Scaffolding of Keap1 to the actin cytoskeleton controls the function of Nrf2 as key regulator of cytoprotective phase 2 genes
Top Cited Papers
- 5 February 2004
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 101 (7) , 2046-2051
- https://doi.org/10.1073/pnas.0308347100
Abstract
Transcription factor Nrf2 regulates basal and inducible expression of phase 2 proteins that protect animal cells against the toxic effects of electrophiles and oxidants. Under basal conditions, Nrf2 is sequestered in the cytoplasm by Keap1, a multidomain, cysteinerich protein that is bound to the actin cytoskeleton. Keap1 acts both as a repressor of the Nrf2 transactivation and as a sensor of phase 2 inducers. Electrophiles and oxidants disrupt the Keap1–Nrf2 complex, resulting in nuclear accumulation of Nrf2, where it enhances the transcription of phase 2 genes via a common upstream regulatory element, the antioxidant response element. Reporter cotransfection–transactivation analyses with a series of Keap1 deletion mutants revealed that in the absence of the double glycine repeat domain Keap1 does not bind to Nrf2. In addition, deletion of either the intervening region or the C-terminal region also abolished the ability of Keap1 to sequester Nrf2, indicating that all of these domains contribute to the repressor activity of Keap1. Immunocytochemical and immunoprecipitation analyses demonstrated that Keap1 associates with actin filaments in the cytoplasm through its double glycine repeat domain. Importantly, disruption of the actin cytoskeleton promotes nuclear entry of an Nrf2 reporter protein. The actin cytoskeleton therefore provides scaffolding that is essential for the function of Keap1, which is the sensor for oxidative and electrophilic stress.Keywords
This publication has 31 references indexed in Scilit:
- Keap1-dependent Proteasomal Degradation of Transcription Factor Nrf2 Contributes to the Negative Regulation of Antioxidant Response Element-driven Gene ExpressionJournal of Biological Chemistry, 2003
- Degradation of Transcription Factor Nrf2 via the Ubiquitin-Proteasome Pathway and Stabilization by CadmiumJournal of Biological Chemistry, 2003
- Phosphatidylinositol 3-Kinase Regulates Nuclear Translocation of NF-E2-Related Factor 2 through Actin Rearrangement in Response to Oxidative StressMolecular Pharmacology, 2002
- The Keap1 BTB/POZ Dimerization Function Is Required to Sequester Nrf2 in CytoplasmJournal of Biological Chemistry, 2002
- Direct evidence that sulfhydryl groups of Keap1 are the sensors regulating induction of phase 2 enzymes that protect against carcinogens and oxidantsProceedings of the National Academy of Sciences, 2002
- Integration and diversity of the regulatory network composed of Maf and CNC families of transcription factorsGene, 2002
- Functional characterization and role of INrf2 in antioxidant response element-mediated expression and antioxidant induction of NAD(P)H:quinone oxidoreductase1 geneOncogene, 2001
- Potency of Michael reaction acceptors as inducers of enzymes that protect against carcinogenesis depends on their reactivity with sulfhydryl groupsProceedings of the National Academy of Sciences, 2001
- Transcription Factor Nrf2 Coordinately Regulates a Group of Oxidative Stress-inducible Genes in MacrophagesJournal of Biological Chemistry, 2000
- The Nrf2 transcription factor contributes both to the basal expression of glutathione S-transferases in mouse liver and to their induction by the chemopreventive synthetic antioxidants, butylated hydroxyanisole and ethoxyquinBiochemical Society Transactions, 2000