Identification of membrane-bound calcium, calmodulin-dependent protein kinase II in canine heart

Mary Frances Jett, Charles M. Schworer, Martha Bass, Thomas R. Soderling

    Research output: Contribution to journalArticle

    16 Scopus citations

    Abstract

    Phospholamban, the putative regulatory proteolipid of the Ca2/Mg2+ ATPase in cardiac sarcoplasmic reticulum, was selectively phosphorylated by a Ca2+/calmodulin (CaM)-dependent protein kinase associated with a cardiac membrane preparation. This kinase also catalyzed the phosphorylation of two exogenous proteins known to be phosphorylated by the multifunctional Ca2+/CaM-dependent protein kinase II Ca2+/CaM-kinase II), i.e., smooth muscle myosin light chains and glycogen synthase a. The latter protein was phosphorylated at sites previously shown to be phosphorylated by the purified multifunctional Ca2+/CaM-kinase II from liver and brain. The membrane-bound kinase did not phosphorylate phosphorylase b or cardiac myosin light chains, although these proteins were phosphorylated by appropriate, specific calmodulin-dependent protein kinases added exogenously. In addition to phospholamban, several other membrane-associated proteins were phosphorylated in a calmodulin-dependent manner. The principal one exhibited a Mr of approximately 56,000, a value similar to that of the major protein (57,000) in a partially purified preparation of Ca2+/CaM-kinase II from the soluble fraction of canine heart that was autophosphorylated in a calmodulin-dependent manner. These data indicate that the membrane-bound, calmodulin-dependent protein kinase that phosphorylates phospholamban in cardiac membranes is not a specific calmodulin-dependent kinase, but resembles the multifunctional Ca2+/CaM-kinase II. Our data indicate that this kinase may be present in both the particulate and soluble fractions of canine heart.

    Original languageEnglish (US)
    Pages (from-to)354-360
    Number of pages7
    JournalArchives of Biochemistry and Biophysics
    Volume255
    Issue number2
    DOIs
    StatePublished - Jun 1987

    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Molecular Biology

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