Regulation of VapC toxins by Ser/Thr phosphorylation of VapB antitoxins in M. tuberculosis

项目摘要 本研究的长期目标是了解结核分枝杆菌毒素-抗毒素 调节系统以促进结核病发病。R21研究的具体目标是 我们的建议是研究我们的假设，即VapB抗毒素的Ser/Thr磷酸化是通过受体型 Ser/Thr蛋白激酶代表了一种新的机制，通过这种机制，VapC毒素可以响应于 环境信号。VapC毒素是M.结核病， 与蛋白质组重塑、生长停滞、抗生素耐受性和在一系列压力下生存的能力有关 与结核病发病机制相关的基因。VapB抗毒素在螯合中的既定作用 同源VapC毒素蛋白和自动调节vapBC基因表达，以及我们最近的发现， 在特定激酶耗竭的情况下，几种VapB蛋白的磷酸化显著降低， 为本文的研究提供了前提。 这项研究有两个目的。在目标1中，我们将确定两个磷酸化的影响， VapB抗毒素对M.表达这些抗毒素及其同源物的结核病 VapC毒素，和ii）这些VapB毒素与它们的同源VapC蛋白的分子相互作用及其 同源启动子。在目标2中，我们将研究这些VapB抗毒素的磷酸化对 VapC酶活性。 这项研究将验证我们的假设，即VapB Ser/Thr磷酸化可能是一种调节VapB Ser/Thr磷酸化的手段。 VapC活性，并将开始表征这种调节发生的分子机制。 本研究的结果为进一步研究丝氨酸/苏氨酸磷酸化是如何影响细胞凋亡的奠定了基础 VapB抗毒素的活性可以起到抑制信号的作用，以控制与VapC毒素的活性相关的VapC毒素。 M.结核生长控制、应激耐受和结核病发病机制。

PROJECT SUMMARY The long-term goal of this research is to understand how Mycobacterium tuberculosis toxin-antitoxin systems are regulated to contribute to tuberculosis pathogenesis. The specific goal of this R21 research proposal is to investigate our hypothesis that Ser/Thr phosphorylation of VapB antitoxins by receptor-type Ser/Thr protein kinases represents a novel mechanism by which VapC toxins can be regulated in response to environmental signals. VapC toxins are the majority of all TA toxins in M. tuberculosis and have been implicated in proteome remodeling, growth arrest, antibiotic tolerance and ability to survive a range of stresses that are relevant for tuberculosis pathogenesis. The established role of VapB antitoxins in sequestering cognate VapC toxin proteins and autoregulating vapBC gene expression, together with our recent finding of significantly decreased phosphorylation of several VapB proteins in the setting of specific kinase depletion, provide the premises for this research. This research proposal has two Aims. In Aim 1 we will determine the effects of phosphorylation of two VapB antitoxins on i) the growth of M. tuberculosis expressing these antitoxins together with their cognate VapC toxins, and ii) the molecular interactions of these VapB toxins with their cognate VapC proteins and their cognate promoters. In Aim 2 we will investigate the effects of phosphorylation of these VapB antitoxins on VapC enzyme activity. This research will test our hypothesis that VapB Ser/Thr phosphorylation may be a means to regulate VapC activity and will begin to characterize the molecular mechanism(s) by which this regulation occurs. Results from this research will provide the foundation for further investigation into how Ser/Thr phosphorylation of VapB antitoxins can function to transduce signals to control the activity of VapC toxins that are relevant for M. tuberculosis growth control, stress tolerance and tuberculosis pathogenesis.