Synergistic activation of RLD-1 by agents triggering PKA and PKC dependent signalling.
RLD-1 and OR-1 are closely related orphan nuclear receptors that can be activated by certain oxysterols. To obtain cells stably expressing RLD-1 or OR-1, CHOK1 cells were successively transfected with a DGRE2-ALP reporter and GR-RLD-1 or GR-OR-1 chimeric constructs. The selected cell clones that showed low background activity of the reporter and maximum fold induction by 22R(OH)cholesterol were used for subsequent experiments. Treatment of the cells with PGE2, TPA, or 8-bromo-cAMP alone did not transactivate the reporter. However, the induction of the reporter by 22R(OH)cholesterol was markedly enhanced in the presence of PGE2, TPA, 8-bromo-cAMP, or forskolin in cells expressing GR-RLD-1. The enhancement was inhibited by H-89 and bisindolylmaleimide, both inhibitors of protein kinases. These results suggest that transactivation by ligand-activated RLD-1 may be further modulated/regulated through other signal transduction pathways involving phosphorylation catalyzed by protein kinases.
Huang
C J
CJ
Department of Biosciences at Novum, Karolinska Institute, Huddinge, Sweden.
Feltkamp
D
D
Nilsson
S
S
Gustafsson
J A
JA
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015232:Dinoprostone / Q000494:pharmacology; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D006888:Hydroxycholesterols / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D000071518:Liver X Receptors; D008301:Maleimides / Q000494:pharmacology; D057093:Orphan Nuclear Receptors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism*; D011988:Receptors, Thyroid Hormone / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013449:Sulfonamides; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D006888:Hydroxycholesterols; D007211:Indoles; D007546:Isoquinolines; D000071518:Liver X Receptors; D008301:Maleimides; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D011988:Receptors, Thyroid Hormone; D013449:Sulfonamides; C003585:22-hydroxycholesterol; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D015232:Dinoprostone; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C088060:bisindolylmaleimide; D013755:Tetradecanoylphorbol Acetate