Organization of the G protein-coupled receptors rhodopsin and opsin in native membranes
Organization of the G protein-coupled receptors rhodopsin and opsin in native membranes
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DOI：
10.1074/jbc.m302536200
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发表时间：
2003-06-13
影响因子：
4.8
通讯作者：
Engel, A
中科院分区：
文献类型：
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作者：
Liang, Y;Fotiadis, D;Engel, A
G蛋白偶联受体（GPCR）是最大的、结构最保守的信号分子家族，参与几乎所有的生理过程。晶体结构仅适用于洗涤剂溶解的光受体视紫红质。此外，该受体是唯一的GPCR，已经证明了天然膜中假定的更高级寡聚体状态（Fotiadis，D.，梁玉，Filipek，S.，Saperstein，D.一、恩格尔，A.，和Palczewski，K.（2003）Nature 421，127 - 128）。在此，我们通过原子力显微镜测定了从野生型小鼠光感受器获得的天然膜中的视紫红质和从Rpe 65-/-突变小鼠的光感受器分离的视蛋白的组织，所述Rpe 65-/-突变小鼠不产生发色团11-顺式-视黄醛。视紫红质的高阶组织是存在的，无论其上的膜被吸附成像的支持。视紫红质和视蛋白形成结构二聚体，以次晶阵列组织。的intradimeric接触可能涉及螺旋IV和V，而主要是螺旋I和II之间的接触和连接螺旋V和VI的细胞质环促进视紫红质二聚体行的形成。行之间的接触是在细胞外侧，涉及螺旋I。这是天然膜中GPCR高阶结构的第一个半经验模型，它对理解这种受体如何与伴侣蛋白相互作用具有深远的意义。
G protein- coupled receptors ( GPCRs), which constitute the largest and structurally best conserved family of signaling molecules, are involved in virtually all physiological processes. Crystal structures are available only for the detergent-solubilized light receptor rhodopsin. In addition, this receptor is the only GPCR for which the presumed higher order oligomeric state in native membranes has been demonstrated ( Fotiadis, D., Liang, Y., Filipek, S., Saperstein, D. A., Engel, A., and Palczewski, K. ( 2003) Nature 421, 127 - 128). Here, we have determined by atomic force microscopy the organization of rhodopsin in native membranes obtained from wild- type mouse photoreceptors and opsin isolated from photoreceptors of Rpe65 -/- mutant mice, which do not produce the chromophore 11- cis-retinal. The higher order organization of rhodopsin was present irrespective of the support on which the membranes were adsorbed for imaging. Rhodopsin and opsin form structural dimers that are organized in paracrystalline arrays. The intradimeric contact is likely to involve helices IV and V, whereas contacts mainly between helices I and II and the cytoplasmic loop connecting helices V and VI facilitate the formation of rhodopsin dimer rows. Contacts between rows are on the extracellular side and involve helix I. This is the first semi- empirical model of a higher order structure of a GPCR in native membranes, and it has profound implications for the understanding of how this receptor interacts with partner proteins.