Supporting data for "Differential protein expression and post-translational modifications in Metronidazole-resistant Giardia duodenalis"

Metronidazole (Mtz) is the frontline drug treatment for multiple anaerobic pathogens, including the gastrointestinal protist, <em>Giardia duodenalis</em>. However, treatment failure is common and linked to <em>in vivo </em>drug resistance. In <em>Giardia</em>, <em>in vitro</em> drug-resistant lines allow controlled experimental interrogation of resistance mechanisms in isogenic cultures. However, resistance-associated changes are inconsistent between lines, phenotypic data are incomplete, and resistance is rarely genetically fixed, highlighted by reversion to sensitivity after drug selection ceases, or via passage through the life cycle. Comprehensive quantitative approaches are required to resolve isolate variability, fully define Mtz resistance phenotypes, and explore the role of post-translational modifications (PTMs) therein. We performed quantitative proteomics to describe differentially expressed proteins (DEPs) in three seminal Mtz resistant (MtzR) lines compared to their isogenic, Mtz-susceptible, parental line. We also probed changes in PTMs including protein acetylation, methylation, ubiquitination and phosphorylation via immunoblotting. We quantified over 1000 proteins in each genotype, recording substantial genotypic variation in DEPs between isotypes. Our data confirms substantial changes in the antioxidant network, glycolysis and electron transport, and indicates links between protein acetylation and Mtz resistance, including cross-resistance to deacetylase inhibitor Trichostatin A (TSA) in Mtz resistant lines. Finally, we performed the first controlled, longitudinal study of Mtz resistance stability, monitoring lines after cessation of drug selection, revealing isolate-dependent phenotypic plasticity. Our data demonstrate understanding of Mtz resistance must be broadened to post-transcriptional and post-translational responses, and that Mtz resistance is polygenic, driven by isolate-dependent variation, and is correlated with changes in protein acetylation networks.