Small molecule-mediated refolding and activation of myosin motor function

Radke, Michael B.; Taft, Manuel H.; Stapel, Britta; Hilfiker‐Kleiner, Denise; Preller, Matthias; Manstein, Dietmar J.

doi:10.7554/elife.01603

Cited by 49 publications

(53 citation statements)

References 53 publications

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“…; Radke et al . ; Spudich, ; Green et al . ), and the search for myosin‐targeted therapeutics has been directed by biochemical and structural models of the interaction between the myosin head domain, actin and ATP, which have been used to screen for and characterize the function of small molecules that bind specifically to cardiac myosin, and activate (Malik et al .…”

Section: Discussionmentioning

confidence: 99%

Omecamtiv mercabil and blebbistatin modulate cardiac contractility by perturbing the regulatory state of the myosin filament

Kampourakis

Zhang

Sun

et al. 2017

The Journal of Physiology

125

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Key points Omecamtiv mecarbil and blebbistatin perturb the regulatory state of the thick filament in heart muscle.Omecamtiv mecarbil increases contractility at low levels of activation by stabilizing the ON state of the thick filament.Omecamtiv mecarbil decreases contractility at high levels of activation by disrupting the acto‐myosin ATPase cycle.Blebbistatin reduces contractility by stabilizing the thick filament OFF state and inhibiting acto‐myosin ATPase.Thick filament regulation is a promising target for novel therapeutics in heart disease. AbstractContraction of heart muscle is triggered by a transient rise in intracellular free calcium concentration linked to a change in the structure of the actin‐containing thin filaments that allows the head or motor domains of myosin from the thick filaments to bind to them and induce filament sliding. It is becoming increasingly clear that cardiac contractility is also regulated through structural changes in the thick filaments, although the molecular mechanisms underlying thick filament regulation are still relatively poorly understood. Here we investigated those mechanisms using small molecules – omecamtiv mecarbil (OM) and blebbistatin (BS) – that bind specifically to myosin and respectively activate or inhibit contractility in demembranated cardiac muscle cells. We measured isometric force and ATP utilization at different calcium and small‐molecule concentrations in parallel with in situ structural changes determined using fluorescent probes on the myosin regulatory light chain in the thick filaments and on troponin C in the thin filaments. The results show that BS inhibits contractility and actin‐myosin ATPase by stabilizing the OFF state of the thick filament in which myosin head domains are more parallel to the filament axis. In contrast, OM stabilizes the ON state of the thick filament, but inhibits contractility at high intracellular calcium concentration by disrupting the actin‐myosin ATPase pathway. The effects of BS and OM on the calcium sensitivity of isometric force and filament structural changes suggest that the co‐operativity of calcium activation in physiological conditions is due to positive coupling between the regulatory states of the thin and thick filaments.

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Section: Discussionmentioning

confidence: 99%

Omecamtiv mercabil and blebbistatin modulate cardiac contractility by perturbing the regulatory state of the myosin filament

Kampourakis

Zhang

Sun

et al. 2017

The Journal of Physiology

125

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“…EMD 57033 is not a direct activator of cardiac myosin-2 and rather acts as pharmacological chaperone. By binding to and refolding of stress-induced misfolded protein, EMD57033 can restore the enzymatic activity of the motor, a function that may improve therapeutic approaches of protein-misfolding diseases including myosinopathies [212]. …”

Section: Regulation By Small Moleculesmentioning

confidence: 99%

Various Themes of Myosin Regulation

Heissler

Sellers

2016

Journal of Molecular Biology

114

127

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Members of the myosin superfamily are actin-based molecular motors that are indispensable for cellular homeostasis. The vast functional and structural diversity of myosins accounts for the variety and complexity of the underlying allosteric regulatory mechanisms that determine the activation or inhibition of myosin motor activity and enable precise timing and spatial aspects of myosin function at the cellular level. This review focuses on the molecular basis of posttranslational regulation of eukaryotic myosins from different classes across species by allosteric intrinsic and extrinsic effectors. First, we highlight the impact of heavy and light chain phosphorylation. Second, we outline intramolecular regulatory mechanisms such as autoinhibition and subsequent activation. Third, we discuss diverse extramolecular allosteric mechanisms ranging from actin-linked regulatory mechanisms to myosin:cargo interactions. At last, we briefly outline the allosteric regulation of myosins with synthetic compounds.

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“…Substances that specifically inhibit or activate myosins have been identified in e.g. 57–60 . Other in depth investigations of various myosins that exploited Diatrack include those of Weith, Diensthuber, and Chizhov.…”

Section: Survey Of Applicationsmentioning

confidence: 99%

Diatrack particle tracking software: Review of applications and performance evaluation

Vallotton

Oijen

Whitchurch

et al. 2017

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Object tracking is an instrumental tool supporting studies of cellular trafficking. There are three challenges in object tracking: the identification of targets; the precise determination of their position and boundaries, and the assembly of correct trajectories. This last challenge is particularly relevant when dealing with densely populated images with low signal-to-noise ratios - conditions that are often encountered in applications such as organelle tracking, virus particle tracking, or single-molecule imaging. We have developed a set of methods that can handle a wide variety of signal complexities. They are compiled into a free software package called Diatrack. Here we review its main features and utility in a range of applications, providing a survey of the dynamic imaging field together with recommendations for effective use. The performance of our framework is shown to compare favorably to a wide selection of custom-developed algorithms, whether in terms of localization precision, processing speed, or correctness of tracks.

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Small molecule-mediated refolding and activation of myosin motor function

Cited by 49 publications

References 53 publications

Omecamtiv mercabil and blebbistatin modulate cardiac contractility by perturbing the regulatory state of the myosin filament

Omecamtiv mercabil and blebbistatin modulate cardiac contractility by perturbing the regulatory state of the myosin filament

Various Themes of Myosin Regulation

Diatrack particle tracking software: Review of applications and performance evaluation

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