Physicochemical properties of glucocorticoid receptors from mouse fibroblasts

Glucocorticoid-bound receptor macromolecules were prepared in three forms from mouse fibroblast cells: the cytosol receptor, the nuclear extractable receptor, and the nuclear residual form obtained by DNase digestion of chromatin samples. These receptor complexes were studied with respect to gel filtration properties, sedimentation velocities in various salt concentrations, partial specific volumes, isoelectric points, and thermal stability properties. The results indicate that the three forms of the receptor differ in their molecular properties, and nuclear translocation and binding ofthe receptor complex is associated with conformational and physical changes consistent with a reduction in apparent molecular weight.