Naslov
Proteome response to mistranslation

Autori
Močibob, Marko ; Pranjić, Marija ; Šemanjski Čurković, Maja ; Spät, Philipp ; Maček, Boris ; Gruić-Sovulj, Ita

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts of the 1st Workshop on Mass Spectrometry in Life Sciences / Novak, Ruđer ; Dulić, Morana ; Horvatić, Anita ; Močibob, Marko ; Pranjić, Marija - Zagreb : University of Zagreb, Faculty of Science, 2022, L2-L2

ISBN
978-953-6076-97-0

Skup
1st Workshop on Mass Spectrometry in Life Sciences

Mjesto i datum
Zagreb, Hrvatska, 24.11.2022. - 26.11.2022

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Proteomika, mistranslacija, izoleucin, norvalin, isoleucil-tRNA-sintetaza, agregacija proteina
(proteomics, mistranslation, isoleucine, norvaline, isoleucyl-tRNA synthetase, protein aggregation)

Sažetak
Mistranslation is an error in protein biosynthesis caused by erroneus incorporation of the amino acids. Aminoacyl-tRNA synthetases (aaRS) play the crucial role in this process, as they supply the ribosome with its substrates, aminoacylated tRNAs (aa-tRNA). If there is a mistake in aa-tRNA synthesis, the erroneous amino acid will be misincorporated into the nascent polypeptide chains, since there are no additional surveillance mechanisms of synthesized aa-tRNAs. Here, we explore the effects of isoleucine mistranslation on Escherichia coli proteome induced by editing-defective isoleucyl-tRNA synthetase (IleRS). Two types of mistranslation were investigated: substitution of isoleucine with valine, the standard proteinogenic amino acid, or with norvaline (Nva), a non-proteinogenic amino acid which accumulates in the cell under anaerobic conditions. We have found that E. coli can tolerate unexpectedly high levels of mistranslation, up to 22 % Ile-to-Val or 18 % Ile- to-Nva substitutions. Analysis of differentially expressed proteins revealed upregulation of chaperones GroES/EL, DnaK/DnaJ/GrpE, HtpG and disaggregase ClpB. Overall, response to Val and Nva mistranslation was similar, with Nva being more toxic. We performed a detailed analysis od DnaK clients. Curiosly, we found very few changes in DnaK interactome, suggesting that DnaK upregulation counteracts increased amount of proteins inherently prone to misfolding, rather than the increased number of different misfolded proteins. The number of DnaK interactors did increase when the bacteria were subjected to mistranslation prior to heat-shock, indicating that mistranslation under heat-shock conditions has caused extensive proteome destabilisation. Consequently, prolonged exposure of mistranslated cells to heat-shock was lethal, pointing to reduced ability of bacteria with increased mistranslation level to adapt to unfavourable environmental conditions. Upregulation of ClpB, a disaggregase working in tandem with DnaK chaperone prompted us to analyse the insoluble proteome fraction, i. e. protein aggregation caused by mistranslation. In IleRS editing-deficient strain mistranslation caused nonspecific and proteome- wide accumulation of protein aggregates, with increased level of mistranslation compared to the soluble proteome fraction (up to 26 % Ile to Val and 20 % Ile to Nva). Disruption of clpB gene promoted aggregation, with mistranslation in aggregates reaching up to 29 % and 28 % for Val and Nva misincorporation, respectively. Thus, the main consequence of protein mistranslation is deposition of mistranslated proteins to insoluble aggregates, normally counteracted by ClpB disaggregase.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Biologija

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