Zhou X Edward, He Yuanzheng, de Waal Parker W, Gao Xiang, Kang Yanyong, Van Eps Ned, Yin Yanting, Pal Kuntal, Goswami Devrishi, White Thomas A, Barty Anton, Latorraca Naomi R, Chapman Henry N, Hubbell Wayne L, Dror Ron O, Stevens Raymond C, Cherezov Vadim, Gurevich Vsevolod V, Griffin Patrick R, Ernst Oliver P, Melcher Karsten, Xu H Eric
VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
Laboratory of Structural Sciences, Center for Structural Biology and Drug Discovery, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
Cell. 2017 Jul 27;170(3):457-469.e13. doi: 10.1016/j.cell.2017.07.002.
G protein-coupled receptors (GPCRs) mediate diverse signaling in part through interaction with arrestins, whose binding promotes receptor internalization and signaling through G protein-independent pathways. High-affinity arrestin binding requires receptor phosphorylation, often at the receptor's C-terminal tail. Here, we report an X-ray free electron laser (XFEL) crystal structure of the rhodopsin-arrestin complex, in which the phosphorylated C terminus of rhodopsin forms an extended intermolecular β sheet with the N-terminal β strands of arrestin. Phosphorylation was detected at rhodopsin C-terminal tail residues T336 and S338. These two phospho-residues, together with E341, form an extensive network of electrostatic interactions with three positively charged pockets in arrestin in a mode that resembles binding of the phosphorylated vasopressin-2 receptor tail to β-arrestin-1. Based on these observations, we derived and validated a set of phosphorylation codes that serve as a common mechanism for phosphorylation-dependent recruitment of arrestins by GPCRs.
G蛋白偶联受体(GPCRs)部分通过与抑制蛋白相互作用介导多种信号传导,抑制蛋白的结合促进受体内化并通过G蛋白非依赖途径进行信号传导。高亲和力的抑制蛋白结合需要受体磷酸化,通常发生在受体的C末端尾巴。在此,我们报道了视紫红质-抑制蛋白复合物的X射线自由电子激光(XFEL)晶体结构,其中视紫红质的磷酸化C末端与抑制蛋白的N末端β链形成一个延伸的分子间β折叠。在视紫红质C末端尾巴残基T336和S338处检测到磷酸化。这两个磷酸化残基与E341一起,与抑制蛋白中的三个带正电荷的口袋形成广泛的静电相互作用网络,其模式类似于磷酸化的血管加压素2型受体尾巴与β抑制蛋白-1的结合。基于这些观察结果,我们推导并验证了一组磷酸化编码,它们作为GPCRs磷酸化依赖性募集抑制蛋白的共同机制。