Identification of thioredoxin target protein networks in cardiac tissues of a transgenic mouse.

The advent of sensitive and robust quantitative proteomics techniques has been emerging as a vital tool for deciphering complex biological puzzles that would have been challenging to conventional molecular biology methods. The method here describes the use of two isotope labeling techniques-isobaric tags for relative and absolute quantification (iTRAQ) and redox isotope-coded affinity tags (ICAT)-to elucidate the cardiovascular redox-proteome changes and thioredoxin 1 (Trx1)-regulated protein network in cardiac-specific Trx1 transgenic mouse models. The strategy involves the use of an amine-labeling iTRAQ technique, gauging the global proteome changes in Trx1 transgenic mice at the protein level, while ICAT, labeling redox-sensitive cysteines, reveals the redox status of cysteine residues. Collectively, these two quantitative proteomics techniques can not only quantify global changes of the cardiovascular proteome but also pinpoint specific redox-sensitive cysteine sites that are subjected to Trx1-catalyzed reduction.