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Updated: Jul 17, 2026
08:31
Antibody-Free Assay for RNA Methyltransferase Activity Analysis
Published on: July 9, 2019
Aurora-B regulates RNA methyltransferase NSUN2.
Shiho Sakita-Suto1, Akifumi Kanda, Fumio Suzuki
1Department of Molecular Radiobiology, Division of Genome Biology, Research Institute for Radiation Biology and Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553, Japan.
Molecular Biology of the Cell
|January 12, 2007
Summary
Aurora-B kinase phosphorylates the RNA methyltransferase NSUN2 at Ser139, regulating its activity and nucleolar assembly during mitosis. This phosphorylation is crucial for controlling RNA processing and nucleolar reformation.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Nucleolar disassembly during mitosis is essential for cell cycle progression.
- RNA processing is halted during mitosis until nucleolar reformation in G1 phase.
- The RNA methyltransferase NSUN2 plays a role in cellular processes.
Purpose of the Study:
- To investigate the role of Aurora-B kinase in regulating the RNA methyltransferase NSUN2.
- To determine how NSUN2 phosphorylation affects its nucleolar localization and enzymatic activity.
- To understand the mechanisms controlling nucleolar assembly and RNA processing during mitosis.
Main Methods:
- Immunofluorescence microscopy to track NSUN2 localization during the cell cycle.
- Western blotting and in vitro kinase assays to study NSUN2 phosphorylation by Aurora-B.
- Co-immunoprecipitation assays to analyze protein-protein interactions.
- Site-directed mutagenesis to create phosphorylation-mimic and non-phosphorylatable NSUN2 variants.
- In vitro methylation assays to assess NSUN2 methyltransferase activity.
Main Results:
- NSUN2 is a novel substrate of Aurora-B kinase, phosphorylated at Serine 139.
- Aurora-B mediated phosphorylation of NSUN2 inhibits its RNA methyltransferase activity.
- Phosphorylation disrupts the association between NSUN2 and NPM1 during mitosis.
- NSUN2 phosphorylation by Aurora-B is a key event in regulating nucleolar protein assembly and RNA processing during mitosis.
Conclusions:
- Aurora-B kinase regulates the assembly of the nucleolar RNA-processing machinery through phosphorylation of NSUN2.
- NSUN2 phosphorylation at Ser139 by Aurora-B modulates its methyltransferase activity, impacting RNA processing.
- These findings elucidate a novel mechanism by which Aurora-B controls cellular events during mitosis.
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