Heart contractile proteins

Berson, G.; Delcayre, Claude; Klotz, Catherine; Schwartz, Ketty; Léger, J.; Stephens, M.D.; Swynghedauw, Bernard

doi:10.1016/s0300-9084(76)80538-x

Cited by 31 publications

(10 citation statements)

References 155 publications

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“…It is interesting to emphasize that the K , of myosin for its substrate, estimated from measurements on the ATP cleavage rate, was identical in all the species studied. This is in agreement with the results obtained in the steadystate [33,34]. These facts show great similarity between the active centres of these myosins.…”

Section: Discussionsupporting

confidence: 93%

“…The horizontal axis indicates the phosphate burst rate in mol P, x mol myosin-' (2 sites per myosin) x 5-l skeletal subfragment-1, whereas the ATP-induced isomerisation k + 2 was lower [32]. The K'-ATPase of myosin in the steady-state does not correlate either with the phosphate burst (see Table 1) or with the shortening speed, at least in the heart [33,34].…”

Section: Discussionmentioning

confidence: 99%

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Early Phosphate Burst of Heart Myosins. Phylogenic Variations

1978

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The phosphate burst of cardiac myosins from different animal species was studied by a rapid quench-flow technique. The rate constant of the phosphate burst varied from one species to another. Moreover it was lower for cardiac myosins than for skeletal myosin. The phosphate burst rate correlated with the ATPase in the steady state and with the muscle-shortening speed.By contrast, the amplitude of the phosphate burst did not vary significantly. Its value was 0.8-0.9 per myosin site for each of the myosins studied. Deviations from this stoichiometry were related to the mode of preparation of the myosin and to denaturation by a high pH.As shown several years ago by Barany [l], the shortening speed of skeletal muscles (expressed in muscle lengths per s) correlates with Ca2+-activated and actin-Mg2+-activated myosin ATPase in the steady state. Later, a similar relationship was observed in the heart [2]. The heart has advantages for such a study since it is homogeneous well characterized muscle and also because it is now well established that its shortening speed is inversely proportional to its weight, i.e. the smaller the heart, the faster it shortens [3].ATP hydrolysis by myosin in the steady-state is slow; by contrast, the transient initial phase is very rapid and proceeds in the same speed range as that of the contractile process. This is the main reason why the transient-state steps are of considerable interest and were studied in detail in the usual model, i.e. rabbit white skeletal muscle myosin [4-111. Transient kinetic evidence indicates that at least two conformations occur (see stars in the equation below), bringing about the cleavage of ATP. The products of the hydrolysis remain bound to the myosin. The following equation [9,12] concerning ATP hydrolysis is now generally accepted:

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Early Phosphate Burst of Heart Myosins. Phylogenic Variations

1978

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“…The syntenic region of the mouse genome was known to encode α tropomyosin, 43 one of several thin filament sarcomere proteins that regulates actinomyosin interactions. 44 By harnessing information from the mouse gene, we cloned the human homologue, TPM1 , mapped this to 15q2 and identified human mutations. Armed with the recognition that 2 HCM genes encoded contractile proteins, the disease gene encoded at 1q3 was soon recognized to be troponin T ( TNNT2 ) 42 .…”

Section: Collaborating Clinicians Families and Researchersmentioning

confidence: 99%

Identifying Sarcomere Gene Mutations in Hypertrophic Cardiomyopathy

Seidman

2011

Circulation Research

246

194

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This article provides an historical and personal perspective on the discovery of genetic causes for hypertrophic cardiomyopathy (HCM). Extraordinary insights of physicians who initially detailed remarkable and varied manifestations of the disorder, collaboration among multidisciplinary teams with skills in clinical diagnostics and molecular genetics, and hard work by scores of trainees, solved the etiologic riddle of HCM, and unexpectedly demonstrated mutations in sarcomere protein genes as the cause of disease. In addition to celebrating 20 years of genetic research in HCM, this article serves as an introductory overview to a thematic review series that will present contemporary advances in the field of hypertrophic heart disease. Through the continued application of advances in genetic methodologies, combined with biochemical and biophysical analyses of the consequences of human mutations, fundamental knowledge about HCM and sarcomere biology has emerged. Expanding research to elucidate the mechanisms by which subtle genetic variation in contractile proteins remodel the human heart remains an exciting opportunity, one with considerable promise to provide new strategies to limit or even prevent HCM pathogenesis.

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“…The changes in enzymatic activity appear to be dependent on the severity and chronicity of the stress (for review see Swynghedauw et al, 1976;Wikman-Coffelt et al, 1979;Scheuer and Bahn, 1979), and may be related to alterations in the synthesis of the molecule. Cardiac myosin consists of two heavy chains (HC) and two each of two different light chains (LCi and LC 2 ) (Weeds and Frank, 1973;Leger et al, 1975). Ventricular myosin has been shown to exist as several isozymes in the normal and abnormal heart (Flink and Morkin, 1977;Flink et al, 1979;Hoh et al, 1979) with differences in the HC subunits.…”

Section: Contractile Proteinsmentioning

confidence: 99%