Seubert Nadine, Royer Yohan, Staerk Judith, Kubatzky Katharina F, Moucadel Virginie, Krishnakumar Shyam, Smith Steven O, Constantinescu Stefan N
Ludwig Institute for Cancer Research, Brussels B-1200, Belgium.
Mol Cell. 2003 Nov;12(5):1239-50. doi: 10.1016/s1097-2765(03)00389-7.
Binding of erythropoietin to the erythropoietin receptor (EpoR) extracellular domain orients the transmembrane (TM) and cytosolic regions of the receptor dimer into an unknown activated conformation. By replacing the EpoR extracellular domain with a dimeric coiled coil, we engineered TM EpoR fusion proteins where the helical TM domains were constrained into seven possible relative orientations. We identify one dimeric TM conformation that imparts full activity to the cytosolic domain of the receptor and signals via JAK2, STAT proteins, and MAP kinase, one partially active orientation that preferentially activates MAP kinase, and one conformation corresponding to the inactive receptor. The active and inactive conformations were independently identified by computational searches for low-energy TM dimeric structures. We propose a specific EpoR-activated interface and suggest its use for structural and signaling studies.
促红细胞生成素与促红细胞生成素受体（EpoR）细胞外结构域的结合，使受体二聚体的跨膜（TM）和胞质区域转变为一种未知的活化构象。通过用二聚化卷曲螺旋取代EpoR细胞外结构域，我们构建了TM EpoR融合蛋白，其中螺旋状的TM结构域被限制在七种可能的相对取向中。我们确定了一种二聚体TM构象，它赋予受体胞质结构域完全活性，并通过JAK2、STAT蛋白和丝裂原活化蛋白激酶（MAP激酶）发出信号；一种部分活性取向，优先激活MAP激酶；以及一种对应于无活性受体的构象。通过对低能量TM二聚体结构的计算搜索，独立鉴定出活性和非活性构象。我们提出了一个特定的EpoR活化界面，并建议将其用于结构和信号研究。
