Intracellular cholesterol transporter which acts in concert with NPC1 and plays an important role in the egress of cholesterol from the lysosomal compartment (PubMed:12591949, PubMed:17018531, PubMed:21315718, PubMed:26296895). Unesterified cholesterol that has been released from LDLs in the lumen of the late endosomes/lysosomes is transferred by NPC2 to the cholesterol-binding pocket in the N-terminal domain of NPC1. May bind and mobilize cholesterol that is associated with membranes. NPC2 binds cholesterol with a 1:1 stoichiometry. Can bind a variety of sterols, including lathosterol, desmosterol and the plant sterols stigmasterol and beta-sitosterol (By similarity). The secreted form of NCP2 regulates biliary cholesterol secretion via stimulation of ABCG5/ABCG8-mediated cholesterol transport (PubMed:21315718). cholesterol(in) = cholesterol(out) Interacts with NPC1 (via the second lumenal domain) in a cholestrol-dependent manner. Interacts with NUS1/NgBR, the interaction stabilizes NCP2 and regulates cholesterol trafficking. Interacts with DHDDS. Interacts with NEDD4L (via C2 domain). Interacts with NPC1L1. Interaction with cell-surface M6PR mediates endocytosis and targeting to lysosomes. Detected in liver and bile (PubMed:21315718). Detected in epididymis (at protein level). Detected in caput epididymis, corpus epididymis, cauda epididymis and ovary (PubMed:10863096). Binds cholesterol in a hydrophobic pocket; there are no hydrogen bonds between the sterol and the protein. N-glycosylated. Belongs to the NPC2 family.