F2 and cystinosis: Our data indicates that the absence of functional Cystinosin downregulates ATP6V0A1 expression (Figure 4), resulting in loss of intracellular acidic pH, decreased autophagy flux, increased autophagosome accumulation (Figure 7), loss of mTORC1 activity (Figure 5), and a compromised mitochondrial structure and function (Figures 6 and 7); moreover, collectively the results suggest a possible mechanistic explanation for the PT dysfunction in cystinosis (Figure 1B).