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.
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.
Taniguchi
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Albert B. Alkek Institute of Biosciences and Technology, Department of Biochemistry & Biophysics, Texas A&M University, Houston 77030-3303, USA.
Matsuzaki
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Nakano
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Kan
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McKeehan
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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
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