The deubiquitinating enzyme ataxin-3, a polyglutamine disease protein, edits Lys63 linkages in mixed linkage ubiquitin chains.

Published

Journal Article

Ubiquitin chain complexity in cells is likely regulated by a diverse set of deubiquitinating enzymes (DUBs) with distinct ubiquitin chain preferences. Here we show that the polyglutamine disease protein, ataxin-3, binds and cleaves ubiquitin chains in a manner suggesting that it functions as a mixed linkage, chain-editing enzyme. Ataxin-3 cleaves ubiquitin chains through its amino-terminal Josephin domain and binds ubiquitin chains through a carboxyl-terminal cluster of ubiquitin interaction motifs neighboring the pathogenic polyglutamine tract. Ataxin-3 binds both Lys(48)- or Lys(63)-linked chains yet preferentially cleaves Lys(63) linkages. Ataxin-3 shows even greater activity toward mixed linkage polyubiquitin, cleaving Lys(63) linkages in chains that contain both Lys(48) and Lys(63) linkages. The ubiquitin interaction motifs regulate the specificity of this activity by restricting what can be cleaved by the protease domain, demonstrating that linkage specificity can be determined by elements outside the catalytic domain of a DUB. These findings establish ataxin-3 as a novel DUB that edits topologically complex chains.

Full Text

Duke Authors

Cited Authors

  • Winborn, BJ; Travis, SM; Todi, SV; Scaglione, KM; Xu, P; Williams, AJ; Cohen, RE; Peng, J; Paulson, HL

Published Date

  • September 2008

Published In

Volume / Issue

  • 283 / 39

Start / End Page

  • 26436 - 26443

PubMed ID

  • 18599482

Pubmed Central ID

  • 18599482

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M803692200

Language

  • eng