Download MendeleyMechanism of K63-linked polyubiquitin recognition and cleavage by the BRCA1-A complex.
Foglizzo, M., Datta, A., Degtjarik, O., Perera, H., Liburd, J., Sykora, U.M., Ganji, S.R., Wildsmith, G., Chandler, F., Campbell, L.J., Calabrese, A.N., Greenberg, R.A., Zeqiraj, E.(2026) Nat Commun 17
- PubMed: 42581301 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41467-026-75795-y
- Primary Citation Related Structures:
9SQV, 9SQW, 9SQY - PubMed Abstract:
Deubiquitylases modulate cellular processes by removing monoubiquitin or cleaving polyubiquitin chains. The ARISC-RAP80 complex partners with BRCA1-BARD1 to form the BRCA1-A supercomplex, which recognises K63-linked ubiquitin chains at DNA damage sites. ARISC-RAP80 contains multiple ubiquitin-binding sites, yet how these influence recognition and cleavage of K63-polyubiquitylated substrates remains unknown. We discover that a composite three-subunit interface allows ARISC-RAP80 to position K63-linked polyubiquitin chains in its catalytic site. Substrate recognition is further supported by RAP80 and non-catalytic ubiquitin-binding sites that impose a compact conformation on K63-polyubiquitylated substrates. This mechanism exploits the inherent flexibility of long ubiquitin chains and differs considerably from other deubiquitylases. Structure-guided mutageneses validate ubiquitin chain interactions, and cell-based assays demonstrate a functional role of the observed interfaces in chromatin recruitment. Our findings define mechanisms of polyubiquitin chain decoding and cleavage by ARISC-RAP80, linking ubiquitin reading and erasing functions to BRCA1-A mediated DNA damage responses.
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK. m.foglizzo@leeds.ac.uk.
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