Anti-Lysosome-associated Membrane Protein 1 (LAMP1, LAMP-1, Lysosome-associated Membrane Glycoprotei

As the name suggests, LAMP1 is a protein primarily associated with the lysosomal membrane. Antibodies to LAMP1 are therefore excellent markers of lysosomes in mammalian cells, though some LAMP1 may also be seen on late endosomes and on the plasma membrane. In a typical cell LAMP1 is associated with spherical vesicles located next to the nucleus and the microtubule organizing center (1). The protein is also known as CD107a, lysosomal associated membrane glycoprotein 1, LGP120 and LAMPA, as the protein was independently discovered and named by several different labs. CD is an abbreviation for "Cluster of Differentiation" and refers to a protocol for the naming of proteins and other surface markers of membranes of human leucocytes defined by binding of specific monoclonal antibodies. LAMP1 is found on the cell surface of lymphocytes undergoing degranulation, a process in which cytoplasmic vesicles fuse with the plasma membrane, and this phenomena resulted in discovery of LAMP1 as a CD protein. The LAMP1 protein has a large N-terminal region which is inside the lysosome, hence topologically external to the cell, which is often refered to as the lumenal domain (2). The lumenal domain consists of two homologous globular seqments separated by a proline rich sequence. Next there is a single membrane spanning domain and a short 11 amino acid C-terminal cytoplasmic tail. This tail region contains, at the extreme C-terminus, a so-called YXXI motif which is responsible for the sorting of the intact molecule to the endosome and lysozome, where Y = tyrosine, I = isoleucine and X = almost any amino acid (3). This motif is found in several other lysosomal proteins, where it functions in the same way. There are 417 amino acids in the human LAMP1 molecule, giving a native molecular weight of 44.8kD. However the N-terminal lumenal segment of LAMP1 is very heavily and variably glycosylated due to the presence of 18 N-linked glycosylation sites, so that on SDS-PAGE and on Western blots the protein runs as a diffuse band at 90-120kD. The HGNC name for this protein is LAMP1. Applications: Suitable for use in Immunofluorescence and Western Blot. Other applications not tested. Recommended Dilution: Immunofluorescence: 1:2000, Western Blot: 1:10,000 using chemiluminescence., Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.