MOLECULAR CHARACTERIZATION OF THE HUMAN MACROPHAGE MANNOSE RECEPTOR - DEMONSTRATION OF MULTIPLE CARBOHYDRATE RECOGNITION-LIKE DOMAINS AND PHAGOCYTOSIS OF YEASTS IN COS-1 CELLS

The macrophage mannose receptor is an integral membrane protein expressed on the surface of tissue macrophages. After ligation ofmannose-rich glycoconjugates or pathogens, the receptor mediates endorytosis and phagocytosis of the bound ligands by macrophages. The cDNAderived primary structure of the mannose receptor predicts a cysteine-rich NH2-terminal domain, followed by a fibronectin type II region. The remainder of the ectodomain is comprised of eight carbohydrate recognition-like domains, followed by a transmembrane region, and a cytoplasmic tail. Transfection of the mannose receptor cDNA into Cos-I cells is necessary for receptor-mediated endorytosis of mannose-rich glycoconjugate as well as phagocytosis of yeasts. Deletion of the cytoplasmic tail results in a mutant receptor that is able to bind but not ingest the ligated pathogens, suggesting that the signal for phagocytosis is contained in the cytoplasmic tail. © 1990, Rockefeller University Press., All rights reserved.