Dual Regulation of the Met4 Transcription Factor by Ubiquitin-Dependent Degradation and Inhibition of Promoter Recruitment

• Laurent Kuras ^[1] ; Astrid Rouillon ^[1] ; Traci Lee ^[2] ; Regine Barbey ^[1] ; Mike Tyers ^[2] ; Dominique Thomas ^[1]
  1. [1] Centre National de la Recherche Scientifique

     Centre National de la Recherche Scientifique

     París, Francia

     
  2. [2] Mount Sinai Hospital

     Mount Sinai Hospital

     Canadá

     
• Localización: Molecular cell, ISSN 1097-2765, Vol. 10, Nº 1, 2002, págs. 69-80
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The ubiquitin system has been recently implicated in various aspects of transcriptional regulation, including proteasome-dependent degradation of transcriptional activators. In yeast, the activator Met4 is inhibited by the SCFMet30 ubiquitin ligase, which recognizes and oligo-ubiquitylates Met4. Here, we demonstrate that in minimal media, Met4 is ubiquitylated and rapidly degraded in response to methionine excess, whereas in rich media, Met4 is oligo-ubiquitylated but remains stable. In the latter growth condition, oligo-ubiquitylated Met4 is not recruited to MET gene promoters, but is recruited to the SAM genes, which are required for production of S-adenosylmethionine, an unstable metabolite that is not present in rich medium. Thus, ubiquitylation not only regulates Met4 by distinct degradation-dependent and -independent mechanisms, but also controls differential recruitment of a single transcription factor to distinct promoters, thereby diversifying transcriptional activator specificity.