Functional and biochemical characterization of the Toxoplasma gondii succinate dehydrogenase complex.

Autor: Silva MF; Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom., Douglas K; Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom., Sandalli S; Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom., Maclean AE; Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom., Sheiner L; Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom.
Jazyk: angličtina
Zdroj: PLoS pathogens [PLoS Pathog] 2023 Dec 11; Vol. 19 (12), pp. e1011867. Date of Electronic Publication: 2023 Dec 11 (Print Publication: 2023).
DOI: 10.1371/journal.ppat.1011867
Abstrakt: The mitochondrial electron transport chain (mETC) is a series of membrane embedded enzymatic complexes critical for energy conversion and mitochondrial metabolism. In commonly studied eukaryotes, including humans and animals, complex II, also known as succinate dehydrogenase (SDH), is an essential four-subunit enzyme that acts as an entry point to the mETC, by harvesting electrons from the TCA cycle. Apicomplexa are pathogenic parasites with significant impact on human and animal health. The phylum includes Toxoplasma gondii which can cause fatal infections in immunocompromised people. Most apicomplexans, including Toxoplasma, rely on their mETC for survival, yet SDH remains largely understudied. Previous studies pointed to a divergent apicomplexan SDH with nine subunits proposed for the Toxoplasma complex, compared to four in humans. While two of the nine are homologs of the well-studied SDHA and B, the other seven have no homologs in SDHs of other systems. Moreover, SDHC and D, that anchor SDH to the membrane and participate in substrate bindings, have no homologs in Apicomplexa. Here, we validated five of the seven proposed subunits as bona fide SDH components and demonstrated their importance for SDH assembly and activity. We further find that all five subunits are important for parasite growth, and that disruption of SDH impairs mitochondrial respiration and results in spontaneous initiation of differentiation into bradyzoites. Finally, we provide evidence that the five subunits are membrane bound, consistent with their potential role in membrane anchoring, and we demonstrate that a DY motif in one of them, SDH10, is essential for complex formation and function. Our study confirms the divergent composition of Toxoplasma SDH compared to human, and starts exploring the role of the lineage-specific subunits in SDH function, paving the way for future mechanistic studies.
Competing Interests: The authors have declared that no competing interests exist.
(Copyright: © 2023 Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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