Distinct roles of autophagy-dependent and -independent functions of FIP200 revealed by generation and analysis of a mutant knock-in mouse model.
Distinct roles of autophagy-dependent and -independent functions of FIP200 revealed by generation and analysis of a mutant knock-in mouse model.
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DOI：
10.1101/gad.276428.115
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发表时间：
2016-04-01
影响因子：
10.5
通讯作者：
Guan JL
中科院分区：
文献类型：
--
作者：
Chen S;Wang C;Yeo S;Liang CC;Okamoto T;Sun S;Wen J;Guan JL
Chen等人建立了FIP200-4A突变敲入小鼠模型，并发现特异性地阻断FIP200与Atg13的相互作用可以在体内消除自噬。对新小鼠模型的分析表明，FIP200的非自噬功能足以通过在肿瘤坏死因子α诱导的细胞凋亡中保持保护作用来完全支持胚胎发生。然而，FIP200介导的典型自噬是支持新生儿存活和肿瘤细胞生长所必需的。自噬是一种进化上保守的细胞过程，由一组必需的自噬基因(ATGs)控制。然而，越来越多的证据表明，大多数(如果不是全部)ATG也具有独立于其在典型自噬中所需的功能，这使得区分特定ATG的自噬依赖或非独立功能对各种生物过程的贡献是困难的。为了区分FIP200(200 kDa的FAK家族相互作用蛋白)的这些功能，我们研究了FIP200与其自噬伙伴Atg13的相互作用。我们发现FIP200的582-585(LQFL)残基是与Atg13相互作用所必需的，这些残基突变为AAAA(命名为FIP200-4A突变体)在体外取消了其典型的自噬功能。此外，我们创建了一个FIP200-4A突变敲入小鼠模型，发现专门阻止FIP200与Atg13的相互作用可以取消体内的自噬，为ULK1/Atg13/FIP200/Atg101复合体在这一过程中的关键作用提供了直接支持，而不是以前的研究依赖于单个组件的完全敲除。对新小鼠模型的分析表明，FIP200的非自噬功能足以通过在肿瘤坏死因子α诱导的细胞凋亡中保持保护作用来完全支持胚胎发生。然而，FIP200介导的典型自噬是支持新生儿存活和肿瘤细胞生长所必需的。这些研究首次提供了遗传证据，将ATG的自噬和非自噬功能与体内不同的生物过程联系起来。
Chen et al. generated a FIP200-4A mutant knock-in mouse model and found that specifically blocking FIP200 interaction with Atg13 abolishes autophagy in vivo. Analysis of the new mouse model showed that nonautophagic functions of FIP200 are sufficient to fully support embryogenesis by maintaining a protective role in TNFα-induced apoptosis. However, FIP200-mediated canonical autophagy is required to support neonatal survival and tumor cell growth. Autophagy is an evolutionarily conserved cellular process controlled through a set of essential autophagy genes (Atgs). However, there is increasing evidence that most, if not all, Atgs also possess functions independent of their requirement in canonical autophagy, making it difficult to distinguish the contributions of autophagy-dependent or -independent functions of a particular Atg to various biological processes. To distinguish these functions for FIP200 (FAK family-interacting protein of 200 kDa), an Atg in autophagy induction, we examined FIP200 interaction with its autophagy partner, Atg13. We found that residues 582–585 (LQFL) in FIP200 are required for interaction with Atg13, and mutation of these residues to AAAA (designated the FIP200-4A mutant) abolished its canonical autophagy function in vitro. Furthermore, we created a FIP200-4A mutant knock-in mouse model and found that specifically blocking FIP200 interaction with Atg13 abolishes autophagy in vivo, providing direct support for the essential role of the ULK1/Atg13/FIP200/Atg101 complex in the process beyond previous studies relying on the complete knockout of individual components. Analysis of the new mouse model showed that nonautophagic functions of FIP200 are sufficient to fully support embryogenesis by maintaining a protective role in TNFα-induced apoptosis. However, FIP200-mediated canonical autophagy is required to support neonatal survival and tumor cell growth. These studies provide the first genetic evidence linking an Atg's autophagy and nonautophagic functions to different biological processes in vivo.