Craig Lab Publications


Tropomyosin and the steric mechanism of muscle regulation

UMMS Affiliation

Department of Cell Biology



Document Type


Medical Subject Headings

Actins; Adenosine Triphosphate; Animals; Calcium; Humans; Kinetics; Microfilaments; Models, Biological; Models, Molecular; Molecular Conformation; Muscles; Myosins; Protein Conformation; Protein Structure, Tertiary; Tropomyosin


Cell Biology


Contraction in all muscles must be precisely regulated and requisite control systems must be able to adjust to changes in physiological and myopathic stimuli. In this chapter, we outline the structural evidence for a steric mechanism that governs muscle activity. The mechanism involves calcium and myosin induced changes in the position of tropomyosin along actin-based thin filaments. This process either blocks or uncovers myosin crossbridge binding sites on actin and consequently regulates crossbridge cycling on thin filaments, the sliding of thin and thick filaments and muscle shortening and force production.

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Citation: Adv Exp Med Biol. 2008;644:95-109.

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Link to Article in PubMed

PubMed ID