The subcellular localization of the beta-galactoside-binding protein of rat lung.
The subcellular localization of the beta-galactoside-binding protein, or lectin, from rat lung was investigated by the specific binding of anti-lectin immunoglobulin G to subcellular fractions. We used both adult and immature (12-day-old) rats; the immature rat lungs have an 8-10-fold greater concentration than adult rat lungs [Powell & Whitney (1980) Biochem. J. 188, 1-8]. In both groups of animals we observed greater specific binding of anti-lectin immunoglobulin G to intracellular membrane (mitochondrial and microsomal fractions) than to plasma membranes. Pre-incubation of membrane fractions with lactose resulted in a marked diminution of anti-lectin immunoglobulin G binding. In the adult rat lung most (approx. 80%) of the lectin activity was membrane-associated. In the immature rat lung only approx. 30% of the lectin activity was membrane associated and most of the beta-galactoside-binding protein appeared to be a soluble cytoplasmic component. The rat lung beta-galactoside-binding protein appeared to have a broad but predominantly intracellular location, being associated with membranes through one of its galactoside-binding sites.
D000367:Age Factors; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D037161:Galectins; D007074:Immunoglobulin G / Q000276:immunology; D066298:In Vitro Techniques; D037102:Lectins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism
D002352:Carrier Proteins; D037161:Galectins; D007074:Immunoglobulin G; D037102:Lectins