Download MendeleyFilament formation and NAD processing by noncanonical human FAM118 sirtuins.
Baretic, D., Missoury, S., Patel, K., Martinez, M., Coste, F., Zhu, K., Smith, R., Kopasz, A.G., Lu, Y., Bigot, N., Chapuis, C., Riou, R., Dukic, N., Goffinont, S., Pressoir, V., Patacko, S., Timinszky, G., Delarue, M., Castaing, B., Ahel, D., Mikoc, A., Huet, S., Ahel, I., Suskiewicz, M.J.(2025) Nat Struct Mol Biol
- PubMed: 41249820
- DOI: https://doi.org/10.1038/s41594-025-01715-1
- Primary Citation of Related Structures:
9R0P, 9R0S, 9R3E - PubMed Abstract:
Sirtuins are an ancient family of enzymes with diverse nicotinamide adenine dinucleotide (NAD)-dependent activities. Here we identify family with sequence similarity 118 member B (FAM118B) and FAM118A-two understudied vertebrate proteins-as vertebrate-specific sirtuins with similarities to bacterial antiphage sirtuins. We show that human FAM118B forms head-to-tail filaments both in vitro and in living human cells, a feature that appears to be conserved in both FAM118B and its paralog FAM118A across vertebrates. While human FAM118B and FAM118A have individually very weak NAD-processing activity in vitro, their interaction leads to markedly increased activity, suggesting a tightly regulated system. The overexpression of wild-type human FAM118B and FAM118A leads to strongly decreased NAD levels in human cells, an effect that is abolished in catalytically dead or filament-deficient mutants. Our study highlights filament formation and NAD processing as conserved mechanisms among immunity-associated sirtuins across evolution.
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
Organizational Affiliation:
