HORMONE-DEPENDENT TRANSACTIVATION BY THE HUMAN ANDROGEN RECEPTOR IS REGULATED BY A DNAJ PROTEIN

Genetic studies were performed to examine the role of eukaryotic dnaJ protein, Ydj1p, in the regulated activation of human androgen receptor (hAR) after heterologous expression in Saccharomyces cerevisiae. Horm one-dependent activation of hAR was measured as a function of lacZ rep orter gene expression, which was defective in ydj1-151 and ydj1-2(Delt a) null mutant strains compared to the wild type. This defect was not due to receptor misfolding, since hAR in both wild type and mutant str ains had a similar capacity to bind hormone. The target for Ydj1p acti on was determined to be the hAR hormone binding domain since an N-term inal fragment lacking this region was constitutively active in both wi ld type and ydj1-151 mutant strains. These data correlate hormone depe ndence of hAR activation with a requirement for Ydj1p function and are consistent with a role for dnaJ proteins in signal transduction by st eroid hormone receptors.