Autophagy allows the degradation of cytosolic endogenous and exogenous material in the lysosome. Substrates are engulfed by double-membrane vesicles, coined autophagosomes, which subsequently fuse with lysosomes. Depending on the involvement of specific receptor proteins, autophagy occurs in a selective or nonselective manner. While this process is well understood at the level of bulky cargo such as mitochondria and bacteria, we know very little about individual proteins and protein complexes that are engulfed and degraded by autophagy. In contrast to the critical role of autophagy in balancing proteostasis, our current knowledge of the autophagic degradome is very limited. Here, we combined proximity labeling with quantitative proteomics to systematically map the protein inventory of autophagosomes. Using this strategy, we uncovered a basal, housekeeping mitophagy pathway that involves piecemeal degradation of mitochondrial proteins in a LC3C- and p62-dependent manner and contributes to mitochondrial homeostasis maintenance when cells rely on oxidative phosphorylation.

自噬使溶酶体中胞质内源性物质和外源性物质降解。底物被双膜囊泡（造币的自噬体）吞没，随后与溶酶体融合。根据特定受体蛋白的参与，自噬以选择性或​​非选择性方式发生。虽然在诸如线粒体和细菌之类的大件货物的水平上已经很好地理解了此过程，但是我们对通过自噬吞噬和降解的单个蛋白质和蛋白质复合物知之甚少。与自噬在平衡蛋白稳态中的关键作用相反，我们目前对自噬降解的认识非常有限。在这里，我们将邻近标记与定量蛋白质组学相结合，以系统地绘制自噬体的蛋白质库存。使用这种策略，我们发现了一个基础，