Download MendeleyThe oxidoreductase PYROXD1 uses NAD(P) + as an antioxidant to sustain tRNA ligase activity in pre-tRNA splicing and unfolded protein response.
Asanovic, I., Strandback, E., Kroupova, A., Pasajlic, D., Meinhart, A., Tsung-Pin, P., Djokovic, N., Anrather, D., Schuetz, T., Suskiewicz, M.J., Sillamaa, S., Kocher, T., Beveridge, R., Nikolic, K., Schleiffer, A., Jinek, M., Hartl, M., Clausen, T., Penninger, J., Macheroux, P., Weitzer, S., Martinez, J.(2021) Mol Cell 81: 2520
- PubMed: 33930333
- DOI: https://doi.org/10.1016/j.molcel.2021.04.007
- Primary Citation of Related Structures:
6ZK7 - PubMed Abstract:
The tRNA ligase complex (tRNA-LC) splices precursor tRNAs (pre-tRNA), and Xbp1-mRNA during the unfolded protein response (UPR). In aerobic conditions, a cysteine residue bound to two metal ions in its ancient, catalytic subunit RTCB could make the tRNA-LC susceptible to oxidative inactivation. Here, we confirm this hypothesis and reveal a co-evolutionary association between the tRNA-LC and PYROXD1, a conserved and essential oxidoreductase. We reveal that PYROXD1 preserves the activity of the mammalian tRNA-LC in pre-tRNA splicing and UPR. PYROXD1 binds the tRNA-LC in the presence of NAD(P)H and converts RTCB-bound NAD(P)H into NAD(P) + , a typical oxidative co-enzyme. However, NAD(P) + here acts as an antioxidant and protects the tRNA-LC from oxidative inactivation, which is dependent on copper ions. Genetic variants of PYROXD1 that cause human myopathies only partially support tRNA-LC activity. Thus, we establish the tRNA-LC as an oxidation-sensitive metalloenzyme, safeguarded by the flavoprotein PYROXD1 through an unexpected redox mechanism.
Organizational Affiliation:
Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
