Myosin ATP Turnover Rate: A Mechanism Involved in Thermogenesis in Resting Skeletal Muscle Fibers

Stewart, Melanie; Franks-Skiba, Kathleen E.; Cooke, Roger M.

doi:10.1016/j.bpj.2009.12.779

Cited by 16 publications

(38 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, near physiologic temperatures (35 °C) the slow phase of basal single ATP turnover is significantly more abundant in HMM than in S1 (p 0.0001). Temperature stability is consistent with the biochemically sequestered SRX state observed in permeablized muscle fibers [6], and the ordered state of the myosin thick-filament observed by fluorescence polarization [22], and X-ray diffraction [23][24][25].…”

Section: Resultssupporting

confidence: 79%

Mavacamten stabilizes the auto-inhibited state of two-headed cardiac myosin

Rohde

Thomas

Muretta

2018

Preprint

View full text Add to dashboard Cite

We used transient biochemical and structural kinetics to elucidate the molecular mechanism of mavacamten, an allosteric cardiac myosin inhibitor and prospective treatment for hypertrophic cardiomyopathy. We find that mavacamten stabilizes an auto-inhibited state of two-headed cardiac myosin, not found in the isolated S1 myosin motor fragment. We determined this by measuring cardiac myosin actin-activated and actin-independent ATPase and single ATP turnover kinetics. A two-headed myosin fragment exhibits distinct auto-inhibited ATP turnover kinetics compared to a single-headed fragment. Mavacamten enhanced this auto-inhibition. It also enhanced auto-inhibition of ADP release. Furthermore, actin changes the structure of the auto-inhibited state by forcing myosin lever-arm rotation. Mavacamten slows this rotation in two-headed myosin but does not prevent it. We conclude that cardiac myosin is regulated in solution by an interaction between its two heads and propose that mavacamten stabilizes this state. Significance StatementSmall-molecule allosteric effectors designed to target and modulate striated and smooth myosin isoforms for the treatment of disease show promise in preclinical and clinical trials. Beta-cardiac myosin is an especially important target, as heart disease remains a primary cause of death in the U.S. One prevalent type of heart disease is hypertrophic cardiomyopathy (HCM), which is hypothesized to result from dysregulated force generation by cardiac myosin. Mavacamten is a potent cardiac myosin ATPase activity inhibitor that improves cardiac output in HCM animal models. Our results show that mavacamten selectively stabilizes a two-head dependent, auto-inhibited state of cardiac myosin in solution. The kinetics and energetics of this state are consistent with the auto-inhibited super-relaxed state, previously only observed in intact sarcomeres. Introduction.Familial hypertrophic cardiomyopathies, abbreviated HCM, represent one of the most common classes of genetic disease, affecting 1 in 500 people [1]. HCM is hypothesized to result from cardiac hyper-contractility [2]. Direct inhibition of force generation by cardiac myosin is thus a putative treatment [3]. Mavacamten (Mava), previously termed Myk461, is a small-molecule allosteric inhibitor of cardiac myosin that shows promise in preclinical and clinical trials for the treatment of HCM [3]. Mavacamten binds with sub-micromolar affinity to cardiac myosin in the presence of adenosine triphosphate (ATP) and inhibits steady-state actin-activated and actin-independent (basal) ATPase cycling and calcium regulated ATPase activity in permeablized cardiac myofibrils [3,4]. Mavacamten also inhibits the kinetics of rigor actin-binding as well as the kinetics of actin-activated phosphate release [4]. It decreases in vitro actin filament sliding velocity in the actomyosin motility assay [4], decreases force generation by skinned cardiac preparations from mouse HCM models [3], and decreases cardiac output in live feline hearts [5]. Mavacamten's effect on cardia...

show abstract

Section: Resultssupporting

confidence: 79%

Mavacamten stabilizes the auto-inhibited state of two-headed cardiac myosin

Rohde

Thomas

Muretta

2018

Preprint

View full text Add to dashboard Cite

show abstract

“…Indeed, when maximally recruited, as during exercise or an intense bout of shivering, muscle can account for up to 90% of whole-body oxygen uptake, an indirect measure of heat production (Stainsby & Lambert, 1979;Zurlo et al, 1990). During muscle contraction, heat is generated by the hydrolysis of ATP from three different ATPases: myosin ATPase (Stewart et al, 2010;Cooke, 2011;Little & Seebacher, 2013), which performs the contractile work, and SERCA (Block, 1994;Dumonteil, Barre & Meissner, 1995;Simonides et al, 2001;Morrissette, Franck & Block, 2003;de Meis, Arruda & Carvalho, 2005;Arruda et al, 2007;Kjelstrup et al, 2008;Bal et al, 2012;Inesi & Tadini-Buoninsegni, 2013;Little & Seebacher, 2013;Sahoo et al, 2013) and Na + /K + ATPase (Guernsey & Morishige, 1979;Muller & Seitz, 1984;Herpin, McBride & Bayley, 1987;Kelly & McBride, 1990;Rolfe & Brown, 1997;Karbowski, 2009), which reset resting ion gradients and membrane potential. To sustain these processes, ATP generation must be increased to match demand.…”

