Role of phospholipids containing docosahexaenoyl chains in modulating the activity of protein kinase C.
It is known that the phospholipids of the brain cells of fish are altered during cold adaptation. In particular, the 1-monounsaturated 2-polyunsaturated phosphatidylethanolamines (PEs) increase 2- to 3-fold upon adaptation to cold. One of the most striking changes is in the 18:1/22:6 species of PE. We determined how this lipid affected the bilayer-to-hexagonal-phase transition temperature of 16:1/16:1 PE. We found that it was more effective in lowering this transition temperature than were other, less unsaturated, PE species. In addition, it was not simply the presence of the 18:1/22:6 acyl chains which caused this effect, since the 18:1/22:6 species of phosphatidylcholine had the opposite effect on this transition temperature. Zwitterionic substances that lower the bilayer-to-hexagonal-phase transition temperature often cause an increase in the activity of protein kinase C (PKC). Indeed, the 18:1/22:6 PE caused an increase in the rate of histone phosphorylation by PKC which was greater than that caused by other, less unsaturated, PEs. The 18:1/22:6 phosphatidylcholine had no effect on this enzyme. The stimulation of the activity of PKC by the 18:1/22:6 PE is a consequence of this lipid's increasing the partitioning of PKC to the membrane.
Giorgione
J
J
Department of Biochemistry, McMaster University, Hamilton, ON, Canada.
Epand
R M
RM
Buda
C
C
Farkas
T
T
D002152:Calorimetry, Differential Scanning; D004789:Enzyme Activation; D008081:Liposomes; D008560:Membrane Fluidity; D010713:Phosphatidylcholines / Q000494:pharmacology; D010714:Phosphatidylethanolamines / Q000494:pharmacology*; D011485:Protein Binding; D011493:Protein Kinase C / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism
C096034:1-oleoyl 2-docosahexaenoyl phosphatidylethanolamine; D008081:Liposomes; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D011994:Recombinant Proteins; C084316:1-oleoyl-2-docosahexaenoyl phosphatidylcholine; D011493:Protein Kinase C