REGULATORY DOMAINS OF PROTEIN PHOSPHATASE-1

活细胞必须持续感知和响应细胞内和细胞外的广泛输入。 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件的多样性（103-104）和冗余性所混淆。 一个明确的需要存在的车辆，允许研究的蛋白质磷酸化-去磷酸化网络的集成系统在短期内在较小的规模。 这种工具将作为分析数量上更复杂的生物体的探路者，并将追踪其发展的历史。 该提议的目的是绘制蓝细菌集胞藻属PCC 6803的蛋白质O-磷酸化[即，靶向丝氨酸、苏氨酸和/或酪氨酸的羟基侧链的那些事件]网络，集胞藻属PCC 6803是一种生物化学复杂且环境适应性强的生物体。这种蓝藻含有一个定量易处理的蛋白质O-磷酸化网络（约102），其显著特征是“真核”蛋白激酶、蛋白质丝氨酸/苏氨酸磷酸酶和蛋白质酪氨酸磷酸酶的同系物。集胞藻PCC 6803是遗传可塑性的，其完整的基因组序列是已知的。 本文概述的研究的具体目标是：1。鉴定集胞藻PCC 6803中通过丝氨酸、苏氨酸和/或酪氨酸残基磷酸化进行修饰的蛋白质。2.鉴定该生物体中丝氨酸、苏氨酸和酪氨酸特异性蛋白激酶和蛋白磷酸酶。 3.确定目标1中鉴定的磷蛋白与目标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的长期目标，映射和建模的分子相互作用的一个完整的信号转导/调节网络在细胞尺度上。

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.