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Regulation of the Functional Properties of Xeroderma Pigmentosum Complementation Group A (XPA) Protein through Lysine Acetylation
Author(s) -
Njeri Catherine,
Kaur Jasmeet,
Turchi John,
Balakrishnan Lata
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb56
Subject(s) - xeroderma pigmentosum , nucleotide excision repair , replication protein a , acetylation , dna repair , dna damage , complementation , dna , chemistry , dna binding protein , microbiology and biotechnology , biology , biochemistry , transcription factor , gene , phenotype
Nucleotide Excision Repair (NER) is the main repair pathway through which DNA damages occurring on account of ultraviolet (UV) or ionizing radiation (IR) are repaired. Xeroderma pigmentosum complementation group A (XPA) protein is a crucial part of the NER multi‐protein complex that plays an indispensable role in recognizing and binding the damaged DNA, as well as positioning other NER proteins optimally for efficient repair of the injury. Studies have shown that XPA can be dynamically acetylated and deacetylated impacting its involvement in the NER repair pathway. Deacetylation of XPA by SIRT1 enhances its interaction with the single strand DNA (ssDNA) binding protein, replication protein A (RPA). Our current research is focused on evaluating the effects of lysine acetylation on the structural and functional properties of XPA. Our mass spectrometry analysis revealed that XPA is in vitro acetylated at multiple sites by p300 and CBP acetyltransferases. We evaluated the effects of acetylation on the DNA binding properties of XPA protein using electrophoretic‐mobility shift assays (EMSA) and bio‐layer interferometry (BLI) technology. Interestingly, our results show that acetylation of XPA significantly lowers its binding affinity for cisplatin damaged DNA. Similar to reports in vivo , analysis of protein‐protein interactions between XPA and RPA, revealed that acetylation of XPA reduces its ability to interact with RPA. Our results suggest that acetylation of XPA negatively affects its role in recognizing, binding and consequently repairing damaged DNA, which in turn may impact subsequent recruitment of RPA. By application, our results present a mechanistic approach towards negatively modulating the effectiveness of the NER pathway, with the aim of improving the efficacy of current chemotherapeutics. Support or Funding Information This work was supported by a grant from the National Institutes of Health GM0983289 (to LB)