Effect of torsinA on membrane proteins reveals a loss of function and a dominant-negative phenotype of the dystonia-associated DeltaE-torsinA mutant.

Published

Journal Article

Most cases of early-onset torsion dystonia (EOTD) are caused by a deletion of one glutamic acid in the carboxyl terminus of a protein named torsinA. The mutation causes the protein to aggregate in perinuclear inclusions as opposed to the endoplasmic reticulum localization of the wild-type protein. Although there is increasing evidence that dysfunction of the dopamine system is implicated in the development of EOTD, the biological function of torsinA and its relation to dopaminergic neurotransmission has remained unexplored. Here, we show that torsinA can regulate the cellular trafficking of the dopamine transporter, as well as other polytopic membrane-bound proteins, including G protein-coupled receptors, transporters, and ion channels. This effect was prevented by mutating the ATP-binding site in torsinA. The dystonia-associated torsinA deletion mutant (DeltaE-torsinA) did not have any effect on the cell surface distribution of polytopic membrane-associated proteins, suggesting that the mutation linked with EOTD results in a loss of function. However, a mutation in the ATP-binding site in DeltaE-torsinA reversed the aggregate phenotype associated with the mutant. Moreover, the deletion mutant acts as a dominant-negative of wild-type torsinA through a mechanism presumably involving association of wild-type and mutant torsinA. Taken together, our results provide evidence for a functional role for torsinA and a loss of function and a dominant-negative phenotype of the DeltaE-torsinA mutation. These properties may contribute to the autosomal dominant nature of the condition.

Full Text

Duke Authors

Cited Authors

  • Torres, GE; Sweeney, AL; Beaulieu, J-M; Shashidharan, P; Caron, MG

Published Date

  • November 2, 2004

Published In

Volume / Issue

  • 101 / 44

Start / End Page

  • 15650 - 15655

PubMed ID

  • 15505207

Pubmed Central ID

  • 15505207

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.0308088101

Language

  • eng

Conference Location

  • United States