The NPC1 gene encodes a large membrane protein that is found in the membranes of lysosomes and endosomes. It is primarily involved in the transport of cholesterol out of lysosomes. The NPC2 gene, on the other hand, encodes a small soluble protein that binds cholesterol in the lysosomal lumen. Together, NPC1 and NPC2 coordinate the removal of cholesterol from lysosomes, a critical process for maintaining cellular lipid homeostasis.
