Characterization of Small Proteins that Regulate Two Component Systems in Escherichia coli

摘要 细菌无处不在，需要在许多环境条件下生存。双组分 系统（TCS），它存在于生活的各个领域，包括各种外部和内部系统。 信号转化为基因表达的变化，对这种生存至关重要。在革兰氏阴性菌模型中， 在大肠杆菌中，有超过20种TCS能够对不同的刺激做出反应。这些 系统由膜上的至少一个传感组氨酸激酶和一个响应组氨酸激酶组成。 调节子，其通常是转录因子。这些蛋白质协同工作， 基因的子集，以帮助确保生存在特定的压力环境。小分子蛋白质 50个或更少的氨基酸通常在标准遗传和生物化学中被忽略。 实验然而，已经发现小蛋白质调节许多反应，包括 沙门氏菌中的毒力、枯草芽孢杆菌中的孢子形成以及低镁诱导的PhoPQ TCS 在大肠杆菌MgrB小蛋白抑制PhoPQ TCS，而另一种小蛋白SafA激活 这个TCS。我们推测E.大肠杆菌也能调节 的TCS。这项建议将使用有针对性的生化和全球表征两个候选小 蛋白质：YshB和ArcB-C，以确定其作用机制。此外，还将创建一个屏幕 鉴定E.大肠杆菌和其他细菌。的结果 这一建议将增加对小蛋白质的了解。更广泛地说，信息 从这项研究中获得的结果可能适用于真核生物激酶，因为它们的作用与细菌激酶相似。 激酶，其可能也由小蛋白质调节。

ABSTRACT Bacteria are ubiquitous and need to survive in numerous environmental conditions. Two component systems (TCS), which are found in all domains of life and transduce a variety of external and internal signals into changes in gene expression, are critical to this survival. In the model Gram-negative organism, Escherichia coli, there are over 20 TCS that are able to respond to different stimuli. These systems are comprised of at least one sensor histidine kinase at the membrane and one response regulator, which is generally a transcription factor. These proteins work in coordination to activate a subset of genes to help ensure survival during specific stressful environments. Small proteins of around 50 amino acids or fewer generally have been overlooked in standard genetic and biochemical experiments. However, small proteins have been found to regulate a number of responses including virulence in Salmonella, sporulation in Bacillus subtilis, and the low magnesium induced PhoPQ TCS in E. coli. The MgrB small protein inhibits the PhoPQ TCS while another small protein, SafA, activates this TCS. We hypothesize that there are other small proteins in E. coli that also regulate the activities of TCS. This proposal will use targeted biochemical and global characterization of two candidate small proteins: YshB and ArcB-C to identify their mechanism of actions. Additionally, a screen will be created to identify small protein regulators of other TCS systems in E. coli and other bacteria. The results from this proposal will add to the growing knowledge about small proteins. More broadly, the information gained from this study could potentially be applied to eukaryotic kinases as they act similarly to bacterial kinases, which likely are also modulated by small proteins.