CryoET reveals actin filaments within platelet microtubules

Tsuji, C.; Bradshaw, M.; Allen, M.; Jackson, M. L.; Mantell, J.; Borucu, U.; Poole, A. W.; Verkade, P.; Hers, I.; Paul, D. M.; Dodding, M.

doi:10.1101/2023.11.24.568450

bioRxiv · 10.1101/2023.11.24.568450

CryoET reveals actin filaments within platelet microtubules

Tsuji, C.·Bradshaw, M.·Allen, M.·Jackson, M. L.·Mantell, J.·Borucu, U.·Poole, A. W.·Verkade, P.·Hers, I.·Paul, D. M.·Dodding, M.

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Abstract

Crosstalk between the actin and microtubule cytoskeletons is essential for many cellular processes. Recent studies have shown that microtubules and F-actin can assemble to form a composite structure where F-actin occupies the microtubule lumen. Whether these cytoskeletal hybrids exist in physiological settings and how they are formed is unclear. Here, we show that the short-crossover Class I actin filament previously identified inside microtubules in human HAP1 cells is cofilin-bound F-actin. Lumenal F-actin can be reconstituted in vitro, but cofilin is not essential. Moreover, actin filaments with both cofilin-bound and canonical morphologies reside within human platelet microtubules under physiological conditions. We propose that stress placed upon the microtubule network during motor-driven microtubule looping and sliding may facilitate the incorporation of actin into microtubules.

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Tsuji, C., Bradshaw, M., Allen, M., Jackson, M. L., Mantell, J., Borucu, U., Poole, A. W., Verkade, P., Hers, I., Paul, D. M., Dodding, M.. 2023-11-25. CryoET reveals actin filaments within platelet microtubules. https://doi.org/10.1101/2023.11.24.568450

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