK was affected when Ca2+ and calmodulin (Ca2+-CaM) were present. The effect of MLCK on the Actin-Myosin Interaction was examined by an in vitro motility assay; the movement of Actin-filaments on a Myosin-coated glass surface was inhibited by increasing the concentration of MLCK. When CaM was present, the inhibition was overcome in a Ca2+-dependent manner at μM levels. The inhibition of the movement by MLCK and the recovery from the inhibition by Ca2+-CaM were not altered whether we use phosphorylated or unphosphorylated Myosin for the assay, ruling out the involvement of the kinase activity of MLCK. (Mol Cell Biochem 190: 85–90, 1999)
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the structure and function of the Actin binding domain of Myosin light chain kinase of smooth muscle
Journal of Biological Chemistry, 1997Co-Authors: Kohichi Hayakawa, Akio Nakamura, Tsuyoshi Okagaki, Hiroko Kishi, Michihiro Imamura, Takashi Takagi, Akiko Iwata, Takeshi Tanaka, Kazuhiro KohamaAbstract:In addition to its kinase activity, the Myosin light chain kinase (MLCK) of smooth muscle has an Actin binding activity through which it can regulate the Actin-Myosin Interaction of smooth muscle (Kohama, K., Okagaki, T., Hayakawa, K., Lin, Y., Ishikawa, R., Shimmen, T., and Inoue, A. (1992) Biochem. Biophys. Res. Commun. 184, 1204-1211). In this study, we have analyzed the Actin binding activity of MLCK and related it to its amino acid sequence by producing native and recombinant fragments of MLCK. Parent MLCK exhibited both calcium ion (Ca2+) and calmodulin (Ca2+/CaM)-sensitive and Ca2+/CaM-insensitive binding to Actin filaments. The native fragment, which consists of the Met1-Lys114 sequence (Kanoh, S., Ito, M., Niwa, E., Kawano, Y., and Hartshorne, D. J. (1993) Biochemistry 32, 8902-8907), and the recombinant NN fragment, which contains this 1-114 sequence, showed only Ca2+/CaM-sensitive binding. An inhibitory effect of the NN fragment on the Actin-Myosin Interaction was observed by assaying in vitro motility and by measuring the Actin-activated ATPase activity of Myosin. The recombinant NN/41 fragment, which is constructed without the Met1-Pro41 sequence of the NN fragment, lost both the Actin binding activity and the inhibitory effect. We confirmed the importance of the 1-41 sequence by using a few synthetic peptides to compete against the NN fragment in binding to Actin filaments. The experiments using recombinant fragments and synthetic peptides also revealed that the site for CaM-binding is the Pro26-Pro41 sequence. The site for the Ca2+/CaM-insensitive binding, which is shown to be localized between the Ca2+/CaM-sensitive site and the central kinase domain of MLCK, exerted no regulatory effects on the Actin-Myosin Interaction.
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Myosin light chain kinase an Actin binding protein that regulates an atp dependent Interaction with Myosin
Trends in Pharmacological Sciences, 1996Co-Authors: Kazuhiro Kohama, Kohichi Hayakawa, Tsuyoshi OkagakiAbstract:Myosin light chain kinase (MLCK) is a key regulator of smooth muscle contraction. The most conspicuous form of regulation is achieved by phosphorylation of the Myosin light chain, allowing Myosin to interact with Actin. This Interaction is regulated by Actin-binding proteins that modulate Actin filaments. In this review Kazuhiro Kohama and colleagues consider MLCK as an Actin-binding protein and attempt to shed light on the cross-talk between the different kinds of regulation of the Actin-Myosin Interaction in smooth muscle. An understanding of these mechanisms will assist the development of compounds with therapeutic importance in muscular disorders.
Sergey Y. Bershitsky - One of the best experts on this subject based on the ideXlab platform.
