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A biotin switch-based proteomics approach identifies 14-3-3? 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 14-3-3?, 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, 14-3-3? is acetylated prior to caspase activation, and supplementation of Xenopus egg extract with glucose-6-phosphate, which promotes caspase-2/14-3-3? binding, enhances 14-3-3?-directed Sirtuin activity. Conversely, inhibiting Sirtuin activity promotes14-3-3? 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 14-3-3? acetylation.

SUBMITTER: Andersen JL

PROVIDER: S-EPMC3417139 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature

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A biotin switch-based proteomics approach identifies 14-3-3ζ as a target of Sirt1 in the metabolic regulation of caspase-2.

Andersen Joshua L JL Thompson J Will JW Lindblom Kelly R KR Johnson Erika S ES Yang Chih-Sheng CS Lilley Lauren R LR Freel Christopher D CD Moseley M Arthur MA Kornbluth Sally S

Molecular cell 20110901 5

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. W ...[more]

PMID: 21884983

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Project description:ObjectiveMetabolic stress primes monocytes for accelerated chemokine-mediated adhesion, migration, and recruitment into vascular lesions by increasing actin remodeling. The mechanism linking metabolic stress to accelerated actin turnover and enhanced monocyte migration was not known. We tested the hypothesis that in metabolically primed monocytes, the acceleration of monocyte chemoattractant protein-1-induced chemotaxis is mediated by the hyperactivation of cofilin.Approach and resultsMetabolic priming was induced by exposing human THP-1 monocytes to diabetic conditions, that is, human native low-density lipoprotein plus high glucose concentrations. In healthy monocytes, monocyte chemoattractant protein-1 induced the phosphorylation and inactivation of cofilin. This response was completely blocked in metabolically primed monocytes but restored by overexpression of the thiol transferase, glutaredoxin 1. Cofilin kinase, LIM kinase 1, and cofilin phosphatase, Slingshot-1L, were not affected by metabolic stress. However, metabolic priming increased 3.8-fold the S-glutathionylation of the Slingshot-1L-binding protein 14-3-3ζ (zeta), resulting in its caspase-dependent degradation. Glutaredoxin 1 overexpression inhibited low-density lipoprotein plus high glucose-induced S-glutathionylation and degradation of 14-3-3ζ. The C25S mutant of 14-3-3ζ was resistant to both S-glutathionylation and degradation induced by low-density lipoprotein plus high glucose. Overexpression of the C25S mutant restored monocyte chemoattractant protein-1-induced cofilin phosphorylation and prevented accelerated migration of metabolically stressed monocytes, suggesting that loss of 14-3-3ζ increases the pool of free Slingshot-1L phosphatase, thereby preventing the phosphorylation and deactivation of cofilin in response to chemokine activation.ConclusionsBy preventing the inactivation of cofilin, metabolic stress-induced degradation of 14-3-3ζ promotes the conversion of blood monocytes into a hypermigratory, proatherogenic phenotype.

Dataset Information

A biotin switch-based proteomics approach identifies 14-3-3? as a target of Sirt1 in the metabolic regulation of caspase-2.

Publications

A biotin switch-based proteomics approach identifies 14-3-3ζ as a target of Sirt1 in the metabolic regulation of caspase-2.

Similar Datasets

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