Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a ubiquitously expressed, basic leucine zipper transcription factor. It regulates the expression of a variety of genes,encoding proteins that play critical roles in cyto-protection, as well as the detoxification and clearance of harmful endogenous and xenobiotic substances. In particular, Nrf2 regulates the expression of antioxidant proteins that confer cyto-protection against oxidative damage. Under normal conditions Nrf2 resides in the cytoplasm in association with Keap1 and Cullin 3. Within the confines of this protein cluster Nrf2 is the target of ubiquitination and rapid turn-over via proteasomal degradation. However, under conditions of cellular oxidative stress the tight association of Nrf2 with Keap1 and Cullin 3 is broken, effectively disrupting the otherwise efficient process of Nrf2 degradation. Once non-ubiquitinated Nrf2 accumulates in the cytoplasm it translocates into the nucleus, whereupon it forms hetero-dimers with Maf. In this configuration Nrf2 binds to antioxidant response element (ARE) sequences resident in the promoter regions of some genes, initiating transcription complex formation, and culminating in the expression of antioxidant proteins.