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Title: Structural basis for corepressor assembly by the orphan nuclear receptor TLX

The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Here we report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. In these structures, TLX adopts an autorepressed conformation in which its helix H12 occupies the coactivator-binding groove. Unexpectedly, H12 in this autorepressed conformation forms a novel binding pocket with residues from helix H3 that accommodates a short helix formed by the conserved ALXXLXXY motif of the Atro box. Mutations that weaken the TLX–Atrophin interaction compromise the repressive activity of TLX, demonstrating that this interaction is required for Atrophin to confer repressor activity to TLX. Moreover, the autorepressed conformation is conserved in the repressor class of orphan nuclear receptors, and mutations of corresponding residues in other members of this class of receptors diminish their repressor activities. Together, our results establish the functional conservation of the autorepressed conformation and define a key sequence motif in the Atro box that is essential for TLX-mediated repression.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5]
  1. Van Andel Research Inst. (VARI), Grand Rapids, MI (United States). Lab. of Structural Sciences; Univ. of Texas Southwestern Medical Center, Dallas, TX (United States). Autophagy Research Center
  2. Van Andel Research Inst. (VARI), Grand Rapids, MI (United States). Lab. of Structural Sciences
  3. Univ. of Texas Southwestern Medical Center, Dallas, TX (United States). Dept. of Molecular Biology
  4. Univ. of California, Riverside, CA (United States). Dept. of Cell Biology and Neuroscience
  5. Van Andel Research Inst. (VARI), Grand Rapids, MI (United States). Lab. of Structural Sciences; Chinese Academy of Sciences (CAS), Shanghai (China). Shanghai Inst. of Materia Medica. Key Lab. of Receptor Research. Van Andel Research Inst.-Shanghai Inst. of Materia Medica (VARI/SIMM) Center
Publication Date:
OSTI Identifier:
1229906
Grant/Contract Number:
DK071662; NS070981; NS088095; GM102545; GM104212; 085P1000817; 2012ZX09301001; 2012CB910403; 2013CB910600; XDB08020303; 2013ZX09507001
Type:
Accepted Manuscript
Journal Name:
Genes and Development
Additional Journal Information:
Journal Volume: 29; Journal Issue: 4; Journal ID: ISSN 0890-9369
Publisher:
Cold Springs Harbor Press
Research Org:
Van Andel Research Inst. (VARI), Grand Rapids, MI (United States); Chinese Academy of Sciences (CAS), Shanghai (China)
Sponsoring Org:
USDOE Office of Science (SC); National Inst. of Health (NIH) (United States); Michigan Economic Development Corporation (United States); Michigan Technology Tri-Corridor (United States); Jay and Betty Van Andel Foundation (United States); Ministry of Science and Technology (China)
Contributing Orgs:
Univ. of Texas Southwestern Medical Center, Dallas, TX (United States); Univ. of California, Riverside, CA (United States)
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; COUP; PNR; SHP; TLX