ABSTRACT

ABSTRACT Reactive oxygen species (ROS) mediate various cellular signal transduction as second messengers. However, excess ROS disrupts cellular functions and homeostasis by oxidizing intracellular molecules. is ROS toxicity is referred to as “oxidative stress”. To control the intracellular oxidation-reduction (redox) status and endure oxidative stress, organisms are equipped with various antioxidant systems. Among these, the redox protein thioredoxin (Trx), together with thioredoxin reductase (TrxR) and NADPH, constitutes the Trx system in mammalian cells. Trx reduces the disulphide bonds formed in intracellular proteins by oxidation and plays a signicant role in maintaining proper cellular functions by retaining the function of proteins altered by ROS. Trx also participates in cellular signal transduction by forming protein complexes called Trx signalosomes with intracellular proteins. e redox status of Trx is altered by various cell stimuli. Trx associates and dissociates with proteins depending on its redox status, switching the intracellular signallling to induce proper cellular responses. In this chapter, we introduce a variety of Trx signalosomes, focussing on the mechanisms of signal transduction depending on the cellular context. Moreover, accumulating data suggest that Trx signalosomes play pivotal roles in diseases related to oxidative stress. We also describe the roles of the Trx signalosome in stressed cells and disease.