Heteromeric nature of glucocorticoid receptors

The wild-type and a mutant receptor of S49.1 lymphoma cells have been shown by photoaffinity labelling to contain steroid-binding polypeptides of Mr 94 000 and 40 000, respectively. We investigated the molybdate-stabilized forms of these receptors and obtained Mr 325 000 and 285 000, respectively, by gel filtration and sedimentation analysis. Mild chymotrypsin treatment of the large wild-type receptor resulted in a form of about Mr 290 000 which contained a steroid-binding polypeptide of Mr 40 000. The data suggest that the high -Mr forms of glucocorticoid receptors are heteromeric in nature and contain one steroid-binding polypeptide per complex.