Invitrogen™ Human LAMP1/CD107a ELISA Kit

LAMP1 (CD107a, lysosome-associated membrane protein-1) together with LAMP-2, is a major constituent of lysosomal membrane, 1-2% of total CD107a is found also on the plasma membrane. LAMP1 is a heavily glycosylated membrane protein which contains a putative signal peptide, 18 sites for N-linked glycosylation, a single membrane-spanning segment and a short (11 amino acid) cytosolic tail. The LAMP proteins are involved in lysosome biogenesis and are required for fusion of lysosomes with phagosomes. LAMP1 is a type 1 integral membrane protein that is transported from trans-Golgi network to endosomes and then lysosomes. Upon cell activation, LAMP1 transfer to the plasma membrane is dependent on a carboyxl-terminal tyrosine based motif (YXXI). Perturbation in the spacing between the tyrosine based motif relative to the membrane abolishes lysosome localization of LAMP1, and this mutant protein then cycles between the plasma membrane and the endosome. Cell surface LAMP1 (and LAMP2) have been shown to promote adhesion of human peripheral blood mononuclear cells (PBMC) to vascular endothelium, therefore, they are possibly involved in the adhesion of PBMC to the site of inflammation. Increased LAMP1 immunoreactivity is observed in neurons and glial cells surrounding senile plaques in Alzheimer’s Disease (AD) cases, and is localized in medullary epithelial cells, single macrophages and lymphocytes in acute thymic involution. LAMP1 is a good marker of mast cell activation.