DIFFERENTIAL IN-VIVO REGULATION OF STEROID-HORMONE RECEPTOR ACTIVATION BY CDC37P

The CDC37 gene is essential for the activity of p60(v-src) when expres sed in yeast cells. Since the activation pathway for p60(v-src) and st eroid hormone receptors is similar, the present study analyzed the hor mone-dependent transactivation by androgen receptors and glucocorticoi d receptors in yeast cells expressing a mutant version of the CDC37 ge ne. In this mutant, hormone-dependent transactivation by androgen rece ptors was defective at both permissive and restrictive temperatures, a lthough transactivation by glucocorticoid receptors was mildly defecti ve only at the restrictive temperature. Cdc37p appears to function via the androgen receptor ligand-binding domain, although it does not inf luence receptor hormone-binding affinity. Models for Cdc37p regulation of steroid hormone receptors are discussed.