Serine 167 is the major estradiol-induced phosphorylation site on the human estrogen receptor.
Serine 167 has been identified by radiolabel and amino acid sequencing as the major estrogen-induced phosphorylation site on the human estrogen receptor (hER) from human MCF-7 mammary carcinoma cells. The phosphorylation of the hER on serine 167 was estrogen-dependent, increasing 4-fold upon estradiol treatment of MCF-7 cells and accounted for almost half of the total [32P]phosphate incorporated into the recombinant hER from Sf9 insect cells and the native hER from MCF-7 cells. Casein kinase II was found to phosphorylate the purified recombinant hER on serine 167 in vitro. In addition, estradiol binding enhanced by 2-fold the phosphorylation of the purified recombinant hER by casein kinase II in vitro. Western blot analysis and [32P]phosphate incorporation confirmed the presence of casein kinase II in Sf9 cells. These results demonstrate that the hER is phosphorylated on serine 167 by casein kinase II in a hormone-dependent manner.
Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, New York 14642.
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Arnold
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Obourn
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Jaffe
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Notides
D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology*; D047390:Casein Kinase II; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D009036:Moths; D009376:Neoplasms, Hormone-Dependent / Q000473:pathology*; D017924:Nucleopolyhedroviruses / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects
D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D010768:Phosphoserine; D004958:Estradiol; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases