Linking redox and calcium signaling via thioredoxins

Reactive oxygen species (ROS) and calcium (Ca2+) are well-established second messengers in plants that transmit signals from an initial stimulus to initiate downstream cellular processes, playing crucial roles in the development and response to adverse environmental conditions of the plant. Upon stimuli, transient increases in ROS and cytosolic free calcium concentration ([Ca2+]cyt) act as early signals. Later, Ca2+ signals can regulate ROS homeostasis by controlling ROS generation, but reciprocally, ROS can modulate Ca2+ signaling by means of post-translational modifications (PTMs) in specific proteins involved in the transport, sensing, and transmission of the signal. Thioredoxins (TRXs) act as ROS scavengers, being able to revert the oxidized, nitrosated, persulfided, and glutathionylated forms of specific proteins, which acts as a PTM reversible mechanism that contributes to fine-tune protein function. In this review, we summarize the crosstalk between Ca2+ and ROS signaling, focusing on the involvement of TRXs.