The highly conserved KEOPS/EKC complex is essential for a universal tRNA modification, t6A

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• The Kinase, Endopeptidase and Other Proteins of small Size (KEOPS)/Endopeptidase-like and Kinase associated to transcribed Chromatin (EKC) complex is involved in transcription, telomere maintenance, and chromosome segregation.
• The precise function of the KEOPS/EKC complex, comprising Kae1, Bud32, and three other proteins, remains largely unknown.

Purpose of the Study:

• To elucidate the exact function of the KEOPS/EKC protein complex.
• To investigate the role of the complex in tRNA modification.

Main Methods:

• Investigated the requirement of the KEOPS/EKC complex for tRNA modification using bacterial and yeast systems.
• Established an in vitro system for t6A synthesis using yeast extracts.
• Assessed the necessity of Kae1 ATPase and Bud32 kinase activities for the modification.

Main Results:

• Demonstrated that the KEOPS/EKC complex is essential for the synthesis of threonyl carbamoyl adenosine (t6A), a universal tRNA modification.
• Showed that the bacterial ortholog YgjD of Kae1 is also required for t6A modification in Escherichia coli.
• Confirmed that both Kae1's ATPase and Bud32's kinase activities are crucial for t6A synthesis.

Conclusions:

• The KEOPS/EKC complex plays a critical role in the universal tRNA modification t6A.
• The findings suggest a fundamental role for t6A modification in cellular processes, potentially explaining previously observed defects in KEOPS/EKC mutants.