title: Affinity labeling of multiplication stimulating activity receptors in membranes from rat and human tissues.
abstract: Plasma membranes from rat adipocytes and liver and from human placenta have been labeled by covalent cross-linking to membrane-bound 125I-labeled multiplication stimulating activity (125I-MSA) with three different bishydroxysuccinimide esters: disuccinimidyl suberate, disuccinimidyl succinate, and ethyleneglycolyl bis(succinimidyl succinate). Dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiographic analysis of the 125I-MSA-labeled material in the presence of dithiothreitol reveals one single-labeled protein migrating with an apparent Mr = 255,000 regardless of the kind and concentration of cross-linker used. Electrophoresis in the absence of reductant indicates that the affinity-labeled species is not disulfide-linked to any other protein in the native plasma membrane, but contains internal disulfide bonds that compact its structure. The labeling of the Mr = 255,000 species increases with increasing concentrations of 125I-MSA between 0.3 and 3 nM. Labeling is abolished in a competitive manner by nonradioactive MSA but not by similar concentrations of insulin, proinsulin, or epidermal growth factor in all three tissues examined. The unique labeling of this Mr = 225,000 membrane component and its selective inhibition by MSA suggest that this protein is a plasma membrane receptor for MSA.
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000345:Affinity Labels / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D005260:Female; D006801:Humans; D007335:Insulin-Like Growth Factor II; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008970:Molecular Weight; D010455:Peptides / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013388:Succinimides / Q000494:pharmacology*
chemical_list: D000345:Affinity Labels; D003432:Cross-Linking Reagents; D010455:Peptides; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D013388:Succinimides; C028721:disuccinimidyl succinate; D007335:Insulin-Like Growth Factor II; C028722:ethylene glycolylbis(succinimidyl succinate); C019358:disuccinimidyl suberate