Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Phosphorylation of PI-specific phospholipase C by protein kinase C in vivo

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:5897882
A phosphoinositide-specific phospholipase C (PI-PLC I) was purified to homogeneity from guinea pig uterus. The purified enzyme migrated as a 62 kDa protein on SDS-polyacrylamide gels. PI-PLC I hydrolyzed all three phosphoinositides exhibiting a greater V/sub max/ for PIP/sub 2/ > PIP > PI. The maximal rate of hydrolysis of PIP and PIP/sub 2/ occurred at 700 nM free calcium. Antibodies specific for PI-PLC I reacted with a 62 kDa protein in membrane and cytosolic fractions from guinea pig uterus. The membrane associated PI-PLC I was tightly bound to the membrane; requiring detergent extraction for complete solubilization. The membrane bound form of PI-PLC I failed to bind lectin affinity columns, suggesting that it was not glycosylated. Using monospecific antibodies, it was demonstrated that PI-PLC I was phosphorylated in vivo. Treatment of rat basophilic leukemic cells with active phorbol esters resulted in a time-dependent increase in the phosphorylation of PI-PLC I. The phosphorylated form of PI-PLC I was found in the cytosolic fraction of untreated cells and in both cytosolic and membrane fractions of cells treated with active phorbol esters. These results suggest that protein kinase C may play an important role in the regulation of phospholipase C in vivo.
Research Organization:
Smith Kline and French Labs., Philadelphia, PA
OSTI ID:
5897882
Report Number(s):
CONF-870644-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
Country of Publication:
United States
Language:
English