Structural basis for defects of Keap1 activity provoked by its point mutations in lung cancer.
Nrf2 regulates the cellular oxidative stress response, whereas Keap1 represses Nrf2 through its molecular interaction. To elucidate the molecular mechanism of the Keap1 and Nrf2 interaction, we resolved the six-bladed beta propeller crystal structure of the Kelch/DGR and CTR domains of mouse Keap1 and revealed that extensive inter- and intrablade hydrogen bonds maintain the structural integrity and proper association of Keap1 with Nrf2. A peptide containing the ETGE motif of Nrf2 binds the beta propeller of Keap1 at the entrance of the central cavity on the bottom side via electrostatic interactions with conserved arginine residues. We found a somatic mutation and a gene variation in human lung cancer cells that change glycine to cysteine in the DGR domain, introducing local conformational changes that reduce Keap1's affinity for Nrf2. These results provide a structural basis for the loss of Keap1 function and gain of Nrf2 function.
Padmanabhan
Balasundaram
B
RIKEN Genomic Sciences Center, Tsurumi, Yokohama 230-0045, Japan.
Tong
Kit I
KI
Ohta
Tsutomu
T
Nakamura
Yoshihiro
Y
Scharlock
Maria
M
Ohtsuji
Makiko
M
Kang
Moon-Il
MI
Kobayashi
Akira
A
Yokoyama
Shigeyuki
S
Yamamoto
Masayuki
M
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics; D045647:DNA Glycosylases / Q000737:chemistry / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000737:chemistry / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D000072019:Kelch-Like ECH-Associated Protein 1; D008175:Lung Neoplasms / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D051267:NF-E2-Related Factor 2 / Q000737:chemistry / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D013329:Structure-Activity Relationship
D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C431364:KEAP1 protein, human; C117301:Keap1 protein, mouse; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D010446:Peptide Fragments; D011506:Proteins; D045647:DNA Glycosylases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C473642:NEIL2 protein, human