Differential contribution of two organelles of endosymbiotic origin to iron-sulfur cluster synthesis and overall fitness in Toxoplasma

Pamukcu, Sarah; Cerutti, Aude; Bordat, Yann; Hem, Sonia; Rofidal, Valérie; Besteiro, Sébastien

doi:10.1371/journal.ppat.1010096

Cited by 25 publications

(50 citation statements)

References 126 publications

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“…Deletion of SufS, however, led to apicoplast disruption and indicated that this enzyme plays another essential role in parasite biology. Similar to what we observed in P. falciparum, deletion of SufS in T. gondii also leads to loss of the apicoplast organelle and parasite death (Pamukcu et al, 2021). Conditional deletion of SufS in the murine malaria parasite P. berghei demonstrated that this enzyme is essential for the development of mosquito-stage parasites, although the status of the apicoplast was not reported in this study (Charan et al, 2017).…”

Section: Discussionsupporting

confidence: 75%

“…The dual roles of SufS may be a feature of the apicoplasts found in other pathogens such as T. gondii. Deletion of T. gondii SufS or MnmA results in apicoplast defects and parasite death (Pamukcu et al, 2021;Yang et al, 2022). Overall, the work presented here reveals a novel metabolic paradigm and exposes new vulnerabilities in malaria parasites that may extend to other related apicomplexan parasites.…”

Section: Discussionmentioning

confidence: 78%

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ThePlasmodium falciparumapicoplast cysteine desulfurase provides sulfur for both iron sulfur cluster assembly and tRNA modification

Prigge

Swift

Elahi

et al. 2022

Preprint

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Iron sulfur clusters (FeS) are ancient and ubiquitous protein cofactors that play fundamental roles in many aspects of cell biology. These cofactors cannot be scavenged or trafficked within a cell and thus must be synthesized in any subcellular compartment where they are required. We examined the FeS synthesis proteins found in the relict plastid organelle, called the apicoplast, of the human malaria parasite Plasmodium falciparum. Using a chemical bypass method, we deleted four of the FeS pathway proteins involved in sulfur acquisition and cluster assembly and demonstrated that they are all essential for parasite survival. However, the effect that these deletions had on the apicoplast organelle differed. Deletion of the cysteine desulfurase SufS led to disruption of the apicoplast organelle and loss of the organellar genome, whereas the other deletions did not affect organelle maintenance. Ultimately, we discovered that the requirement of SufS for organelle maintenance is not driven by its role in FeS biosynthesis, but rather, by its function in generating sulfur for use by MnmA, a tRNA modifying enzyme that we localized to the apicoplast. By complementing the activity of the parasite MnmA and SufS with a bacterial MnmA and its cognate cysteine desulfurase, we showed that the parasite SufS provides sulfur for both FeS biosynthesis and tRNA modification in the apicoplast. The dual role of parasite SufS is likely to be found in other plastid-containing organisms and highlights the central role of this enzyme in plastid biology.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 78%

ThePlasmodium falciparumapicoplast cysteine desulfurase provides sulfur for both iron sulfur cluster assembly and tRNA modification

Prigge

Swift

Elahi

et al. 2022

Preprint

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“…Transcriptional control of IscU by iron levels has been observed in a number of organisms(Garland et al, 1999;Tong and Rouault, 2006) and regulation of an IscA homolog by iron has been observed in bacteria(Andrews et al, 2003). Given the recent interest in iron sulfur biogenesis in T. gondii as a target for drug development(Aw et al, 2021;Pamukcu et al, 2021), these ndings suggest a currently unknown mechanism regulating this essential metabolic pathway. Beyond transcription, we found that under normal conditions, ΔVIT parasites attempted to compensate by increasing the activity (although not expression) of catalase and possibly other antioxidants, however this increase was not su cient to…”

