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Modulation of Striated Muscle Function is Reflected by Thick Filament Structure.

Published online by Cambridge University Press:  02 July 2020

Rhea J.C. Levine
Affiliation:
Department of Neurobiology and Anatomy, MCP Hahnemann School of Medicine and Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA
Irina Kulakovskaya
Affiliation:
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA
H. Lee Sweeney
Affiliation:
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA
Saul Winegrad
Affiliation:
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA
Zhaohui Yang
Affiliation:
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA
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Extract

In mammalian skeletal and cardiac muscles, regulation of activity occurs when calcium binds to troponin on thin filaments, which ultimately results in exposure of myosin-binding sites on actin. However, modulation of contractile function, affecting such parameters as calcium sensitivity, the rate of rise of tension, the expression of maximum tension and/or the rate of onset of relaxation, is also calcium dependent. It is, in part, a property of the thick filament itself and its component myosin and/or accessory proteins. Among these are phosphorylation of myosin regulatory light chains or light chain 2 (RLCs; LC2) and in cardiac, but not skeletal fibers, phosphorylation of myosin-binding protein C (MyBP-C).

Gentle methods of separating thick filaments from small tissue specimens, subjected to various experimental protocols designed to explore the functional parameters of such modulatory activities, allow examination of any accompanying structural changes.

Type
Philadelphia—The Other Motor City: Muscle and Non-Muscle Motility. A Dedication to Dr. Lee Peachey
Copyright
Copyright © Microscopy Society of America

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References

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