The neurodegenerative disease protein ataxin-1 antagonizes the neuronal survival function of myocyte enhancer factor-2.

Journal Article

Ataxin-1 is a neurodegenerative disorder protein whose mutant form causes spinocerebellar ataxia type-1 (SCA1). Evidence suggests that ataxin-1 may function as a transcription repressor. However, neither the importance of this putative transcriptional repression activity in neural cytotoxicity nor the transcriptional targets of ataxin-1 are known. Here we identify the MEF2-HDAC4 transcriptional complex involved in neuron survival as a target of ataxin-1. We show that ataxin-1 binds specifically to histone deacetylase-4 (HDAC4) and MEF2 and colocalizes with them in nuclear inclusion bodies. Significantly, these interactions are greatly reduced by the S776A mutation, which largely abrogates the cytotoxicity of ataxin-1. Supporting the importance of these interactions, we show that wild type ataxin-1 represses MEF2-dependent transcription, whereas the S776A mutant is less potent. Furthermore, overexpression of MEF2 can partially reverse cytotoxicity caused by ataxin-1. Our results identify the MEF2-HDAC4 complex as a target for ataxin-1 transcriptional repression activity and suggest a novel pathogenic mechanism whereby ataxin-1 sequesters and inhibits the neuronal survival factor MEF2.

Full Text

Duke Authors

Cited Authors

  • Bolger, TA; Zhao, X; Cohen, TJ; Tsai, C-C; Yao, T-P

Published Date

  • October 5, 2007

Published In

Volume / Issue

  • 282 / 40

Start / End Page

  • 29186 - 29192

PubMed ID

  • 17646162

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M704182200

Language

  • eng

Conference Location

  • United States