Quantitative Analysis of Redox-Sensitive Proteome with DIGE and ICAT

Abstract

Oxidative modifications of protein thiols are important mechanisms for regulating protein functions. The present study aimed to compare the relative effectiveness of two thiol-specific quantitative proteomic techniques, difference gel electrophoresis (DIGE) and isotope coded affinity tag (ICAT), for the discovery of redox-sensitive proteins in heart tissues. We found that these two methods were largely complementary; each could be used to reveal a set of unique redox-sensitive proteins. Some of these proteins are low-abundant signaling proteins and membrane proteins. From DIGE analysis, we found that both NF-kappaB-repressing protein and epoxide hydrolase were sensitive to H 2O 2 oxidation. In ICAT analysis, we found that specific cysteines within sacroplasmic endoplamic reticulum calcium ATPase 2 and voltage-dependent anion-selective channel protein 1 were sensitive to H 2O 2 oxidation. From these analyses, we conclude that both methods should be employed for proteome-wide studies, to maximize the possibility of identifying proteins containing redox-sensitive cysteinyl thiols in complex biological systems.