1. Distinct roles of autophagy-dependent and -independent functions of FIP200 revealed by generation and analysis of a mutant knock-in mouse model
- Author
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Chun Chi Liang, Chenran Wang, Takako Okamoto, Syn Kok Yeo, Song Chen, Shaogang Sun, Jian Wen, and Jun-Lin Guan
- Subjects
0301 basic medicine ,Programmed cell death ,Mutant ,Autophagy-Related Proteins ,Embryonic Development ,Mice, Nude ,Apoptosis ,Biology ,BAG3 ,medicine.disease_cause ,03 medical and health sciences ,Mice ,Genetics ,medicine ,Autophagy ,Tumor Cells, Cultured ,Animals ,Humans ,Gene Knock-In Techniques ,Cell Proliferation ,Mutation ,Tumor Necrosis Factor-alpha ,Intracellular Signaling Peptides and Proteins ,Autophagy-related protein 13 ,ULK1 ,Survival Analysis ,Cell biology ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,HEK293 Cells ,Female ,Apoptosis Regulatory Proteins ,Function (biology) ,Developmental Biology ,Research Paper - Abstract
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.
- Published
- 2016