endogenous and xenobiotic electrophiles. After detoxification by glutathione (GSH) conjugation catalyzed by GSTs, the body can eliminate potentially harmful and toxic compounds. GSTs are induced by NRF2 activation and represent an important route of detoxification. The UDP-glucuronosyltransferase (UGT) family catalyze the conjugation of a glucuronic acid moiety to a variety of endogenous and exogenous substances, making them more water-soluble and readily excreted. Important substrates for glucuronidation include bilirubin and acetaminophen. NRF2 has been shown to induce UGT1A1 and UGT1A6. Multidrug resistance-associated proteins (Mrps) are important membrane transporters that efflux various compounds from various organs and into bile or plasma, with subsequent excretion in the feces or urine, respectively. Mrps have been shown to be upregulated by NRF2 and alteration in their expression can dramatically alter the pharmacokinetics and toxicity of compounds. Kelch-like ECH-associated protein 1 is also a primary target of NFE2L2. Several interesting studies have also identified this hidden circuit in NRF2 regulations. In the mouse Keap1 (INrf2) gene, Lee and colleagues found that an AREs located on a negative strand can subtly connect Nrf2 activation to Keap1 transcription. When examining NRF2 occupancies in human lymphocytes, Chorley and colleagues identified an approximately 700 bp locus within the KEAP1 promoter region was consistently top rank enriched, even at the whole-genome scale. These basic findings have depicted a mutually influenced pattern between NRF2 and KEAP1. NRF2-driven KEAP1 expression characterized in human cancer contexts, especially in human squamous cell cancers, implicated a new perspective in understanding NRF2 signaling regulation. Tissue distribution NRF2 is ubiquitously expressed with the highest concentrations (in descending order) in the kidney, muscle, lung, heart, liver, and brain. Clinical relevance Dimethyl fumarate, marketed as Tecfidera by Biogen Idec, was approved by the Food and Drug Administration in March 2013 following the conclusion of a Phase III clinical trial which demonstrated that the drug reduced relapse rates and increased time to progression of disability in people with multiple sclerosis. The mechanism of action of dimethyl fumarate is not well understood. Dimethyl fumarate (and its metabolite, monomethyl fumarate) activates the NRF2 pathway and has been identified as a nicotinic acid receptor agonist in vitro. The label includes warnings about the risk of anaphylaxis and angioedema, progressive multifocal leukoencephalopathy (PML), lymphopenia, and liver damage; other adverse effects include flushing and gastrointestinal events, such as diarrhea, nausea, and upper abdominal pain. The dithiolethiones are a class of organosulfur compounds, of which oltipraz, an