Molecular Mechanisms of Phytochrome Signaling

描述（由申请人提供）：光敏色素是胆蛋白光传感器，使光合生物能够适应正光和负光环境。最近在非光合细菌和真菌中发现的光敏色素证明光敏色素祖先及其古老的信号伙伴已经进化成高等真核生物信号系统的组成部分。这些研究试图确定四吡咯和光信号是如何被光敏色素分子感知和传播并转导到下游目标分子的，特别是解决了光敏色素通过调节其内在的蛋白激酶活性作为线性四吡咯（胆红素）和光的传感器的假设。胆磷脂普遍存在于需氧生物中，似乎在后生动物中起着重要的信号作用，其水平与缺氧、异种生物诱导的氧化应激和血管损伤有关。因此，这种古老信号通路的机制对于理解和调节包括人类在内的其他真核生物的类似信号系统具有重要意义。除了找到调节植物（我们的主要食物来源）的光响应性和生产力的新方法外，这些研究的另一个长期结果是基于光敏色素的新光疗法的发展。长期目标是在分子水平上确定光敏色素家族每个成员调控功能的结构基础。这一认识不仅将有助于设计新的方法来调节具有重要农艺意义的作物物种的光介导生长和发育，而且将促进基于光敏色素的技术的发展，以调节活细胞内重要的生化过程（例如转录、蛋白质稳定性和/或蛋白质定位）。

DESCRIPTION (provided by applicant): Phytochromes are biliprotein light sensors that enable photosynthetic organisms to adapt to positive and negative light environments. The recent discovery of phytochromes in nonphotosynthetic bacteria and fungi document that phytochrome ancestors and their ancient signaling partners have evolved into components of signaling systems found in higher eukaryotes. These studies seek to define how tetrapyrrole and light signals are perceived by and propagated within the phytochrome molecule and transduced to downstream target molecules, specifically addressing the hypothesis that phytochromes function as sensors of linear tetrapyrrole (bilins) and light via regulation of their intrinsic protein kinase activities. Ubiquitous to aerobic organisms, bilins appear to play important signaling roles in metazoans, their levels being linked to anoxia, xenobiotic-induced oxidative stress and vascular damage. The mechanism of this ancient signaling pathway is therefore of fundamental importance for understanding and regulating analogous signaling systems in other eukaryotes, including humans. In addition to leading to new approaches to regulate light responsiveness and productivity of plants, our primary food source, another long term consequence of these studies is the development of phytochrome-based approaches for new light-based therapies. The long term goal is to define the structural basis for the regulatory functions of each member of the extended phytochrome family at the molecular level. This understanding will not only enable the design of new approaches for regulation of light-mediated growth and development of agronomically important crop species, but will facilitate development of phytochrome-based technologies for regulation of important biochemical processes (e.g., transcription, protein stability and/or protein localization) within living cells.