Effect of Ca2+ on cross-bridge turnover kinetics in skinned single rabbit psoas fibers: implications for regulation of muscle contraction - PubMed (original) (raw)

Effect of Ca2+ on cross-bridge turnover kinetics in skinned single rabbit psoas fibers: implications for regulation of muscle contraction

B Brenner. Proc Natl Acad Sci U S A. 1988 May.

Abstract

The effect of Ca2+ upon the rate constant of force redevelopment following a period of isotonic shortening with immediate restretch to the starting sarcomere length was studied in rabbit psoas fibers at 5 degrees C. Control experiments support the assumption that the rate constant of force redevelopment represents isometric cross-bridge turnover kinetics (fapp + gapp), where fapp and gapp are the rate constants characterizing the transitions from the non-force-generating states to the force-generating states and back to the non-force-generating states, respectively. Parallel measurements of the rate constant of force redevelopment and of force, stiffness, and fiber ATPase during isometric contraction allow the effect of Ca2+ upon fapp and gapp to be determined. Analysis reveals that Ca2+ has a marked effect upon fapp, while gapp remains approximately unchanged. Furthermore, in the range above 25-30% of maximum Ca2+ activation, regulation of force, stiffness, and ATPase is mediated through changes in fapp. Below this range, however, it cannot be ruled out that, in addition, cross-bridges are also switched in and out of the turnover process ("recruitment"). As a consequence of regulation through turnover kinetics, both Ca2+ sensitivity and the slope of force-pCa (-log[Ca2+]) relations are shown to be affected by the ratio fapp/gapp, which may represent an important mechanism of modulation of contractile function in addition to modulation through changes within the regulatory protein system.

PubMed Disclaimer

Cited by

Myosin Isoform-Dependent Effect of Omecamtiv Mecarbil on the Regulation of Force Generation in Human Cardiac Muscle.
Scellini B, Piroddi N, Dente M, Pioner JM, Ferrantini C, Poggesi C, Tesi C. Scellini B, et al. Int J Mol Sci. 2024 Sep 10;25(18):9784. doi: 10.3390/ijms25189784. Int J Mol Sci. 2024. PMID: 39337273 Free PMC article.
Postprandial cardiac hypertrophy is sustained by mechanics, epigenetic, and metabolic reprogramming in pythons.
Crocini C, Woulfe KC, Ozeroff CD, Perni S, Cardiello J, Walker CJ, Wilson CE, Anseth K, Allen MA, Leinwand LA. Crocini C, et al. Proc Natl Acad Sci U S A. 2024 Sep 3;121(36):e2322726121. doi: 10.1073/pnas.2322726121. Epub 2024 Aug 19. Proc Natl Acad Sci U S A. 2024. PMID: 39159386 Free PMC article.
The Contractile Machines of the Heart.
Morano I. Morano I. Adv Exp Med Biol. 2024;1441:417-433. doi: 10.1007/978-3-031-44087-8_21. Adv Exp Med Biol. 2024. PMID: 38884723 Review.
A Laing distal myopathy-associated proline substitution in the β-myosin rod perturbs myosin cross-bridging activity.
Buvoli M, Wilson GC, Buvoli A, Gugel JF, Hau A, Bönnemann CG, Paradas C, Ryba DM, Woulfe KC, Walker LA, Buvoli T, Ochala J, Leinwand LA. Buvoli M, et al. J Clin Invest. 2024 May 1;134(9):e172599. doi: 10.1172/JCI172599. J Clin Invest. 2024. PMID: 38690726 Free PMC article.
Assessing Cardiac Contractility From Single Molecules to Whole Hearts.
Garg A, Lavine KJ, Greenberg MJ. Garg A, et al. JACC Basic Transl Sci. 2023 Oct 11;9(3):414-439. doi: 10.1016/j.jacbts.2023.07.013. eCollection 2024 Mar. JACC Basic Transl Sci. 2023. PMID: 38559627 Free PMC article. Review.

References

1. Pflugers Arch Gesamte Physiol Menschen Tiere. 1967;296(1):70-90 - PubMed
1. Prog Biophys Biophys Chem. 1957;7:255-318 - PubMed
1. Biophys J. 1969 Apr;9(4):547-70 - PubMed
1. J Physiol. 1970 Nov;211(1):19-35 - PubMed
1. Q Rev Biophys. 1969 Nov;2(4):351-84 - PubMed

Effect of Ca2+ on cross-bridge turnover kinetics in skinned single rabbit psoas fibers: implications for regulation of muscle contraction - PubMed (original) (raw)