The BACK domain in BTB-kelch proteins

Trends Biochem Sci. 2004 Dec;29(12):634-7. doi: 10.1016/j.tibs.2004.10.003.


A novel conserved motif--the BACK (for BTB and C-terminal Kelch) domain--is found in the majority of proteins that contain both the BTB domain and kelch repeats. Many kelch-repeat proteins are involved in organization of the cytoskeleton via interaction with actin and intermediate filaments, whereas BTB domains have multiple cellular roles, including recruitment to E3 ubiquitin ligase complexes. The identification of the BACK domain in BTB and kelch proteins, and its high conservation across metazoan genomes, suggest an important function for this domain with a possible role in substrate orientation in Cullin3-based E3 ligase complexes.

Publication types

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

MeSH terms

  • Actins / chemistry*
  • Actins / metabolism
  • Amino Acid Sequence
  • Animals
  • Conserved Sequence
  • Drosophila Proteins* / chemistry
  • Drosophila Proteins* / metabolism
  • Genome*
  • Humans
  • Microfilament Proteins* / chemistry
  • Microfilament Proteins* / metabolism
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Ubiquitin-Protein Ligases* / chemistry
  • Ubiquitin-Protein Ligases* / metabolism


  • Actins
  • Drosophila Proteins
  • Microfilament Proteins
  • kel protein, Drosophila
  • Ubiquitin-Protein Ligases