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Myosin rod phosphorylation and the catch state of molluscan muscles

L Castellani, C Cohen

    Science (New York, N.Y.)
    |January 16, 1987
    PubMed

    Insights

    Molluscan smooth muscles exhibit prolonged tension ("catch") linked to protein phosphorylation. Phosphorylation of myosin in the muscle rod may control the transition from catch to relaxation.

    Area of Science:

    • Biochemistry
    • Muscle Physiology
    • Molecular Biology

    Background:

    • The
    • catch
    • state in molluscan smooth muscles represents a prolonged tension phase.
    • This phenomenon is mechanistically linked to protein phosphorylation levels.

    Purpose of the Study:

    • To investigate the role of protein phosphorylation in molluscan smooth muscle
    • catch
    • tension.
    • To identify the specific molecular targets of phosphorylation involved in regulating muscle tone.

    Main Methods:

    • Mechanical measurements of smooth muscle tension.
    • Isolation and biochemical analysis of myosin from molluscan muscles.
    • Endogenous kinase assays to study myosin phosphorylation.

    Main Results:

    • Catch
    • tension correlates with protein phosphorylation.
    • Myosin isolated from these muscles undergoes phosphorylation in its rod portion.
    • An endogenous kinase is responsible for this myosin rod phosphorylation.

    Conclusions:

    • The myosin rod is a key target for phosphorylation in molluscan smooth muscle.
    • Myosin rod phosphorylation likely regulates the transition between
    • catch
    • and relaxation states.
    • This phosphorylation mechanism offers insights into smooth muscle contractility regulation.

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