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Acidosis modifies effects of phosphorylated tropoMyosin on the Actin-Myosin Interaction in the myocardium
Journal of Muscle Research and Cell Motility, 2021Co-Authors: Galina V. Kopylova, Sergey Y. Bershitsky, Alexander M Matyushenko, Dmitrii I Levitsky, Valentina Y. Berg, Daniil V. ShchepkinAbstract:Phosphorylation of α-tropoMyosin (Tpm1.1), a predominant Tpm isoform in the myocardium, is one of the regulatory mechanisms of the heart contractility. The Tpm 1.1 molecule has one site of phosphorylation, Ser283. The degree of the Tpm phosphorylation decreases with age and also changes in heart pathologies. Myocardial pathologies, in particular ischemia, are usually accompanied by pH lowering in the cardiomyocyte cytosol. We studied the effects of acidosis on the structural and functional properties of the pseudo-phosphorylated form of Tpm1.1 with the S283D substitution. We found that in acidosis, the Interaction of the N- and C-ends of the S283D Tpm molecules decreases, whereas that of WT Tpm does not change. The pH lowering increased thermostability of the complex of F-Actin with S283D Tpm to a greater extent than with WT Tpm. Using an in vitro motility assay with NEM- modified Myosin as a load, we assessed the effect of the Tpm pseudo-phosphorylation on the force of the Actin-Myosin Interaction. In acidosis, the force generated by Myosin in the Interaction with thin filaments containing S283D Tpm was higher than with those containing WT Tpm. Also, the pseudo-phosphorylation increased the Myosin ability to resist a load. We conclude that ischemia changes the effect of the phosphorylated Tpm on the contractile function of the myocardium.
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cardiomyopathy associated mutations in tropoMyosin differently affect Actin Myosin Interaction at single molecule and ensemble levels
Journal of Muscle Research and Cell Motility, 2019Co-Authors: G. V. Kopylova, D. V. Shchepkin, Alexander M Matyushenko, Dmitrii I Levitsky, S R Nabiev, Natalia A Koubassova, Sergey Y. BershitskyAbstract:In the heart, mutations in the TPM1 gene encoding the α-isoform of tropoMyosin lead, in particular, to the development of hypertrophic and dilated cardiomyopathies. We compared the effects of hypertrophic, D175N and E180G, and dilated, E40K and E54K, cardiomyopathy mutations in TPM1 gene on the properties of single Actin-Myosin Interactions and the characteristics of the calcium regulation in an ensemble of Myosin molecules immobilised on a glass surface and interActing with regulated thin filaments. Previously, we showed that at saturating Ca2+ concentration the presence of Tpm on the Actin filament increases the duration of the Interaction. Here, we found that the studied Tpm mutations differently affected the duration: the D175N mutation reduced it compared to WT Tpm, while the E180G mutation increased it. Both dilated mutations made the duration of the Interaction even shorter than with F-Actin. The duration of the attached state of Myosin to the thin filament in the optical trap did not correlate to the sliding velocity of thin filaments and its calcium sensitivity in the in vitro motility assay. We suppose that at the level of the molecular ensemble, the cooperative mechanisms prevail in the manifestation of the effects of cardiomyopathy-associated mutations in Tpm.
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effect of interchain disulfide crosslinking in the tropoMyosin molecule on Actin Myosin Interaction in the atrial myocardium
Bulletin of Experimental Biology and Medicine, 2019Co-Authors: D. V. Shchepkin, Sergey Y. Bershitsky, Alexander M Matyushenko, G. V. KopylovaAbstract:TropoMyosin (Tpm) is one of the main regulatory proteins in the myocardium. In some heart pathologies, interchain disulfide crosslinking in the Tpm molecule occurs. In the ventricle, this change in the structural properties of the Tpm molecule affects calcium regulation of the Actin-Myosin Interaction. Using an in vitro motility assay, we found that Tpm crosslinking does not affect the Actin-Myosin Interaction in the atria. We assume that the intramolecular crosslinking of Tpm in the atrium does not play such a crucial role in the pathogenesis of heart failure as it plays in the heart ventricles.
