Autophagy responsible for cellular self-degradation : molecular machinery and roles in development, differentiation, and diseases

为了降解自己的成分，细胞拥有自噬能力。将部分胞浆和细胞器送入溶酶体。自噬不仅有助于细胞成分的周转，而且有助于细胞和组织的重建；它是间接诱导的，并在大范围内降解细胞内结构。由于自噬的异常诱导在多种疾病中经常被观察到，自噬的病理作用受到研究者的关注。在这个项目中，我们旨在阐明自噬的分子机制及其在发育、分化和疾病中的作用。1)我们鉴定了哺乳动物的ATG10是一种催化ATG12与ATG5共价结合的酶；2)我们证明了自噬小体和溶酶体之间的融合需要从内吞体到自噬小体；3)我们发现了一个800 kDa的蛋白质复合体，其中包括ATG5-ATG2结合物，并鉴定了一个新的蛋白质Atg16L作为该复合体的组成部分；4)我们获得了Lc3的脂化导致其定位于自噬小体的证据，并证明了两个Lc3同源物GABARAP和GATE16可以与自噬小体结合；5)我们获得了广泛表达GFP-Lc3的转基因小鼠，这有助于研究自噬在发育和组织分化过程中的诱导；自噬防止引起退行性疾病的未折叠蛋白和入侵宿主细胞的病原菌在细胞内繁殖。7)我们发现与引起SARS的冠状病毒相关的小鼠肝炎病毒利用自噬小体在宿主细胞内繁殖。

To degrade their own components, cells possess autophagy that. delivers part of the cytosol and organelles into lysosomes. Autophagy contributes not only turnover of cellular constituents but also reconstruction of cells and tissue; it is induced circumstantially and degrades the intracellular structure at large-scale. Since abnormal induction of autophagy has been often observed in diverse diseases, pathological role of autophagy has the attention of investigators. In this project, we aimed for elucidation of molecular machinery of autophagy and its role in development, differentiation, and diseases.Our results are as follows. 1) we identified mammalian Atg10 as a enzyme catalyzing covalent binding of Atg12 with Atg5, 2) we showed that fusion between autophagosomes and lysosomes requires transport from endosomes to autophagosomes, 3) we found a large 800kDa proteins complex including the Atg5-Atgl2 conjugate and identified a novel protein Atg16L as a component of the complex, 4) we obtained a evidence that lipidation of LC3 cause its localization to autophagosomes and demonstrated that two LC3 homologues, GABARAP and GATE16, could bind to autophagosomes like LC3, 5) we produced transgenic mouse expressing GFP-LC3 ubiquitously, which is useful to examine induction of autophagy during development and tissue differentiation,6) we found new function of autophagy ; autophagy prevents intracellular multiplication of both unfolded proteins causing degenerative diseases and pathogenic bacteria that have invaded host cells, 7) we discovered that mouse hepatitis virus related to coronavirus causing SARS utilizes autophagosomes to multiply inside host cells.