Activation of cytosolic glucocorticoid-receptor complexes in intact WEHI-7 cells does not dephosphorylate the steroid-binding protein.

摘要: Abstract In order to determine the ratio of phosphates hormone-binding sites on nonactivated (non-DNA-binding) glucocorticoid receptors in WEHI-7 mouse thymoma cells, we have extracted these from cells grown a steady state with 32P, labeled them saturating concentration [3H]dexamethasone 21-mesylate, purified using monoclonal antibody, and analyzed by polyacrylamide gel electrophoresis under denaturing reducing conditions. The complexes contained approximately 5 mol phosphate/mol bound steroid. Only half were associated 100-kDa protein which is 21-mesylate. remaining 90-kDa non-steroid-binding component complex. Dual label studies, [35S]methionine measure receptor 32P phosphates, enabled us phosphate content, relative protein, both activated cytosolic generated intact exposed triamcinolone acetonide at 37 degrees C. total amount complex roughly that complex, decrease being accounted for dissociation phosphoprotein accompanies activation. However, 35S counts steroid-binding same complexes. These results indicate there no net change phosphorylation glucocorticoid-receptor upon activation cell.