Activation of the rat liver cytosol glucocorticoid receptor by sephacryl S-300 filtration in the presence and absence of molybdate. Physical properties of the receptor and evidence for an activation inhibitor.
The DNA-binding and physical properties of the rat liver cytosol glucocorticoid receptor were determined before and after Sephacryl S-300 filtration in the presence or absence of molybdate. Cytosol was prepared and labeled with [3H]triamcinolone acetonide in buffer containing molybdate. Prior to gel filtration, only 5 +/- 3% (mean +/- S.E.) of labeled receptors bound to DNA-cellulose. After gel filtration in the presence and absence of molybdate, the per cent of labeled receptors binding to DNA-cellulose was 57 +/- 10% and 83 +/- 1%, respectively. Nonreceptor fractions from the Sephacryl S-300 column contained a heat-stable factor which blocked receptor activation but did not block the binding of activated receptors to DNA-cellulose. The activation inhibitor eluted from the column in the region of the albumin standard, but after heating its size was considerably reduced (Mr less than 3500). Receptors activated by Sephacryl S-300 filtration underwent the same size changes in the presence or absence of molybdate. Prior to gel filtration, the S20,w of labeled receptors in the presence of molybdate was 9.2 +/- 0.2 S. After filtration in the presence and absence of molybdate, the S20,w of labeled receptors was 4.2 +/- 0.2 and 4.4 +/- 0.1 S, respectively. The Stokes radius (Rs) of labeled receptors after gel filtration in either the presence or absence of molybdate was 65 +/- 1 A. From the Rs and S20,w values, the molecular weight (Mr) of activated receptors was calculated to be 115,000 to 121,000, which was in close agreement with the Mr of affinity-labeled receptors determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
D000818:Animals; D002482:Cellulose / Q000031:analogs & derivatives / Q000378:metabolism; D002850:Chromatography, Gel; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000031:analogs & derivatives / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D008982:Molybdenum / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011965:Receptors, Glucocorticoid / Q000187:drug effects / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D014222:Triamcinolone Acetonide / Q000378:metabolism
C033190:DNA-cellulose; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D008982:Molybdenum; D002482:Cellulose; D004247:DNA; D014222:Triamcinolone Acetonide