TOR-in(g) the nucleus

Cell Cycle. 2007 Jan 1;6(1):25-9. doi: 10.4161/cc.6.1.3675. Epub 2007 Jan 6.

Abstract

Target of rapamycin (TOR) is a central component of the eukaryotic growth regulatory network. TOR controls the expression of diverse genes by all three RNA polymerases, including ribosome biogenesis, utilization and transport of nutrients, and stress-related genes. Until recently, TOR was thought to be a classical signaling kinase that regulates transcription factors in the cytoplasm. However, our recent study shows that in yeast, TOR dynamically shuttles between the cytoplasm and nucleus, and binds to 35S ribosomal DNA (rDNA) promoter. Importantly, nuclear localization and promoter-binding is crucial for TOR to control RNA polymerase (Pol) I-dependent 35S rDNA transcription. In contrast, either cytoplasmic or nuclear TOR is sufficient to regulate Pol II-dependent transcription. These observations suggest that TOR in the nucleus plays an important role in gene regulation, and that TOR takes a multifaceted approach to control expression of different genes.

Publication types

  • Review

MeSH terms

  • Animals
  • Cell Nucleus / genetics*
  • Cell Nucleus / metabolism*
  • Humans
  • Protein Serine-Threonine Kinases
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • Saccharomyces cerevisiae Proteins
  • Protein Serine-Threonine Kinases
  • target of rapamycin protein, S cerevisiae