Human LIMPII/SR-B2 Lumenal Loop Biotinylated Antibody

LIMPII (Lysosomal Integral Membrane Protein II), also known as LPG85 (85 kDa lysosomal membrane sialoglycoprotein) and as CD36 antigen-like 2 (CD36L2), is a major lysosomal membrane protein. It belongs to the scavenger receptor class B subfamily and is designated member 2 (SR-B2). Other mammalian members of this family include SR-B1 (alternatively known as Cla-1 and CD36L1), and SR-B3 (CD36) (1‑3). SR-B/CD36 family members are type III integral membrane proteins with an N- as well as a C-terminal cytoplasmic tail, and a large extracellular (or lumenal in the case of LIMPII) loop containing similarly spaced cysteine residues and multiple glycosylation sites. The C-terminal cytoplasmic tail has a di-leucine-based motif that mediates effective lysosomal targeting. LIMPII is widely expressed on all tissues and cell types so far examined. It is also expressed on the surface of activated platelets. LIMPII binds thrombospondin-1, but the biological significance of this interaction is not known. LIMPII-thrombospondin interaction may contribute to the pro-adhesive changes of activated platelets during coagulation, and inflammation (1). Overexpression of LIMPII causes an enlargement of early endosomes and late endosomes, suggesting that LIMPII may play a role in lysosome/endosome biogenesis (4). Mice deficient in LIMPII are impaired in membrane transport processes, resulting in ureteric pelvic junction obstruction, deafness and peripheral neuropathy (5).