Formation of the ∼350-kDa Apg12-Apg5•Apg16 multimeric complex, mediated by Apg16 oligomerization, is essential for autophagy in yeast
Formation of the ∼350-kDa Apg12-Apg5•Apg16 multimeric complex, mediated by Apg16 oligomerization, is essential for autophagy in yeast
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DOI：
10.1074/jbc.m111889200
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发表时间：
2002-05-24
影响因子：
4.8
通讯作者：
Ohsumi, Y
中科院分区：
文献类型：
--
作者：
Kuma, A;Mizushima, N;Ohsumi, Y
自噬负责将细胞质成分递送至溶酶体/液泡进行降解，是真核细胞中的主要降解途径。该过程需要类泛素蛋白缀合系统，其中 Apg12 与 Apg5 共价结合。在酿酒酵母中，Apg12-Apg5 缀合物进一步与小卷曲螺旋蛋白 Apg16 相互作用。 Apg12-Apg5 和 Apg16 位于细胞质和自噬体前结构中，在自噬体形成中发挥重要作用。在这里，我们表明 Apg12-Apg5 缀合物和 Apg16 在胞质溶胶中形成类似的 350-kDa 复合物。由于 Apg16 被认为形成同源寡聚体，因此我们生成了一个体内系统，使我们能够控制 Apg16 的寡聚状态。通过该系统，我们证明了类似 350-kDa 复合物的形成和自噬活性取决于 Apg16 的寡聚状态。这些结果表明，Apg12-Apg5缀合物和Apg16形成由Apg16同源寡聚体介导的多聚体复合物，并且类似的350-kDa复合物的形成是酵母中自噬所必需的。
Autophagy, responsible for the delivery of cytoplasmic components to the lysosome/vacuole for degradation, is the major degradative pathway in eukaryotic cells. This process requires a ubiquitin-like protein conjugation system, in which Apg12 is covalently bound to Apg5. In the yeast Saccharomyces cerevisiae, the Apg12-Apg5 conjugate further interacts with a small coiled-coil protein, Apg16. The Apg12-Apg5 and Apg16 are localized in the cytosol and pre-autophagosomal structures and play an essential role in autophagosome formation. Here we show that the Apg12-Apg5 conjugate and Apg16 form a similar to350-kDa complex in the cytosol. Because Apg16 was suggested to form a homo-oligomer, we generated an in vivo system that allowed us to control the oligomerization state of Apg16. With this system, we demonstrated that formation of the similar to350-kDa complex and autophagic activity depended on the oligomerization state of Apg16. These results suggest that the Apg12-Apg5 conjugate and Apg16 form a multimeric complex mediated by the Apg16 homo-oligomer, and formation of the similar to350-kDa complex is required for autophagy in yeast.