Phosphorylation of placental membrane proteins by a calcium- and phospholipid-dependent protein kinase.
The 30 000 g precipitate of homogenized rat placenta was incubated with 32P-adenosine triphosphate (ATP); several endogenous proteins were specifically phosphorylated in the presence of 0.5 mM calcium and phosphatidylserine (105K protein at mid pregnancy, and 78K protein at the latter part of pregnancy). The calcium- and phospholipid-dependent protein kinase activity in the 30 000 g precipitate was six times greater than the activity in the supernatant fraction. The total protein kinase C activity in the precipitate was considerably greater at the end of pregnancy than it was at mid pregnancy. Diethylaminoethyl cellulose-purified membrane-bound protein kinase C was slightly inhibited by inhibitors of lipoxygenase, NDGA or ETYA, but not by SHAM or BW755C. Haemin and polylysine strongly inhibited this activity.
Okuyama
T
T
Ishiura
S
S
Villee
C A
CA
D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D002396:Catechols / Q000494:pharmacology; D004789:Enzyme Activation; D005260:Female; D009637:Masoprocol; D008565:Membrane Proteins / Q000378:metabolism*; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology / Q000502:physiology*; D010766:Phosphorylation; D010920:Placenta / Q000201:enzymology / Q000378:metabolism; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002396:Catechols; D008565:Membrane Proteins; D010718:Phosphatidylserines; D010743:Phospholipids; D011257:Pregnancy Proteins; D009637:Masoprocol; D011493:Protein Kinase C; D002118:Calcium