title: TSC2 N-terminal lysine acetylation status affects to its stability modulating mTORC1 signaling and autophagy.
abstract: There is a growing evidence of the role of protein acetylation in different processes controlling metabolism. Sirtuins (histone deacetylases nicotinamide adenine dinucleotide-dependent) activate autophagy playing a protective role in cell homeostasis. This study analyzes tuberous sclerosis complex (TSC2) lysine acetylation, in the regulation of mTORC1 signaling activation, autophagy and cell proliferation. Nicotinamide 5mM (a concentration commonly used to inhibit SIRT1), increased TSC2 acetylation in its N-terminal domain, and concomitantly with an augment in its ubiquitination protein status, leading to mTORC1 activation and cell proliferation. In contrast, resveratrol (RESV), an activator of sirtuins deacetylation activity, avoided TSC2 acetylation, inhibiting mTORC1 signaling and promoting autophagy. Moreover, TSC2 in its deacetylated state was prevented from ubiquitination. Using MEF Sirt1 +/+ and Sirt1 -/- cells or a SIRT1 inhibitor (EX527) in MIN6 cells, TSC2 was hyperacetylated and neither NAM nor RESV were capable to modulate mTORC1 signaling. Then, silencing Tsc2 in MIN6 or in MEF Tsc2-/- cells, the effects of SIRT1 modulation by NAM or RESV on mTORC1 signaling were abolished. We also observed that two TSC2 lysine mutants in its N-terminal domain, derived from TSC patients, differentially modulate mTORC1 signaling. TSC2 K599M variant presented a lower mTORC1 activity. However, with K106Q mutant, there was an activation of mTORC1 signaling at the basal state as well as in response to NAM. This study provides, for the first time, a relationship between TSC2 lysine acetylation status and its stability, representing a novel mechanism for regulating mTORC1 pathway.
authors.affiliation: Faculty of Pharmacy, Department of Biochemistry and Molecular Biology II, Complutense University of Madrid, Madrid 28040, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: García-Aguilar
authors.affiliation: Faculty of Pharmacy, Department of Biochemistry and Molecular Biology II, Complutense University of Madrid, Madrid 28040, Spain; Spanish Biomedical Research Center in Diabetes and associated metabolic disorders (CIBERDEM), Instituto de Salud Carlos III, Spain. Electronic address: cguillen@ucm.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Guillén
authors.affiliation: Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Nellist
authors.affiliation: Naomi Berrie Diabetes Center, Department of Medicine, Columbia University, New York, NY 10032, USA.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bartolomé
authors.affiliation: Faculty of Pharmacy, Department of Biochemistry and Molecular Biology II, Complutense University of Madrid, Madrid 28040, Spain; Spanish Biomedical Research Center in Diabetes and associated metabolic disorders (CIBERDEM), Instituto de Salud Carlos III, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Benito
mesh_terms: D000107:Acetylation; D000818:Animals; D001343:Autophagy / Q000187:drug effects; D002227:Carbazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006801:Humans; D008239:Lysine; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009536:Niacinamide / Q000494:pharmacology; D000072417:Protein Domains; D011499:Protein Processing, Post-Translational; D055550:Protein Stability; D034622:RNA Interference; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects; D056564:Sirtuin 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D013267:Stilbenes / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C550547:6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide; D002227:Carbazoles; D056572:Histone Deacetylase Inhibitors; D046912:Multiprotein Complexes; D013267:Stilbenes; C000624653:TSC2 protein, human; C000624654:Tsc2 protein, mouse; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins; D009536:Niacinamide; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; C447939:SIRT1 protein, human; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; D008239:Lysine; D000077185:Resveratrol
keywords: Acetylation; Proliferation; Stability; TSC2; Ubiquitination; mTORC1