Lysosomal membrane glycoprotein which plays an important role in lysosome biogenesis, autophagy, and cholesterol homeostasis (By similarity). Also plays an important role in NK-cells cytotoxicity. Mechanistically, participates in cytotoxic granule movement to the cell surface and perforin trafficking to the lytic granule. In addition, protects NK-cells from degranulation-associated damage induced by their own cytotoxic granule content. Presents carbohydrate ligands to selectins. Also implicated in tumor cell metastasis (By similarity). Interacts with ABCB9; this interaction strongly stabilizes ABCB9 and protects ABCB9 against lysosomal degradation. Interacts with FURIN. This protein shuttles between lysosomes, endosomes, and the plasma membrane (By similarity). Colocalizes with OSBPL1A at the late endosome (By similarity). O- and N-glycosylated; some of the N-glycans attached to LAMP-1 are polylactosaminoglycans. Belongs to the LAMP family.