Fig. 3. Regulation of lysosome function by sphingolipids and modulating enzymes in podocytes. Lysosome trafficking and fusion to autophagosome and MVB are dependent on the TRPML1 channel-mediated Ca²⁺ release in podocytes. Lysosomal ASM converts SM into CER and AC converts CER to Sph. These sphingolipids, SM, Cer, and Sph had different effects on TRPML1 channel activity in podocytes, with inhibition by SM, no effect from Cer, but enhancement by Sph. SM, sphingomyelin; Cer; ceramide; Sph, sphingosine.