Section: Evolution Of Skeletal Muscle As a Thermogenic Organ (1) mentioning

confidence: 99%

The role of skeletal‐muscle‐based thermogenic mechanisms in vertebrate endothermy

2014

View full text Add to dashboard Cite

Thermogenesis is one of the most important homeostatic mechanisms that evolved during vertebrate evolution. Despite its importance for the survival of the organism, the mechanistic details behind various thermogenic processes remain incompletely understood. Although heat production from muscle has long been recognized as a thermogenic mechanism, whether muscle can produce heat independently of contraction remains controversial. Studies in birds and mammals suggest that skeletal muscle can be an important site of non-shivering thermogenesis (NST) and can be recruited during cold adaptation, although unequivocal evidence is lacking. Much research on thermogenesis during the last two decades has been focused on brown adipose tissue (BAT). These studies clearly implicate BAT as an important site of NST in mammals, in particular in newborns and rodents. However, BAT is either absent, as in birds and pigs, or is only a minor component, as in adult large mammals including humans, bringing into question the BAT-centric view of thermogenesis. This review focuses on the evolution and emergence of various thermogenic mechanisms in vertebrates from fish to man. A careful analysis of the existing data reveals that muscle was the earliest facultative thermogenic organ to emerge in vertebrates, long before the appearance of BAT in eutherian mammals. Additionally, these studies suggest that muscle-based thermogenesis is the dominant mechanism of heat production in many species including birds, marsupials, and certain mammals where BAT-mediated thermogenesis is absent or limited. We discuss the relevance of our recent findings showing that uncoupling of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) by sarcolipin (SLN), resulting in futile cycling and increased heat production, could be the basis for NST in skeletal muscle. The overall goal of this review is to highlight the role of skeletal muscle as a thermogenic organ and provide a balanced view of thermogenesis in vertebrates.

show abstract

“…Studies in skinned muscle fibres further demonstrated that the ordered array of myosin heads, characteristic of relaxed thick filaments becomes reversibly disordered by RLC phosphorylation, thus increasing myosin head mobility and accessibility to actin [38]. Recent studies from the Cooke laboratory using epifluorescence of mant-nucleotides in the presence of blebbistatin suggest that the non-phosphorylated myosin heads are highly ordered in relaxed skinned skeletal [39] and cardiac [40] muscle fibres, and become vastly disordered upon phosphorylation. We hypothesize that the D166V mutation may stabilize a disordered conformation of myosin cross-bridges in Tg-D166V muscle fibres, and that their lack of ordered orientation could be further magnified by phosphorylation.…”

Section: Molecular Mechanisms Of Rlc Phosphorylation In Tg-d166v Heartsmentioning

confidence: 99%

The effect of myosin RLC phosphorylation in normal and cardiomyopathic mouse hearts

Muthu

Kazmierczak

Jones

et al. 2012

J Cellular Molecular Medi

View full text Add to dashboard Cite

Phosphorylation of the myosin regulatory light chain (RLC) by Ca2+-calmodulin–activated myosin light chain kinase (MLCK) is known to be essential for the inotropic function of the heart. In this study, we have examined the effects of MLCK-phosphorylation of transgenic (Tg) mouse cardiac muscle preparations expressing the D166V (aspartic acid to valine)–RLC mutation, identified to cause familial hypertrophic cardiomyopathy with malignant outcomes. Our previous work with Tg-D166V mice demonstrated a large increase in the Ca2+ sensitivity of contraction, reduced maximal ATPase and force and a decreased level of endogenous RLC phosphorylation. Based on studies demonstrating the beneficial and/or protective effects of cardiac myosin phosphorylation for heart function, we hypothesized that an ex vivo phosphorylation of Tg-D166V cardiac muscle may rescue the detrimental contractile phenotypes observed earlier at the level of single myosin molecules and in Tg-D166V papillary muscle fibres. We showed that MLCK-induced phosphorylation of Tg-D166V cardiac myofibrils and muscle fibres was able to increase the reduced myofibrillar ATPase and reverse an abnormally increased Ca2+ sensitivity of force to the level observed for Tg-wild-type (WT) muscle. However, in contrast to Tg-WT, which displayed a phosphorylation-induced increase in steady-state force, the maximal tension in Tg-D166V papillary muscle fibres decreased upon phosphorylation. With the exception of force generation data, our results support the notion that RLC phosphorylation works as a rescue mechanism alleviating detrimental functional effects of a disease causing mutation. Further studies are necessary to elucidate the mechanism of this unexpected phosphorylation-induced decrease in maximal tension in Tg-D166V–skinned muscle fibres.

show abstract

Myosin ATP Turnover Rate: A Mechanism Involved in Thermogenesis in Resting Skeletal Muscle Fibers

Cited by 16 publications

References 0 publications

Mavacamten stabilizes the auto-inhibited state of two-headed cardiac myosin

Mavacamten stabilizes the auto-inhibited state of two-headed cardiac myosin

The role of skeletal‐muscle‐based thermogenic mechanisms in vertebrate endothermy

The effect of myosin RLC phosphorylation in normal and cardiomyopathic mouse hearts

Contact Info

Product

Resources

About