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FLASH GENE
Symbol LIG3 contributors: mct/npt - updated : 01-10-2015
HGNC name ligase III, DNA, ATP-dependent
HGNC id 6600
PROTEIN
PHYSICAL PROPERTIES
STRUCTURE
motifs/domains
  • a BRCT domain
  • a PARP-type zinc finger
  • HOMOLOGY
    Homologene
    FAMILY
  • DNA ligase family
  • CATEGORY enzyme
    SUBCELLULAR LOCALIZATION     intracellular
    intracellular,cytoplasm,organelle,mitochondria
    intracellular,cytoplasm,cytoskeleton,microtubule,centrosome
    intracellular,nucleus,nucleoplasm
    intracellular,nucleus,chromatin/chromosome
    text
  • present in the mitochondria, where its role in mitochondrial DNA (mtDNA) maintenance is independent of XRCC1
  • basic FUNCTION
  • can correct defective DNA strand-break repair
  • and sister chromatid exchange following treatment with ionizing radiation and alkylating agents
  • required for microhomology-mediated end joining of DNA double-strand breaks
  • critical biological role of LIG3 is to maintain mtDNA integrity and not XRCC1-dependent DNA repair
  • LIG3 function was central to mitochondrial DNA maintenance 0)
  • promotes alternative nonhomologous end-joining during chromosomal translocation formation
  • crucial for cell survival due to its catalytic function in mitochondria
  • restricted to higher eukaryotes and has been associated with base excision (BER) and single strand break repair (SSBR)
  • XRCC1, a LIG3-stabilizing cofactor, and LIG3 itself have been very widely assumed to provide major end-ligation functions in A-EJ (alternative end-joining)
  • remarkable ability for LIG3 to backup DSB repair by NHEJ in addition to its essential function in the mitochondria
  • LIG1 and LIG3 cooperate in alternative non-homologous end-joining
  • LIG1 is not absolutely required for cellular DNA replication and repair and either LIG3 or LIG4 can substitute for the role of LIG1 in joining Okazaki fragments
  • LIG3 isoforms were seven times more efficient than LIG1 at ligating nicked DNA under optimal conditions
  • CELLULAR PROCESS nucleotide, replication
    nucleotide, repair, recombination
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
  • complexing with XRCC1
  • INTERACTION
    DNA
    RNA
    small molecule
    protein
  • interacts with DNA-repair protein XRCC1 (translocation of XRCC1 with LIG3 from centrosomes to chromosomes in response to DNA damage in mitotic cells)
  • LIG1 was critical for DNA repair, but acted in a cooperative manner with LIG3
  • interacting with POLG (interaction of DNA ligase III and DNA polymerase gamma is required for proper maintenance of the mitochondrial genome)
  • functional flexibility and interchangeability between LIG1 and LIG3
  • DNA repair partners of TDP1 include PARP1, XRCC1, ligase III and PNKP from the base excision repair (BER) pathway
  • cell & other
    REGULATION
    ASSOCIATED DISORDERS
    ANIMAL & CELL MODELS