CD107b, also known as lysosomal-associated membrane protein 2 (LAMP-2), is a heavily glycosylated, type I transmembrane protein that constitutes one of the two major sialoglycoproteins on lysosomal membranes that can be used to distinguish lysosomes from other organelles.1 CD107b is similar in structure to Mac-1 and is expressed primarily on epithelial cells and macrophages in a variety of organs in normal and Beige mutant mice.2