Phosphorylation of the human 1,25-dihydroxyvitamin D3 receptor by cAMP-dependent protein kinase, in vitro, and in transfected COS-7 cells.
We report that the human 1,25-dihydroxyvitamin D3 receptor is an efficient substrate for cAMP-dependent protein kinase, in vitro. This phosphorylation reaction is rapid and neither dependent upon nor significantly affected by the presence of the 1,25-dihydroxyvitamin D3 ligand. Preliminary mapping experiments utilizing C-terminal truncation mutants reveal that the primary site(s) of phosphorylation, in vitro, is localized between amino acids 133 and 201. Cotransfection of the catalytic subunit of murine cAMP-dependent protein kinase and the human 1,25-dihydroxyvitamin D3 receptor into monkey kidney (COS-7) cells not only results in a dramatic kinase-dependent increase in receptor phosphorylation but also elicits an attenuation in 1,25-dihydroxyvitamin D3-dependent transcriptional activation of a reporter gene. These observations suggest a potential role for cAMP-dependent protein kinase in the modulation of 1,25-dihydroxyvitamin D3 receptor-mediated gene regulation.
Department of Biochemsitry, College of Medicine, University of Arizona, Tucson 85724.
P W
PW
Jurutka
J C
JC
Hsieh
M R
MR
Haussler
D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D066298:In Vitro Techniques; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000378:metabolism*; D014162:Transfection
D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D011494:Protein Kinases