Plant Photosensory Receptor CRY Signaling Mechanism

摘要 生物体如何对光作出反应以及光感受器如何调节光反应 是生物学中的基本问题。我们的长期目标是找到这些现象的分子解释 问题，使用隐花红光受体作为模型系统。隐花色素(CREY)是 蓝/UV-A光感受器和/或昼夜节律振荡器的核心成分 包括人类在内的进化谱系。我的实验室专注于植物的研究 隐花色素。在之前的资助期中，我们发现了两个主要的CRY2信号 转导机制：CIB1(隐色素相互作用bHLH1)为基础的转录- 光敏色素A1/结构性抑制因子SPA1/COP1的调控机制 基于光形态发生的蛋白质降解-调节机制。最近，我们发现了一个 负责蓝光调控的CIB相互作用蛋白FOF1(F-box of Flowering 1) CIB1的降解；两种新的蓝光特异性CRY2相互作用蛋白：PRR5(伪 响应调节器5)，它是生物钟的核心蛋白，以及一种新的蛋白BIC1(Blue- 抑制蓝光依赖的磷酸化、降解和 CRY1和CRY2的活性。基于这些发现和新开发的工具，我们建议 研究光信号转导的三个关键问题：光化学机制 CREL光感受器的光激发、功能调控机制 CRY复合体，以及依赖于新的编码序列(CDS)的潜在机制 蓝光对CRY2表达的调控。

Summary How organisms respond to light and how photosensory receptors mediate light responses are basic questions in biology. Our long-term goal is to find the molecular explanation of these questions, using the cryptochrome photoreceptor as a model system. Cryptochromes (CRY) are the blue/UV-A light receptors and/or core components of the circadian oscillator found in all evolutionary lineages including human. My laboratory focuses on the study of plant cryptochromes. In the previous funding periods, we discovered two major CRY2 signal transduction mechanisms: the CIB1 (Cryptochrome-Interacting bHLH 1)-based transcription- regulatory mechanism and SPA1/COP1 (Suppressor of Phytochrome A 1/Constitutive Photomorphogenesis 1)-based proteolysis-regulatory mechanism. More recently, we identified a CIB-interacting protein FOF1 (F-box of Flowering 1) responsible for the blue light-regulated degradation of CIB1; two new blue light-specific CRY2-interacting proteins: PRR5 (Pseudo Response Regulator 5) that is a core protein of the circadian clock, and a novel protein BIC1 (Blue- light Inhibitor of CRYs 1) that suppresses blue light-dependent phosphorylation, degradation, and activities of CRY1 and CRY2. Based on these discoveries and newly developed tools, we propose to study three key issues of light signal transduction: the photochemical mechanism underlying photoexcitation of the CRY photoreceptor, mechanisms governing the function and regulation of the CRY complexome, and the mechanism underlying a novel coding sequence (CDS)-dependent blue light regulation of CRY2 expression.