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DNA ligase-4 (LIG4)
Function:
- efficiently joins single-strand breaks in a double-stranded polydeoxynucleotide (ATP-dependent)
- role in DNA nonhomologous end joining (NHEJ) required for double-strand break repair & V(D)J recombination
- binds to XRCC4
- the LIG4-XRCC4 complex has probably a 1:2 stoichiometry
- LIG4-XRCC4 complex is responsible for the NHEJ ligation step, & 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
- the LIG4-XRCC4 heteromer associates in a DNA-dependent manner with the DNA-dependent protein kinase complex DNA-PK, formed by the Ku p70/p86 dimer (G22P1/G22P2) & PRKDC
ATP + (deoxyribonucleotide)(n) + (deoxyribonucleotide)(m)
AMP + diphosphate + (deoxyribonucleotide)(n+m)
Structure:
- belongs to the ATP-dependent DNA ligase family
- contains 2 BRCT domains
Compartment: nucleus
Expression: testis, thymus, prostate & heart
Pathology:
- defects in LIG4 are the cause of LIG4 syndrome
General
ATP-dependent DNA ligase
phosphoprotein
Properties
SIZE: entity length = 911 aa
MW = 104 kD
COMPARTMENT: cell nucleus
MOTIF: lysine residue {K273}
Thr phosphorylation site {T347}
BRCA1 C-terminal (BRCT) motif
SITE: 654-743
BRCA1 C-terminal (BRCT) motif
SITE: 808-911
References
- UniProt :accession P49917
- LIG4base; Note: LIG4 mutation db
http://bioinf.uta.fi/LIG4base/
- Wikipedia; Note: DNA ligase entry
http://en.wikipedia.org/wiki/DNA_ligase
Databases & Figures
OMIM correlations
MORBIDMAP 601837
UniProt P49917
PFAM correlations
Kegg hsa:3981
ENZYME 6.5.1.1
Figures/diagrams/slides/tables related to DNA ligase-4