REGULATORY DOMAINS OF PROTEIN PHOSPHATASE-1

活细胞必须不断地感知和响应广泛的细胞内和细胞外输入。必须对这些信息进行处理，以便作出适当、全面和有效的反应。这项复杂的任务需要将信号转导“级联”紧密集成到计算复杂的网络中。蛋白质磷酸化-去磷酸化过程构成了这种网络的重要核心组成部分。在哺乳动物细胞中，将调控网络理解为完整系统的任务被其组成部分的多样性（103-104）和冗余性所混淆。在短期内，很明显需要一种工具来将蛋白质磷酸化-去磷酸化网络作为一个综合系统进行研究。这些工具将成为分析更多数量复杂生物体的探路者，并将追踪它们的发展历史。本提案的目的是绘制蓝藻Synechocystis sp. PCC 6803的蛋白质o -磷酸化（即针对丝氨酸，苏氨酸和/或酪氨酸的羟基侧链的事件）网络，这是一种生化复杂和环境适应性强的生物。这种蓝藻含有一个定量可处理的蛋白质o -磷酸化网络（约102），其显著特征是“真核”蛋白激酶、蛋白丝氨酸/苏氨酸磷酸酶和蛋白酪氨酸磷酸酶的同源物。聚囊藻（Synechocystis sp. PCC 6803）具有遗传延展性，其完整的基因组序列是已知的。本文概述了研究的具体目的：1。鉴定聚胞菌PCC 6803中丝氨酸、苏氨酸和/或酪氨酸残基磷酸化修饰的蛋白。2. 鉴定丝氨酸、苏氨酸和酪氨酸特异性蛋白激酶和蛋白磷酸酶。3. 鉴定目的1中鉴定的磷酸化蛋白与目的2中鉴定的蛋白激酶和蛋白磷酸酶之间的生理相关酶-底物关系。这些目标的实现将有助于我们在细胞尺度上绘制和建模完整信号转导/调节网络的分子相互作用的长期目标。

Living cells must continuously sense and respond to a broad spectrum of intra- and extra-cellular inputs. This information must be processed so as to produce a response that is appropriate, comprehensive, and efficient. This complex task requires the intimate integration of signal transduction 'cascades' into computationally-sophisticated networks. Protein phosphorylation-dephosphorylation processes constitute prominent, core components of such networks. In mammalian cells the task of understanding regulatory networks as complete systems is confounded by the multiplicity (103-104) and redundancy of their components. A clear need exists for vehicles to permit study of the protein phosphorylation-dephosphorylation networks as integrated systems on a smaller scale in the near term. Such vehicles will serve as pathfinders for the analysis of more quantitatively complex organisms and will trace the history of their development. The objective of this proposal is to map the protein O-phosphorylation [i.e. those events targeting the hydroxyl side chains of serine,threonine, and/or tyrosine] network of the cyanobacterium Synechocystis sp. PCC 6803, a biochemically complex and environmentally adaptable organism. This cyanobacterium contains a quantitatively tractable protein O-phosphorylation network (approximately 102) that prominently features homologs of 'eukaryotic' protein kinases, protein- serine/threonine phosphatases, and protein-tyrosine phosphatases. Synechocystis sp. PCC 6803 is genetically malleable and its complete genome sequence is known. The specific aims of the study outlined herein are: 1. To identify the proteins in Synechocystis sp. PCC 6803 that undergo modification via phosphorylation of serine, threonine, and/or tyrosine residues. 2. To identify the serine, threonine, and tyrosine-specific protein kinases and protein phosphatases in this organism. 3. To identify physiologically-relevant enzyme-substrate relationships between the phosphoproteins indentified in aim 1 and the protein kinases and protein phosphatases identified in aim 2. The realization of these aims will contribute to our long-term goal of mapping and modeling the molecular interplay of a complete signal transduction/regulatory network on a cellular scale.