title: Distinct roles of autophagy-dependent and -independent functions of FIP200 revealed by generation and analysis of a mutant knock-in mouse model.
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.
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Song
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Chenran
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Syn
authors.initials: S
authors.lastname: Yeo
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Liang
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Takako
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Shaogang
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Wen
authors.affiliation: Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
authors.forename: Jun-Lin
authors.initials: JL
authors.lastname: Guan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001343:Autophagy / Q000235:genetics*; D000071183:Autophagy-Related Proteins; D049109:Cell Proliferation / Q000235:genetics; D004195:Disease Models, Animal; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D055879:Gene Knock-In Techniques; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009154:Mutation; D016019:Survival Analysis; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C000608442:ATG13 protein, mouse; D051017:Apoptosis Regulatory Proteins; D000071183:Autophagy-Related Proteins; D047908:Intracellular Signaling Peptides and Proteins; C428743:Rb1cc1 protein, mouse; D014409:Tumor Necrosis Factor-alpha
keywords: FIP200; autophagy; embryogenesis; knock-in mutant mouse; tumor growth