Protein kinase C of a human megakaryoblastic leukemic cell line (MEG-01). Analysis of subspecies and activation by diacylglycerol and free fatty acids.
Protein kinase C (PKC) from a human megakaryoblastic leukemic cell line (MEG-01) was resolved into two fractions by hydroxyapatite column chromatography, which are indistinguishable from the brain type II (beta I/beta II) and type III (alpha) subspecies, by biochemical and immunoblot analysis. In the presence of both phosphatidylserine and diacylglycerol, several free unsaturated fatty acids (FFA's), such as arachidonic, oleic, linoleic and linolenic acids, further enhanced the enzyme activation, and allowed the enzyme to exhibit almost full activity at nearly basal levels of Ca2+ concentration. The concentration of unsaturated FFA's giving rise to the maximum enzyme activation was around 2 x 10(-5) M. Palmitic and stearic acids were inactive. The result implies that, in addition to diacylglycerol, the receptor-mediated release of unsaturated FFA's from membrane phospholipids may also take part in the activation of PKC.
Kitagawa
Y
Y
Department of Biochemistry, Kobe University School of Medicine, Japan.
Matsuo
Y
Y
Minowada
J
J
Nishizuka
Y
Y
D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002845:Chromatography; D004075:Diglycerides / Q000494:pharmacology*; D004357:Drug Synergism; D004789:Enzyme Activation / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology*; D006801:Humans; D015151:Immunoblotting; D008533:Megakaryocytes / Q000166:cytology / Q000201:enzymology*; D010718:Phosphatidylserines / Q000494:pharmacology; D011493:Protein Kinase C / Q000737:chemistry / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D001095:Arachidonic Acids; D004075:Diglycerides; D005230:Fatty Acids, Nonesterified; D010718:Phosphatidylserines; D016718:Arachidonic Acid; D011493:Protein Kinase C; D002118:Calcium