Differential cross-bridge kinetics of FHC myosin mutations R403Q and R453C in heterozygous mouse myocardium.

The kinetic effects of the cardiac myosin point mutations R403Q and R453C, which underlie lethal forms of familial hypertrophic cardiomyopathy (FHC), were assessed using isolated myosin and skinned strips taken from heterozygous (R403Q/+ and R453C/+) male mouse hearts. Compared with wild-type (WT) mice, actin-activated ATPase was increased by 38% in R403Q/+ and reduced by 45% in R453C/+, maximal velocity of regulated thin filament (V(RTF)) in the in vitro motility assay was increased by 8% in R403Q/+ and was not different in R453C/+, myosin concentration at half-maximal V(RTF) was reduced by 30% in R403Q/+ and not different in R453C/+, and the characteristic frequency for oscillatory work production (b frequency), determined by sinusoidal analysis in the skinned strip at maximal calcium activation, was 27% lower in R403Q/+ and 18% higher in R453C/+. The calcium sensitivity for isometric tension in the skinned strip was not different in R403Q/+ (pCa(50) 5.64 +/- 0.02) and significantly enhanced in R453C/+ (5.82 +/- 0.03) compared with WT (5.58 +/- 0.02). We conclude that isolated myosin and skinned strips of R403Q/+ and R453C/+ myocardium show marked differences in cross-bridge kinetic parameters and in calcium sensitivity of force production that indicate different functional roles associated with the location of each point mutation at the molecular level.

[1]  R. Roberts,et al.  Familial hypertrophic cardiomyopathy: a paradigm of the cardiac hypertrophic response to injury. , 1998, Annals of medicine.

[2]  J. Potter.  Preparation of troponin and its subunits. , 1982, Methods in enzymology.

[3]  J. Seidman,et al.  Diastolic dysfunction and altered energetics in the alphaMHC403/+ mouse model of familial hypertrophic cardiomyopathy. , 1998, The Journal of clinical investigation.

[4]  Richard T. Lee,et al.  Consequences of Pressure Overload on Sarcomere Protein Mutation-Induced Hypertrophic Cardiomyopathy , 2003, Circulation.

[5]  N. Alpert,et al.  Cardiac troponin T isoforms demonstrate similar effects on mechanical performance in a regulated contractile system. , 2002, American journal of physiology. Heart and circulatory physiology.

[6]  J. Spudich,et al.  Purification of muscle actin. , 1982, Methods in cell biology.

[7]  H. Sugi,et al.  Mechanisms of Work Production and Work Absorption in Muscle , 2012, Advances in Experimental Medicine and Biology.

[8]  L. Leinwand,et al.  Gender and aging in a transgenic mouse model of hypertrophic cardiomyopathy. , 2001, American journal of physiology. Heart and circulatory physiology.

[9]  U. Sigwart,et al.  New concepts in hypertrophic cardiomyopathies, part I. , 2001, Circulation.

[10]  M Kawai,et al.  Crossbridge scheme and the kinetic constants of elementary steps deduced from chemically skinned papillary and trabecular muscles of the ferret. , 1993, Circulation research.

[11]  J. Seidman,et al.  Altered Crossbridge Kinetics in the a MHC 403 / 1 Mouse Model of Familial Hypertrophic Cardiomyopathy , 1999 .

[12]  Guiping Yang,et al.  An α-cardiac myosin heavy chain gene mutation impairs contraction and relaxation function of cardiac myocytes. , 1999, American journal of physiology. Heart and circulatory physiology.

[13]  J. Potter.  [22] Preparation of troponin and its subnits , 1982 .

[14]  J. Seidman,et al.  The Genetic Basis for Cardiomyopathy from Mutation Identification to Mechanistic Paradigms , 2001, Cell.

[15]  I. Rayment,et al.  Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[16]  I. Olivotto,et al.  New concepts in hypertrophic cardiomyopathies. , 2002, Circulation.

[17]  D. Warshaw,et al.  Enhanced force generation by smooth muscle myosin in vitro. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[18]  J. Seidman,et al.  Characteristics and prognostic implications of myosin missense mutations in familial hypertrophic cardiomyopathy. , 1992, The New England journal of medicine.

[19]  S. Lowey,et al.  Functional consequences of mutations in the myosin heavy chain at sites implicated in familial hypertrophic cardiomyopathy. , 2002, Trends in cardiovascular medicine.

[20]  J. Spudich,et al.  Variable surface loops and myosin activity: Accessories to a motor , 2000, Journal of Muscle Research & Cell Motility.

[21]  J. Moore,et al.  Work production and work absorption in muscle strips from vertebrate cardiac and insect flight muscle fibers. , 1998, Advances in experimental medicine and biology.

[22]  Masataka Kawai,et al.  Sinusoidal analysis: a high resolution method for correlating biochemical reactions with physiological processes in activated skeletal muscles of rabbit, frog and crayfish , 1980, Journal of Muscle Research & Cell Motility.

[23]  M. Dalakas,et al.  Missense mutations in the beta-myosin heavy-chain gene cause central core disease in hypertrophic cardiomyopathy. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[24]  E. Homsher,et al.  Regulation of contraction in striated muscle. , 2000, Physiological reviews.

[25]  H. T. ter Keurs,et al.  Maximal actomyosin ATPase activity and in vitro myosin motility are unaltered in human mitral regurgitation heart failure. , 1996, Circulation research.

[26]  P. A. Lanzetta,et al.  An improved assay for nanomole amounts of inorganic phosphate. , 1979, Analytical biochemistry.

[27]  J. D. Pardee,et al.  [18] Purification of muscle actin , 1982 .

[28]  U. Sigwart,et al.  New concepts in hypertrophic cardiomyopathies, part II. , 2001, Circulation.

[29]  N. Alpert,et al.  Protection of Human Left Ventricular Myocardium From Cutting Injury With 2,3 -Butanedione Monoxime , 1989, Circulation research.

[30]  J. Seidman,et al.  Single-molecule mechanics of R403Q cardiac myosin isolated from the mouse model of familial hypertrophic cardiomyopathy. , 2000, Circulation research.

[31]  S. Lowey,et al.  Preparation of myosin and its subfragments from rabbit skeletal muscle. , 1982, Methods in enzymology.

[32]  Frederick J. Schoen,et al.  A Mouse Model of Familial Hypertrophic Cardiomyopathy , 1996, Science.

[33]  R. Godt,et al.  Influence of temperature upon contractile activation and isometric force production in mechanically skinned muscle fibers of the frog , 1982, The Journal of general physiology.

[34]  F J Schoen,et al.  Comparison of Two Murine Models of Familial Hypertrophic Cardiomyopathy , 2001, Circulation research.

[35]  M. Ikebe,et al.  Functional analysis of the mutations in the human cardiac beta-myosin that are responsible for familial hypertrophic cardiomyopathy. Implication for the clinical outcome. , 1996, The Journal of clinical investigation.

[36]  A. Marian,et al.  The molecular genetic basis for hypertrophic cardiomyopathy. , 2001, Journal of molecular and cellular cardiology.

[37]  J. Seidman,et al.  Altered crossbridge kinetics in the alphaMHC403/+ mouse model of familial hypertrophic cardiomyopathy. , 1999, Circulation research.