泛素化及自噬参与蛋白降解及抗原提呈的研究进展

Progress on the role of ubiquitination and autophagy in protein degradation and antigen presentation

细胞内所有的蛋白质都在不断的被降解，并被新合成的蛋白质所取代。真核细胞内主要有两条蛋白降解途径，分别为泛素一蛋白酶体系统途径和白噬途径，两条途径都在维持细胞内稳态方面起着重要的作用。泛素-蛋白酶体系统是由泛素介导的一种高度复杂的蛋白降解机制，它通过一种特定的方式降解并再循环利用细胞内的蛋白，而自噬是一种自我降解过程，它通过溶酶体介导的方式降解蛋白。被降解的蛋白可以被提呈至MHCⅡ类分子或MHCⅠ类分子，从而激发有效的T细胞反应。此文就这两个途径参与蛋白降解及抗原提呈的相关研究进展进行综述。

All proteins in cells are continually being degraded and replaced. Eukaryotes have two major intracellular protein degradation pathways, namely the ubiquitin-proteasome system and autophagy. Both of them are proteolytic pathways essential in the maintenance of cellular homeostasis. The ubiquitin-proteasom system is highly complex and mediated by ubiquitin, which participates in intracellular protein degradation in a specific manner. Autophagy is a self-degradation process that acts through a lysosome-mediated trafficking pathway to de- grade and recycle intracellular components. Proteins degraded through the two pathways can be presented to MHC class II molecules and MHC class I molecules to stimulate efficient T-cell responses. This article reviews the ad- vances on the two pathways involved in protein degradation and antigen presentation.