Myosin phosphorylation improves contractile economy of mouse fast skeletal muscle during staircase potentiation

Bunda, Jordan; Gittings, William; Vandenboom, Rene

doi:10.1242/jeb.167718

Cited by 7 publications

(4 citation statements)

References 57 publications

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“…In other invertebrate muscles there is no troponin regulation, but there is direct regulation through the regulatory light chain of the myosin heads [68]. This light chain in all muscles can be reversibly phosphorylated and this also has a modulatory effect on activation even in vertebrate striated muscles [69,70]. In vertebrate cardiac muscles, C-protein (MyBP-C) can also be phosphorylated and it too can modulate the contractile response [71,72].…”

Section: Striated Muscle Sarcomeres and The Contractile Mechanismmentioning

confidence: 99%

Special Issue: The Actin-Myosin Interaction in Muscle: Background and Overview

Squire

2019

IJMS

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Muscular contraction is a fundamental phenomenon in all animals; without it life as we know it would be impossible. The basic mechanism in muscle, including heart muscle, involves the interaction of the protein filaments myosin and actin. Motility in all cells is also partly based on similar interactions of actin filaments with non-muscle myosins. Early studies of muscle contraction have informed later studies of these cellular actin-myosin systems. In muscles, projections on the myosin filaments, the so-called myosin heads or cross-bridges, interact with the nearby actin filaments and, in a mechanism powered by ATP-hydrolysis, they move the actin filaments past them in a kind of cyclic rowing action to produce the macroscopic muscular movements of which we are all aware. In this special issue the papers and reviews address different aspects of the actin-myosin interaction in muscle as studied by a plethora of complementary techniques. The present overview provides a brief and elementary introduction to muscle structure and function and the techniques used to study it. It goes on to give more detailed descriptions of what is known about muscle components and the cross-bridge cycle using structural biology techniques, particularly protein crystallography, electron microscopy and X-ray diffraction. It then has a quick look at muscle mechanics and it summarises what can be learnt about how muscle works based on the other studies covered in the different papers in the special issue. A picture emerges of the main molecular steps involved in the force-producing process; steps that are also likely to be seen in non-muscle myosin interactions with cellular actin filaments. Finally, the remarkable advances made in studying the effects of mutations in the contractile assembly in causing specific muscle diseases, particularly those in heart muscle, are outlined and discussed.

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Section: Striated Muscle Sarcomeres and The Contractile Mechanismmentioning

confidence: 99%

Special Issue: The Actin-Myosin Interaction in Muscle: Background and Overview

Squire

2019

IJMS

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“…Whether this is also true for concentric force potentiation remains to be determined but leaves open the possibility that our results may actually underestimate the influence of potentiation on neuromuscular efficiency. Finally, although not measured in the current work, previous studies from our laboratory have quantified genotype-dependent differences in myosin phosphorylation (e.g., Bowslaugh et al, 2016;Bunda et al, 2018;Gittings et al, 2011). In summary, although not a surrogate for the intact neuromuscular system, results from our in vitro muscle model may provide some insights into the reduced motor unit discharge rate displayed by human skeletal muscle during potentiation.…”

Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 89%

Posttetanic potentiation improves neuromuscular efficiency of mouse muscle in vitro

Laidlaw¹,

Vandenboom²

2022

Physiological Reports

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Neuromuscular efficiency is defined as the ratio of work output to stimulation rate. The purpose of these experiments was to test the hypothesis that neuromuscular efficiency would be increased in proportion to posttetanic potentiation, that is, the stimulation‐induced increase in work output displayed by rodent fast‐twitch muscle. To this end, extensor digitorum longus muscles from wild‐type and skeletal myosin light chain kinase knockout (skMLCK −/− ) mice were surgically isolated and suspended in vitro (25°C). Concentric force development during shortening at 70% of maximal unloaded shortening velocity was tested at stimulus frequencies between 10 and 80 Hz both before and after a potentiating tetanus. A strong genotype‐dependent difference in the potentiation of concentric work output was observed; concentric work output of wild‐type muscles was increased by 51%–88% while that of skMLCK −/− muscles was increased by only 20%–34% across the frequencies tested. As a result, comparison of work – frequency plots revealed that the frequency required for peak and 50% peak unpotentiated work of wild‐type muscles was decreased from ~80 to 52 Hz and from ~48 to 21 Hz, respectively. By contrast, the frequency required for peak and 50% peak unpotentiated work of skMLCK −/− muscles was decreased from ~80 to 68 Hz and from ~51 to 41 Hz, respectively. Thus, wild‐type muscles with the ability to phosphorylate myosin displayed larger increases in neuromuscular efficiency than skMLCK −/− muscles (25–30 vs 10–15 Hz, respectively). This suggests that the presence of myosin phosphorylation may ameliorate or mitigate fatigue mechanisms associated with high‐frequency stimulation rates.

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“…skMLCK consists only of a kinase domain and a C‐terminal regulatory region. Phosphorylation of skeletal muscle myosin RLC by skMLCK enhances the contractile output and economy of skeletal muscle (Bunda et al, 2018). Unlike sm/nmMLCK and skMLCK, both caMLCK and MLCK4 have constitutive kinase activity in the absence of Ca 2+ /CaM (Chang, Mahajan, et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the myosin light chain kinase (MLCK) gene of Locusta migratoria and the encoded MLCK

Wei,

Zhang,

2024

Insect Molecular Biology

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Myosin light chain kinase (MLCK) is a dedicated kinase of myosin regulatory light chain (RLC), playing an essential role in the regulation of muscle contraction and cell motility. Much of the knowledge about MLCK comes from the study of vertebrate MLCK, and little is known about insect MLCK. Here, we identified the single MLCK gene in the locust Locusta migratoria, which spans over 1400 kb, includes 62 exons and accounts for at least five transcripts. We found that the five distinct transcripts of the locust MLCK gene are expressed in a tissue‐specific manner, including three muscle‐specific isoforms and two generic isoforms. To characterise the kinase activity of locust MLCK, we recombinantly expressed LmMLCK‐G, the smallest locust MLCK isoform, in insect Sf9 cells. We demonstrated that LmMLCK‐G is a Ca2+/calmodulin‐dependent kinase that specifically phosphorylates serine 50 of locust muscle myosin RLC (LmRLC). Additionally, we found that almost all LmRLC molecules in the flight muscle and the hindleg muscles of adult locusts are phosphorylated.

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Myosin phosphorylation improves contractile economy of mouse fast skeletal muscle during staircase potentiation

Cited by 7 publications

References 57 publications

Special Issue: The Actin-Myosin Interaction in Muscle: Background and Overview

Special Issue: The Actin-Myosin Interaction in Muscle: Background and Overview

Posttetanic potentiation improves neuromuscular efficiency of mouse muscle in vitro

Characterisation of the myosin light chain kinase (MLCK) gene of Locusta migratoria and the encoded MLCK

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