Role of protein kinase C in the phosphorylation of cardiac myosin light chain 2

Venema, Richard C.; Raynor, Robert L.; Noland, Thomas A.; Kuo, J.F.

doi:10.1042/bj2940401

Cited by 97 publications

(83 citation statements)

References 44 publications

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“…32 P]ATP (specific activity, 250 Ci/M) for 45 min at room temperature (26,28). Proteins were then denatured, dissolved, and electrophoresed on 8% SDS-polyacrylamide gels.…”

Section: Methodsmentioning

confidence: 99%

Hypercontractile Properties of Cardiac Muscle Fibers in a Knock-in Mouse Model of Cardiac Myosin-binding Protein-C

Witt¹,

Gerull²,

Davies³

et al. 2001

Journal of Biological Chemistry

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Myosin-binding protein-C (MyBP-C) is a component of all striated-muscle sarcomeres, with a well established structural role and a possible function for force regulation. Multiple mutations within the gene for cardiac MyBP-C, one of three known isoforms, have been linked to familial hypertrophic cardiomyopathy. Here we generated a knock-in mouse model that carries N-terminalshortened cardiac MyBP-C. The mutant protein was designed to have a similar size as the skeletal MyBP-C isoforms, whereas known myosin and titin binding sites as well as the phosphorylatable MyBP-C motif were not altered. We have shown that mutant cardiac MyBP-C is readily incorporated into the sarcomeres of both heterozygous and homozygous animals and can still be phosphorylated by cAMP-dependent protein kinase. Although histological characterization of wild-type and mutant hearts did not reveal obvious differences in phenotype, left ventricular fibers from homozygous mutant mice exhibited an increased Ca 2؉ sensitivity of force development, particularly at lower Ca 2؉ concentrations, whereas maximal active force levels remained unchanged. The results allow us to propose a model of how cMyBP-C may affect myosin-head mobility and to rationalize why N-terminal mutations of the protein in some cases of familial hypertrophic cardiomyopathy could lead to a hypercontractile state.

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“…32 P]ATP (specific activity, 250 Ci/M) for 45 min at room temperature (26,28). Proteins were then denatured, dissolved, and electrophoresed on 8% SDS-polyacrylamide gels.…”

Section: Methodsmentioning

confidence: 99%

Hypercontractile Properties of Cardiac Muscle Fibers in a Knock-in Mouse Model of Cardiac Myosin-binding Protein-C

Witt¹,

Gerull²,

Davies³

et al. 2001

Journal of Biological Chemistry

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“…The regulatory myosin light chain (MLC 2 ) is also phosphorylated by PKC, which is stimulatory (138)(139)(140), but further studies are needed to confirm this role. Cardiac myosin-binding protein C (cMyBP-C) is a thick filament protein containing accessible phosphorylation sites (141).…”

Section: Myofibrillar Assembly In Congestive Hfmentioning

confidence: 99%

Myofibrillar remodelling in cardiac hypertrophy, heart failure and cardiomyopathies

Macháčková¹,

Barta²,

Dhalla³

2006

Canadian Journal of Cardiology

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“…In smooth muscle, both threonine 18 and serine 19 can be phosphorylated by MLCK (28), and sequence similarities between the smooth and striated muscle RLCs suggest that serine 14 in skeletal muscle is also a target for MLCK phosphorylation. An additional consideration in the construct's design was that other kinases such as Rho kinase and protein kinase C have the ability to phosphorylate RLC2 at serine 15 as well as at other amino acid residues (5,29,30). Thus, to ensure that phosphorylation would not occur on the transgenically encoded protein, serines 14, 15, and 19 were each mutated and replaced by alanine (Fig.…”

Section: Transgenicmentioning

confidence: 99%

Abnormal Cardiac Structure and Function in Mice Expressing Nonphosphorylatable Cardiac Regulatory Myosin Light Chain 2

Sanbe¹,

Fewell²,

Gulick³

et al. 1999

Journal of Biological Chemistry

114

102

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A role for myosin phosphorylation in modulating normal cardiac function has long been suspected, and we hypothesized that changing the phosphorylation status of a cardiac myosin light chain might alter cardiac function in the whole animal. To test this directly, transgenic mice were created in which three potentially phosphorylatable serines in the ventricular isoform of the regulatory myosin light chain were mutated to alanines. Lines were obtained in which replacement of the endogenous species in the ventricle with the nonphosphorylatable, transgenically encoded protein was essentially complete. The mice show a spectrum of cardiovascular changes. As previously observed in skeletal muscle, Ca 2؉ sensitivity of force development was dependent upon the phosphorylation status of the regulatory light chain. Structural abnormalities were detected by both gross histology and transmission electron microscopic analyses. Mature animals showed both atrial hypertrophy and dilatation. Echocardiographic analysis revealed that as a result of chamber enlargement, severe tricuspid valve insufficiency resulted in a detectable regurgitation jet. We conclude that regulated phosphorylation of the regulatory myosin light chains appears to play an important role in maintaining normal cardiac function over the lifetime of the animal.The roles of the regulatory myosin light chains (RLCs) 1 and the reversible post-translational modifications they undergo in striated muscle are beginning to be defined. In skeletal muscle, a serine at the amino end of the protein can be phosphorylated by a sarcoplasmic kinase (1), and it is now clear that RLCs in the different striated muscles are phosphorylated to differing degrees, leading presumably to different physiological effects. In smooth muscle, RLC phosphorylation by myosin light chain kinase (MLCK), which is activated by a Ca 2ϩ /calmodulin-dependent pathway, is responsible for initiating muscle contraction (2, 3). However, in skeletal and cardiac muscle, in which the thin, rather than thick, filament mediates control of contraction, RLC phosphorylation does not activate contraction but appears to play a modulatory role. In skinned skeletal muscle fibers, RLC phosphorylation increases sensitivity to activating Ca 2ϩ such that there is a significant leftward shift in the force-Ca 2ϩ relationship (4 -6). Increased RLC phosphorylation in skeletal muscle is also associated with potentiation of isometric twitch tension with repeated activation and inactivation of contraction (7, 8), rate of force production (9 -11), and maximum Ca 2ϩ -stimulated MgATPase activity (12). The mechanistic basis for the effects of RLC phosphorylation in striated muscle is hypothesized to be a lessening of the weak interaction of the myosin head with the myosin backbone and is probably due to a net charge change in a critical region of the protein (13). Upon phosphorylation, the myosin heads move away from the backbone to a position closer to actin, which presumably increases the rate at which myosin-actin interaction...

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Role of protein kinase C in the phosphorylation of cardiac myosin light chain 2

Cited by 97 publications

References 44 publications

Hypercontractile Properties of Cardiac Muscle Fibers in a Knock-in Mouse Model of Cardiac Myosin-binding Protein-C

Hypercontractile Properties of Cardiac Muscle Fibers in a Knock-in Mouse Model of Cardiac Myosin-binding Protein-C

Myofibrillar remodelling in cardiac hypertrophy, heart failure and cardiomyopathies

Abnormal Cardiac Structure and Function in Mice Expressing Nonphosphorylatable Cardiac Regulatory Myosin Light Chain 2

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