MCOLN1 and lysosomal storage disease: Secondly, lysosomal storage disorders such as NPC disease are associated with defects in lysosomal Ca2+ homeostasis [46], and activation of the lysosomal ion channel transient receptor potential channel 1 (TRPML1) by small-molecule activator ML-SA1 was shown to rescue lysosomal trafficking in NPC-/--macrophages [30].