title: SIRT1 deacetylates APE1 and regulates cellular base excision repair.
abstract: Apurinic/apyrimidinic endonuclease-1 (APE1) is an essential enzyme in the base excision repair (BER) pathway. Here, we show that APE1 is a target of the SIRTUIN1 (SIRT1) protein deacetylase. SIRT1 associates with APE1, and this association is increased with genotoxic stress. SIRT1 deacetylates APE1 in vitro and in vivo targeting lysines 6 and 7. Genotoxic insults stimulate lysine acetylation of APE1 which is antagonized by transcriptional upregulation of SIRT1. Knockdown of SIRT1 increases cellular abasic DNA content, sensitizing cells to death induced by genotoxic stress, and this vulnerability is rescued by overexpression of APE1. Activation of SIRT1 with resveratrol promotes binding of APE1 to the BER protein X-ray cross-complementing-1 (XRCC1), while inhibition of SIRT1 with nicotinamide (NAM) decreases this interaction. Genotoxic insult also increases binding of APE1 to XRCC1, and this increase is suppressed by NAM or knockdown of SIRT1. Finally, resveratrol increases APE activity in XRCC1-associated protein complexes, while NAM or knockdown of SIRT1 suppresses this DNA repair activity. These findings identify APE1 as a novel protein target of SIRT1, and suggest that SIRT1 plays a vital role in maintaining genomic integrity through regulation of the BER pathway.
authors.affiliation: University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
authors.forename: Tohru
authors.initials: T
authors.lastname: Yamamori
authors.forename: Jeremy
authors.initials: J
authors.lastname: DeRicco
authors.forename: Asma
authors.initials: A
authors.lastname: Naqvi
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Hoffman
authors.forename: Ilwola
authors.initials: I
authors.lastname: Mattagajasingh
authors.forename: Kenji
authors.initials: K
authors.lastname: Kasuno
authors.forename: Saet-Byel
authors.initials: SB
authors.lastname: Jung
authors.forename: Cuk-Seong
authors.initials: CS
authors.lastname: Kim
authors.forename: Kaikobad
authors.initials: K
authors.lastname: Irani
mesh_terms: D000107:Acetylation; D002460:Cell Line; D004260:DNA Repair; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000378:metabolism; D008741:Methyl Methanesulfonate / Q000633:toxicity; D009153:Mutagens / Q000633:toxicity; D056564:Sirtuin 1 / Q000032:analysis / Q000378:metabolism*; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; D009153:Mutagens; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D008741:Methyl Methanesulfonate; C447939:SIRT1 protein, human; D056564:Sirtuin 1; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D008239:Lysine