title: Characterization of Rauscher murine leukemia virus envelope glycoprotein receptor in membranes from murine fibroblasts.
abstract: Plasma membrane preparations from KA31 (mouse) cells contained receptors for the binding of Rauscher murine leukemia virus (R-MuLV) envelope glycoprotein, gp70. This binding was demonstrated by gel filtration of a mixture of the microsomal fraction of the cells and 125I-labeled gp70. A rapid and convenient assay was developed to measure the complex formation between the membrane receptors and gp70 involving specific precipitation of the complex by 3 to 4% polyethylene glycol. The complex formation was responsive to the concentrations of both the receptor and gp70 and also to changes in temperature and pH. The gp70 binding was a noncooperative, saturable process, and an association constant of 3.5 X 10(8) M-1 was estimated from the binding data. The complex formation was reversible and a near-total exchange of 125I-labeled gp70 in the complex was achieved by incubation with excess of unlabeled gp70. The complex formation was inhibited by protein denaturing agents, guanidine-hydrochloride and urea. Pretreatment of the membrane fractions with either chymotrypsin or phospholipase C led to a loss of the membrane-associated receptor activity, indicating that a lipoprotein structure was important for the receptor function, consistent with the observation that nonionic detergents strongly inhibited the complex formation.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002460:Cell Line; D003902:Detergents / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010447:Peptide Hydrolases / Q000494:pharmacology; D010740:Phospholipases / Q000494:pharmacology; D011925:Rauscher Virus; D011991:Receptors, Virus / Q000378:metabolism*; D013696:Temperature; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D003902:Detergents; D006023:Glycoproteins; D011991:Receptors, Virus; D014764:Viral Proteins; D010740:Phospholipases; D006026:Glycoside Hydrolases; D010447:Peptide Hydrolases; D002118:Calcium