Immune Disease Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA.
Nat Struct Mol Biol. 2011 Aug 7;18(9):984-9. doi: 10.1038/nsmb.2092.
To our knowledge, no structural study to date has characterized, in an intact receptor, the coupling of conformational change in extracellular domains through a single-pass transmembrane domain to conformational change in cytoplasmic domains. Here we examine such coupling, and its unexpected complexity, using nearly full-length epidermal growth factor receptor (EGFR) and negative-stain EM. The liganded, dimeric EGFR ectodomain can couple both to putatively active, asymmetrically associated kinase dimers and to putatively inactive, symmetrically associated kinase dimers and monomers. Inhibitors that stabilize the active or inactive conformation of the kinase active site, as well as mutations in the kinase dimer interface and a juxtamembrane phosphorylation site, shift the equilibrium among the three kinase association states. This coupling of one conformation of an activated receptor ectodomain to multiple kinase-domain arrangements reveals previously unanticipated complexity in transmembrane signaling and facilitates regulation of receptor function in the juxtamembrane and cytoplasmic environments.
据我们所知，迄今为止，尚无结构研究在完整的受体中表征细胞外结构域构象变化通过单次跨膜结构域与细胞内结构域构象变化的偶联。在这里，我们使用近乎全长的表皮生长因子受体（EGFR）和负染 EM 来研究这种偶联及其意想不到的复杂性。配体结合的二聚体 EGFR 胞外结构域既能与假定的活性、不对称相关的激酶二聚体，也能与假定的无活性、对称相关的激酶二聚体和单体偶联。稳定激酶活性位点的活性或无活性构象的抑制剂、激酶二聚体界面和跨膜区磷酸化位点的突变，会改变三种激酶缔合状态之间的平衡。这种激活的受体胞外结构域的一种构象与多种激酶结构域排列的偶联，揭示了跨膜信号传递中以前未预料到的复杂性，并促进了受体在跨膜区和细胞质环境中的功能调节。
