Aliases for LIG4 Gene
External Ids for LIG4 Gene
Previous GeneCards Identifiers for LIG4 Gene
The protein encoded by this gene is a DNA ligase that joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction. This protein is essential for V(D)J recombination and DNA double-strand break (DSB) repair through nonhomologous end joining (NHEJ). This protein forms a complex with the X-ray repair cross complementing protein 4 (XRCC4), and further interacts with the DNA-dependent protein kinase (DNA-PK). Both XRCC4 and DNA-PK are known to be required for NHEJ. The crystal structure of the complex formed by this protein and XRCC4 has been resolved. Defects in this gene are the cause of LIG4 syndrome. Alternatively spliced transcript variants encoding the same protein have been observed. [provided by RefSeq, Jul 2008]
GeneCards Summary for LIG4 Gene
LIG4 (Ligase IV, DNA, ATP-Dependent) is a Protein Coding gene. Diseases associated with LIG4 include lig4 syndrome and dubowitz syndrome. Among its related pathways are Disease and Chks in Checkpoint Regulation. GO annotations related to this gene include protein C-terminus binding and DNA ligase activity. An important paralog of this gene is LIG3.
UniProtKB/Swiss-Prot for LIG4 Gene
Efficiently joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction. Involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair and V(D)J recombination. The LIG4-XRCC4 complex 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.
Ligases catalyze the joining of two molecules with concomitant hydrolysis of the diphosphate bond in ATP or a similar triphosphate. They belong to the E.C. 6 class, which also includes synthases and carboxylases. DNA ligases play an integral role in DNA repair and replication: they catalyze the formation of phosphodiester bonds, using ATP as a co-factor. These enzymes are divided into three classes: DNA ligase I, III and IV. DNA ligase I links Okazaki fragments to form a continuous strand of DNA. DNA ligase III is involved in base excision repair. Finally, DNA ligase IV is involved in the repair of DNA double-strand breaks by non-homologous end joining (NHEJ).