Structural characterization of a noncovalent complex between ubiquitin and the transactivation domain of the erythroid-specific factor EKLF

Structure. 2013 Nov 5;21(11):2014-24. doi: 10.1016/j.str.2013.08.027. Epub 2013 Oct 17.

Abstract

Like other acidic transactivation domains (TAD), the minimal TAD from the erythroid-specific transcription factor EKLF (EKLFTAD) has been shown to contribute both to its transcriptional activity as well as to its ubiquitin(UBI)-mediated degradation. In this article, we examine the activation-degradation role of the acidic TAD of EKLF and demonstrate that the first 40 residues (EKLFTAD1) within this region form a noncovalent interaction with UBI. Nuclear magnetic resonance (NMR) structural studies of an EKLFTAD1-UBI complex show that EKLFTAD1 adopts a 14-residue α helix that forms the recognition interface with UBI in a similar manner as the UBI-interacting helix of Rabex5. We also identify a similar interaction between UBI and the activation-degradation region of SREBP1a, but not with the activation-degradation regions of p53, GAL4, and VP16. These results suggest that select activation-degradation regions like the ones found in EKLF and SREBP1a function in part through their ability to form noncovalent interactions with UBI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Binding Sites
  • Cell Line
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Kruppel-Like Transcription Factors / chemistry*
  • Kruppel-Like Transcription Factors / genetics
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Interaction Domains and Motifs
  • Protein Stability
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Ubiquitin / chemistry*
  • Ubiquitin / genetics

Substances

  • Kruppel-Like Transcription Factors
  • Ubiquitin
  • erythroid Kruppel-like factor

Associated data

  • PDB/2MBH