Modifying specific cysteines of the electrophile-sensing human Keap1 protein is insufficient to disrupt binding to the Nrf2 domain Neh2

• Aimee L. Eggler

  Center for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607; and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907

• Guowen Liu

  Center for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607; and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907

• John M. Pezzuto

  Center for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607; and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907

• Richard B. van Breemen

  Center for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607; and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907

• Andrew D. Mesecar

  Center for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607; and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907

抄録

The risks of cancer and other degenerative diseases caused by reactive oxygen species and electrophiles can be reduced by the up-regulation of detoxifying enzymes. A major mechanism whereby these protective enzymes are induced occurs through activation of the antioxidant response element (ARE) by the oxidative-stress sensor protein Kelch-like ECH-associated protein 1 (Keap1) and the transcription factor NF-E2-related factor 2 (Nrf2). Under basal conditions, Keap1 sequesters Nrf2 in the cytoplasm by binding to its Neh2 domain. Chemical inducers such as sulforaphane are known to react with Keap1 cysteine residues, thereby promoting Nrf2 nuclear accumulation and hence ARE activation. A widely accepted model for Nrf2 nuclear accumulation is that modification of Keap1 cysteines leads directly to dissociation of the Keap1-Nrf2 complex. This model is based on studies with mouse proteins and has served as the experimental basis and hypothesis for numerous investigations. Through a combination of chemical, mass spectrometry, and isothermal titration calorimetry methods, we have tested the direct-dissociation model using a series of ARE inducers: sulforaphane, isoliquiritigenin, 15-deoxy-Δ12,14-prostaglandin-J2, menadione, 1-Cl-2,4-dinitrobenzene, and biotinylated iodoacetamide. Surprisingly, these data suggest that the direct disruption model for Keap1-Nrf2 is incorrect. The relative reactivity of human Keap1 cysteines was determined. In addition to the same five cysteines identified for mouse Keap1, two highly reactive and previously unobserved cysteines were identified. Based on these results, a model is proposed that should aid in the understanding of Keap1-Nrf2 signaling mechanisms.

収録刊行物

• Proceedings of the National Academy of Sciences

  Proceedings of the National Academy of Sciences 102 (29), 10070-10075, 2005-07-08

  Proceedings of the National Academy of Sciences

キーワード

• Multidisciplinary

詳細情報

• CRID: 1362262945512444800
• NII論文ID: 30016303513
• DOI: 10.1073/pnas.0502402102
• ISSN: 10916490
• ISSN: 00278424
• Web Site: https://pnas.org/doi/pdf/10.1073/pnas.0502402102
• データソース種別:
  • Crossref
  • CiNii Articles