Does actin bind to the ends of thin filaments in skeletal muscle?

S. Ishiwata, T. Funatsu

    Research output: Contribution to journalArticle

    37 Citations (Scopus)

    Abstract

    We examined whether or not purified actin binds to the ends of thin filaments in rabbit skeletal myofibrils. Phase-contrast, fluorescence, and electron microscopic observations revealed that actin does not bind to the ends of thin filaments of intact myofibrils. However, in I-Z-I brushes prepared by dissolving thick filaments at high ionic strength, marked binding of actin to the free ends, i.e., the pointed ends, of thin filaments was observed when actin was added at an early phase of polymerization. As the polymerization of actin proceeded, the binding efficiency decreased. The critical actin concentration for this binding was higher than that for polymerization in solution. The binding of G-actin was not observed at low ionic strength. On the basis of these results, we suggest that a particular structure suppressing the binding of actin is present at the free ends of thin filaments in intact myofibrils and that a part of the end structure population is eliminated or modified at high ionic strength so that further binding of actin becomes possible. The myofibril and I-Z-I brush appear to be useful systems for studies aimed at elucidating the organization mechanisms of actin filaments in vivo.

    Original languageEnglish
    Pages (from-to)282-291
    Number of pages10
    JournalJournal of Cell Biology
    Volume100
    Issue number1
    Publication statusPublished - 1985

    Fingerprint

    Actins
    Skeletal Muscle
    Myofibrils
    Polymerization
    Osmolar Concentration
    Actin Cytoskeleton
    Fluorescence
    Electrons
    Rabbits
    Population

    ASJC Scopus subject areas

    • Cell Biology

    Cite this

    Does actin bind to the ends of thin filaments in skeletal muscle? / Ishiwata, S.; Funatsu, T.

    In: Journal of Cell Biology, Vol. 100, No. 1, 1985, p. 282-291.

    Research output: Contribution to journalArticle

    Ishiwata, S & Funatsu, T 1985, 'Does actin bind to the ends of thin filaments in skeletal muscle?', Journal of Cell Biology, vol. 100, no. 1, pp. 282-291.
    Ishiwata, S. ; Funatsu, T. / Does actin bind to the ends of thin filaments in skeletal muscle?. In: Journal of Cell Biology. 1985 ; Vol. 100, No. 1. pp. 282-291.
    @article{40dcb54d20ab4531ac5168c352bf1904,
    title = "Does actin bind to the ends of thin filaments in skeletal muscle?",
    abstract = "We examined whether or not purified actin binds to the ends of thin filaments in rabbit skeletal myofibrils. Phase-contrast, fluorescence, and electron microscopic observations revealed that actin does not bind to the ends of thin filaments of intact myofibrils. However, in I-Z-I brushes prepared by dissolving thick filaments at high ionic strength, marked binding of actin to the free ends, i.e., the pointed ends, of thin filaments was observed when actin was added at an early phase of polymerization. As the polymerization of actin proceeded, the binding efficiency decreased. The critical actin concentration for this binding was higher than that for polymerization in solution. The binding of G-actin was not observed at low ionic strength. On the basis of these results, we suggest that a particular structure suppressing the binding of actin is present at the free ends of thin filaments in intact myofibrils and that a part of the end structure population is eliminated or modified at high ionic strength so that further binding of actin becomes possible. The myofibril and I-Z-I brush appear to be useful systems for studies aimed at elucidating the organization mechanisms of actin filaments in vivo.",
    author = "S. Ishiwata and T. Funatsu",
    year = "1985",
    language = "English",
    volume = "100",
    pages = "282--291",
    journal = "Journal of Cell Biology",
    issn = "0021-9525",
    publisher = "Rockefeller University Press",
    number = "1",

    }

    TY - JOUR

    T1 - Does actin bind to the ends of thin filaments in skeletal muscle?

    AU - Ishiwata, S.

    AU - Funatsu, T.

    PY - 1985

    Y1 - 1985

    N2 - We examined whether or not purified actin binds to the ends of thin filaments in rabbit skeletal myofibrils. Phase-contrast, fluorescence, and electron microscopic observations revealed that actin does not bind to the ends of thin filaments of intact myofibrils. However, in I-Z-I brushes prepared by dissolving thick filaments at high ionic strength, marked binding of actin to the free ends, i.e., the pointed ends, of thin filaments was observed when actin was added at an early phase of polymerization. As the polymerization of actin proceeded, the binding efficiency decreased. The critical actin concentration for this binding was higher than that for polymerization in solution. The binding of G-actin was not observed at low ionic strength. On the basis of these results, we suggest that a particular structure suppressing the binding of actin is present at the free ends of thin filaments in intact myofibrils and that a part of the end structure population is eliminated or modified at high ionic strength so that further binding of actin becomes possible. The myofibril and I-Z-I brush appear to be useful systems for studies aimed at elucidating the organization mechanisms of actin filaments in vivo.

    AB - We examined whether or not purified actin binds to the ends of thin filaments in rabbit skeletal myofibrils. Phase-contrast, fluorescence, and electron microscopic observations revealed that actin does not bind to the ends of thin filaments of intact myofibrils. However, in I-Z-I brushes prepared by dissolving thick filaments at high ionic strength, marked binding of actin to the free ends, i.e., the pointed ends, of thin filaments was observed when actin was added at an early phase of polymerization. As the polymerization of actin proceeded, the binding efficiency decreased. The critical actin concentration for this binding was higher than that for polymerization in solution. The binding of G-actin was not observed at low ionic strength. On the basis of these results, we suggest that a particular structure suppressing the binding of actin is present at the free ends of thin filaments in intact myofibrils and that a part of the end structure population is eliminated or modified at high ionic strength so that further binding of actin becomes possible. The myofibril and I-Z-I brush appear to be useful systems for studies aimed at elucidating the organization mechanisms of actin filaments in vivo.

    UR - http://www.scopus.com/inward/record.url?scp=0021999557&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=0021999557&partnerID=8YFLogxK

    M3 - Article

    C2 - 3880755

    AN - SCOPUS:0021999557

    VL - 100

    SP - 282

    EP - 291

    JO - Journal of Cell Biology

    JF - Journal of Cell Biology

    SN - 0021-9525

    IS - 1

    ER -