{"doi":"10.1101/2022.09.29.510132","title":"Discovery of E6AP AZUL binding to UBQLN1/2 in cells, phase-separated droplets, and an AlphaFold-NMR integrated structure","abstract":"Abstract The E3 ligase E6AP/UBE3A has a dedicated binding site in the 26S proteasome provided by the RAZUL domain of substrate receptor hRpn10/S5a/PSMD4. Guided by RAZUL sequence similarity, we test and demonstrate here that the E6AP AZUL binds transiently to the UBA of proteasomal shuttle factor UBQLN1/2. Despite a weak binding affinity, E6AP AZUL is recruited to UBQLN2 phase-separated droplets and E6AP interacts with UBQLN1/2 in cells. Steady-state and transfer NOE experiments indicate direct interaction of AZUL with the UBQLN1 UBA domain. Intermolecular contacts identified by NOESY data were combined with AlphaFold2-Multimer predictions to yield an AZUL:UBA model structure. We also identify a concentration-dependent oligomerization domain directly adjacent to UBQLN1/2 UBA (UBA-adjacent, UBAA) that is α-helical and allosterically reconfigured by AZUL binding to UBA. These data lead to a model of E6AP recruitment to UBQLN1/2 by AZUL:UBA interaction and provide fundamental information on binding requirements for interactions in droplets and cells.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2022,"id":304449,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9497,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":316960,"name":"Xiang Chen","orcid":"0000-0002-0036-0212","position":1,"is_corresponding":false},{"id":438117,"name":"Wazo Myint","orcid":"0000-0002-2055-5180","position":2,"is_corresponding":false},{"id":997856,"name":"Olumide Kayode","orcid":null,"position":3,"is_corresponding":false},{"id":997313,"name":"Varvara Folimonova","orcid":"0000-0002-7208-5328","position":4,"is_corresponding":false},{"id":575828,"name":"Anthony Cruz","orcid":"0000-0002-4858-993X","position":5,"is_corresponding":false},{"id":311319,"name":"Katarzyna Skorupka","orcid":"0000-0002-6631-6011","position":6,"is_corresponding":false},{"id":438121,"name":"Hiroshi Matsuo","orcid":"0000-0002-4559-6157","position":7,"is_corresponding":false},{"id":316963,"name":"Kylie J. Walters","orcid":"0000-0001-7590-2891","position":8,"is_corresponding":false},{"id":325212,"name":"Gwen R. Buel","orcid":"0000-0003-2917-3055","position":0,"is_corresponding":true}],"reference_count":72,"raw_metadata":null,"created_at":"2026-07-19T00:32:32.651796Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}