Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair

Abstract FAN1 is a DNA dependent nuclease whose proper function is essential for maintaining human health. For example, a genetic variant in FAN1, Arg507 to His hastens onset of Huntington’s disease, a repeat expansion disorder for which there is no cure. How the Arg507His mutation affects FAN1 stru...

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Main Authors: F. Li, A. S. Phadte, M. Bhatia, S. Barndt, A. R. Monte Carlo III, C-F. D. Hou, R. Yang, S. Strock, A. Pluciennik
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-59323-y
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author F. Li
A. S. Phadte
M. Bhatia
S. Barndt
A. R. Monte Carlo III
C-F. D. Hou
R. Yang
S. Strock
A. Pluciennik
author_facet F. Li
A. S. Phadte
M. Bhatia
S. Barndt
A. R. Monte Carlo III
C-F. D. Hou
R. Yang
S. Strock
A. Pluciennik
author_sort F. Li
collection DOAJ
description Abstract FAN1 is a DNA dependent nuclease whose proper function is essential for maintaining human health. For example, a genetic variant in FAN1, Arg507 to His hastens onset of Huntington’s disease, a repeat expansion disorder for which there is no cure. How the Arg507His mutation affects FAN1 structure and enzymatic function is unknown. Using cryo-EM and biochemistry, we have discovered that FAN1 arginine 507 is critical for its interaction with PCNA, and mutation of Arg507 to His attenuates assembly of the FAN1–PCNA complex on a disease-relevant extrahelical DNA extrusions formed within DNA repeats. This mutation concomitantly abolishes PCNA–FAN1–dependent cleavage of such extrusions, thus unraveling the molecular basis for a specific mutation in FAN1 that dramatically hastens the onset of Huntington’s disease. These results underscore the importance of PCNA to the genome stabilizing function of FAN1.
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spelling doaj-art-623b745b2ebc46e19898231d4eaab2ad2025-08-20T02:25:08ZengNature PortfolioNature Communications2041-17232025-05-0116111610.1038/s41467-025-59323-yStructural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repairF. Li0A. S. Phadte1M. Bhatia2S. Barndt3A. R. Monte Carlo III4C-F. D. Hou5R. Yang6S. Strock7A. Pluciennik8Department of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Molecular Biology, Princeton UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityDepartment of Biochemistry and Molecular Biology, Thomas Jefferson UniversityAbstract FAN1 is a DNA dependent nuclease whose proper function is essential for maintaining human health. For example, a genetic variant in FAN1, Arg507 to His hastens onset of Huntington’s disease, a repeat expansion disorder for which there is no cure. How the Arg507His mutation affects FAN1 structure and enzymatic function is unknown. Using cryo-EM and biochemistry, we have discovered that FAN1 arginine 507 is critical for its interaction with PCNA, and mutation of Arg507 to His attenuates assembly of the FAN1–PCNA complex on a disease-relevant extrahelical DNA extrusions formed within DNA repeats. This mutation concomitantly abolishes PCNA–FAN1–dependent cleavage of such extrusions, thus unraveling the molecular basis for a specific mutation in FAN1 that dramatically hastens the onset of Huntington’s disease. These results underscore the importance of PCNA to the genome stabilizing function of FAN1.https://doi.org/10.1038/s41467-025-59323-y
spellingShingle F. Li
A. S. Phadte
M. Bhatia
S. Barndt
A. R. Monte Carlo III
C-F. D. Hou
R. Yang
S. Strock
A. Pluciennik
Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair
Nature Communications
title Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair
title_full Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair
title_fullStr Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair
title_full_unstemmed Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair
title_short Structural and molecular basis of PCNA-activated FAN1 nuclease function in DNA repair
title_sort structural and molecular basis of pcna activated fan1 nuclease function in dna repair
url https://doi.org/10.1038/s41467-025-59323-y
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