Signal transduction by bacterial Ser/Thr kinases

细菌 Ser/Thr 激酶的信号转导

• 批准号: 217482-2008
• 负责人: LeMoual, Hervé
• 金额: $ 1.82万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=424933
• 关键词: Signal; transduction; bacterial; Ser; Thr

Reversible phosphorylation controlled by protein kinases and protein phosphatases is a central regulatory mechanism that allows cells to adapt to environmental changes. In bacteria, phosphorylation is accomplished primarily by two-component regulatory systems that phosphorylate histidine and aspartate residues. In the last decade, phosphorylation of bacterial proteins on serine, threonine and tyrosine residues by eukaryotic-like protein kinases has also been found to play a major role in signaling. Little is known about the mechanism of action and signaling pathways controlled by eukaryotic-like protein kinases in bacteria. We identified in the genomes of Salmonella enterica serovar Typhi (S. Typhi), the etiologic agent of typhoid fever, a cluster of genes that is not present in other Salmonella serovars for which the genome has been sequenced. This gene cluster consists of three open reading frames encoding proteins with homology to Ser/Thr protein kinases (prkX and prkY) and protein phosphatase 2C (prpZ). These three genes of opposing functions appear to control a signaling pathway specific to S. Typhi. We showed that deletion of the three genes affects the long-term survival of S. Typhi in macrophages, indicating that these genes are involved in virulence. Here, we propose to better characterize this signaling pathway by examining the enzymatic activities of the three proteins as well as their regulation by covalent modification and identifying the physiological substrate(s) that is(are) reversibly phosphorylated by the three proteins. The proposed research has the potential to provide the first detailed picture of an "eukaryotic-like" phosphorylation cascade that could be involved in the long-term persistence of S. Typhi during infection.

由蛋白激酶和蛋白磷酸酶控制的可逆磷酸化是细胞适应环境变化的一种中央调节机制。在细菌中，磷酸化主要是通过磷酸化组氨酸和天冬氨酸残基的双组分调节系统完成的。在过去的十年中，细菌蛋白在丝氨酸、苏氨酸和酪氨酸残基上的磷酸化也被发现在信号转导中发挥了重要作用。细菌中受真核样蛋白激酶控制的作用机制和信号通路知之甚少。我们在伤寒沙门氏菌(S.Typhi)的基因组中发现了伤寒的病原体，这是一组在其他沙门氏菌血清型中不存在的基因，其基因组已经测序。该基因簇由三个开放阅读框组成，编码与丝氨酸/苏氨酸蛋白激酶(prkX和prkY)和蛋白磷酸酶2C(PrpZ)同源的蛋白质。这三个功能相反的基因似乎控制着伤寒沙门氏菌特有的信号通路。我们发现这三个基因的缺失会影响伤寒沙门氏菌在巨噬细胞中的长期存活，这表明这些基因与毒力有关。在这里，我们建议通过检测这三种蛋白质的酶活性及其共价修饰对它们的调节，并鉴定被这三种蛋白质可逆磷酸化的生理底物(S)来更好地表征这一信号通路。这项拟议的研究有可能为伤寒沙门氏菌在感染过程中的长期持续存在提供第一幅“真核生物样的”磷酸化级联的详细图景。