2GUT

Solution structure of the trans-activation domain of the human co-activator ARC105


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 15 
  • Selection Criteria: lowest NOE target function with no NOE violations > 0.5 A, and angular violations > 5 deg 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

An ARC/Mediator subunit required for SREBP control of cholesterol and lipid homeostasis.

Yang, F.Vought, B.W.Satterlee, J.S.Walker, A.K.Jim Sun, Z.-Y.Watts, J.L.Debeaumont, R.Mako Saito, R.Hyberts, S.G.Yang, S.Macol, C.Iyer, L.Tjian, R.van den Heuvel, S.Hart, A.C.Wagner, G.Naar, A.M.

(2006) Nature 442: 700-704

  • DOI: 10.1038/nature04942

  • PubMed Abstract: 
  • The sterol regulatory element binding protein (SREBP) family of transcription activators are critical regulators of cholesterol and fatty acid homeostasis. We previously demonstrated that human SREBPs bind the CREB-binding protein (CBP)/p300 acetyltr ...

    The sterol regulatory element binding protein (SREBP) family of transcription activators are critical regulators of cholesterol and fatty acid homeostasis. We previously demonstrated that human SREBPs bind the CREB-binding protein (CBP)/p300 acetyltransferase KIX domain and recruit activator-recruited co-factor (ARC)/Mediator co-activator complexes through unknown mechanisms. Here we show that SREBPs use the evolutionarily conserved ARC105 (also called MED15) subunit to activate target genes. Structural analysis of the SREBP-binding domain in ARC105 by NMR revealed a three-helix bundle with marked similarity to the CBP/p300 KIX domain. In contrast to SREBPs, the CREB and c-Myb activators do not bind the ARC105 KIX domain, although they interact with the CBP KIX domain, revealing a surprising specificity among structurally related activator-binding domains. The Caenorhabditis elegans SREBP homologue SBP-1 promotes fatty acid homeostasis by regulating the expression of lipogenic enzymes. We found that, like SBP-1, the C. elegans ARC105 homologue MDT-15 is required for fatty acid homeostasis, and show that both SBP-1 and MDT-15 control transcription of genes governing desaturation of stearic acid to oleic acid. Notably, dietary addition of oleic acid significantly rescued various defects of nematodes targeted with RNA interference against sbp-1 and mdt-15, including impaired intestinal fat storage, infertility, decreased size and slow locomotion, suggesting that regulation of oleic acid levels represents a physiologically critical function of SBP-1 and MDT-15. Taken together, our findings demonstrate that ARC105 is a key effector of SREBP-dependent gene regulation and control of lipid homeostasis in metazoans.


    Organizational Affiliation

    Massachusetts General Hospital Cancer Center, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ARC/MEDIATOR, Positive cofactor 2 glutamine/Q-rich-associated protein
A
77Homo sapiensMutation(s): 0 
Gene Names: MED15 (ARC105, CTG7A, PCQAP, TIG1, TNRC7)
Find proteins for Q96RN5 (Homo sapiens)
Go to Gene View: MED15
Go to UniProtKB:  Q96RN5
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 15 
  • Selection Criteria: lowest NOE target function with no NOE violations > 0.5 A, and angular violations > 5 deg 
  • Olderado: 2GUT Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-08-08
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance