Activity and cellular functions of the deubiquitinating enzyme and polyglutamine disease protein ataxin-3 are regulated by ubiquitination at lysine 117.

Published

Journal Article

Deubiquitinating enzymes (DUbs) play important roles in many ubiquitin-dependent pathways, yet how DUbs themselves are regulated is not well understood. Here, we provide insight into the mechanism by which ubiquitination directly enhances the activity of ataxin-3, a DUb implicated in protein quality control and the disease protein in the polyglutamine neurodegenerative disorder, Spinocerebellar Ataxia Type 3. We identify Lys-117, which resides near the catalytic triad, as the primary site of ubiquitination in wild type and pathogenic ataxin-3. Further studies indicate that ubiquitin-dependent activation of ataxin-3 at Lys-117 is important for its ability to reduce high molecular weight ubiquitinated species in cells. Ubiquitination at Lys-117 also facilitates the ability of ataxin-3 to induce aggresome formation in cells. Finally, structure-function studies support a model of activation whereby ubiquitination at Lys-117 enhances ataxin-3 activity independent of the known ubiquitin-binding sites in ataxin-3, most likely through a direct conformational change in or near the catalytic domain.

Full Text

Duke Authors

Cited Authors

  • Todi, SV; Scaglione, KM; Blount, JR; Basrur, V; Conlon, KP; Pastore, A; Elenitoba-Johnson, K; Paulson, HL

Published Date

  • December 10, 2010

Published In

Volume / Issue

  • 285 / 50

Start / End Page

  • 39303 - 39313

PubMed ID

  • 20943656

Pubmed Central ID

  • 20943656

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

Digital Object Identifier (DOI)

  • 10.1074/jbc.M110.181610

Language

  • eng

Conference Location

  • United States