Structural insights into interactions of C/EBP transcriptional activators with the Taz2 domain of p300

Acta Crystallogr D Biol Crystallogr. 2014 Jul;70(Pt 7):1914-21. doi: 10.1107/S1399004714009262. Epub 2014 Jun 29.


Members of the C/EBP family of transcription factors bind to the Taz2 domain of p300/CBP and mediate its phosphorylation through the recruitment of specific kinases. Short sequence motifs termed homology boxes A and B, which comprise their minimal transactivation domains (TADs), are conserved between C/EBP activators and are necessary for specific p300/CBP binding. A possible mode of interaction between C/EBP TADs and the p300 Taz2 domain was implied by the crystal structure of a chimeric protein composed of residues 1723-1818 of p300 Taz2 and residues 37-61 of C/EBPℇ. The segment corresponding to the C/EBPℇ TAD forms two orthogonally disposed helices connected by a short linker and interacts with the core structure of Taz2 from a symmetry-related molecule. It is proposed that other members of the C/EBP family interact with the Taz2 domain in the same manner. The position of the C/EBPℇ peptide on the Taz2 protein interaction surface suggests that the N-termini of C/EBP proteins are unbound in the C/EBP-p300 Taz2 complex. This observation is in agreement with the known location of the docking site of protein kinase HIPK2 in the C/EBPβ N-terminus, which associates with the C/EBPβ-p300 complex.

Keywords: HIPK2; ligand binding; molecular recognition; transcription.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Amino Acid Sequence
  • CCAAT-Enhancer-Binding Proteins / chemistry
  • CCAAT-Enhancer-Binding Proteins / metabolism*
  • Crystallography, X-Ray
  • Molecular Sequence Data
  • Phosphorylation
  • Protein Conformation
  • Sequence Homology, Amino Acid
  • p300-CBP Transcription Factors / chemistry*


  • CCAAT-Enhancer-Binding Proteins
  • p300-CBP Transcription Factors

Associated data

  • PDB/3T92