Protein kinase C stimulatory activity in the pseudopregnant rat ovary.
Ovarian cytosol from pseudopregnant rats was heated to 80-90 degrees C for 2 min and precipitated proteins removed by centrifugation. The supernatant of the heated ovarian cytosol contained no protein kinase C activity but when added to a control preparation containing protein kinase C, enzyme activity was increased to 200% of control. The stimulatory activity was stable to heating for 10 min, was retained on a centrifugal filtration device with a 100,000 M(r) cut-off, did not affect cAMP-dependent protein kinase, was not extractable in petroleum ether or chloroform/methanol (2:1), and enhanced the phosphorylation of protein kinase C-specific peptide substrates. The stimulatory factor was calcium-dependent and could substitute for phosphatidylserine and diacylglycerol in the protein kinase C assay. This stimulatory factor may provide a mechanism whereby the response of protein kinase C to hormonal activation could be regulated by the cell.
Eyster
K M
KM
Department of Physiology and Pharmacology, University of South Dakota, Vermillion.
Waller
M S
MS
Johnson
M J
MJ
D000818:Animals; D001685:Biological Factors / Q000302:isolation & purification / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000502:physiology; D003600:Cytosol / Q000737:chemistry / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006358:Hot Temperature; D008055:Lipids / Q000494:pharmacology; D010053:Ovary / Q000737:chemistry* / Q000201:enzymology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011555:Pseudopregnancy / Q000378:metabolism*; D051381:Rats; D014020:Tissue Extracts / Q000494:pharmacology
D001685:Biological Factors; D008055:Lipids; D014020:Tissue Extracts; D000242:Cyclic AMP; D011493:Protein Kinase C; D002118:Calcium