Download MendeleyStructural basis of K11/K48-branched ubiquitin chain recognition by the human 26S proteasome.
Draczkowski, P., Chen, S.N., Chen, T., Wang, Y.S., Shih, H.A., Huang, J.Y.C., Tsai, M.C., Lin, S.Y., Lin, S., Viner, R., Chang, Y.C., Wu, K.P., Hsu, S.D.(2025) Nat Commun 16: 9094-9094
- PubMed: 41093839 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41467-025-64719-x
- Primary Citation Related Structures:
8JRI, 8JRT, 8JTI, 8K0G - PubMed Abstract:
Beyond the canonical K48-linked homotypic polyubiquitination for proteasome-targeted proteolysis, K11/K48-branched ubiquitin (Ub) chains are involved in fast-tracking protein turnover during cell cycle progression and proteotoxic stress. Here, we report cryo-EM structures of human 26S proteasome in a complex with a K11/K48-branched Ub chain. The structures revealed a multivalent substrate recognition mechanism involving a hitherto unknown K11-linked Ub binding site at the groove formed by RPN2 and RPN10 in addition to the canonical K48-linkage binding site formed by RPN10 and RPT4/5 coiled-coil. Additionally, RPN2 recognizes an alternating K11-K48-linkage through a conserved motif similar to the K48-specific T1 binding site of RPN1. The insights gleaned from these structures explain the molecular mechanism underlying the recognition of the K11/K48-branched Ub as a priority signal in the ubiquitin-mediated proteasomal degradation.
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
Organizational Affiliation:
