title: TOR regulates late steps of ribosome maturation in the nucleoplasm via Nog1 in response to nutrients.
abstract: The protein kinase TOR (target of rapamycin) controls several steps of ribosome biogenesis, including gene expression of rRNA and ribosomal proteins, and processing of the 35S rRNA precursor, in the budding yeast Saccharomyces cerevisiae. Here we show that TOR also regulates late stages of ribosome maturation in the nucleoplasm via the nuclear GTP-binding protein Nog1. Nog1 formed a complex that included 60S ribosomal proteins and pre-ribosomal proteins Nop7 and Rlp24. The Nog1 complex shuttled between the nucleolus and the nucleoplasm for ribosome biogenesis, but it was tethered to the nucleolus by both nutrient depletion and TOR inactivation, causing cessation of the late stages of ribosome biogenesis. Furthermore, after this, Nog1 and Nop7 proteins were lost, leading to complete cessation of ribosome maturation. Thus, the Nog1 complex is a critical regulator of ribosome biogenesis mediated by TOR. This is the first description of a physiological regulation of nucleolus-to-nucleoplasm translocation of pre-ribosome complexes.
authors.affiliation: Faculty of Science, Shizuoka University, Shizuoka, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Honma
authors.forename: Aiko
authors.initials: A
authors.lastname: Kitamura
authors.forename: Ryo
authors.initials: R
authors.lastname: Shioda
authors.forename: Hironori
authors.initials: H
authors.lastname: Maruyama
authors.forename: Kanako
authors.initials: K
authors.lastname: Ozaki
authors.forename: Yoko
authors.initials: Y
authors.lastname: Oda
authors.forename: Thierry
authors.initials: T
authors.lastname: Mini
authors.forename: Paul
authors.initials: P
authors.lastname: Jenö
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Maki
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Yonezawa
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
authors.forename: Masaru
authors.initials: M
authors.lastname: Ueno
authors.forename: Masahiro
authors.initials: M
authors.lastname: Uritani
authors.forename: Michael N
authors.initials: MN
authors.lastname: Hall
authors.forename: Takashi
authors.initials: T
authors.lastname: Ushimaru
mesh_terms: D001693:Biological Transport, Active; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D019204:GTP-Binding Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D012335:RNA, Ribosomal / Q000502:physiology; D012269:Ribosomal Proteins / Q000378:metabolism / Q000502:physiology*; D012270:Ribosomes / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism* / Q000502:physiology*; D020123:Sirolimus / Q000494:pharmacology
chemical_list: D003470:Culture Media; C475027:NOG1 protein, S cerevisiae; C451799:NOP7 protein, S cerevisiae; D009687:Nuclear Proteins; C084787:RLP7 protein, S cerevisiae; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; C578384:Rlp24 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017346:Protein Serine-Threonine Kinases; C500749:target of rapamycin protein, S cerevisiae; D019204:GTP-Binding Proteins; D020123:Sirolimus