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the effect of experimental hyperthyroidism on characteristics of Actin Myosin Interaction in fast and slow skeletal muscles
Biochemistry, 2018Co-Authors: G. V. Kopylova, D. V. Shchepkin, Sergey Y. BershitskyAbstract:The molecular mechanism of the failure of contractile function of skeletal muscles caused by oxidative damage to Myosin in hyperthyroidism is not fully understood. Using an in vitro motility assay, we studied the effect of Myosin damage caused by oxidative stress in experimental hyperthyroidism on the Actin-Myosin Interaction and its regulation by calcium. We found that hyperthyroidism-induced oxidation of Myosin is accompanied by a decrease in the sliding velocity of the regulated thin filaments in the in vitro motility assay, and this effect is increased with the duration of the pathological process.
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The isoforms of α-Actin and Myosin affect the Ca2+ regulation of the Actin-Myosin Interaction in the heart.
Biochemical and biophysical research communications, 2017Co-Authors: D. V. Shchepkin, Larisa V. Nikitina, Sergey Y. Bershitsky, G. V. KopylovaAbstract:Myocardium of mammals contains a wide range of isoforms of proteins that provides contractile function of the heart. These are two isoforms of ventricular and two of atrial Myosin, α- and β-tropoMyosin, and two isoforms of α-Actin: cardiac and skeletal. We believe that the difference in the amino acid sequence of α-Actin can affect the calcium regulation of the Actin-Myosin Interaction. To test this hypothesis, we investigated effects of the isoforms of α-Actin, cardiac and skeletal, and the isoforms of cardiac Myosin on the calcium regulation of the Actin-Myosin Interaction in an in vitro motility assay using reconstructed regulated thin filaments. The results show that isoforms of α-Actin and the ratio of α/β-chains of Tpm differently affect the calcium regulation of the Actin-Myosin Interaction in myocardium in dependence on cardiac Myosin isoforms.
Yurii S Borovikov - One of the best experts on this subject based on the ideXlab platform.
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40 kda Actin binding protein of thin filaments of the mussel crenomytilus grayanus inhibits the strong bond formation between Actin and Myosin head during the atpase cycle
Biochemistry, 2012Co-Authors: Vladimir V Sirenko, A H Simonyan, A V Dobrzhanskaya, Nikolay S Sheludko, Yurii S BorovikovAbstract:Mobility and spatial orientation of a novel 40-kDa Actin-binding protein from the smooth muscle of the mussel Crenomytilus grayanus was studied by polarized fluorometry. The influence of this protein on orientation and mobility of the Myosin heads was investigated during modeling the different stages of the ATPase cycle. The 40-kDa Actin-binding protein affected the strong Actin-Myosin binding. We suggest that the 40-kDa Actin-binding protein is involved in regulation of the Actin-Myosin Interaction in the smooth muscle of the mussel.
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the effect of the asp175asn and glu180gly tpm1 mutations on Actin Myosin Interaction during the atpase cycle
Biochimica et Biophysica Acta, 2012Co-Authors: Nikita A Rysev, Charles Redwood, Olga E Karpicheva, Yurii S BorovikovAbstract:Abstract Hypertrophic cardiomyopathy (HCM), characterized by cardiac hypertrophy and contractile dysfunction, is a major cause of heart failure. HCM can result from mutations in the gene encoding cardiac α-tropoMyosin (TM). To understand how the HCM-causing Asp175Asn and Glu180Gly mutations in α-tropoMyosin affect on Actin–Myosin Interaction during the ATPase cycle, we labeled the SH1 helix of Myosin subfragment-1 and the Actin subdomain-1 with the fluorescent probe N-iodoacetyl-N′-(5-sulfo-1-naphtylo)ethylenediamine. These proteins were incorporated into ghost muscle fibers and their conformational states were monitored during the ATPase cycle by measuring polarized fluorescence. For the first time, the effect of these α-tropoMyosins on the mobility and rotation of subdomain-1 of Actin and the SH1 helix of Myosin subfragment-1 during the ATP hydrolysis cycle have been demonstrated directly by polarized fluorimetry. Wild-type α-tropoMyosin increases the amplitude of the SH1 helix and subdomain-1 movements during the ATPase cycle, indicating the enhancement of the efficiency of the work of cross-bridges. Both mutant TMs increase the proportion of the strong-binding sub-states, with the effect of the Glu180Gly mutation being greater than that of Asp175Asn. It is suggested that the alteration in the concerted conformational changes of actoMyosin is likely to provide the structural basis for the altered cardiac muscle contraction.
