The major signaling pathways activated in response to oxidative stress. ROS can originate from metabolic activity or from external environmental signals and are modulated by antioxidants to nontoxic levels at which point they serve as signaling molecules. ROS can activate gene transcription in two ways: either via transcription factors (such as, NFκB, AP-1 and ARE-binding proteins, ARE-BP) that can interact directly with specific DNA motifs, including ARE, on promoters of target genes; or via activation of MAP kinase cascades, which in turn activate transcription factors that trigger target gene transcription. The degree to which a given pathway is activated is dependent on the nature and duration of the stress, as well as on cell type and developmental stage.
