Nrf2 possesses a redox-sensitive nuclear exporting signal in the Neh5 transactivation domain.
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.
Li
Wenge
W
Department of Pharmaceutics, Ernest-Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA.
Yu
Si-Wang
SW
Kong
A-N Tony
AN
D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D051267:NF-E2-Related Factor 2 / Q000502:physiology*; D049790:Nuclear Export Signals; D017434:Protein Structure, Tertiary; D013347:Subcellular Fractions / Q000378:metabolism; D015533:Transcriptional Activation
D005231:Fatty Acids, Unsaturated; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D049790:Nuclear Export Signals; D006861:Hydrogen Peroxide; C038753:leptomycin B