REGULATORY DOMAINS OF PROTEIN PHOSPHATASE-1

活细胞必须持续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，以便产生适当、全面和有效的回应。这项复杂的任务需要将信号转导“级联”紧密地整合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类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)和冗余所混淆。在短期内，显然需要载体将蛋白质磷酸化-去磷酸化网络作为一个较小规模的综合系统进行研究。这种运载工具将作为分析更多数量复杂生物的探路者，并将追溯它们的发展历史。这项建议的目的是定位蓝藻聚胞藻的蛋白质O-磷酸化[即那些针对丝氨酸、苏氨酸和/或酪氨酸的羟基侧链的事件]网络。PCC 6803，一种生物化学复杂且环境适应性强的有机体。这种蓝藻含有一个可定量处理的蛋白O-磷酸化网络(约102个)，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。聚球藻。PCC 6803具有遗传延展性，其完整基因组序列已知。本研究的具体目的是：1.鉴定聚球藻中的蛋白质。通过丝氨酸、苏氨酸和/或酪氨酸残基的磷酸化进行修饰的PCC 6803。2.鉴定该生物体中丝氨酸、苏氨酸和酪氨酸特异的蛋白激酶和蛋白磷酸酶。3.确定AIM 1中鉴定的磷酸化蛋白与AIM 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水平上定位和模拟完整的信号转导/调控网络的分子相互作用。

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.