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Title | E3 ligase autoinhibition by C-degron mimicry maintains C-degron substrate fidelity. |
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Journal, issue, pages | Mol Cell, Vol. 83, Issue 5, Page 770-786.e9, Year 2023 |
Publish date | Mar 2, 2023 |
Authors | Daniel C Scott / Moeko T King / Kheewoong Baek / Clifford T Gee / Ravi Kalathur / Jerry Li / Nicholas Purser / Amanda Nourse / Sergio C Chai / Sivaraja Vaithiyalingam / Taosheng Chen / Richard E Lee / Stephen J Elledge / Gary Kleiger / Brenda A Schulman / |
PubMed Abstract | E3 ligase recruitment of proteins containing terminal destabilizing motifs (degrons) is emerging as a major form of regulation. How those E3s discriminate bona fide substrates from other proteins ...E3 ligase recruitment of proteins containing terminal destabilizing motifs (degrons) is emerging as a major form of regulation. How those E3s discriminate bona fide substrates from other proteins with terminal degron-like sequences remains unclear. Here, we report that human KLHDC2, a CRL2 substrate receptor targeting C-terminal Gly-Gly degrons, is regulated through interconversion between two assemblies. In the self-inactivated homotetramer, KLHDC2's C-terminal Gly-Ser motif mimics a degron and engages the substrate-binding domain of another protomer. True substrates capture the monomeric CRL2, driving E3 activation by neddylation and subsequent substrate ubiquitylation. Non-substrates such as NEDD8 bind KLHDC2 with high affinity, but its slow on rate prevents productive association with CRL2. Without substrate, neddylated CRL2 assemblies are deactivated via distinct mechanisms: the monomer by deneddylation and the tetramer by auto-ubiquitylation. Thus, substrate specificity is amplified by KLHDC2 self-assembly acting like a molecular timer, where only bona fide substrates may bind before E3 ligase inactivation. |
External links | Mol Cell / PubMed:36805027 / PubMed Central |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 1.37 - 8.2 Å |
Structure data | EMDB-16370: Structure of CUL2-KLHDC2 E3 ligase autoinhibited by C-degron mimicry PDB-8ebl: PDB-8ebm: PDB-8ebn: |
Chemicals | ChemComp-HOH: |
Source |
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Keywords | LIGASE / E3 ligase |