title: Molecular cloning of cDNAs encoding lamp A, a human lysosomal membrane glycoprotein with apparent Mr approximately equal to 120,000.
abstract: Although several lysosomal membrane glycoproteins have been characterized by using specific antibodies, none of the studies so far elucidated the amino acid sequence of a lysosomal membrane glycoprotein. Here we describe cDNA clones encoding for one of the lysosome-associated membrane proteins with apparent Mr approximately equal to 120,000, lamp A. The amino acid sequence based on the fully coded cDNA shows that as many as 18 potential N-glycosylation sites can be found in the total of 385 amino acid residues. The results obtained by endoglycosidase F digestion support the conclusion that this glycoprotein contains 18 N-glycans. These N-glycosylation sites are clustered in two domains; one contains 10 and the other contains 8 N-glycosylation sites. These domains are separated by a (proline-serine)-rich region that has a distinct homology to the IgA hinge structure. The first N-glycosylated domain is elongated to a potential leader peptide toward the NH2-terminal end. The second N-glycosylated domain, on the other hand, is connected to a putative transmembrane portion consisting of hydrophobic amino acids. This segment, in turn, is elongated to a short cytoplasmic segment composed of 11 amino acid residues at the COOH-terminal end.
mesh_terms: D000595:Amino Acid Sequence; D015703:Antigens, CD; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D006801:Humans; D007137:Immunoglobulin alpha-Chains / Q000235:genetics; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight
chemical_list: D015703:Antigens, CD; D007137:Immunoglobulin alpha-Chains; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D004247:DNA