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Identification of a coiled coil in Werner syndrome protein that facilitates multimerization and promotes exonuclease processivity

Publication Type : Journal Article

Publisher : Journal of Biological Chemistry

Source : Journal of Biological Chemistry, Volume 285, Number 33, p.25699-25707 (2010)

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Keywords : 4 nitroquinoline 1 oxide, 4 nitroquinoline 1 oxides, 4-Nitroquinoline-1-oxide, amino acid sequence, article, Blotting, camptothecin, Camptothecins, Chromatography, Coiled coil, Coiled coil regions, Coiled-coil domains, controlled study, Diseases, DNA, DNA damage, DNA-dependent protein kinase, enzyme active site, enzyme activity, enzyme phosphorylation, Exodeoxyribonucleases, Exonuclease, Exonuclease activity, Exonucleases, gel, Genes, genomic instability, Hela Cells, helicase, Helicases, human, human cell, Human cells, Humans, Immunoprecipitation, In-cell, In-vivo, Kinase activity, Multimeric, Multimerization, Multimers, Nuclease domain, Over-expression, Phosphorylation, Phosphorylation sites, polymerase chain reaction, priority journal, Processivity, protein determination, protein domain, protein expression, protein function, protein multimerization, protein processing, Protein Structure, Proteins, RecQ Helicases, sensitivity analysis, structure analysis, Tertiary, Werner syndrome, Werner syndrome protein, Western

Campus : Amritapuri

School : School of Biotechnology

Department : biotechnology

Year : 2010

Abstract : Werner syndrome (WS) is a rare progeroid disorder characterized by genomic instability, increased cancer incidence, and early onset of a variety of aging pathologies. WS is unique among early aging syndromes in that affected individuals are developmentally normal, and phenotypic onset is in early adulthood. The protein defective in WS (WRN) is a member of the large RecQ family of helicases but is unique among this family in having an exonuclease. RecQ helicases form multimers, but the mechanism and consequence of multimerization remain incompletely defined. Here, we identify a novel heptad repeat coiled coil region between the WRN nuclease and helicase domains that facilitates multimerization of WRN. We mapped a novel and unique DNA-dependent protein kinase phosphorylation site proximal to the WRN multimerization region. However, phosphorylation at this site affected neither exonuclease activity nor multimericstate. We found that WRN nuclease is stimulated by DNA-dependent protein kinase independently of kinase activity or WRN nuclease multimeric status. In addition, WRN nuclease multimerization significantly increased nuclease processivity. We found that the novel WRN coiled coil domain is necessary for multimerization of the nuclease domain and sufficient to multimerize with full-length WRN in human cells. Importantly, correct homomultimerization is required for WRN function in vivo as overexpression of this multimerization domain caused increased sensitivity to camptothecin and 4-nitroquinoline 1-oxide similar to that in cells lacking functional WRN protein.

Cite this Research Publication : J. J. Pcf Perry, Asaithamby, Ad, Barnebey, Aa, Kiamanesch, Fd, Chen, D. Jd, Han, Se, Tainer, J. Aac, and Yannone, S. Mab, “Identification of a coiled coil in Werner syndrome protein that facilitates multimerization and promotes exonuclease processivity”, Journal of Biological Chemistry, vol. 285, pp. 25699-25707, 2010.

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