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: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-05-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-59323-y |
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| Summary: | 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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| ISSN: | 2041-1723 |