title: Intermolecular NH2-/carboxyl-terminal interactions in androgen receptor dimerization revealed by mutations that cause androgen insensitivity.
abstract: Structural alignment of the human androgen receptor dimer was investigated by introducing steroid binding domain mutations that cause partial or complete androgen insensitivity into fusion proteins containing the full-length androgen receptor or the steroid binding domain. Most of the mutants had unchanged apparent equilibrium androgen binding affinity and increased dissociation rates of [3H]methyltrienolone and required increased dihydrotestosterone concentrations for transcriptional activation. In a 2-hybrid protein interaction assay in mammalian cells, the steroid binding domain interacts with an NH2-terminal-DNA binding domain fragment and with the full-length androgen receptor at physiological androgen concentrations in a dose-dependent manner. However, mutations at Val-889 and Arg-752 disrupt the NH2-/carboxyl-terminal interaction when introduced into the steroid binding domain fragment but not when present in the full-length androgen receptor. The N-C bimolecular interaction reduces the dissociation rate of bound androgen and slows the degradation rate of the carboxyl-terminal steroid binding domain fragment. The results suggest that steroid binding domain residues Val-889 and Arg-752 are critical to the NH2-/carboxyl-terminal interaction and that an intermolecular N-C interaction occurs during receptor dimerization that results in an antiparallel arrangement of androgen receptor monomers.
authors.affiliation: Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
authors.forename: E
authors.initials: E
authors.lastname: Langley
authors.forename: J A
authors.initials: JA
authors.lastname: Kemppainen
authors.forename: E M
authors.initials: EM
authors.lastname: Wilson
mesh_terms: D000728:Androgens / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D006224:Cricetinae; D019281:Dimerization; D006801:Humans; D008297:Male; D016296:Mutagenesis; D011485:Protein Binding; D011944:Receptors, Androgen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000728:Androgens; D011944:Receptors, Androgen