The lysosomal integral membrane protein 2 (LIMP2) is a heavily glycosylated type III transmembrane protein, the majority of which exists in the lumen of the lysosome and a cytoplasmic domain of approximately 20 amino acids. A deficiency of LIMP2 in mice causes uretic pelvic junction obstruction, deafness, and peripheral neuropathy associated with impaired vesicular trafficking and distribution of apically expressed proteins. More recently, LIMP2 was shown to act as a receptor to bind beta-glucocerebrosidase, the enzyme defective in Gaucher disease, a lysosomal storage disorder. LIMP2-deficient mice showed missorted as well as secreted beta-glucocerebrosidase, suggesting that LIMP2 also functions as the mannose-6-phosphate-independent trafficking receptor.
