Tsunoda S, Zuker C S
Haward Hughes Medical Institute, University of California, San Diego 92093-0649, USA.
Cell Calcium. 1999 Nov;26(5):165-71. doi: 10.1054/ceca.1999.0070.
Phototransduction in Drosophila has emerged as an attractive model system for studying the organization of signaling cascades in vivo. In photoreceptor neurons, the multivalent PDZ protein INAD serves as a scaffold to assemble different components of the phototransduction pathway, including the effector PLC, the light-activated ion channel TRP, and a protein kinase C involved in deactivation of the light response. INAD is required for organizing and maintaining signaling complexes in the rhabdomeres of photoreceptors. This macromolecular organization endows photoreceptors with many of their signaling properties, including high sensitivity, fast activation and deactivation kinetics, and exquisite feedback regulation by small localized changes in [Ca2+]i. Assembly of transduction components into signaling complexes is also an important cellular strategy for ensuring specificity of signaling while minimizing unwanted cross-talk. In this report, we review INAD's role as a signal transduction scaffold and its role in the assembly and localization of photoreceptor complexes.
果蝇中的光转导已成为研究体内信号级联组织的一个有吸引力的模型系统。在光感受器神经元中，多价PDZ蛋白INAD作为一个支架，组装光转导途径的不同组分，包括效应器磷脂酶C、光激活离子通道TRP，以及参与光反应失活的蛋白激酶C。INAD是在光感受器的微绒毛中组织和维持信号复合物所必需的。这种大分子组织赋予光感受器许多信号特性，包括高灵敏度、快速激活和失活动力学，以及通过[Ca2+]i的小局部变化进行的精确反馈调节。将转导组分组装成信号复合物也是确保信号特异性同时最小化不必要串扰的重要细胞策略。在本报告中，我们综述了INAD作为信号转导支架的作用及其在光感受器复合物组装和定位中的作用。
