Ubiquitin-interacting motifs inhibit aggregation of polyQ-expanded huntingtin

J Biol Chem. 2007 Mar 30;282(13):10096-10103. doi: 10.1074/jbc.M611151200. Epub 2007 Feb 2.


Expansion of polyglutamine (polyQ) tracts within proteins underlies a number of neurodegenerative diseases, such as Huntington disease, Kennedy disease, and spinocerebellar ataxias. The resulting mutant proteins are unstable, forming insoluble aggregates that are associated with components of the ubiquitin system, including ubiquitin, ubiquitin-like proteins, and proteins that bind to ubiquitin. Given the presence of these ubiquitin-binding proteins in the insoluble aggregates, we examined whether heterologous expression of short motifs that bind ubiquitin, termed ubiquitin-interacting motifs (UIMs), altered the aggregation of polyQ-expanded huntingtin (Htt), the protein product of the Huntington disease gene. We found that a subset of UIMs associated with mutant Htt. The ability to interact with ubiquitin was necessary, but not sufficient, for interaction with mutant Htt. Furthermore, we found that expression of single, isolated UIMs inhibited aggregation of mutant Htt. These data suggest that isolated UIMs might serve as potential inhibitors of polyQ-aggregation in vivo.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / physiology
  • Amino Acid Sequence
  • Cell Line
  • Humans
  • Huntingtin Protein
  • Molecular Sequence Data
  • Nerve Tissue Proteins / antagonists & inhibitors
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Peptides / antagonists & inhibitors
  • Peptides / genetics
  • Peptides / metabolism*
  • Ubiquitin / antagonists & inhibitors
  • Ubiquitin / metabolism*


  • HTT protein, human
  • Huntingtin Protein
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • Peptides
  • Ubiquitin
  • polyglutamine