Effect of the 90 kDa heat shock protein, HSP90, on glucocorticoid receptor binding to DNA-cellulose.
Glucocorticoid receptors in the IM-9 human lymphoblastoid cell line were affinity labeled with [3H]dexamethasone 21-mesylate and activated to a DNA-binding form by filtration through a Bio-Gel A-1.5m column. The 90 kDa heat shock protein, HSP90, was identified by labeling IM-9 cells with 35S-methionine at both 37 degrees C and 42 degrees C and purified to near homogeneity by sequential chromatography through DE52 and hydroxyapatite. Addition of purified HSP90 to activated, affinity labeled glucocorticoid receptors in a molecular ratio of 16 to 1 inhibited the binding of the receptors to DNA-cellulose. HSP90 did not affect the binding of other proteins to DNA-cellulose, indicating that the inhibitory effect of HSP90 was specific for the glucocorticoid receptor. These results suggest that HSP90 may associate with the glucocorticoid receptor, masking its DNA-binding site and thereby inhibiting receptor interaction with DNA.
Howard
K J
KJ
Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio.
Distelhorst
C W
CW
D000345:Affinity Labels / Q000378:metabolism; D001667:Binding, Competitive; D002460:Cell Line; D002482:Cellulose / Q000031:analogs & derivatives* / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000031:analogs & derivatives* / Q000378:metabolism; D003907:Dexamethasone / Q000031:analogs & derivatives / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006360:Heat-Shock Proteins; D006801:Humans; D008715:Methionine / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism*
D000345:Affinity Labels; C033190:DNA-cellulose; D006360:Heat-Shock Proteins; D011965:Receptors, Glucocorticoid; D003907:Dexamethasone; D002482:Cellulose; D004247:DNA; D008715:Methionine; C031710:dexamethasone 21-methanesulfonate