title: SIRT1 mediates FOXA2 breakdown by deacetylation in a nutrient-dependent manner.
abstract: The Forkhead transcription factor FOXA2 plays a fundamental role in controlling metabolic homeostasis in the liver during fasting. The precise molecular regulation of FOXA2 in response to nutrients is not fully understood. Here, we studied whether FOXA2 could be controlled at a post-translational level by acetylation. By means of LC-MS/MS analyses, we identified five acetylated residues in FOXA2. Sirtuin family member SIRT1 was found to interact with and deacetylate FOXA2, the latter process being dependent on the NAD+-binding catalytic site of SIRT1. Deacetylation by SIRT1 reduced protein stability of FOXA2 by targeting it towards proteasomal degradation, and inhibited transcription from the FOXA2-driven G6pase and CPT1a promoters. While mutation of the five identified acetylated residues weakly affected protein acetylation and stability, mutation of at least seven additional lysine residues was required to abolish acetylation and reduce protein levels of FOXA2. The importance of acetylation of FOXA2 became apparent upon changes in nutrient levels. The interaction of FOXA2 and SIRT1 was strongly reduced upon nutrient withdrawal in cell culture, while enhanced Foxa2 acetylation levels were observed in murine liver in vivo after starvation for 36 hours. Collectively, this study demonstrates that SIRT1 controls the acetylation level of FOXA2 in a nutrient-dependent manner and in times of nutrient shortage the interaction between SIRT1 and FOXA2 is reduced. As a result, FOXA2 is protected from degradation by enhanced acetylation, hence enabling the FOXA2 transcriptional program to be executed to maintain metabolic homeostasis.
authors.affiliation: Center for Molecular Medicine, Department of Molecular Cancer Research, Section Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands, and Netherlands Metabolomics Centre, Leiden, The Netherlands; Erasmus Medical Center Rotterdam, Department of Gastroenterology and Hepatology, Rotterdam, The Netherlands.
authors.forename: Rogier
authors.initials: R
authors.lastname: van Gent
authors.affiliation: Center for Molecular Medicine, Department of Molecular Cancer Research, Section Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands, and Netherlands Metabolomics Centre, Leiden, The Netherlands.
authors.forename: Claudio
authors.initials: C
authors.lastname: Di Sanza
authors.affiliation: Center for Molecular Medicine, Department of Molecular Cancer Research, Section Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands, and Netherlands Metabolomics Centre, Leiden, The Netherlands.
authors.forename: Niels J F
authors.initials: NJ
authors.lastname: van den Broek
authors.affiliation: University Medical Center Utrecht, Department of Cell Biology, Utrecht, The Netherlands.
authors.forename: Veerle
authors.initials: V
authors.lastname: Fleskens
authors.affiliation: Center for Molecular Medicine, Department of Molecular Cancer Research, Section Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands, and Netherlands Metabolomics Centre, Leiden, The Netherlands.
authors.forename: Aukje
authors.initials: A
authors.lastname: Veenstra
authors.affiliation: Center for Molecular Medicine, Department of Molecular Cancer Research, Section Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands, and Netherlands Metabolomics Centre, Leiden, The Netherlands.
authors.forename: Gerdine J
authors.initials: GJ
authors.lastname: Stout
authors.affiliation: Center for Molecular Medicine, Department of Molecular Cancer Research, Section Metabolic Diseases, University Medical Center Utrecht, Utrecht, The Netherlands, and Netherlands Metabolomics Centre, Leiden, The Netherlands.
authors.forename: Arjan B
authors.initials: AB
authors.lastname: Brenkman
mesh_terms: D000107:Acetylation; D021581:Active Transport, Cell Nucleus; D000821:Animal Feed; D000818:Animals; D002384:Catalysis; D002460:Cell Line; D005786:Gene Expression Regulation; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism; D051379:Mice; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D056564:Sirtuin 1 / Q000378:metabolism*; D013217:Starvation; D014158:Transcription, Genetic
chemical_list: C496503:Foxa2 protein, mouse; D051542:Hepatocyte Nuclear Factor 3-beta; D056564:Sirtuin 1