Structural basis for negative regulation of hypoxia-inducible factor-1alpha by CITED2

Nat Struct Biol. 2003 Jul;10(7):504-12. doi: 10.1038/nsb936.


Expression of hypoxia-responsive genes is mediated by the heterodimeric transcription factor hypoxia-inducible factor-1 (HIF-1) in complex with the p300/CREB-binding protein (p300/CBP) transcriptional coactivator. The protein CITED2, which binds p300/CBP, is thought to be a negative regulator of HIF-1 transactivation. We show that the CITED2 transactivation domain (TAD) disrupts a complex of the HIF-1alpha C-terminal TAD (C-TAD) and the cysteine-histidine-rich 1 (CH1) domain of p300/CBP by binding CH1 with high affinity. The high-resolution solution structure of the CITED2 TAD-p300 CH1 complex shows that the CITED2 TAD, like the HIF-1alpha C-TAD, folds on a helical, Zn2+-containing CH1 scaffold. The CITED2 TAD binds a different, more extensive surface of CH1 than does the HIF-1alpha C-TAD. However, a conserved 'LPXL' sequence motif in CITED2 and HIF-1alpha interacts with an overlapping binding site on CH1. Mutation of the LPEL sequence in full-length CITED2 abolishes p300 binding in vivo. These findings reveal that CITED2 regulates HIF-1 by competing for a hot spot on the p300 CH1 domain.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Circular Dichroism
  • DNA-Binding Proteins*
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Models, Molecular
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Binding
  • Protein Conformation
  • Repressor Proteins*
  • Sequence Homology, Amino Acid
  • Trans-Activators / metabolism
  • Trans-Activators / physiology*
  • Transcription Factors / chemistry*
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*


  • CITED2 protein, human
  • DNA-Binding Proteins
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Repressor Proteins
  • Trans-Activators
  • Transcription Factors

Associated data

  • PDB/1P4Q