The androgen receptor (AR) is a multidomain transcription factor consisting of an aminoterminal domain (NTD), a DNA binding domain (DBD) and a ligand binding domain (LBD). Binding of androgens marks the start of a sequence of intra- and interdomain communications, DNA binding, coregulator recruitment and gene activation. Besides the DBD-mediated dimerization on the DNA, there is a functionally relevant N/C interaction. The contribution of the intra- and intermolecular N/C interactions to AR function and its spatiotemporal organization have been well documented. Most recently, the first crystal structure of AR-LBD dimer was solved (Gallastegui et al. in preparation). Here, we investigated the functional relevance of the LBD dimerization by mutational analysis. Several mutations that are predicted to either disrupt or stabilize AR LBDLBD interactions were introduced in the full size AR, and the resulting mutant receptors were investigated for their ability to transactivate, for their capacity to bind androgens and for their ability to bind DNA. Since the mutations that disrupt the LBD dimer also decrease DNA binding, the involvement of the AR DBD is tested via swapping experiments with ER DBD and GR DBD. Furthermore, we have confirmed the presence of the LBD-dimer in a cellular context using biochemical approaches. At the moment, we are testing the influence of dimer disrupting and dimer stabilizing mutations on the outcome of these biochemical assays.
Presenting author: Christine Helsen, Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000 Leuven, Belgium. Email: firstname.lastname@example.org.