Transporters, an important but poorly studied area of Toxoplasma gondii.

Membrane transporters play a vital role in the obligate intracellular parasite Toxoplasma gondii, mediating the acquisition of nutrients from host cells, the regulation of ion gradients, and the maintenance of metabolic homeostasis. Despite their central importance for parasite survival, pathogenesis, and drug resistance, the majority of T. gondii transporters remain poorly characterized. Key unresolved questions include the mechanisms underlying purine nucleotide transport across the plasma membrane and the import/export of metabolites for core pathways in the apicoplast (e.g., thiamine, isopentenyl diphosphate[IPP]/dimethylallyl diphosphate [DMAPP], and coproporphyrinogen III) and mitochondria (e.g., amino acids and cofactors). Recent advances in bioinformatics and CRISPR-based phenotypic screening have enabled systematic identification of transporter candidates. This review summarizes current knowledge of T. gondii transporters localized to the plasma membrane, apicoplast, mitochondria, endoplasmic reticulum, and Golgi apparatus, highlighting their roles in nutrient acquisition, metabolic crosstalk, and organellar function. Furthermore, we propose a screening strategy integrating transmembrane domain prediction, CRISPR phenotyping, and hyperLOPIT-based protein localization to prioritize uncharacterized transporters for functional study. These insights underscore the potential of transporters as therapeutic targets and provide a roadmap for future research into the physiology of T. gondii.