Domain analysis of PNKP–XRCC1 interactions: Influence of genetic variants of XRCC1
| Autor: | Inbal Mermershtain, Rajam S. Mani, Ismail Abdou, Michael Weinfeld, J. N. Mark Glover, Michael J. Hendzel, Mesfin Fanta |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
DNA repair Polynucleotide Kinase Phosphatase CHO Cells Biochemistry Polymorphism Single Nucleotide Protein–protein interaction 03 medical and health sciences chemistry.chemical_compound XRCC1 Cricetulus Animals Protein Interaction Domains and Motifs Protein Interaction Maps Kinase activity Molecular Biology 030102 biochemistry & molecular biology Cell Biology Cell biology Phosphotransferases (Alcohol Group Acceptor) 030104 developmental biology DNA Repair Enzymes X-ray Repair Cross Complementing Protein 1 chemistry Protein Structure and Folding Phosphorylation DNA DNA Damage |
| Popis: | Polynucleotide kinase/phosphatase (PNKP) and X-ray repair cross-complementing 1 (XRCC1) are key proteins in the single-strand DNA break repair pathway. Phosphorylated XRCC1 stimulates PNKP by binding to its forkhead-associated (FHA) domain, whereas nonphosphorylated XRCC1 stimulates PNKP by interacting with the PNKP catalytic domain. Here, we have further studied the interactions between these two proteins, including two variants of XRCC1 (R194W and R280H) arising from single-nucleotide polymorphisms (SNPs) that have been associated with elevated cancer risk in some reports. We observed that interaction of the PNKP FHA domain with phosphorylated XRCC1 extends beyond the immediate, well-characterized phosphorylated region of XRCC1 (residues 515-526). We also found that an XRCC1 fragment, comprising residues 166-436, binds tightly to PNKP and DNA and efficiently activates PNKP's kinase activity. However, interaction of either of the SNP-derived variants of this fragment with PNKP was considerably weaker, and their stimulation of PNKP was severely reduced, although they still could bind DNA effectively. Laser microirradiation revealed reduced recruitment of PNKP to damaged DNA in cells expressing either XRCC1 variant compared with PNKP recruitment in cells expressing WT XRCC1 even though WT and variant XRCC1s were equally efficient at localizing to the damaged DNA. These findings suggest that the elevated risk of cancer associated with these XRCC1 SNPs reported in some studies may be due in part to the reduced ability of these XRCC1 variants to recruit PNKP to damaged DNA. |
| Databáze: | OpenAIRE |
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