in-silico examination of androgen receptor-ntd interacting co-regulators reveals possible common features

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 355-388-Sex Hormone Receptor Action & Reaction
Basic/Translational
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-368
Ravi Jasuja1, Ran Xue*2, Brandon Xia3, Jeen Lorthe3, Mikhail N Zakharov4, Shalender Bhasin1 and James Costello3
1Brigham & Women's Hospital, Boston, MA, 2Brigham & Women's Hospital, 3Boston University, 4Boston University School of Medi, Boston, MA
Background: Androgen receptor (AR) plays an important role in development and maturation of diverse reproductive and skeletal phenotypes. Amongst the three functional domains within AR, intrinsically disordered region of AR amino terminal domain (AR-NTD) is of particular interest as it is an important regulatory component of AR transcriptional machinery and interacts with multiple co-activators, co-repressors and kinases. We tested the hypothesis that interacting proteins in these families share sequence and/or structure, enabling specificity in their association with AR. Identification of such motifs would allow for rational development of peptide regulators for activation or ablation of AR activity. 

Methods: We performed NCBI database scan in order to identify proteins interacting with AR. A comprehensive database was generated encompassing the sequence, function, interaction motif and structural components of the interacting proteins. Subsequently, non-homologous co-regulators showing direct interaction with AF-1 or AF-5 were subject to motif prediction based on sequence similarity. MEME, the common motif finding analysis tool was used. Additionally, homology modeling was applied to build predicted 3D structure for proteins in our database with SWISS MODEL. The motifs identified by MEME were then located on these models. Evolutionary study based on MSA was preformed to detect possible evolutionary pattern among proteins sharing these motifs.

Results: MEME analysis identified families of motifs that were shared amongst the interaction proteins. Subsequently, Swiss Model was utilized to model the 3D structures of the interacting proteins to identify the spatial location of the common motifs. Interestingly, we find that the many of the motifs were exposed on the surface suggesting promiscuity for the physical interaction with AR. Spatial overlap in 3D substructure alignment of the common motifs (utilizing PyMOL) suggests a functional commonality within sub-families. When additional sequence conservation analysis was performed (by ClustalW2), these sub-families of co-activators showed an interesting evolutionary concordance amongst species (humans to c. elegans). The co-regulators show a clear clustering into three homologus groups while transitioning from drosophila melanogaster to Danio rerio.

Conclusion: Together, these data suggest that although the AR-NTD is highly disordered, there are specific conformations that must be populated for signaling regulation. We find that AR-NTD interacting proteins share conserved, exposed and common motifs which likely seek a consensus sequence on the conformationally flexible AR-NTD. A detailed conformational mapping of AR-NTD and shared (sequence and 3D structure) motifs on interacting proteins would enable identification of novel peptide inhibitors/activators to regulate AR-signaling.

Nothing to Disclose: RJ, RX, BX, JL, MNZ, SB, JC

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: Evan's Foundation Award [RJ], 5R01AG037193-08 (SB)