1.A.11.1.8
AMT of 514 aas and 11 TMSs. Trypanosoma cruzi, the etiologic agent of Chagas disease, undergoes drastic metabolic changes when it transits between a vector and mammalian hosts. Amino acid catabolism leads to the production of NH₄⁺, which must be detoxified. Cruz-Bustos et al. 2018 identified an intracellular ammonium transporter of T. cruzi (TcAMT) that localizes to acidic compartments (reservosomes, lysosomes). TcAMT possesses all conserved and functionally important residues that form the pore in other ammonium transporters. Functional expression in Xenopus oocytes followed by a two-electrode voltage clamp showed an inward current that is NH₄⁺ dependent at a resting membrane potential lower than -120 mV and is not pH dependent, suggesting that TcAMT is an NH₄⁺or NH3/H⁺ transporter. Ablation of TcAMT resulted in defects in epimastigote and amastigote replication, differentiation, and resistance to starvation and osmotic stress (Cruz-Bustos et al. 2018).