TOR regulates late steps of ribosome maturation in the nucleoplasm via Nog1 in response to nutrients.
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.
Honma
Yoshimi
Y
Faculty of Science, Shizuoka University, Shizuoka, Japan.
Kitamura
Aiko
A
Shioda
Ryo
R
Maruyama
Hironori
H
Ozaki
Kanako
K
Oda
Yoko
Y
Mini
Thierry
T
Jenö
Paul
P
Maki
Yasushi
Y
Yonezawa
Kazuyoshi
K
Hurt
Ed
E
Ueno
Masaru
M
Uritani
Masahiro
M
Hall
Michael N
MN
Ushimaru
Takashi
T
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
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