{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRecent analyses have revealed that UBBP4, a pseudogene traditionally thought to be nonfunctional, is actively expressed and encodes a variant of ubiquitin—termed UbKEKS—with four specific amino acid substitutions (Q2K, K33E, Q49K, N60S). This variant is produced as part of an emerging paradigm in which certain pseudogene products, once dismissed as noncoding, can in fact contribute to posttranslational modifications of proteins."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n \nThe conjugation of UbKEKS to its target proteins demonstrates functional characteristics that differ from canonical ubiquitylation. Quantitative proteomics indicates that UbKEKS preferentially modifies proteins such as lamins. Perturbation of UBBP4 expression, exemplified by its knockout, results in cellular phenotypes including slowed cell division and mislocalization of lamin A into the nucleolus, suggesting that UbKEKS-mediated modification alters key aspects of nuclear organization and cell cycle regulation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n\nThese findings underscore the notion that modifications previously attributed solely to ubiquitin might also be mediated by ubiquitin variants originating from pseudogene products. The identification of UbKEKS challenges conventional views of pseudogenes as inert genomic fossils and implies a broader, previously unrecognized complexity in the regulation of protein dynamics and cell function."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Marie-Line Dubois, Anna Meller, Sondos Samandi, et al. "}, {"type": "b", "children": [{"type": "t", "text": "UBB pseudogene 4 encodes functional ubiquitin variants."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nat Commun (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41467-020-15090-6"}], "href": "https://doi.org/10.1038/s41467-020-15090-6"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "32161257"}], "href": "https://pubmed.ncbi.nlm.nih.gov/32161257"}]}]}]}