PROTEIN-KINASE-C AND PHOSPHATIDYLSERINE BIND TO MR 110,000/115,000 POLYPEPTIDES ENRICHED IN CYTOSKELETAL AND POSTSYNAPTIC DENSITY PREPARATIONS

  • 5 October 1986
    • journal article
    • research article
    • Vol. 261  (28) , 3327-3332
Abstract
The selective binding of protein kinase C to nitrocellulose-immobilized polypeptides from rat brain and human erythrocytes was investigated. Bound enzyme was detected immunochemically with a monospecific protein kinase C antibody, or by using radiolabeled enzyme. Two polypeptides from erythrocyte membranes with Mr values of 110,000 and 115,000 bound protein kinase C in the presence of phosphatidylserine (PS) and were highly enriched in the cytoskeletal fraction. A prominent protein kinase C-binding polypeptide at Mr about 115,000 was also evident in brain cytoplasm, postsynaptic densities, and nuclei. Overlays of electrophoretic blots with 14C-phospholipids revealed that the protein kinase C-binding polypeptides also bound PS but not other phospholipids. The binding of both protein kinase C and PS was markedly inhibited after phosphorylation of the Mr 110,000/115,000 polypeptides with the kinase itself. The relevance of the results to the binding of protein kinase C to membranes and to phospholipid-cytoskeletal interactions is discussed.