Activity and cellular functions of the deubiquitinating enzyme and polyglutamine disease protein ataxin-3 are regulated by ubiquitination at lysine 117. J Biol Chem 2010 Dec 10;285(50):39303-13
Date
10/15/2010Pubmed ID
20943656Pubmed Central ID
PMC2998082DOI
10.1074/jbc.M110.181610Scopus ID
2-s2.0-78649811312 (requires institutional sign-in at Scopus site) 84 CitationsAbstract
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.
Author List
Todi SV, Scaglione KM, Blount JR, Basrur V, Conlon KP, Pastore A, Elenitoba-Johnson K, Paulson HLMESH terms used to index this publication - Major topics in bold
AnimalsAtaxin-3
Binding Sites
Catalysis
Fibroblasts
Gene Expression Regulation
Humans
Lysine
Machado-Joseph Disease
Mice
Nerve Tissue Proteins
Neurodegenerative Diseases
Nuclear Proteins
Protein Conformation
Repressor Proteins
Structure-Activity Relationship
Transfection
Ubiquitin
