Disruption of the Nα-Acetyltransferase NatB Causes Sensitivity to Reductive Stress in Arabidopsis thaliana.

A - Papers appearing in refereed journals

Huber, M., Armbruster, L., Etherington, R. D., De La Torre, C., Hawkesford, M. J., Sticht, C., Gibbs, D. J., Hell, R. and Wirtz, M. 2022. Disruption of the Nα-Acetyltransferase NatB Causes Sensitivity to Reductive Stress in Arabidopsis thaliana. Frontiers in Plant Science. 12, p. 799954. https://doi.org/10.3389/fpls.2021.799954

AuthorsHuber, M., Armbruster, L., Etherington, R. D., De La Torre, C., Hawkesford, M. J., Sticht, C., Gibbs, D. J., Hell, R. and Wirtz, M.
Abstract

In Arabidopsis thaliana, the evolutionary conserved N-terminal acetyltransferase (Nat) complexes NatA and NatB co-translationally acetylate 60% of the proteome. Both have recently been implicated in the regulation of plant stress responses. While NatA mediates drought tolerance, NatB is required for pathogen resistance and the adaptation to high salinity and high osmolarity. Salt and osmotic stress impair protein folding and result in the accumulation of misfolded proteins in the endoplasmic reticulum (ER). The ER-membrane resident E3 ubiquitin ligase DOA10 targets misfolded proteins for degradation during ER stress and is conserved among eukaryotes. In yeast, DOA10 recognizes conditional degradation signals (Ac/N-degrons) created by NatA and NatB. Assuming that this mechanism is preserved in plants, the lack of Ac/N-degrons required for efficient removal of misfolded proteins might explain the sensitivity of NatB mutants to protein harming conditions. In this study, we investigate the response of NatB mutants to dithiothreitol (DTT) and tunicamycin (TM)-induced ER stress. We report that NatB mutants are hypersensitive to DTT but not TM, suggesting that the DTT hypersensitivity is caused by an over-reduction of the cytosol rather than an accumulation of unfolded proteins in the ER. In line with this hypothesis, the cytosol of NatB depleted plants is constitutively over-reduced and a global transcriptome analysis reveals that their reductive stress response is permanently activated. Moreover, we demonstrate that doa10 mutants are susceptible to neither DTT nor TM, ruling out a substantial role of DOA10 in ER-associated protein degradation (ERAD) in plants. Contrary to previous findings in yeast, our data indicate that N-terminal acetylation (NTA) does not inhibit ER targeting of a substantial amount of proteins in plants. In summary, we provide further evidence that NatB-mediated imprinting of the proteome is vital for the response to protein harming stress and rule out DOA10 as the sole recognin for substrates in the plant ERAD pathway, leaving the role of DOA10 in plants ambiguous.

KeywordsN-terminal acetylation; Co-translational modification; N-acetyltransferase NatB; ER-associated degradation; DOA10; Proteostasis; Reductive stress; N-degron
Year of Publication2022
JournalFrontiers in Plant Science
Journal citation12, p. 799954
Digital Object Identifier (DOI)https://doi.org/10.3389/fpls.2021.799954
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDesigning Future Wheat - WP1 - Increased efficiency and sustainability
Publisher's version
Output statusPublished
Publication dates
Online03 Jan 2022
Publication process dates
Accepted22 Nov 2021
PublisherFrontiers Media SA
ISSN1664-462X

Permalink - https://repository.rothamsted.ac.uk/item/98784/disruption-of-the-n-acetyltransferase-natb-causes-sensitivity-to-reductive-stress-in-arabidopsis-thaliana

98 total views
95 total downloads
0 views this month
2 downloads this month
Download files as zip