9m0y
Local refinement of stacked like DDB1-DDA1-DET1-Ube2e2-COP1 complex (layer 2)
Structural highlights
FunctionCOP1_HUMAN E3 ubiquitin-protein ligase that mediates ubiquitination and subsequent proteasomal degradation of target proteins. E3 ubiquitin ligases accept ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfers the ubiquitin to targeted substrates. Involved in JUN ubiquitination and degradation. Directly involved in p53 (TP53) ubiquitination and degradation, thereby abolishing p53-dependent transcription and apoptosis. Ubiquitinates p53 independently of MDM2 or RCHY1. Probably mediates E3 ubiquitin ligase activity by functioning as the essential RING domain subunit of larger E3 complexes. In contrast, it does not constitute the catalytic RING subunit in the DCX DET1-COP1 complex that negatively regulates JUN, the ubiquitin ligase activity being mediated by RBX1. Involved in 14-3-3 protein sigma/SFN ubiquitination and proteasomal degradation, leading to AKT activation and promotion of cell survival. Ubiquitinates MTA1 leading to its proteasomal degradation. Upon binding to TRIB1, ubiquitinates CEBPA, which lacks a canonical COP1-binding motif (Probable).[1] [2] [3] [4] [5] [6] [7] [8] Publication Abstract from PubMedUbiquitin modifications regulate fundamental cellular activities by modulating protein stability and function. The ubiquitin ligase COP1, which is present across species from plants to humans, plays a crucial role in the ubiquitination of developmental transcription factors. While COP1 can function independently, it can also be incorporated into CULLIN4-RING ubiquitin ligase (CRL4) complexes through the DET1 adaptor protein. Despite its biological significance, the structural and functional mechanisms of COP1 and DET1-containing complexes remains poorly understood. Here we present the cryo-electron microscopy structures of human COP1 in complex with DDB1-DDA1-DET1 and Ube2e2, revealing an inactive stacked assembly state. Co-expression with COP1 substrates including c-Jun or ETS2 disrupts this configuration, inducing a conformational rearrangement into a distinct dimeric state that allows substrate access. Structural modelling identifies the spatial organization of COP1 WD40 domains where substrate recruits. DET1 serves as a structural scaffold, bridging COP1 and Ube2e2 to initiate potential ubiquitin addition on substrates, while DDB1 recruits the CULLIN4-RBX1 complex to facilitate Ube2d3-mediated ubiquitin chain elongation. These results reveal the dynamic interplay between the structural states of the CRL4(DET1-COP1) E3 ligase complex and its substrate specific activation mechanism, offering mechanistic insights into ubiquitination regulation and a basis for future studies on E3 ligase dynamics. Cryo-EM structure of the human COP1-DET1 ubiquitin ligase complex.,Wang S, Teng F, Stjepanovic G, Rao F, Su MY Nat Commun. 2026 Jan 15;17(1):543. doi: 10.1038/s41467-026-68375-7. PMID:41540009[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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