在自噬体形成过程中，Atg4B是控制LC3成熟以及LC3去脂化的关键蛋白。研究表明磷酸化、糖基化等修饰能影响Atg4B的活性及其与LC3的结合，但这些修饰并不能完全阐明Atg4B对LC3的不同处理作用，说明还存在其他功能调节方式。我们预实验发现活性氧能可逆抑制Atg4B的活性并诱导自噬，但具体的氧化修饰机制以及该修饰如何调控自噬并不明确。另外，Atg4B被氧化后可形成二硫键和寡聚体两种形式，且存在于线粒体结合的内质网膜组分中。基于此，本项目拟在前期Atg4B的测活方法和抑制剂表征（Autophagy，2012，2019）的基础上深入研究。旨在回答Atg4B可逆氧化修饰的具体作用机制和发生部位，以及如何调节LC3去脂化及自噬体形成等关键科学问题。本研究将揭示一种新的Atg4B活性调控方式，为理解Atg4B在LC3处理过程所起的关键作用提供依据，对完善和拓宽自噬基础理论具有重要研究价值。

Atg4B is a critical protein to regulate the formation of autophagosomes. It is required for LC3 priming and LC3 delipidation. Previous studies have shown that post-translational modifications, such as phosphorylation and glycosylation, could alter the activity of Atg4B and the binding affinity between Atg4B and LC3. However, these reported modifications are not complete, which means there must be some other ways to regulate the function of Atg4B. We previously found that the activity of Atg4B could be reversibly suppressed by ROS with autophagy being induced simultaneously. However, the redox modification mechanism and its effect on autophagy are still unclear. In addition, after oxidation, Atg4B could form different forms of disulfide bonds and oligomers and could be detected at the fraction of mitochondria-associated ER membranes. Based on our previous works on activity detection and inhibitor characterization of Atg4B, we will further study and answer the key scientific questions: what is the mechanism of reversible oxidative modification of Atg4B? Where does the modification occurred? How does oxidative modification affect the activity of Atg4B and the formation of autophagosomes? This study will disclose a novel mode for the regulation of Atg4B activity, and offer more data to further understand the key effects of Atg4B on different processes of LC3 priming and delipidation, which manifests important research value for the development of the basic theory of autophagy.