{"doi":"10.1101/2024.10.03.616566","title":"UBR4 regulates a MetAP2-dependent Arg/N-degron pathway","abstract":"ABSTRACT The open reading frame does more than merely encode a linear peptide sequence; it is a reservoir of regulatory information. Here, as part of investigations into how the N-terminal amino acids regulate translation, we serendipitously uncovered a new N-degron that revealed an additional layer of regulation in these pathways. Using reporter assays, we discovered that peptides bearing position 3 arginine or lysine residues at the N-terminus were rapidly degraded in mammalian cells. We found this pathway requires MetAP2, which co-translationally cleaves the N-terminal methionine preceding second position threonine and valines to initiate protein decay. We used CRISPR-Cas9 to knockout key N-recognins and found that these N-degrons are exclusively targeted by the E3 ligase UBR4, but not by UBR1 or UBR2. Together, our results characterize a new N-degron pathway that reveals a unique role for MetAP2 and UBR4 in mediating protein decay. SIGNIFICANCE The Arg/N-degron pathway targets position 1 or 2 N-terminal Lys and Arg residues via UBR Box E3 ligases to trigger protein decay. Here we show that UBR4 can specifically recognize position 3 Lys and Arg N-termini upon methionine removal by the methionine amino peptidase MetAP2. Accordingly, proteins that bear N-terminal residues that are processed by MetAP1 are unaffected by the loss or inhibition of MetAP2. Using a combination of reporter assays, and bioinformatic approaches were identified endogenous proteins whose N-termini are recognized by this MetAP2-dependent Arg/N-degron pathway. Thus, our results expand the number of Arg/N-degron substrates and describe a new mechanism through which they are targeted.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2024,"id":492072,"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":0.9507,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1005796,"name":"Emma C. Horton","orcid":"0000-0001-9730-7380","position":1,"is_corresponding":false},{"id":563255,"name":"Olivia S. Rissland","orcid":"0000-0002-2619-6019","position":2,"is_corresponding":false},{"id":469621,"name":"Evan J. Morrison","orcid":"0000-0003-2867-7665","position":0,"is_corresponding":true}],"reference_count":37,"raw_metadata":null,"created_at":"2026-07-19T02:08:49.768795Z","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":[]}