Nuclear factor erythroid-2-related factor 1 (NRF1) and NRF2 are essential for maintaining redox homeostasis and coordinating cellular stress responses. They are highly homologous transcription factors that regulate the expression of genes bearing antioxidant-response elements (AREs). Genetic ablation of NRF1 or NRF2 results in vastly different phenotypic outcomes, implying that they play different roles and may be differentially regulated. Kelch-like ECH-associated protein 1 (KEAP1) is the main negative regulator of NRF2 and mediates ubiquitylation and degradation of NRF2 through its NRF2-ECH homology-like domain 2 (Neh2). Here, we report that KEAP1 binds to the Neh2-like (Neh2L) domain of NRF1 and stabilizes it. Consistently, NRF1 is more stable in KEAP1(+/+) than in KEAP1(-/-) isogenic cell lines, whereas NRF2 is dramatically stabilized in KEAP1(-/-) cells. Replacing NRF1's Neh2L domain with NRF2's Neh2 domain renders NRF1 sensitive to KEAP1-mediated degradation, indicating that the amino acids between the DLG and ETGE motifs, not just the motifs themselves, are essential for KEAP1-mediated degradation. Systematic site-directed mutagenesis identified the core amino acid residues required for KEAP1-mediated degradation and further indicated that the DLG and ETGE motifs with correct spacing are insufficient as a KEAP1 degron. Our results offer critical insights into our understanding of the differential regulation of NRF1 and NRF2 by KEAP1 and their different physiological roles.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/627124 |
| Date | 09 February 2018 |
| Creators | Tian, Wang, de la Vega, Montserrat Rojo, Schmidlin, Cody J., Ooi, Aikseng, Zhang, Donna D. |
| Contributors | Univ Arizona, Dept Pharmacol & Toxicol |
| Publisher | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2018 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Relation | http://www.jbc.org/lookup/doi/10.1074/jbc.RA117.000428 |
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