Keap1-dependent Proteasomal Degradation of Transcription Factor Nrf2 Contributes to the Negative Regulation of Antioxidant Response Element-driven Gene Expression*

By Michael T. McMahon, K. Itoh, Masayuki Yamamoto, J. Hayes. Journal of Biological Chemistry, 2003

1,150 citations recorded by the source corpus.

Keap1 is a negative regulator of Nrf2, a bZIP transcription factor that mediates adaptation to oxidative stress. Previous studies suggested this negative regulation is a consequence of Keap1 controlling the subcellular distribution of Nrf2. We now report that Keap1 also controls the total cellular level of Nrf2 protein. In the RL34 non-transformed rat liver cell line, Nrf2 was found to accumulate rapidly in response to oxidative stress caused by treatment with sulforaphane, and the accumulation resulted from inhibition of proteasomal-mediated degradation of the bZIP protein. By heterologously expressing in COS1 cells epitope-tagged Nrf2 and an Nrf2ΔETGE mutant lacking the Keap1-binding site, in both the presence and absence of Keap1 we demonstrate that Nrf2 is subject to ubiquitination and proteasomal degradation independently of both Keap1 and the redox environment of the cell. In oxidatively stressed cells, this is the sole mechanism responsible for Nrf2 degradation. However, under homeostatic conditions Nrf2 is subject to a substantially more rapid mode of proteasomal degradation than it is in oxidatively stressed cells, and this rapid turnover of Nrf2 requires it to interact with Keap1. Within Nrf2, the N-terminal Neh2 domain is identified as the redox-sensitive degron. These data suggest that Keap1 negatively regulates Nrf2 by both enhancing its rate of proteasomal degradation and altering its subcellular distribution.

Subfields: Molecular Biology

View Paper: https://www.semanticscholar.org/paper/cf97437f9bd0d70725231496de9fd035f898d3d4

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Citations in the corpus

Transcriptional Regulation by Nrf2 (2017, background): “The Neh2 domain contains two highly conserved amino acid stretches, the DLG and ETGE motifs, which mediate the interaction with Nrf2 negative regulator Kelch-like ECH-associated protein 1 (Keap1) and seven lysine residues targeted for ubiquitylation and subsequent proteasomal degradation of Nrf2 (60”
Nrf2 is controlled by two distinct β-TrCP recognition motifs in its Neh6 domain, one of which can be modulated by GSK-3 activity. (2012, background): “1/V5mNrf2Δ17-32) have been described previously (4,24).”
The cytoprotective role of the Keap1–Nrf2 pathway (2011, methodology): “…and diethyl maleate (DEM), and each time the inducer was shown to stabilise Nrf2 (Nguyen et al. 2003; McMahon et al. 2003; Itoh et al. 2003), whereas the level of Nrf2 mRNA was unaffected by the addition of inducers (Stewart et al. 2003; Nguyen et al. 2003; McMahon et al. 2003; Itoh et al. 2003).”
Molecular mechanisms of the Keap1–Nrf2 pathway in stress response and cancer evolution (2011, background): “The Neh2 domain localized in the N-terminal region of Nrf2 is essential for Keap1-dependent degradation of Nrf2 (McMahon et al. 2003, 2004; Zhang et al. 2004), and this domain directly associates with the b-barrel structure of Keap1, designated as the DC domain (Tong et al. 2006a) (Fig.”
Ferroptosis as a target for protection against cardiomyopathy (2019, background): “Upon translocating to the nucleus, Nrf2 binds to the antioxidant response element (ARE) in the upstream promoter region of several antioxidative genes—includingHmox1—thereby initiating their transcription (26).”
Molecular Mechanisms of Nrf2-Mediated Antioxidant Response (2009, neutral): “Nrf2 is a short-live protein, rapidly degraded in a ubiquitin-dependent manner [23,34,58].”
The Nrf2 cell defence pathway: Keap1-dependent and -independent mechanisms of regulation. (2013, background): “mKeap1 to 30 min in cells under the same conditions coexpressing the mutant mNrf2 ETGE-V5 with wild-type mKeap1 [35].”