@article{oai:teapot.lib.ocha.ac.jp:00034696, author = {Murakami-Murofushi, Kimiko and Uchiyama, Naoko and Kobayashi, Tetsuyuki and Murofushi, Hiromu}, issue = {2}, journal = {お茶の水女子大學自然科學報告}, month = {Mar}, note = {application/pdf, 紀要論文, A unique cyclic phosphatidic acid (cPA), named PHYLPA, which was originally isolated from myxoamoebae of a true slime mold, Physarum polycephalum, and composed of cyclic phosphate and cyclopropane-containing hexadecanoic acid (1-3), was shown to stimulate the Gq protein-coupled signal transduction system and activity of protein kinase C (PKC) in vitro. When fibroblast cells were treated with PHYLPA, phosphoinositide hydrolysis and Ca^<2+> mobilization were immediately occurred, and a specific PKC substrate, MARKS, was markedly phosphorylated. Some derivatives of PHYLPA synthesized chemically also showed the obvious stimulatory effects on MARKS phosphorylation. These results show that cPA may act on a cell surface, specific receptor which activates Gq protein, a member of trimeric G protein, and phosphoinositide breakdown and PKC activation occur subsequently. While, cPA obviously stimulated purified PKC activity, and the extent of activation was much higher than that by usual lysophosphatidic acid (LPA) or diacylglycerol (DG). This indicates the possibility that the cPA may be generated by the lipolytic action from p\ lasma membrane and activates PKC directly in the cell. cPA activated both conventional PKC (cPKC) and novel PKC (nPKC), former of which has Ca^<2+> -regulatory domain, and latter one has not, at different extents. One of the stereoisomers of natural PHYLPA, assigned as sodium 3-O-[(9'S,10'R)-9',10'-methanohexadecanoyl]-sn-glycerol 1,2-cyclic phosphate, showed an apparently high stimulatory activity on these enzymes.}, pages = {29--38}, title = {STIMULATION OF Gq PROTEIN-COUPLED SIGNAL TRANSDUCTION BY CYCLIC PHOSPHATIDIC ACID (cPA) AND ACTIVATION OF PROTEIN KINASE C IN VITRO}, volume = {48}, year = {1998} }