title: Protein kinase C subspecies in rat brain synapses and phosphorylation of growth-associated protein.
abstract: Synaptosomes isolated from rat hippocampus contained the alpha- and beta-subspecies of protein kinase C (PKC), but not the gamma-subspecies, whereas postsynaptic pyramidal cells contained all these three subspecies. The PKC enzymes were activated synergistically by diacylglycerol and cis-unsaturated fatty acids including docosahexaenoic acid which is abundant in brain phospholipids. The phosphorylation of a PKC-specific substrate, growth-associated protein (GAP-43), which is associated predominantly with presynaptic membranes, was also protein (GAP-43), which is associated predominantly with presynaptic membranes, was also stimulated by diacylglycerol and cis-unsaturated fatty acids, particularly at the micromolar range of Ca2+ concentrations. The results presented suggest that cis-unsaturated fatty acids together with diacyglycerol may take part in the phosphorylation of GAP-43 in presynaptic membranes presumably by the alpha- or beta-subspecies of PKC even after the Ca2+ concentrations return to the basal level.
authors.affiliation: Department of Biochemistry, Kobe University School of Medicine.
authors.forename: H
authors.initials: H
authors.lastname: Mishima
mesh_terms: D000818:Animals; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D019922:GAP-43 Protein; D006624:Hippocampus / Q000201:enzymology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000096:biosynthesis* / Q000145:classification / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D013574:Synaptosomes / Q000201:enzymology*
chemical_list: D004075:Diglycerides; D019922:GAP-43 Protein; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D011493:Protein Kinase C