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PubMed · 12145307

The Keap1 BTB/POZ dimerization function is required to sequester Nrf2 in cytoplasm.

Laurie M Zipper·R Timothy Mulcahy
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Abstract

Transactivation of phase II detoxification enzymes and antioxidant proteins is mediated by the Cap'N'Collar transcription factor, Nrf2, which is sequestered in the cytoplasm by the actin-binding protein Keap1. Mutation of a conserved serine (S104A) within the Keap1 BTB/POZ domain disrupts Keap1 dimerization and eliminates the ability of Keap1 to sequester Nrf2 in the cytoplasm and repress Nrf2 transactivation. Disruption of endogenous Keap1 dimerization using BTB/POZ dominant negative proteins also inhibits the ability of Keap1 to retain Nrf2 in the cytoplasm. Exposure to an electrophilic agent that induces Nrf2 release and nuclear translocation disrupts formation of a Keap1 complex in vivo. Collectively, these data support the conclusion that Keap1 dimerization is required for Nrf2 sequestration and transcriptional repression. Furthermore, exposure to inducing agents disrupts the Keap1 dimerization function and results in Nrf2 release.

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Active Transport, Cell NucleusAdaptor Proteins, Signal TransducingAmino Acid SequenceAnimalsBlotting, WesternCarrier ProteinsCell LineCell NucleusCytoplasmCytoskeletal ProteinsDNA, ComplementaryDNA-Binding ProteinsDimerizationGenes, ReporterGreen Fluorescent ProteinsHumansKelch-Like ECH-Associated Protein 1LuciferasesLuminescent ProteinsMiceMicroscopy, FluorescenceMitogen-Activated Protein KinasesModels, BiologicalMolecular Sequence DataMutagenesis, Site-DirectedMutationNF-E2-Related Factor 2Precipitin TestsProtein Structure, TertiarySequence Homology, Amino AcidSerineTrans-ActivatorsTranscription, GeneticTranscriptional ActivationTransfectionp38 Mitogen-Activated Protein KinasesJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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Laurie M Zipper, R Timothy Mulcahy. 2002-07-26. The Keap1 BTB/POZ dimerization function is required to sequester Nrf2 in cytoplasm.. https://doi.org/10.1074/jbc.m206530200

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