Molecular and genetic dissection of the cytosolic ADP-Heptose-ALPK1-TIFA signaling pathway

ADP-DD-庚糖是合成脂多糖所需的细菌代谢物，脂多糖是革兰氏阴性菌细胞壁的组分。最近，一个新的先天性免疫信号转导途径，目前在人类细胞的胞质溶胶已被确定。在该途径中，ADP-DD-庚糖激活α蛋白激酶1（ALPK1），这是一种与蛋白激酶主要亚家族无关的非典型蛋白激酶。ALPK1磷酸化蛋白TIFA，诱导其寡聚化并与TRAF6相互作用。TRAF6然后经历寡聚化，激活其E3连接酶活性。与TRAF6在其他先天免疫信号传导途径中的作用类似，TRAF6 E3连接酶被提出产生Lys63连接的泛素寡聚体，从而激活主蛋白激酶TAK1，其驱动导致炎症介质产生和分泌的所有后续事件，以对抗细菌感染。我们已经证实TRAF6的表达对于该途径的操作是必不可少的，但令人惊讶地发现TRAF6的E3连接酶活性不是。这一发现表明，关于这种新的信号通路，还有很多东西有待发现。有趣的是，ALPK1中的特定突变被发现是几种人类疾病的原因，包括螺旋体腺瘤，螺旋体癌和ROSAH，这是一种仅在2019年发现的免疫疾病。该项目的目的是剖析细胞溶质ADP-DD-Heptose-ALPK1-TIFA信号通路的分子细节，以确定该通路的新组分，并了解ALPK1突变如何导致人类疾病。该项目将涉及分子和细胞生物学、蛋白质化学、细胞信号和免疫学方面各种最先进技术的培训。项目提供量化技能培训

ADP-DD-heptose is a bacterial metabolite required for the synthesis of lipopolysaccharide, a component of the cell wall of gram negative bacteria. Recently, a new innate immune signal transduction pathway present in the cytosol of human cells has been identified. In this pathway ADP-DD-heptose activates alpha protein kinase 1 (ALPK1), an atypical protein kinase that is unrelated to the main subfamily of protein kinases. ALPK1 phosphorylates the protein TIFA, inducing it's oligomerisation and interaction with TRAF6. TRAF6 then undergoes oligomerisation activating it's E3 ligase activity. Similar to the role of TRAF6 in other innate immune signalling pathways, the TRAF6 E3 ligase was proposed to generate Lys63-linked ubiquitin oligomers thereby activating the master protein kinase TAK1 which drives all the subsequent events that lead to the production and secretion of the inflammatory mediators to combat the bacterial infection. We have confirmed that the expression of TRAF6 is essential for the operation of the pathway, but surprisingly found that the E3 ligase activity of TRAF6 is not. This finding indicates that much still remins to be discovered about this novel signalling pathway. Interestingly, particular mutations in ALPK1 have been found to to be the cause of several human diseases, including spiroadenoma, spiroadenocarcinoma and ROSAH, an immune disease that was only discovered in 2019. The aim of the project is to dissect the molecular details of the cytosolic ADP-DD-Heptose-ALPK1-TIFA signaling pathway, to identify novel components of the pathway and to understand how mutations in ALPK1 cause human disease. The project will involve training in a variety of state of the art techniques in molecular and cell biology, protein chemistry, cell signalling and immunology.. Project provides training in Quantitative Skills