title: Ligand-dependent and -independent interactions with the transforming growth factor type II and I receptor subunits reside in the aminoterminal portion of the ectodomain of the type III subunit.
abstract: The type III receptor for transforming growth factor beta (TGFbeta), which exhibits no kinase activity, binds TGFbeta1 and TGFbeta2 and is involved in assembly and activity of the multi-subunit TGFbeta signal transduction complex. Recently we showed that TGFbeta receptor type III (TbetaRIII) can participate in a complex composed of the dimeric TGFbeta ligand and a type III, II, and I receptor subunit. The interaction of the TbetaRIII subunit with TbetaRII is TGFbeta-dependent, whereas interaction with TbetaRI is TGFbeta-independent. Here we use coexpression of the three types of TGFbeta receptors in baculoviral-infected insect cells to determine which parts of the unglycosylated TbetaRIII receptor participate in the binding of TGFbeta, the TGFbeta-dependent interaction with TbetaRII and the TGFbeta-independent interaction with TbetaRI. The results suggest that the first 500 amino acid residues in the aminoterminal portion of TbetaRIII exhibit all three properties.
authors.affiliation: Albert B. Alkek Institute of Biosciences and Technology, Department of Biochemistry & Biophysics, Texas A&M University, Houston 77030-3303, USA.
authors.forename: A
authors.initials: A
authors.lastname: Taniguchi
authors.forename: K
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: K
authors.initials: K
authors.lastname: Nakano
authors.forename: M
authors.initials: M
authors.lastname: Kan
authors.forename: W L
authors.initials: WL
authors.lastname: McKeehan
mesh_terms: D030201:Activin Receptors, Type I; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D006493:Heparin / Q000378:metabolism; D008024:Ligands; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism*; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D008024:Ligands; D011509:Proteoglycans; D018125:Receptors, Transforming Growth Factor beta; D011993:Recombinant Fusion Proteins; D016212:Transforming Growth Factor beta; C071736:betaglycan; D006493:Heparin; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II