title: A biotin switch-based proteomics approach identifies 14-3-3ζ as a target of Sirt1 in the metabolic regulation of caspase-2.
abstract: While lysine acetylation in the nucleus is well characterized, comparatively little is known about its significance in cytoplasmic signaling. Here we show that inhibition of the Sirt1 deacetylase, which is primarily cytoplasmic in cancer cell lines, sensitizes these cells to caspase-2-dependent death. To identify relevant Sirt1 substrates, we developed a proteomics strategy, enabling the identification of a range of putative substrates, including 14-3-3ζ, a known direct regulator of caspase-2. We show here that inhibition of Sirtuin activity accelerates caspase activation and overrides caspase-2 suppression by nutrient abundance. Furthermore, 14-3-3ζ is acetylated prior to caspase activation, and supplementation of Xenopus egg extract with glucose-6-phosphate, which promotes caspase-2/14-3-3ζ binding, enhances 14-3-3ζ-directed Sirtuin activity. Conversely, inhibiting Sirtuin activity promotes14-3-3ζ dissociation from caspase-2 in both egg extract and human cultured cells. These data reveal a role for Sirt1 in modulating apoptotic sensitivity, in response to metabolic changes, by antagonizing 14-3-3ζ acetylation.
authors: Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
authors: Joshua L
authors: JL
authors: Andersen
authors: J Will
authors: JW
authors: Thompson
authors: Kelly R
authors: KR
authors: Lindblom
authors: Erika S
authors: ES
authors: Johnson
authors: Chih-Sheng
authors: CS
authors: Yang
authors: Lauren R
authors: LR
authors: Lilley
authors: Christopher D
authors: CD
authors: Freel
authors: M Arthur
authors: MA
authors: Moseley
authors: Sally
authors: S
authors: Kornbluth
mesh_terms: D048948:14-3-3 Proteins / Q000235:genetics* / Q000378:metabolism; D000107:Acetylation; D000818:Animals; D017209:Apoptosis; D001710:Biotin / Q000235:genetics* / Q000378:metabolism; D053143:Caspase 2 / Q000235:genetics* / Q000378:metabolism; D016923:Cell Death; D045744:Cell Line, Tumor; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D040901:Proteomics; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D001710:Biotin; D053143:Caspase 2; D056564:Sirtuin 1