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bioRxiv · 10.64898/2026.08.13.744621

The centromere localization domain of kinetoplastid kinetochore protein KKT2 recognizes the free N-terminus of histone H3

Ciszek, A.·Ludzia, P.·Marciano, G.·Allen, W.·Ishii, M.·Forsyth, S.·Wood, C. W.·Redfield, C.·Akiyoshi, B.
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Abstract

Kinetochores are multiprotein complexes that drive chromosome segregation in eukaryotes. Kinetoplastids, a group of early-diverging eukaryotes that lack canonical kinetochore components, have a unique set of kinetochore proteins. How their kinetochores are assembled specifically at centromeres in the absence of a centromere-specific histone H3 variant CENP-A remains unknown. Here, we demonstrate that the centromere localization (CL) domain of KKT2 has similarities to a ZZ domain. An invariant aspartate present in histone H3-binding ZZ domains is conserved in the KKT2 CL domain. Using nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC), we show that Trypanosoma brucei KKT2 CL binds the N-terminus of histone H3. Strikingly, even mono-methylation of the N-terminal amino group of histone H3 abolishes the binding. Our study raises a possibility that centromere-specific kinetochore assembly in T. brucei is ensured by abundant N-terminal methylations of histone H3 in non-centromeric regions.

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Ciszek, A., Ludzia, P., Marciano, G., Allen, W., Ishii, M., Forsyth, S., Wood, C. W., Redfield, C., Akiyoshi, B.. 2026-08-18. The centromere localization domain of kinetoplastid kinetochore protein KKT2 recognizes the free N-terminus of histone H3. https://doi.org/10.64898/2026.08.13.744621

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