The <i>Toxoplasma</i> plant‐like vacuolar compartment (<scp>PLVAC</scp>)

Stasic, Andrew J.; Moreno, Silvia N. J.; Carruthers, Vern B.; Dou, Zhicheng

doi:10.1111/jeu.12951

Cited by 14 publications

(16 citation statements)

References 142 publications

(268 reference statements)

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“…However, even if the TORC complex was lost in these organisms, the lysosome might have retained the function as a metabolic signaling hub for a distinct nutrient sensing machinery (5, 60). T. gondii possesses a lysosomal-like organelle named PLVAC (39) whose proteome is still poorly characterized with only a few membrane proteins identified and only one peptide/amino acid transporter, TgCRT (40). Amino acid transporters have been implicated in sensing of specific amino acids from inside the lysosome and modulating activity of the TORC1 complex (61).…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, arginine, the TORC1 activator amino acid sensed by the lysosomal transporter SLC38A9, is a key determinant of T. gondii differentiation, since its starvation was found to trigger differentiation of replicative tachyzoites into bradyzoites (38). T. gondii possesses a lysosome-like organelle termed the plant-like vacuolar compartment (PLVAC) that plays multiple functions as digestive organelle, being involved in ion storage and homeostasis, endocytosis, and autophagy (39). So far, only one PLVAC transporter has been characterized, the T. gondii homologue of Plasmodium chloroquine resistance transporter (TgCRT), which likely exports products of proteolytic digestion (peptides, amino acids) from the PLVAC into the parasite cytoplasm (40).…”

Section: Introductionmentioning

confidence: 99%

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AToxoplasma gondiiputative arginine transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation

Piro,

Masci,

Kannan

et al. 2023

Preprint

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Toxoplasma gondiiis a protozoan parasite that infects a broad spectrum of hosts and can colonize many organs and cell types. The ability to reside within a wide range of different niches requires substantial adaptability to diverse microenvironments. Very little is known about how this parasite senses various milieus and adapts its metabolism to survive, replicate during the acute stage, and then differentiate to the chronic stage. Most eukaryotes, from yeast to mammals, rely on a nutrient sensing machinery involving the TORC complex as master regulator of cell growth and cell cycle progression. The lysosome functions as a signaling hub where TORC complex assembles and is activated by transceptors, which both sense and transport amino acids, including the arginine transceptor SLC38A9. While most of the TORC components are lost inT. gondii, indicating the evolution of a distinct nutrient sensing mechanism, the parasite’s lysosomal plant-like vacuolar compartment (PLVAC) may still serve as a sensory platform for controlling parasite growth and differentiation. Using SLC38A9 to query theT. gondiiproteome, we identified four putative amino acid transporters, termed TgAAT1-4, that structurally resemble the SLC38A9 arginine transceptor. Assessing their expression and sub-cellular localization, we found that one of them, TgAAT1, localized to the PLVAC and is necessary for normal parasite extracellular survival and bradyzoite differentiation. Moreover, we show that TgAAT1 is involved in the PLVAC efflux of arginine, an amino acid playing a key role inT. gondiidifferentiation, further supporting the hypothesis that TgAAT1 might play a role in nutrient sensing.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

AToxoplasma gondiiputative arginine transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation

Piro,

Masci,

Kannan

et al. 2023

Preprint

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“…In the current study, we investigated the effect of three phytohormones (ABA, GIBB, and KIN) on the replication potential of T. gondii tachyzoites. T. gondii is an apicomplexan parasite known to harbor the algae-derived apicoplast as well as the plant-like vacuolar compartment (PLVAC) (Stasic et al 2022). Therefore, it is assumed that plant-derived phytohormones may exhibit a significant effect on cell-signaling pathways related to organelles shared with plant organisms (Nagamune et al 2008, Andrabi et al 2018).…”

Section: Discussionmentioning

confidence: 99%

Phytohormones regulate asexualToxoplasma gondiireplication

Wagner,

Bangoura,

Wiedmer

et al. 2023

Preprint

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The protozoan Toxoplasma (T.) gondii is a zoonotic disease agent causing systemic infection in warm-blooded intermediate hosts, including humans. During acute infections, the parasite infects host cells and multiplies intracellularly in the asexual tachyzoite stage. In this stage of the life cycle, invasion, multiplication, and egress are the most critical events in parasite replication. T. gondii features diverse cell organelles to support these processes, including the so-called apicoplast, an endosymbiont-derived vestigial plastid originating from an alga ancestor. Previous studies have highlighted that phytohormones can modify the calcium-mediated secretion, e.g., of adhesins involved in parasite movement and cell invasion processes. The present study aimed to elucidate the influence of different plant hormones on the replication of asexual tachyzoites in a human foreskin fibroblast (HFF) host cell culture. T. gondii replication was measured by the determination of T. gondii DNA copies via qPCR. Three selected phytohormones, namely abscisic acid (ABA), gibberellic acid (GIBB), and kinetin (KIN)as representatives of different plant hormone groups were tested. Moreover, the influence of typical cell culture media components on the phytohormone effects was assessed. Our results indicate that ABA is able to induce a significant increase of T. gondii DNA copies in typical supplemented cell culture medium when applied in concentrations of 20 or 2 ng/microliter, respectively. In contrast, depending on the culture medium composition, GIBB may potentially serve as T. gondii growth inhibitor and may be further investigated as a potential treatment for toxoplasmosis.

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“…Disruption of proteins that localize to the PLVAC and ELC or proteins that are typically involved in endosomal trafficking has been shown to cause defects in the biogenesis of rhoptries and micronemes (11,16,21–23). Furthermore, endolysosomal proteases have been shown to proteolytically process immature ROP and MIC proteins (16,19,20). Together, this evidence supports the convergence of endocytic and exocytic pathways in T. gondii .…”

Section: Introductionmentioning

confidence: 99%

Characterization and functional analysis ofToxoplasmaGolgi-associated proteins identified by proximity labelling

Pasquarelli,

Quan,

Cheng

et al. 2024

Preprint

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Toxoplasma gondii possesses a highly polarized secretory pathway that contains both broadly conserved eukaryotic organelles and unique apicomplexan organelles which play essential roles in the parasite's lytic cycle. As in other eukaryotes, the T. gondii Golgi apparatus sorts and modifies proteins prior to their distribution to downstream organelles. Many of the typical trafficking factors found involved in these processes are missing from apicomplexan genomes, suggesting that these parasites have evolved unique proteins to fill these roles. Here we identify a novel Golgi-localizing protein (ULP1) which contains structural homology to the eukaryotic trafficking factor p115/Uso1. We demonstrate that depletion of ULP1 leads to a dramatic reduction in parasite fitness and replicative ability. Using ULP1 as bait for TurboID proximity labelling and immunoprecipitation, we identify eleven more novel Golgi-associated proteins and demonstrate that ULP1 interacts with the T. gondii COG complex. These proteins include both conserved trafficking factors and parasite-specific proteins. Using a conditional knockdown approach, we assess the effect of each of these eleven proteins on parasite fitness. Together, this work reveals a diverse set of novel T. gondii Golgi-associated proteins that play distinct roles in the secretory pathway. As several of these proteins are absent outside of the Apicomplexa, they represent potential targets for the development of novel therapeutics against these parasites.

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The Toxoplasma plant‐like vacuolar compartment (PLVAC)

Cited by 14 publications

References 142 publications

AToxoplasma gondiiputative arginine transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation

AToxoplasma gondiiputative arginine transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation

Phytohormones regulate asexualToxoplasma gondiireplication

Characterization and functional analysis ofToxoplasmaGolgi-associated proteins identified by proximity labelling

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