Plant photoreceptor CRY2 and Signaling Mechanism

描述(申请人提供)：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。我们的长期目标是利用隐花色素光感受器作为模型系统，找到这些问题的分子解释。隐花色素(CRY)是蓝光/UV-A光受体和/或昼夜节律振荡器的核心成分，存在于包括人类在内的所有进化谱系中。我的实验室专注于植物隐色素的研究。在之前的资助阶段，我们发现了两种主要的CRY2信号转导机制：基于CIB1(隐色素相互作用的bHLH1)的转录调控机制和基于SPA1/COP1(光敏色素A1/结构性光形态发生1的抑制物)的蛋白分解调控机制。最近，我们发现了一个负责蓝光调控的CIB1降解的CIB相互作用蛋白FOF1(F-box of Flowering 1)；两个新的蓝光特异的CRY2相互作用蛋白：作为生物钟核心蛋白的PRR5(伪反应调节因子5)，以及一个新的蛋白BIC1(蓝光抑制CRY1)，它抑制了依赖蓝光的磷酸化、降解以及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：光激发CRY2光感受器的光化学机制，调控CRY2复合体功能和调控的机制，以及依赖于编码序列(CDS)的新型蓝光调控CRY2表达的机制。

DESCRIPTION (provided by applicant): 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) tha 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.