Immunological evidence for the transmembrane nature of the rat liver receptor for asialoglycoproteins.

Antibodies raised in goats against the rat hepatic receptor for desialylated glycoproteins were perfused through a rat liver and were specifically retained by the liver. These antireceptor antibodies also bound specifically to hepatocyte plasma membranes oriented with their cytoplasmic surface outward on polylysine-derivatized beads. These two phenomena were judged to be properties of distinct subpopulations of the antibody preparation because: (i) maximal adsorption of antibodies with membranes on polylysine beads did not affect subsequent retention by the perfused liver, and (ii) whereas perfusion resulted in a depletion of antibodies capable of blocking ligand binding, adsorption by the everted membrane preparation led to a relative enrichment of blocking antibodies. These results are interpreted as indicative of distinct antigenic determinants of the receptor being present on the two faces of the membrane and demonstrate a transbilayer disposition of the asialoglycoprotein receptor.