Yeast gene KTI13 (alias DPH8) operates in the initiation step of diphthamide synthesis on elongation factor 2

Authors:

Meike Arend1, Koray Ütkür1, Harmen Hawer1, Klaus Mayer2, Namit Ranjan3, Lorenz Adrian4, Ulrich Brinkmann2 and Raffael Schaffrath1

doi: doi: 10.15698/mic2023.09.804
Volume 10, pp. 195 to 203, published 08/08/2023.

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Affiliations:

1 Institute of Biology, Division of Microbiology, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany.
2 Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center München, Nonnenwald 2, 82377 Penzberg, Germany.
3 Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
4 Environmental Biotechnology, Helmholtz Centre for Environmental Research – UFZ, 04318 Leipzig, Germany.

Keywords: 

budding yeast; EF2 diphthamide modification; diphtheria toxin; tRNA modification; elongator; tRNase zymocin.

Corresponding Author(s):

Raffael Schaffrath, Institute of Biology, Division of Microbiology, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany; schaffrath@uni-kassel.de

Conflict of interest statement:

KM and UB are employed by and members of Roche Pharma Research & Early Development, and are co-inventors on patent applications that cover assays to de-tect presence or absence of diphthamide. Roche is interested in targeted therapies and diagnostics. All other authors declare no conflict of interest.

Please cite this article as:

Meike Arend, Koray Ütkür, Harmen Hawer, Klaus Mayer, Na-mit Ranjan, Lorenz Adrian, Ulrich Brinkmann and Raffael Schaffrath (2023). Yeast gene KTI13 (alias DPH8) operates in the initiation step of diphthamide synthesis on elongation factor 2. Microbial Cell 10(9): 195-203. doi: 10.15698/mic2023.09.804

© 2023 Arend et al.. This is an open-access article released under the terms of the Creative Commons Attribution (CC BY) license, which allows the unrestricted use, distribution, and reproduction in any medium, provided the original author and source are acknowledged.

Abstract:

In yeast, Elongator-dependent tRNA modifications are regulated by the Kti11•Kti13 dimer and hijacked for cell killing by zymocin, a tRNase ribotoxin. Kti11 (alias Dph3) also controls modification of elongation factor 2 (EF2) with diphthamide, the target for lethal ADP-ribosylation by diphtheria toxin (DT). Diphthamide formation on EF2 involves four biosynthetic steps encoded by the DPH1-DPH7 network and an ill-defined KTI13 function. On further examining the latter gene in yeast, we found that kti13Δ null-mutants maintain unmodified EF2 able to escape ADP-ribosylation by DT and to survive EF2 inhibition by sordarin, a diphthamide-dependent antifungal. Consistently, mass spectrometry shows kti13Δ cells are blocked in proper formation of amino-carboxyl-propyl-EF2, the first diphthamide pathway intermediate. Thus, apart from their common function in tRNA modification, both Kti11/Dph3 and Kti13 share roles in the initiation step of EF2 modification. We suggest an alias KTI13/DPH8 nomenclature indicating dual-functionality analogous to KTI11/DPH3.