title: Activation of protein kinase C with cardiolipin-containing liposomes in relation to membrane-protein interaction.
abstract: Many cytoplasmic proteins, including Ca2+- and phospholipid-dependent protein kinase (protein kinase C) of polymorphonuclear leukocytes (PMNs) associate in Ca2+-dependent manner with phospholipid liposomes containing cardiolipin (CL), as in the case of phosphatidylserine (PS)-containing liposomes. A crude protein kinase C fraction was purified by association of the enzyme with CL-containing liposomes (flotation method). The partially purified protein kinase C from rat brain or guinea pig PMN was activated by the CL-containing liposomes in the presence of dioleoylglycerol (DG) and Ca2+. This activation was analogous to that of PS. The half maximum activity was obtained with 20 microM CL in the presence of 1 microM Ca2+ and 5 microM DG. Many of the cytoplasmic proteins which associate with CL-containing liposomes were preferentially phosphorylated by membrane-associated protein kinase C in the presence of DG and Ca2+. These results suggest that the association of cytoplasmic protein kinase C with the membrane has an important role in regulation of protein kinase C activity in relation to the association of other cytoplasmic proteins to the membrane.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002308:Cardiolipins / Q000494:pharmacology*; D003600:Cytosol / Q000201:enzymology; D004789:Enzyme Activation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008081:Liposomes; D008297:Male; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002308:Cardiolipins; D008081:Liposomes; D011493:Protein Kinase C