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Updated: Sep 25, 2025
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Studying RNA Interactors of Protein Kinase RNA-Activated during the Mammalian Cell Cycle
Published on: March 5, 2019
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Reversible RNA phosphorylation stabilizes tRNA for cellular thermotolerance.
Takayuki Ohira1, Keiichi Minowa2, Kei Sugiyama2
1Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan. ohira_t@chembio.t.u-tokyo.ac.jp.
Nature
|April 28, 2022
Summary
Thermophilic archaea stabilize tRNAs using a unique 2'-phosphouridine (Up47) modification. This reversible modification, mediated by ArkI and KptA enzymes, enhances tRNA structural rigidity in extreme environments.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Post-transcriptional modifications are crucial for tRNA stability and function.
- Thermophilic organisms possess heavily modified tRNAs for thermal stability under extreme conditions.
Purpose of the Study:
- To identify and characterize novel tRNA modifications in thermophilic archaea.
- To elucidate the structural and functional roles of these modifications and the enzymes involved.
Main Methods:
- Atomic structure determination of archaeal tRNAs.
- Identification and characterization of RNA modifying enzymes (ArkI and KptA homologue).
- Enzymatic assays and growth studies of knockout strains.
Main Results:
- Discovery of 2 -phosphouridine (Up47) in thermophilic archaeal tRNAs.
- Up47 enhances tRNA thermal stability and nuclease resistance by stabilizing a unique core structure.
- Identification of ArkI as the RNA kinase responsible for Up47 formation and an archaeal KptA homologue as the dephosphorylating enzyme.
- ArkI knockout strains exhibit growth defects at high temperatures.
Conclusions:
- Up47 is a reversible tRNA modification essential for thermophilic archaeal growth.
- The ArkI- and KptA-mediated modification system fine-tunes tRNA structural rigidity in extreme environments.
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