title: TOR-in(g) the nucleus.
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.
authors.affiliation: Department of Pharmacology and Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
authors.forename: Chi Kwan
authors.initials: CK
authors.lastname: Tsang
authors.forename: X F Steven
authors.initials: XF
authors.lastname: Zheng
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D017346:Protein Serine-Threonine Kinases; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D017346:Protein Serine-Threonine Kinases; C500749:target of rapamycin protein, S cerevisiae