Integrated control of Caulobacter cell physiology by visible light and stress

可见光和应激对柄杆菌细胞生理学的综合控制

基本信息

批准号：
8469050
负责人：
Sean Crosson
金额：
$ 29.41万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-01 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8469050
关键词：
Adhesions Affect Antibiotics Area Aspartate Bacteria Bacterial Model Biochemical Biological Models Biology Brucella Brucella abortus Caulobacter Caulobacter crescentus Cell Adhesion Cell Cycle Regulation Cell Survival Cell physiology Cells Cellular Stress Cellular biology ChIP-on-chip Chemicals Complex Cues DNA Binding Data Development Environment Evolution Experimental Models Feedback Genes Genetic Genetic Transcription Genomics Goals Growth Health Human Individual Light Lipopolysaccharides Mediating Methods Microbe Molecular Molecular Genetics Oxidative Stress Pathogenesis Pathway interactions Perception Phosphorylation Photobiology Physiology Pilum Prokaryotic Cells Proteins Regulation Research Role Shock Sigma Factor Signal Transduction Signaling Protein Staphylococcus aureus Starvation Stimulus Stress System Temperature Testing Time Virulence Virulence Factors Visible Radiation base biological adaptation to stress cell envelope chimeric gene in vivo insight novel overexpression pathogen promoter protein-histidine kinase research study response

项目摘要

DESCRIPTION (provided by applicant): The environment of a cell has a profound influence on its physiology, development, and evolution. Caulobacter crescentus, a bacterial model for the study of cell cycle control and development, provides an excellent experimental system to investigate the molecular basis of environmental perception and adaptation. The goal of this proposal is to define the molecular and cellular mechanisms of how light and stress signals are integrated by a bacterium to regulate the cell envelope and cell adhesion. LOV-histidine kinases (LOV-HKs), a newly-discovered class of blue-light photosensors, are conserved across a range of prokaryotes. Although the regulatory roles of LOV- HKs are not well understood, these signaling proteins have recently been shown to control virulence in Brucella abortus and cell adhesion in Caulobacter in response to light. Prior to these discoveries, neither Caulobacter nor Brucella were known or presumed to respond to visible light. Indeed, the majority of species encoding LOV-HKs are chemotrophs with no predicted photobiology. We have uncovered a regulatory network in Caulobacter in which the LOV-HK, LovK, and the receiver protein, LovR, form a form a regulatory feedback loop with CT, an envelope stress sigma factor that is critical for cell survival under osmotic and oxidative stress. The experiments detailed in this proposal will test the hypothesis that LovK/LovR system is part of a novel signaling network in which classical two- component signaling and C-dependent control of transcription intersect to regulate the composition of the cell envelope in response to multiple physical and chemical cues in the environment. We will use a combination of methods to define how interaction between the chemical and light environments affect cellular stress adaptation, cell envelope composition, and cell adhesion. Specifically, we will answer the following questions: (i) How does the LovK/LovR two-component system regulate cell envelope composition and cell adhesion in response to light, (ii) What are the regulatory interactions between the LovK/LovR photosensory network and the CT stress-response network, and (iii) What are the transcriptional targets of CT, CU, and PhyR, three sigma factors that appear to be regulated by CT? Time permitting, we use genetic and biochemical screens to identify additional regulators in the LovK/LovR adhesion pathway. Our experiments will advance our understanding of photoregulation by LOV-HKs, an important new area of prokaryotic biology that impacts bacterial pathogenesis. More generally, these studies will provide important data on mechanisms bacteria use to sense and integrate multiple environmental stimuli in a fluctuating environment, which is critical for bacterial cell survival.

描述（由申请人提供）：细胞的环境对其生理、发育和进化具有深远的影响。新月柄杆菌是一种用于研究细胞周期控制和发育的细菌模型，为研究环境感知和适应的分子基础提供了一个优秀的实验系统。该提案的目标是定义细菌如何整合光和应激信号以调节细胞包膜和细胞粘附的分子和细胞机制。 LOV-组氨酸激酶 (LOV-HK) 是一类新发现的蓝光光传感器，在一系列原核生物中是保守的。尽管 LOV-HK 的调节作用尚不清楚，但这些信号蛋白最近已被证明可以控制流产布鲁氏菌的毒力和响应光的柄杆菌的细胞粘附。在这些发现之前，柄杆菌和布鲁氏菌均不为人所知或被认为对可见光有反应。事实上，大多数编码 LOV-HK 的物种都是趋化生物，没有预测的光生物学。我们在 Caulobacter 中发现了一个调节网络，其中 LOV-HK、LovK 和受体蛋白 LovR 与 CT 形成调节反馈环路，CT 是一种包膜应激 Sigma 因子，对于渗透和氧化应激下的细胞生存至关重要。本提案中详述的实验将检验这一假设，即 LovK/LovR 系统是一种新型信号传导网络的一部分，其中经典的双组分信号传导和 C 依赖性转录控制相交叉，以调节细胞包膜的组成，以响应多种物理信号。以及环境中的化学线索。我们将使用多种方法来定义化学和光环境之间的相互作用如何影响细胞应激适应、细胞包膜组成和细胞粘附。具体来说，我们将回答以下问题：（i）LovK/LovR双组分系统如何调节细胞包膜组成和细胞粘附以响应光，（ii）LovK/LovR光传感网络和细胞之间的调节相互作用是什么？ CT 应激反应网络，以及 (iii) CT、CU 和 PhyR（似乎受 CT 调节的三个西格玛因子）的转录靶标是什么？如果时间允许，我们使用遗传和生化筛选来识别 LovK/LovR 粘附途径中的其他调节因子。我们的实验将增进我们对 LOV-HK 光调节的理解，LOV-HK 是影响细菌发病机制的原核生物学的一个重要新领域。更一般地说，这些研究将提供有关细菌在波动环境中感知和整合多种环境刺激的机制的重要数据，这对于细菌细胞的生存至关重要。