{"entity":{"id":"lig4","kind":"target","name":"LIG4","aka":["DNA ligase 4"],"tldr":"LIG4 (DNA ligase 4) is an enzyme. The public catalogues list it as a DNA repair gene, and the evidence so far is association rather than a proven role.","summary":"DNA ligase involved in DNA non-homologous end joining (NHEJ); required for double-strand break (DSB) repair and V(D)J recombination. Catalyses the NHEJ ligation step of the broken DNA during DSB repair by resealing the DNA breaks after the gap filling is completed. Joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction.\n\nOpen Targets scores its association with cancer at 0.54 (direct and indirect evidence; datatypes literature 0.88, animal model 0.51, genetic association 0.44, genetic literature 0.76).","asOf":"2026-09-23","links":[{"label":"HGNC HGNC:6601","url":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:6601"},{"label":"UniProt P49917","url":"https://www.uniprot.org/uniprotkb/P49917/entry"},{"label":"NCBI Gene 3981","url":"https://www.ncbi.nlm.nih.gov/gene/3981"},{"label":"Ensembl ENSG00000174405","url":"https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000174405"}],"tags":["cancer-genes-wave"],"related":["open-targets"],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":["homologous-recombination-repair"],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: UniProt keyword \"DNA repair\". Evidence tier \"association-only\" is the strongest of those signals.","Prevalence not recorded: none of the sources gives a positivity rate."],"provenance":{"editedBy":"scripts/fetch-cancer-genes.ts (CIViC, Open Targets, IntOGen, HGNC, UniProt)","editedOn":"2026-09-23"},"symbol":"LIG4","role":["dna-repair"],"evidenceTier":"association-only","sources":[{"label":"HGNC HGNC:6601","url":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:6601","note":"approved symbol, name, aliases, locus and cross-references (hgnc_complete_set.txt)"},{"label":"UniProt P49917","url":"https://www.uniprot.org/uniprotkb/P49917/entry","note":"protein name, function text, keywords and locations (REST API)"},{"label":"Open Targets ENSG00000174405","url":"https://platform.opentargets.org/target/ENSG00000174405/associations","note":"association with cancer (MONDO_0004992) 0.54;  (GraphQL API, CC0)"}],"hgnc":"HGNC:6601","ensembl":"ENSG00000174405","uniprot":"P49917","entrez":"3981","biology":"DNA ligase involved in DNA non-homologous end joining (NHEJ); required for double-strand break (DSB) repair and V(D)J recombination. Catalyses the NHEJ ligation step of the broken DNA during DSB repair by resealing the DNA breaks after the gap filling is completed. Joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction. LIG4 is mechanistically flexible: it can ligate nicks as well as compatible DNA overhangs alone, while in the presence of XRCC4, it can ligate ends with 2-nucleotides (nt) microhomology and 1-nt gaps. Forms a subcomplex with XRCC4; the LIG4-XRCC4 subcomplex is responsible for the NHEJ ligation step and XRCC4 enhances the joining activity of LIG4. Binding of the LIG4-XRCC4 complex to DNA ends is dependent on the assembly of the DNA-dependent protein kinase complex DNA-PK to these DNA ends. Location: Nucleus (UniProt). Locus 13q33.3 (HGNC).","whereFound":[],"targetClass":"enzyme","prevalence":[]},"route":"/targets/lig4/","neighbours":{"collection":[{"id":"open-targets","kind":"collection","name":"Open Targets Platform","route":"/collections/open-targets/"}],"pathway":[{"id":"homologous-recombination-repair","kind":"pathway","name":"Double-strand break repair: HR versus end joining","route":"/pathways/homologous-recombination-repair/"}]}}