Fasting, but Not Aging, Dramatically Alters the Redox Status of Cysteine Residues on Proteins in Drosophila melanogaster.

Katja E Menger,Helena M Cochemé,Edward T Chouchani,Michael P Murphy,Ian M Fearnley,Linda Partridge,Shujing Ding,Andrew M James,Michael E Harbour

doi:10.1016/j.celrep.2015.05.033

Abstract

SummaryAltering the redox state of cysteine residues on protein surfaces is an important response to environmental challenges. Although aging and fasting alter many redox processes, the role of cysteine residues is uncertain. To address this, we used a redox proteomic technique, oxidative isotope-coded affinity tags (OxICAT), to assess cysteine-residue redox changes in Drosophila melanogaster during aging and fasting. This approach enabled us to simultaneously identify and quantify the redox state of several hundred cysteine residues in vivo. Cysteine residues within young flies had a bimodal distribution with peaks at ∼10% and ∼85% reversibly oxidized. Surprisingly, these cysteine residues did not become more oxidized with age. In contrast, 24 hr of fasting dramatically oxidized cysteine residues that were reduced under fed conditions while also reducing cysteine residues that were initially oxidized. We conclude that fasting, but not aging, dramatically alters cysteine-residue redox status in D. melanogaster.

Highlights

Organisms are continually exposed to environmental challenges that dramatically alter redox processes, changing the reduction potential of redox couples as well as the production of evanescent reactive species (Go and Jones, 2013; Murphy, 2012)
Intermittent starvation can be effective in improving health and extending lifespan, and it may mediate some of the effects of dietary restriction (DR) (Fontana and Partridge, 2015)
Cysteine residues were stabilized by homogenization in trichloroacetic acid (TCA) to prevent artifactual thiol oxidation and disulfide shuffling (Held and Gibson, 2012; Leichert et al, 2008), proteins were precipitated and processed for oxidative isotope-coded affinity tags (OxICAT) analysis (Figure 1B)

Summary

Introduction

Organisms are continually exposed to environmental challenges that dramatically alter redox processes, changing the reduction potential of redox couples as well as the production of evanescent reactive species (Go and Jones, 2013; Murphy, 2012). These redox changes can disrupt the molecular machinery of the organism, and cells contain short-term adaptive mechanisms and a parallel capacity for activating gene expression to maintain resilience. While the molecular mechanisms underlying the benefits of fasting are obscure (Robertson and Mitchell, 2013), redox alterations are likely to be central

Results

Discussion

Conclusion