WDR23 regulates NRF2 independently of KEAP1

PLoS Genet. 2017 Apr 28;13(4):e1006762. doi: 10.1371/journal.pgen.1006762. eCollection 2017 Apr.

Abstract

Cellular adaptation to stress is essential to ensure organismal survival. NRF2/NFE2L2 is a key determinant of xenobiotic stress responses, and loss of negative regulation by the KEAP1-CUL3 proteasome system is implicated in several chemo- and radiation-resistant cancers. Advantageously using C. elegans alongside human cell culture models, we establish a new WDR23-DDB1-CUL4 regulatory axis for NRF2 activity that operates independently of the canonical KEAP1-CUL3 system. WDR23 binds the DIDLID sequence within the Neh2 domain of NRF2 to regulate its stability; this regulation is not dependent on the KEAP1-binding DLG or ETGE motifs. The C-terminal domain of WDR23 is highly conserved and involved in regulation of NRF2 by the DDB1-CUL4 complex. The addition of WDR23 increases cellular sensitivity to cytotoxic chemotherapeutic drugs and suppresses NRF2 in KEAP1-negative cancer cell lines. Together, our results identify WDR23 as an alternative regulator of NRF2 proteostasis and uncover a cellular pathway that regulates NRF2 activity and capacity for cytoprotection independently of KEAP1.

MeSH terms

  • Amino Acid Motifs / genetics
  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / metabolism
  • Cell Line, Tumor
  • Cullin Proteins / genetics
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Kelch-Like ECH-Associated Protein 1 / genetics*
  • Kelch-Like ECH-Associated Protein 1 / metabolism
  • NF-E2-Related Factor 2 / genetics*
  • NF-E2-Related Factor 2 / metabolism
  • Neoplasms / genetics*
  • Neoplasms / pathology
  • Proteasome Endopeptidase Complex / genetics
  • Proteasome Endopeptidase Complex / metabolism
  • Protein Binding / genetics
  • Repressor Proteins / genetics*
  • Repressor Proteins / metabolism
  • Signal Transduction

Substances

  • Caenorhabditis elegans Proteins
  • Cullin Proteins
  • Kelch-Like ECH-Associated Protein 1
  • NF-E2-Related Factor 2
  • Repressor Proteins
  • WDR-23 protein, C elegans
  • CUL-3 protein, C elegans
  • Proteasome Endopeptidase Complex