Modulation of calcium-mediated inactivation of ionic currents by Ca2+/calmodulin-dependent protein kinase II

M. Sakakibara, D. L. Alkon, R. DeLorenzo, J. R. Goldenring, J. T. Neary, E. Heldman

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    56 Scopus citations

    Abstract

    Iontophoretic injection of Ca2+ causes reduction of I0A (an early rapidly activating and inactivating K+ current) and I0C (a late Ca2+-dependent K+ current) measured across the isolated type B soma membrane (Alkon et al., 1984, 1985; Alkon and Sakakibara, 1984, 1985). Similarly, voltage-clamp conditions which cause elevation of [Ca2+]i are followed by reduction of I0A and I0C lasting 1–3 min. Iontophoretic injection of highly purified Ca2+/CaM-dependent protein kinase II (CaM kinase II) isolated from brain tissue (Goldenring et al., 1983) enhanced and prolonged this Ca2+-mediated reduction of I0A and I0C. ICa2+, a voltage-dependent Ca2+ current, also showed some persistent reduction under these conditions. Iontophoretic injection of heat-inactivated enzyme had no effect. Agents that inhibit or block Ca2+/CaM-dependent phosphorylation produced increased I0A and I0C amplitudes and prevented the effects of CaM kinase II injection. The results reported here and in other studies implicate Ca2+-stimulated phosphorylation in the regulation of type B soma ionic currents.

    Original languageEnglish
    Pages (from-to)319-327
    Number of pages9
    JournalBiophysical Journal
    Volume50
    Issue number2
    DOIs
    StatePublished - 1 Jan 1986

    ASJC Scopus subject areas

    • Biophysics

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