两位美国科学家因研究细胞膜表面受体的突出贡献，分享2012年诺贝尔化学奖。
 

　　 2012年诺贝尔化学奖被授予两位美国科学家：罗伯特•莱夫科维茨（Robert J. Lefkowitz）和布莱恩•科比尔卡（Brian Kobilka），以表彰他们在G蛋白偶联受体（G-protein-coupled receptors，GPCRs）研究上所做的突出贡献。G蛋白偶联受体是环境信息进入细胞内部的门户，并触发细胞内一系列响应。大约半数药物通过G蛋白 偶联受体产生效应。 
   背景解析：细胞表面的灵巧受体
   数十亿细胞精密地协调工作，构成了你的身体。每个细胞通过微小的受体感知环境，以适应新情况。罗伯特•莱夫科维茨和布莱恩•科比尔卡对这类受体中的重要一族——G蛋白偶联受体——取得了突破性的研究成果，因此获得2012年诺贝尔化学奖。
长期以来，细胞如何感知环境一直是个迷。科学家早已知道，肾上腺素（adrenalin）等激素可以产生显著的效果：提升血压、加速心跳。他们怀疑，在细胞表面有这些激素的某种接收器。但在20世纪的大部分时间里，人们并不清楚这些接收器由什么组成，以及它们如何工作。
    1968年，莱夫科维茨开始利用放射性同位素追踪这些受体。他将碘同位素结合到多种激素上，然后通过观测同位素的放射性，他发现了若干种受体，包括一种肾 上腺素受体即β-肾上腺素受体（β-adrenergic receptor）。他的研究团队从细胞膜上提取到这种受体并初步阐明其工作机制。
    在1980年代，该研究团队取得了下一个重大突破。新加入的科比尔卡开始尝试从庞大的人类基因组中分离出编码β-肾上腺素受体的基因。为此，他采用了一种 创造性的方法，并由此获得成功。研究人员在分析β-肾上腺素受体基因的同时，发现这种受体与眼睛中捕获光线的一种受体相似。这使他们意识到存在一大类受 体，它们结构相似并以同样的方式实现功能。
    这就是我们今天所知的“G蛋白偶联受体”，对应大约一千个基因。这些受体种类繁多，感受对象涵盖光、味道、气味、肾上腺素、组织胺 （histamine）、多巴胺（dopamine）和血清素（serotonin，即5-羟色胺）等。大约半数的药物通过G蛋白偶联受体产生效用。
    莱夫科维茨和科比尔卡的研究对于我们认识G蛋白偶联受体的功能有重要贡献。在2011年，科比尔卡取得又一突破。他和他的研究团队成功地捕获到β-肾上腺 素受体被一个激素分子激活并向细胞内传递信号的瞬间图像。这幅图像本身就是分子研究的杰作——数十年探索的结晶。

Nobel Prize 2012 in Chemistry for Studies of G-Protein-Coupled Receptors

For a long time, it remained a mystery how cells could sense their environment. Scientists knew that hormones such as adrenalin had powerful effects: increasing blood pressure and making the heart beat faster. They suspected that cell surfaces contained some kind of recipient for hormones. But what these receptors actually consisted of and how they worked remained obscured for most of the 20th Century.
Lefkowitz started to use radioactivity in 1968 in order to trace cells' receptors. He attached an iodine isotope to various hormones, and thanks to the radiation, he managed to unveil several receptors, among those a receptor for adrenalin: β-adrenergic receptor. His team of researchers extracted the receptor from its hiding place in the cell wall and gained an initial understanding of how it works.
The team achieved its next big step during the 1980s. The newly recruited Kobilka accepted the challenge to isolate the gene that codes for the β-adrenergic receptor from the gigantic human genome. His creative approach allowed him to attain his goal. When the researchers analyzed the gene, they discovered that the receptor was similar to one in the eye that captures light. They realized that there is a whole family of receptors that look alike and function in the same manner.
Today this family is referred to as G-protein–coupled receptors. About a thousand genes code for such receptors, for example, for light, flavour, odour, adrenalin, histamine, dopamine and serotonin. About half of all medications achieve their effect through G-protein–coupled receptors.
The studies by Lefkowitz and Kobilka are crucial for understanding how G-protein–coupled receptors function. Furthermore, in 2011, Kobilka achieved another break-through; he and his research team captured an image of the β-adrenergic receptor at the exact moment that it is activated by a hormone and sends a signal into the cell. This image is a molecular masterpiece – the result of decades of research.