Acyl chain dependence of diacylglycerol activation of protein kinase C activity in vitro.
Stimulation of protein kinase C (PKC) activity in lipid vesicles in vitro was achieved by pure molecular species of diacylglycerol (DAG), specifically 1-stearoyl-2-acyl-sn-glycerol substituted with 2-arachidonoyl,2-eicosapentaenoyl or 2-docosahexaenoyl (SAG, SEG, and SDG, respectively). PKC activity was measured in lipid vesicles containing 30 mol% 1-palmitoyl-2-oleoyl-sn-glycerol-3-phospho-L-serine (POPS), 68-70 mol% 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (POPC), and 0-2 mol% DAG in the presence of 20 microM calcium. Our results demonstrate that amplification of PKC activity differs significantly among these molecular species of DAG. In particular, SDG at 0.5 mol% is more potent in increasing PKC activity than is dioleoylglycerol (DOG), SEG, or SAG, and SAG and SDG at 1.0 and 2.0 mol% have similar potencies which are greater than those of DOG or SEG. These findings demonstrate that sn-2 substitutions in DAG by specific n-3 and n-6 polyunsaturated fatty acids increase the potency of DAG to stimulate PKC activity in vitro.
Marignani
P A
PA
Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
Epand
R M
RM
Sebaldt
R J
RJ
D004075:Diglycerides / Q000378:metabolism / Q000494:pharmacology*; D004789:Enzyme Activation; D010766:Phosphorylation; D011493:Protein Kinase C / Q000187:drug effects* / Q000378:metabolism
D004075:Diglycerides; D011493:Protein Kinase C