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confidence: 99%

The vacuolar iron transporter mediates iron detoxification in Toxoplasma gondii

Aghabi

Sloan

Dou

et al. 2022

Preprint

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Iron is essential to living cells, acting as a cofactor in a number of important enzymes in metabolism; however in the absence of correct storage iron forms dangerous oxygen radicals. In both yeast and plants, iron is stored in a membrane-bound vacuole through the action of a vacuolar iron transporter (VIT). This transporter is conserved in the apicomplexan family of obligate intracellular parasites, including in Toxoplasma gondii, a pathogen of medical and veterinary importance. Here, we assess the role of VIT, and iron storage, in T. gondii. We show that iron is restricted to a compartment in the parasite that does not overlap with zinc. By deleting VIT we find a slight growth defect in vitro, however the absence of VIT leads to hypersensitivity to iron, confirming its essential role in iron detoxification in the parasite. This hypersensitivity can be rescued by scavenging of oxygen radicals. In the absence of VIT, parasites store less iron and are at a growth disadvantage when moving into an iron-depleted environment. We show parasite VIT expression is regulated by iron levels at both the transcript and protein level, and by altering the distribution of VIT within the cell. In the absence of VIT, we find that T. gondii responds by altering expression of genes with a role in iron metabolism and by increasing the activity of the antioxidant protein catalase. We also show that iron detoxification has an important role both in parasite survival within macrophages and in virulence in a mouse model. Together, by demonstrating a critical role for VIT during iron detoxification in T. gondii, we reveal the importance of iron storage in the parasite and provide the first insight into the machinery involved.

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“…Log 2 fold changes and adjusted p values from RNAseq experiment comparing parasites cultured for 24 hours in 100µM DFO to untreated parasites. Table S3 -FeS synthesis pathway genes (Pamukcu et al, 2021b) with log 2 fold changes and adjusted p values from RNAseq data. Table S4 -Genes upregulated in T. gondii bradyzoites (log 2 fold changes > 2, adjusted p value < 0.05) from Waldman et al 2020 in low iron conditions Table S5 -Raw output file from SIREs web server (Campillos et al, 2010) identifying putative IRE-like sequences in curated T. gondii transcriptome.…”

Section: Supplementary Tablesmentioning

confidence: 99%

Keeping FIT: Iron-mediated post-transcriptional regulation inToxoplasma gondii

Sloan,

Scott,

Harding

2023

Preprint

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Iron is required to support almost all life; however, levels must be carefully regulated to maintain homeostasis. Although the obligate parasiteToxoplasma gondiirequires iron, how it responds when iron becomes limiting has not been investigated. Here, we show that iron depletion triggers significant transcriptional changes in the parasite, including in pathways that require iron. Interestingly, we find that a subset ofT. gondiitranscripts contain stem-loop structures which have been associated with post-transcriptional iron-mediated regulation in other cellular systems. We validate one of these (found in the 3’ UTR of TGME49_261720) using a reporter cell line. We show that the presence of the stem-loop containing UTR is sufficient to confer accumulation at the transcript and protein levels under low iron. We show that this response is dose and time-dependent and is specific for iron. Using immunoprecipitation, we show that the metabolic enzyme aconitase is capable of binding to mRNA, includingfit, and that the presence of thefitUTR leads to stabilisation of the transcript under low iron conditions. These results demonstrate the existence of iron-mediated post-transcriptional regulation inToxoplasmafor the first time, and show that the metabolic enzyme aconitase may have an additional role as an RNA-binding protein.

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Differential contribution of two organelles of endosymbiotic origin to iron-sulfur cluster synthesis and overall fitness in Toxoplasma

Cited by 25 publications

References 126 publications

ThePlasmodium falciparumapicoplast cysteine desulfurase provides sulfur for both iron sulfur cluster assembly and tRNA modification

ThePlasmodium falciparumapicoplast cysteine desulfurase provides sulfur for both iron sulfur cluster assembly and tRNA modification

The vacuolar iron transporter mediates iron detoxification in Toxoplasma gondii

Keeping FIT: Iron-mediated post-transcriptional regulation inToxoplasma gondii

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