Regulatory mechanisms of mitochondria-specific autophagy via the TORC1 signaling pathway

TORC1信号通路对线粒体特异性自噬的调节机制

• 批准号: 19J20223
• 负责人: LIU YANG
• 金额: $ 1.98万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2019
• 资助国家: 日本
• 起止时间: 2019-04-25 至 2022-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-19J20223/
• 关键词: Mitophagy; Mitochondria; Autophagy; Yeast; mitophagy; yeast; TORC1

I mainly worked on the molecular mechanisms underlying mitophagy initiation in yeast this year. Based on an Atg32-Atg11 interaction assay for cells lacking core Atg proteins, Atg1 is the sole core Atg protein critical for efficient mitophagy initiation under respiratory conditions. I also found that Atg1 acts in Atg32 phosphorylation. Atg32 can be phosphorylated by purified Atg1 in an in vitro phosphorylation assay, raising the high possibility that Atg1 directly phosphorylates Atg32 during mitophagy induction. Expression of an Atg1 variant defective in Atg1-Atg8 and Atg1-Atg11 interactions reduced Atg32 phosphorylation and mitophagy, suggesting that Atg8 and Atg11 serve to recruit Atg1 to the mitophagy initiation complex. Also, Atg1 can be co-immunoprecipitated with Atg32, which is significantly suppressed in cells lacking Atg8 and Atg11, indicating Atg1 targeted mitochondria via its interactions with Atg8 and Atg11. Notably, these defects were restored by deletion of Ppg1, a protein phosphatase that negatively regulates Atg32-mediated mitophagy. Taken together, Atg1 could serve as the direct kinase for Atg32 phosphorylation and is critical for mitophagy induction in yeast under respiratory conditions.

今年我主要研究酵母中线粒体自噬启动的分子机制。基于缺乏核心Atg蛋白的细胞的Atg 32-Atg 11相互作用测定，Atg 1是在呼吸条件下对有效的线粒体自噬起始至关重要的唯一核心Atg蛋白。我还发现Atg 1在Atg 32磷酸化中起作用。Atg 32可以在体外磷酸化试验中被纯化的Atg 1磷酸化，提高了Atg 1在线粒体自噬诱导过程中直接磷酸化Atg 32的可能性。Atg 1-Atg 8和Atg 1-Atg 11相互作用中缺陷的Atg 1变体的表达降低了Atg 32磷酸化和线粒体自噬，表明Atg 8和Atg 11用于将Atg 1招募到线粒体自噬起始复合物。此外，Atg 1可以与Atg 32共免疫沉淀，Atg 32在缺乏Atg 8和Atg 11的细胞中被显著抑制，表明Atg 1通过与Atg 8和Atg 11的相互作用靶向线粒体。值得注意的是，这些缺陷通过Ppg 1的缺失而恢复，Ppg 1是一种负调节Atg 32介导的线粒体自噬的蛋白磷酸酶。综上所述，Atg 1可以作为Atg 32磷酸化的直接激酶，并且在呼吸条件下对酵母中的线粒体自噬诱导至关重要。

项目成果

The TORC1 signaling pathway regulates respiration-induced mitophagy in yeast.

• DOI: 10.1016/j.bbrc.2018.05.123
• 发表时间: 2018-07
• 期刊: Biochemical and biophysical research communications
• 影响因子: 3.1
• 作者: Yang Liu;K. Okamoto