Collaborative Research: Role of Arrestin Phosphorylation in the Photoresponse

视觉中细胞的第一步是光传导，光能量被分子机制捕获，最终导致神经信号到达大脑。光感受器细胞中发生了一系列的生化反应，其中一个关键步骤是激活一类名为G-蛋白的蛋白质。激活通过磷酸化发生，即在蛋白质中添加一个磷酸基团；随后的失活涉及去磷酸化。调节磷酸化速度和数量的蛋白质之一被称为arrestin。虽然许多研究都研究了光信号的激活，但很少有人研究信号关闭的方式，这就是这里的重点。这个合作项目结合了分子生物学、生物化学和细胞生理学的方法来研究G蛋白连接的膜受体分子的上调和下调。所使用的系统是马蹄蟹的光感受器，它几十年来一直是无脊椎动物光接收的模型，也提供了与我们对脊椎动物光传导的知识进行极好的比较。这项工作的结果将增加对视觉过程调节的关键理解，并具有超越光接收和视觉的影响，延伸到细胞通讯中的信号转导和一般的细胞生物学。

The first cellular step in vision is phototransduction, when light energy is captured by molecular mechanisms that finally lead to a nerve signal to the brain. A cascade of biochemical reactions occurs in the photoreceptor cell, and one of the key steps is the activation of a class of proteins called G-proteins. The activation occurs by phosphorylation, the addition of a phosphate group to the protein; subsequent deactivation involves dephosphorylation. One of the proteins regulating the rate and amount of phosphorylation is called arrestin. While much research has studied the activation of the light signal, few have worked on the way the signal is turned off, and that is the focus here. This collaborative project combines approaches from molecular biology, biochemistry and cellular physiology to investigate the up- and down-regulation of G-protein linked membrane receptor molecules. The system used is the photoreceptor of the horseshoe crab, Limulus, which has been a model for invertebrate photoreception for decades and also provides excellent comparisons to our knowledge of vertebrate phototransduction. Results from this work will add critical understanding about regulation of visual processes, and have an impact extending beyond photoreception and vision to signal transduction in cell communication and to cellular biology in general.