A Conserved Deubiquitinating Enzyme Controls Cell Growth by Regulating RNA Polymerase I Stability

• Published in: Cell reports (Cambridge) 2012-08, Vol.2 (2), p.372-385
• Main Authors: Richardson, Lauren A., Reed, Benjamin J., Charette, J. Michael, Freed, Emily F., Fredrickson, Eric K., Locke, Melissa N., Baserga, Susan J., Gardner, Richard G.
• Format: Article
• Language: English
• Subjects: Cell Nucleolus - genetics; Cell Nucleolus - metabolism; DNA-directed RNA polymerase; Enzyme Stability - physiology; Enzymes; Genetic Complementation Test; Humans; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Nucleoli; proteomics; Ribosomes; RNA Polymerase I - genetics; RNA Polymerase I - metabolism; RNA, Fungal - biosynthesis; RNA, Fungal - genetics; RNA, Ribosomal - biosynthesis; RNA, Ribosomal - genetics; rRNA; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Ubiquitin Thiolesterase - genetics; Ubiquitin Thiolesterase - metabolism; Ubiquitination - physiology
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2012.07.009

Eukaryotic ribosome biogenesis requires hundreds of trans-acting factors and dozens of RNAs. Although most factors required for ribosome biogenesis have been identified, little is known about their regulation. Here, we reveal that the yeast deubiquitinating enzyme Ubp10 is localized to the nucleolus and that ubp10Δ cells have reduced pre-rRNAs, mature rRNAs, and translating ribosomes. Through proteomic analyses, we found that Ubp10 interacts with proteins that function in rRNA production and ribosome biogenesis. In particular, we discovered that the largest subunit of RNA polymerase I (RNAPI) is stabilized via Ubp10-mediated deubiquitination and that this is required in order to achieve optimal levels of ribosomes and cell growth. USP36, the human ortholog of Ubp10, complements the ubp10Δ allele for RNAPI stability, pre-rRNA processing, and cell growth in yeast, suggesting that deubiquitination of RNAPI may be conserved in eukaryotes. Our work implicates Ubp10/USP36 as a key regulator of rRNA production through control of RNAPI stability. [Display omitted] ► Ubp10 is localized to the nucleolus and interacts with ribosome biogenesis proteins ► ubp10Δ cells are reduced in pre-rRNAs, mature rRNAs, and translating ribosomes ► Ubp10 regulates the ubiquitination and stability of RNA polymerase I ► Human USP36 complements ubp10Δ for RNA polymerase I deubiquitination and stability Eukaryotic ribosome biogenesis requires hundreds of trans-acting factors, and although most ribosome biogenesis factors have been identified, little is known about their regulation. Gardner and colleagues find that the yeast deubiquitinating enzyme Ubp10 is localized to the nucleolus and that ubp10Δ cells have reduced pre-rRNAs, mature rRNAs, and translating ribosomes. Furthermore, they found that the largest subunit of RNA polymerase I is stabilized via Ubp10-mediated deubiquitination and that this is required for optimal levels of ribosomes and cell growth.