title: Role of phospholipids containing docosahexaenoyl chains in modulating the activity of protein kinase C.
abstract: 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.
authors.affiliation: Department of Biochemistry, McMaster University, Hamilton, ON, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Giorgione
authors.forename: R M
authors.initials: RM
authors.lastname: Epand
authors.forename: C
authors.initials: C
authors.lastname: Buda
authors.forename: T
authors.initials: T
authors.lastname: Farkas
mesh_terms: 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
chemical_list: 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