Two Component Signal Transduction Networks in Myxococcus xanthus

题目：黄粘球菌的双组分信号转导网络智力优势：黄粘球菌是一种具有分化、细胞间通讯、表面运动和生物复杂性的细菌模型。它整合来自环境的复杂刺激来调节决策过程，最终形成抗压力孢子。一类关键的信号系统由“两个组件”（传感器和调节器）组成，它们直接将环境刺激与行为和基因表达的控制联系起来。通常，传感器和调节器是由染色体上彼此相邻的基因编码的，因此预测它们包含特定的“双组分系统”（TCS）来调节细胞的生物学。黄豆属植物编码至少144个传感器组氨酸激酶（HK）和150个反应调节蛋白（RR），其中许多似乎是随机定位在染色体上。因此，M.xanthus拥有细菌世界中最复杂和最大的信号转导能力之一。由于这些进化相关的双组分蛋白之间存在显著的相似性，因此防止不希望的“串扰”（异常信号或错误通信），同时管理系统之间的真正交叉调节是调节M.xanthus群落结构的关键特征。为了探究TCS保持特异性或传递交叉调控的特征，本研究将重点关注黄豆状芽孢杆菌中高度相似的系统子集，这些系统存在于染色体上的基因簇中。先前的工作表明，在m.s aanthus中，两个这样的系统之间的复杂相互作用影响孢子的形成。对这些通路的进一步解剖发现，传感器HK对其靶调节因子既作为激酶又作为磷酸酶起作用。目前的研究将验证一个假设，即单个氨基酸残基（在适当的环境下）是黄原草中大多数传感器激酶蛋白的磷酸酶活性所必需的。由于几乎所有的细菌传感器激酶中都存在类似的序列，因此提出的研究将影响对几乎所有细菌中类似系统的理解。该计划旨在鉴定黄原草中高度相关的TCS信号蛋白家族中激酶和磷酸酶活性所必需的残基。生化研究将确定这些系统是否保持绝缘或显示交叉调节。相互作用伙伴的网络分析将使用遗传学和生物化学进行评估。系统生物学建模工作也将用于预测已识别网络的控制和功能，并可扩展到m .xanthus的其余信号系统。本研究成果将广泛影响信号转导领域，理解复杂环境下的多细胞相互作用，物种间相互作用，并促进通过系统生物学识别其他生物的信号通路相互作用。教育：实验室非常重视对博士后、研究生和本科生的指导，并在培训后将个人置于强大的研究环境中。博士后和学生因其成就获得了奖学金和国家认可。在过去的十年中，PI参与了多个nsf资助的教育项目，并在国际公认的项目中任教。

Title: Two Component Signal Transduction Networks in Myxococcus xanthusIntellectual Merit: Myxococcus xanthus is a bacterial model for differentiation, intercellular communication, surface motility and bio-complexity. It integrates complex stimuli from its environment to regulate a decision-making process which culminates in formation of stressresistant spores. One critical class of signaling systems is comprised by "two components" (a sensor and a regulator) that directly link environmental stimuli to control of behavior and gene expression. Typically, the sensor and regulator are encoded by genes adjacent to one another on the chromosome and are thus predicted to comprise specific "two-componentsystem" (TCS) to regulate the biology of the cell. M.xanthus encodes at least 144 sensor histidine kinases (HK) and 150 response regulator (RR) proteins, many of which appear to be randomly positioned on the chromosome. As such, M.xanthus possesses one of the most complex and largest repertoires for signal transduction capacity in the bacterial world. Due to significant similarity between these evolutionarily related two-component proteins, prevention of undesired "cross-talk" (aberrant signaling or miscommunication) while also managing bona fide cross-regulation between systems is a critical feature for regulation of M.xanthus community structure. To probe features of TCS that maintain specificity or impart cross-regulation, the proposed study will focus on a subset of highly similar systems in M. xanthus delineated by their presence within gene clusters on the chromosome. Previous work demonstrated complex interactions between two such systems in M.xanthus that affects spore formation. Further dissection of the those pathways led to the finding that the sensor HK functions both as a kinase and as a phosphatase towards its target regulator. The current study will test the hypothesis that a single amino acid residue (in the appropriate context) is exclusively required for phosphatase activity for the majority of sensor kinase proteins in M.xanthus. Because similar sequences exist in nearly all bacterial sensor kinases, the proposed studies will impact understanding of similar systems in nearly all bacteria. The plan is to identify those residues exclusively required for kinase and phosphatase activity in a family of highly related TCS signaling proteins in M.xanthus. Biochemical studies will determine if these systems remain insulated or display cross-regulation. Network analysis of the interacting partners will be assessed using both genetics and biochemistry. A Systems Biology modeling effort will also be utilized to predict control and functionality for identified networks and can be extended to the remainder of the signaling systems in M.xanthus.Broader Impacts. Research: Results from this study will broadly impact the signal transduction field, understanding multicellular interactions in complex environments, interspecies interactions, and facilitate identification of signaling pathway interactions via systems biology in other organisms. Education: The laboratory places a strong emphasis on mentoring postdocs, graduate students, and undergraduates and has a consistent record of placing individuals in strong research environments following their training. Postdocs and students have received fellowships and national recognition for their accomplishments. The PI has participated in multiple NSF-funded educational programs over the past decade and taught in internationally recognized programs.