Nrf2 possesses a redox-sensitive nuclear exporting signal in the Neh5 transactivation domain

Department of Pharmaceutics, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA.
Journal of Biological Chemistry (Impact Factor: 4.6). 10/2006; 281(37):27251-63. DOI: 10.1074/jbc.M602746200
Source: PubMed

ABSTRACT NF-E2-related factor 2 (Nrf2) is the key transcription factor regulating the antioxidant response. Previous studies identified a nuclear localization signal (NLS) in the basic region and a nuclear exporting signal (NES) in the leucine zipper domain of Nrf2. In this study, we characterize a new functional NES (175LLSIPELQCLNI186) in the transactivation (TA) domain of Nrf2. A green fluorescence protein (GFP)-tagged Nrf2 segment (amino acids162-295) called GFP-NESTA exhibited a cytosolic distribution that could be disrupted by L184A mutation or leptomycin B treatment. Chimeric expression of this NESTA with a nuclear protein GAL4DBD could expel GAL4DBD into the cytoplasm. A variety of oxidants, including sulforaphane, tert-butylhydroquinone, and H2O2, could effectively induce nuclear translocation of GFP-NESTA. Mutational studies showed that cysteine 183 may mediate the redox response of NESTA. The discovery of multiple NLS/NES motifs in Nrf2 and the redox sensitivity of NESTA imply Nrf2 may be self-sufficient to sense and transduce oxidative signals into the nucleus, consequently initiating antioxidant gene transcription.

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