The function of NPC1 (NPC intracellular cholesterol transporter 1, Ensembl gene identifier ENSG00000141458) is as follows. Intracellular cholesterol transporter which acts in concert with NPC2 and plays an important role in the egress of cholesterol from the endosomal/lysosomal compartment (PubMed:10821832, PubMed:12554680, PubMed:18772377, PubMed:27238017, PubMed:9211849, PubMed:9927649). 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 (PubMed:18772377, PubMed:19563754, PubMed:27238017, PubMed:27378690, PubMed:28784760, PubMed:9211849, PubMed:9927649). Cholesterol binds to NPC1 with the hydroxyl group buried in the binding pocket (PubMed:19563754). Mediates cholesterol transfer from lysosomes to endoplasmic reticulum by tethering endosomal/lysosomal compartments and endoplasmic reticulum membrane contact sites where it interacts with sterol transport protein GRAMD1B (PubMed:31537798). Binds oxysterol with higher affinity than cholesterol. May play a role in vesicular trafficking in glia, a process that may be crucial for maintaining the structural and functional integrity of nerve terminals (Probable). Inhibits cholesterol-mediated mTORC1 activation throught its interaction with SLC38A9 (PubMed:28336668). {ECO:0000269|PubMed:10821832, ECO:0000269|PubMed:12554680, ECO:0000269|PubMed:18772377, ECO:0000269|PubMed:19563754, ECO:0000269|PubMed:27238017, ECO:0000269|PubMed:27378690, ECO:0000269|PubMed:28336668, ECO:0000269|PubMed:28784760, ECO:0000269|PubMed:31537798, ECO:0000269|PubMed:9211849, ECO:0000269|PubMed:9927649, ECO:0000305}. (Microbial infection) Acts as an endosomal entry receptor for ebolavirus. {ECO:0000269|PubMed:21866103, ECO:0000269|PubMed:25855742, ECO:0000269|PubMed:32855215}.