[Role of C-kinase in development and function of human placental chorionic tissue].
C-kinase is an intracellular protein kinase which is activated by Ca2+ and phospholipid, and plays a crucial role in signal transduction and cell proliferation. To clarify the possibility that C-kinase regulates the growth or maturation of placental tissues, I have purified C-kinase from human placental chorion by sequential column chromatography, determined the substrate specificity of the purified C-kinase, and then investigated the effects of various hormones on the phosphorylation of placental chorionic membrane proteins. The results were as follows: 1) pH optimum of C-kinase was 8.0, apparent Ka for Ca2+ was 1 X 10(-5) M and Ka for phosphatidylserine was 80 micrograms/ml. 2) One of the cytoskeletal proteins, filamin, was phosphorylated specifically by the purified C-kinase. 3) The C-kinase activity increased with placental growth. The enzyme activity in the 3rd. trimester of pregnancy was 5 times higher than that in the 1st. trimester. 4) C-kinase activity was inhibited by hCG and markedly stimulated by DHA or DHAS. These results suggest that C-kinase is involved in the specific functions of the placenta.
D002118:Calcium / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000502:physiology; D003285:Contractile Proteins / Q000378:metabolism; D005260:Female; D064448:Filamins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008840:Microfilament Proteins / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D010766:Phosphorylation; D010920:Placenta / Q000502:physiology*; D011247:Pregnancy; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D013379:Substrate Specificity
D006063:Chorionic Gonadotropin; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D010743:Phospholipids; D011493:Protein Kinase C; D002118:Calcium