Abstract：
The main process of downregulation of G protein-coupled receptors is desensitization by which the receptor is extruded from the plasma membrane and directed to the endosomal compartment for recycling. Typically, the first step of this phenomenon consists in the recruitment of the protein β-arrestin induced by the agonist. Melatonin receptors undergo the same process: melatonin leads to the recruitment of β-arrestin and is subsequently sent away from the membrane, leading to a de facto stop of the melatonin receptor-mediated G protein signaling, because the receptors are not at the membrane level to receive the message brought by melatonin. The way one can measure this recruitment is based on the elegant technique of enzyme fragment complementation by which two parts of an enzyme are fused to two partners and reform an active enzyme upon the formation of the complex between these two partners. The basic way to set up this technique is presented here.
摘要：
G蛋白偶联受体下调的主要过程是脱敏，通过脱敏将受体从质膜中挤出并引导到内体区室进行再循环。通常,这种现象的第一步是由激动剂诱导的β-抑制蛋白的募集。褪黑素受体经历相同的过程：褪黑素导致β-抑制素的募集，随后从膜中被送走，导致褪黑素受体介导的G蛋白信号事实上停止，因为受体不在膜水平接收褪黑激素带来的信息。测量这种募集的方法是基于酶片段互补的优雅技术，通过该技术，酶的两个部分与两个伴侣融合，并在这两个伴侣之间形成复合物时重新形成活性酶。这里介绍了建立这种技术的基本方法。
