Estrogen modulates Ca(2+)-independent lipid-stimulated kinase in the rabbit corpus luteum of pseudopregnancy. Identification of luteal estrogen-modulated lipid-stimulated kinase as protein kinase C delta.
Rabbit corpora lutea were tested for the presence of phosphorylative responses sensitive to estrogen. Luteal Ca(2+)-independent lipid-stimulated kinase activity was detected by phosphorylation of the endogenous substrate, p76. Estrogen treatment, by way of estradiol-17 beta implant, increased levels of the lipid-stimulated phosphoprotein 2-3-fold throughout pseudopregnancy. Midpseudopregnant rabbit luteal extracts were further evaluated to determine the identity of the lipid-stimulated kinase. Results of low pH-activated phosphorylation were consistent with the identification of p76 as an autophosphorylated member of the protein kinase C (PKC) family. Partial purification of the luteal lipid-stimulated kinase was performed using sequential DEAE-cellulose/hydroxylapatite chromatographies and using gel filtration. Western immunoblot with type-specific anti-PKC delta antiserum showed coelution of kinase p76 activity with immunoreactive PKC delta. Immunoblot analysis confirmed that luteal levels of PKC delta were increased by estrogen treatment.
Maizels
E T
ET
Department of Cell Biology, Northwestern University Medical School, Chicago, Illinois 60611.
Miller
J B
JB
Cutler
R E
RE
Jackiw
V
V
Carney
E M
EM
Mizuno
K
K
Ohno
S
S
Hunzicker-Dunn
M
M
D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology*; D006063:Chorionic Gonadotropin; D002845:Chromatography; D002850:Chromatography, Gel; D003338:Corpus Luteum / Q000201:enzymology*; D004075:Diglycerides / Q000494:pharmacology*; D017886:Durapatite; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006882:Hydroxyapatites; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D010718:Phosphatidylserines / Q000494:pharmacology*; D010766:Phosphorylation; D006656:Protamine Kinase; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011555:Pseudopregnancy / Q000201:enzymology*; D011817:Rabbits; D012826:Silicone Elastomers
D006063:Chorionic Gonadotropin; D004075:Diglycerides; D006882:Hydroxyapatites; D007527:Isoenzymes; D010718:Phosphatidylserines; D012826:Silicone Elastomers; D004958:Estradiol; D017886:Durapatite; D011494:Protein Kinases; D006656:Protamine Kinase; D011493:Protein Kinase C; D002118:Calcium; C013965:diolein