Different electrostatic potentials define ETGE and DLG motifs as hinge and latch in oxidative stress response.
Nrf2 is the regulator of the oxidative/electrophilic stress response. Its turnover is maintained by Keap1-mediated proteasomal degradation via a two-site substrate recognition mechanism in which two Nrf2-Keap1 binding sites form a hinge and latch. The E3 ligase adaptor Keap1 recognizes Nrf2 through its conserved ETGE and DLG motifs. In this study, we examined how the ETGE and DLG motifs bind to Keap1 in a very similar fashion but with different binding affinities by comparing the crystal complex of a Keap1-DC domain-DLG peptide with that of a Keap1-DC domain-ETGE peptide. We found that these two motifs interact with the same basic surface of either Keap1-DC domain of the Keap1 homodimer. The DLG motif works to correctly position the lysines within the Nrf2 Neh2 domain for efficient ubiquitination. Together with the results from calorimetric and functional studies, we conclude that different electrostatic potentials primarily define the ETGE and DLG motifs as a hinge and latch that senses the oxidative/electrophilic stress.
Tong
Kit I
KI
Graduate School of Comprehensive Human Sciences, Center for TARA, JST-ERATO Environmental Response Project, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan.
Padmanabhan
Balasundaram
B
Kobayashi
Akira
A
Shang
Chengwei
C
Hirotsu
Yosuke
Y
Yokoyama
Shigeyuki
S
Yamamoto
Masayuki
M
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002151:Calorimetry; D002460:Cell Line; D018360:Crystallography, X-Ray; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D000072019:Kelch-Like ECH-Associated Protein 1; D051379:Mice; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D055672:Static Electricity; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D025801:Ubiquitin / Q000378:metabolism