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Evidence For the Presence of the Asialoglycoprotein Receptor in Coated Vesicles Isolated from Rat Liver
Author(s) -
Steer Clifford J.,
Wall Doris A.,
Ashwell Gilbert
Publication year - 2007
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840030507
Subject(s) - vesicle , asialoglycoprotein receptor , clathrin adaptor proteins , biochemistry , chemistry , integral membrane protein , receptor , membrane , membrane protein , clathrin , chromatography , biophysics , biology , in vitro , hepatocyte
Coated vesicles were isolated from rat liver by a modification of the procedure described by Nandi et al. for bovine brain (Proc. Natl. Acad. Sci. U.S.A. 1982; 79:5881–5885). The hepatic receptor for asialoglycoproteins was shown to be an integral constitutent of these vesicles as evidenced by their ability to bind 125 I‐asialo‐orosomucoid in a specific and saturable manner. The specific binding activity of the purified vesicles was 17‐fold greater than that of the original liver homogenate based on a protein determination. Binding was 97% latent and was made fully manifest only after removal of the clathrin coat and disruption of the exposed smooth membrane vesicles by detergent. Based on this finding, it was concluded that the binding protein for asialoglycoproteins was oriented toward the inner surface of the vesicle. In addition, evidence is presented that purification procedures employing detergent may result in coated vesicles deficient in one or more integral membrane proteins.