10         20         30         40         50         60
         |          |          |          |          |          |
MEVQLGLGRV YPRPPSKTYR GAFQNLFQSV REVIQNPGPR HPEAASAAPP GASLLLLQQQ - 60
QQQQQQQQQQ QQQQQQQQET SPRQQQQQQG EDGSPQAHRR GPTGYLVLDE EQQPSQPQSA - 120
LECHPERGCV PEPGAAVAAS KGLPQQLPAP PDEDDSAAPS TLSLLGPTFP GLSSCSADLK - 180
DILSEASTMQ LLQQQQQEAV SEGSSSGRAR EASGAPTSSK DNYLGGTSTI SDNAKELCKA - 240
VSVSMGLGVE ALEHLSPGEQ LRGDCMYAPL LGVPPAVRPT PCAPLAECKG SLLDDSAGKS - 300
TEDTAEYSPF KGGYTKGLEG ESLGCSGSAA AGSSGTLELP STLSLYKSGA LDEAAAYQSR - 360
DYYNFPLALA GPPPPPPPPH PHARIKLENP LDYGSAWAAA AAQCRYGDLA SLHGAGAAGP - 420
GSGSPSAAAS SSWHTLFTAE EGQLYGPCGG GGGGGGGGGG GGGGGGGGGG GGEAGAVAPY - 480
GYTRPPQGLA GQESDFTAPD VWYPGGMVSR VPYPSPTCVK SEMGPWMDSY SGPYGDMRLE - 540
TARDHVLPID YYFPPQKTCL ICGDEASGCH YGALTCGSCK VFFKRAAEGK QKYLCASRND - 600
CTIDKFRRKN CPSCRLRKCY EAGMTLGARK LKKLGNLKLQ EEGEASSTTS PTEETTQKLT - 660
VSHIEGYECQ PIFLNVLEAI EPGVVCAGHD NNQPDSFAAL LSSLNELGER QLVHVVKWAK - 720
ALPGFRNLHV DDQMAVIQYS WMGLMVFAMG WRSFTNVNSR MLYFAPDLVF NEYRMHKSRM - 780
YSQCVRMRHL SQEFGWLQIT PQEFLCMKAL LLFSIIPVDG LKNQKFFDEL RMNYIKELDR - 840
IIACKRKNPT SCSRRFYQLT KLLDSVQPIA RELHQFTFDL LIKSHMVSVD FPEMMAEIIS - 900
VQVPKILSGK VKPIYFHTQ

The actions of androgens are mediated through the androgen receptor (AR), an intracellular receptor that belongs to the steroid nuclear receptor superfamily. The actions of male sex hormones testosterone and dihydrotestosterone are facilitated by the AR. Consisting of three domains, androgen receptor contains the ligand binding domain (LBD), the DNA binding domain (DBD), and the amino terminal domain (NTD). At the C-terminus, the LBD (amino acids 663-919) is responsible for dimerization, androgen binding, and ligand dependent transactivation. The DBD (amino acids 548-612) controls recognition of, and binding to DNA target sequences and receptor dimerization. At the amino terminal end, the NTD (amino acids 142-485) is critical for transactivation, and protein interactions with the LBD. Binding of the NTD to its target protein transcription factor (TFIIF) results in a disorder to order transition, creating more stability within the structure. The largest stretch of glutamines [within the NTD] is of particular interest because expansion of this sequence from on-average 22 to greater than 40 residues results in the neuromuscular degenerative condition spinal bulbar muscular atrophy or Kennedy's Disease. In addition, polymorphisms in this polyglutamine stretch have been associated with prostate cancer risk, male infertility, and rheumatoid arthritis. Steroid hormone receptors are ligand-activated transcription factors that regulate eukaryotic gene expression and affect cellular proliferation and differentiation in target tissues. Transcription factor activity is modulated by bound coactivator and corepressor proteins. Transcription activation is down-regulated by NR0B2. Activated, but not phosphorylated, by HIPK3.