PMID:18973764

Citation	Ko, SI, Park, JH, Park, MJ, Kim, J, Kang, LW and Han, YS (2008) Human ribosomal protein S3 (hRpS3) interacts with uracil-DNA glycosylase (hUNG) and stimulates its glycosylase activity. Mutat. Res. 648:54-64
Abstract	Human ribosomal protein S3 (hRpS3) is a small ribosomal subunit showing apurinic/apyrimidinic (AP) lyase activity and has been suggested to play a role in the cellular DNA-damage response pathway. However, the functional interactions between hRpS3 and other base excision repair (BER) DNA glycosylases have not been reported. We identified, for the first time, the interaction between hRpS3 and human uracil-DNA glycosylase (hUNG) and investigated the functional consequences of this interaction. hRpS3 was shown to interact with hUNG in co-immunoprecipitation assay using transiently transfected HEK293 cells and GST pull-down assay using microbial expression systems. In an assay using a 5'-end-radiolabeled 39-mer oligonucleotide duplex containing a U/G mismatch, hRpS3 dramatically stimulated the uracil-excision activity of hUNG, whereas hRpS3 alone had no cleavage activity. Pre-incubation of hRpS3 with the U/G mismatch containing DNA duplex also increased the hUNG uracil-excision activity; however, hRpS3 did not increase the DNA binding activity of hUNG in a trapping assay of hUNG and the U/G mismatch containing DNA duplex using UV cross-linking. hRpS3 has been suggested to stimulate the uracil-excision activity of hUNG by enhancing its dissociation from AP sites and increasing its turn-over rate. The disruption of hRpS3 by small-interfering RNA (siRNA-hRpS3) transfection reduced the uracil-excision activity preserved in cell extracts, whereas the supplement of purified hRpS3 retained uracil-excision activity. These results strongly suggest that hRpS3 may be involved in the uracil-excision pathway, probably by participating in the DNA repair mechanism to remove uracil generated by the deamination of cytosine in DNA, and by preventing C/G-->T/A transition mutations.
Links	PubMed Online version:10.1016/j.mrfmmm.2008.09.013
Keywords	Base Pair Mismatch/physiology; Cells, Cultured; DNA/metabolism; DNA Repair/physiology; DNA-(Apurinic or Apyrimidinic Site) Lyase/metabolism; Enzyme Activation; Gene Knockdown Techniques; Humans; Point Mutation/physiology; Protein Binding; Recombinant Proteins/genetics; Recombinant Proteins/metabolism; Ribosomal Proteins/metabolism; Ribosomal Proteins/physiology; Transfection; Uracil/metabolism; Uracil-DNA Glycosidase/genetics; Uracil-DNA Glycosidase/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HUMAN:UNG	enables	GO:0003684: damaged DNA binding	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
HUMAN:UNG	involved_in	GO:0097510: base-excision repair, AP site formation via deaminated base removal	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
HUMAN:UNG	enables	GO:0005515: protein binding	ECO:0000353: physical interaction evidence used in manual assertion	UniProtKB:P23396	F		Seeded From UniProt	complete
HUMAN:UNG	enables	GO:0043024: ribosomal small subunit binding	ECO:0000353: physical interaction evidence used in manual assertion	UniProtKB:P23396	F		Seeded From UniProt	complete
HUMAN:RS3	involved_in	GO:0032079: positive regulation of endodeoxyribonuclease activity	ECO:0000314: direct assay evidence used in manual assertion		P	has_input:(UniProtKB:P27695)	Seeded From UniProt	complete
HUMAN:RS3	involved_in	GO:1905053: positive regulation of base-excision repair	ECO:0000314: direct assay evidence used in manual assertion		P	has_input:(UniProtKB:P13051)	Seeded From UniProt	complete
HUMAN:RS3	enables	GO:0019899: enzyme binding	ECO:0000353: physical interaction evidence used in manual assertion	UniProtKB:P13051	F		Seeded From UniProt	complete
HUMAN:APEX1	enables	GO:0003906: DNA-(apurinic or apyrimidinic site) endonuclease activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
HUMAN:APEX1	enables	GO:0008081: phosphoric diester hydrolase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete

References

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