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molluscan twitchin can control Actin Myosin Interaction during atpase cycle
Archives of Biochemistry and Biophysics, 2010Co-Authors: Yurii S Borovikov, Nikolay S Sheludko, Stanislava V AvrovaAbstract:The effect of twitchin, a thick filament protein of molluscan muscles, on Actin-Myosin Interaction at several mimicked sequential steps of the ATPase cycle was investigated using fluorescent probes specifically bound to Cys707 of Myosin subfragment-1 and Cys374 of Actin incorporated into ghost muscle fibers. The multi-step changes in mobility and spatial arrangement of Myosin SH1 helix and Actin subdomain-1 during the ATPase cycle have been revealed. For the first time, the inhibition of movement of Myosin SH1 helix and Actin subdomain-1 during the ATPase cycle and the decrease in the Myosin head and Actin affinity in the presence of unphosphorylated twitchin have been demonstrated. Phosphorylation of twitchin by the catalytic subunit of protein kinase A reversed this effect. These data imply a novel property of twitchin consisting in its ability to regulate in a phosphorylation-dependent manner the Actin-Myosin Interaction during the ATPase cycle by the inhibition of transformation of the weak-binding actoMyosin states into the strong-binding ones.
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caldesmon inhibits the Actin Myosin Interaction by changing its spatial orientation and mobility during the atpase activity cycle
Biochemical and Biophysical Research Communications, 2007Co-Authors: Natalia Kulikova, Olga E Pronina, Renata Dabrowska, Yurii S BorovikovAbstract:Abstract Orientation and mobility of acrylodan fluorescent probe specifically bound to caldesmon Cys580 incorporated into muscle ghost fibers decorated with Myosin S1 and containing tropomysoin was studied in the presence or absence of MgADP, MgAMP-PNP, MgATPγS or MgATP. Modeling of various intermediate states of actoMyosin has shown discrete changes in orientation and mobility of the dye dipoles which is the evidence for multistep changes in the structural changes of caldesmon during the ATPase hydrolysis cycle. It is suggested that S1 Interaction with Actin results in nucleotide-dependent displacement of the C-terminal part of caldesmon molecule and changes in its mobility. Thus inhibition of the actoMyosin ATPase activity may be due to changes in caldesmon position on the thin filament and its Interaction with Actin. Our new findings described in the present paper as well as those published recently elsewhere might conciliate the two existing models of molecular mechanism of inhibition of the actoMyosin ATPase by caldesmon.
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calcium modulates conformational changes in f Actin induced by smooth muscle heavy meroMyosin
FEBS Letters, 1998Co-Authors: S V Avrova, Yurii S Borovikov, Natalia N Efimova, Samuel ChackoAbstract:The effect of Ca2+ on conformational changes in rhodamine-phalloidin-labeled F-Actin induced by binding of smooth muscle heavy meroMyosin (HMM) with either phosphorylated or dephosphorylated regulatory light chains (LC20) was studied by polarized fluorimetry. LC20 phosphorylation caused alterations in the F-Actin structure typical of the force-producing (strong-binding) state, while dephosphorylation of the chains led to alterations typical of the formation of non-force-producing (weak-binding) state of the actoMyosin complex. The presence of Ca2+ enhanced the effect of LC20 phosphorylation and weakened the effect of LC20 dephosphorylation. These data suggest that Ca2+ modulates Actin-Myosin Interaction in smooth muscle by promoting formation of the strong-binding state.
