MECHANISTIC INSIGHTS INTO THE REGULATION OF AN MTB PROTEIN TYROSINE PHOSPHATASE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 酪氨酸磷酸化是一个重要的信号，它紧密地调节许多由免疫系统介导的细胞反应。蛋白酪氨酸磷酸酶(PTP)通过其内在的去磷酸化活性来拮抗这些关键的信号转导途径。细胞内的病原体，如结核分枝杆菌(Mtb)，可以分泌PTPs来逃避宿主的反应或实现免疫逃避。两种Mtb PTPs(PTPA和PtpB)的催化机制、细胞功能和宿主底物在很大程度上尚不清楚。我将研究PtpB？S自抑制盖，这是一种阻止潜在底物以及活性氧物种(ROS)进入蛋白质？S活性部位的结构特征。我将从结构上表征当盖子打开时发生的构象变化，氧化如何影响蛋白质的开放和闭合形式，以及蛋白质与可能阻止分枝杆菌感染和持久性的抑制剂结合的蛋白质。这些研究将提供对Mtb PTPs及其在干扰宿主信号中的作用的更多机制的理解。这些研究中使用的蛋白质结构将包括野生型、野生型氧化、盖子打开突变体、盖子打开突变体-氧化以及带有和不带有抑制剂的缺失的LID蛋白。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Tyrosine phosphorylation is an important signal that tightly regulates many cellular responses mediated by the immune system. Protein tyrosine phosphatases (PTP) antagonize these key signal transduction pathways though their intrinsic dephosphorylation activity. Intracellular pathogens, such as Mycobacterium tuberculosis (Mtb), may secrete PTPs to evade host responses or achieve immune escape. The catalytic mechanisms, cellular functions and host substrates of the two Mtb PTPs (PtpA and PtpB) are largely unknown. I will investigate PtpB?s autoinhibitory lid, a structural feature that blocks potential substrates as well as reactive oxygen species (ROS) access to the protein?s active site. I will structurally characterize the conformational changes that occur when the lid opens, how oxidation affects the open and closed forms of the protein, and protein bound to inhibitors that may block mycobacterial infection and persistence. These studies will provide a greater mechanistic understanding of Mtb PTPs and their role in interfering with host signaling. The protein constructs used in these studies will include wild-type, wild-type oxidized, lid opening mutants, lid opening mutants-oxidized, and deleted lid protein with and without inhibitor.