title: Structure and properties of the cellular receptor for transforming growth factor type beta.
abstract: Swiss 3T3 cells respond to picomolar concentrations of type beta transforming growth factor (TGF-beta) with a dose-dependent increase in the formation of colonies in soft agar, a decrease in the growth of cells in monolayer culture, and changes in morphology. This indicates that these cells have functional TGF-beta receptors able to mediate a biological response. Binding analysis revealed a single class of TGF-beta binding sites (80 000 per cell) with a Kd approximately 50 pM. Receptors were affinity-labeled by covalent attachment to 125I-TGF-beta with bis(sulfosuccinimidyl) suberate (BS3). The complexes formed were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of 100 mM dithiothreitol and migrated as Mr approximately 180 000 complexes in 3-10% linear gradient gels. The apparent size of these complexes was larger in gels with a higher percentage of acrylamide. The labeling of the 125I-TGF-beta-receptor complexes was inhibited by the presence of excess unlabeled TGF-beta but was unaffected by other growth factors. These complexes could be formed by cross-linking whole cells, intact membranes, or solubilized membranes, demonstrating that the TGF-beta receptor is located on the plasma membrane and can be solubilized without destruction of its ability to bind TGF-beta. A larger Mr approximately 360 000 complex was present in 3-10% linear gradient gels without reduction or after extensive cross-linking, suggesting that the receptor consists of two subunits of similar size attached by disulfide bonds. Since BS3 is membrane-impermeable, at least a portion of both subunits is located on the outer surface of the plasma membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.forename: B O
authors.initials: BO
authors.lastname: Fanger
authors.forename: L M
authors.initials: LM
authors.lastname: Wakefield
authors.forename: M B
authors.initials: MB
authors.lastname: Sporn
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D051379:Mice; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta; D015291:Transforming Growth Factors
chemical_list: D006133:Growth Substances; D046911:Macromolecular Substances; D010455:Peptides; D011956:Receptors, Cell Surface; D018125:Receptors, Transforming Growth Factor beta; D015291:Transforming Growth Factors