Protein kinase C and phosphatidylserine bind to Mr 110,000/115,000 polypeptides enriched in cytoskeletal and postsynaptic density preparations.
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.
D000818:Animals; D003599:Cytoskeleton / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D007163:Immunosorbent Techniques; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure*
D008565:Membrane Proteins; D010455:Peptides; D010718:Phosphatidylserines; D011493:Protein Kinase C