LAMP1 and LAMP2 (lysosome-associated membrane protein 1 and 2) are two abundant lysosomal membrane proteins. Both are transmembrane proteins and heavily glycosylated at the amino-terminal luminal side of the lysosomal inner leaflet, which protects the proteins from proteolysis. The carboxy terminus of LAMP1 is exposed to the cytoplam and contains a tyrosine sorting motif which targets LAMP to lysosomal membranes.