Taniguchi A, Matsuzaki K, Nakano K, Kan M, McKeehan W L
Albert B. Alkek Institute of Biosciences and Technology, Department of Biochemistry & Biophysics, Texas A&M University, Houston 77030-3303, USA.
In Vitro Cell Dev Biol Anim. 1998 Mar;34(3):232-8. doi: 10.1007/s11626-998-0129-3.
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.
转化生长因子β（TGFβ）的III型受体不具有激酶活性，可结合TGFβ1和TGFβ2，并参与多亚基TGFβ信号转导复合物的组装和活性。最近我们发现，TGFβIII型受体（TβRIII）可参与由二聚体TGFβ配体以及III型、II型和I型受体亚基组成的复合物。TβRIII亚基与TβRII的相互作用依赖于TGFβ，而与TβRI的相互作用则不依赖于TGFβ。在此，我们利用杆状病毒感染的昆虫细胞中共表达三种类型的TGFβ受体，以确定未糖基化的TβRIII受体的哪些部分参与TGFβ的结合、与TβRII的TGFβ依赖性相互作用以及与TβRI的TGFβ非依赖性相互作用。结果表明，TβRIII氨基末端部分的前500个氨基酸残基具有所有这三种特性。
