Cell-free reconstitution reveals synergistic stabilization of microtubule doublets by PACRG and FAP20
Abstract Ciliary microtubule doublets, consisting of an incomplete B-tubule on the surface of a complete A-microtubule, form the fundamental structural framework of motile and sensory cilia/flagella. Ciliary proteins PACRG and FAP20, which are essential for flagellar stability and function, localize to the junction between the A- and the B-tubule. However, their precise role in microtubule doublet assembly and dynamics remains unknown. Here, using a cell-free assay, TIRF-microscopy, and cryo-electron tomography, we demonstrate that in combination PACRG and FAP20 stabilize B-tubule dynamics and microtubule doublet architecture. We show that together these proteins localize to the B-tubules in distinct, high-density patches, which locally stabilize B-tubule by decreasing its depolymerization velocity and increasing its rescue frequency. Cryo-tomography of in vitro reconstructed microtubule doublets in presence of PACRG and FAP20 reveals reduced B-tubule curvature fluctuations, promoting a more rigid and aligned conformation. Altogether, our findings suggest that PACRG and FAP20 function synergistically to reinforce microtubule doublet stability, ensuring ciliary integrity and function.
Authors
- Marcus Braun (ORCID: https://orcid.org/0000-0003-2026-2238)
- Zdeněk Lánský (ORCID: https://orcid.org/0000-0001-8474-053X)
- Arya Krishnan (ORCID: https://orcid.org/0000-0002-0872-6928)
- Daria Khuntsariya
- Daniel Rozbeský (ORCID: https://orcid.org/0000-0001-6546-8219)
- Virginie Hamel (ORCID: https://orcid.org/0000-0001-5092-2343)
- Paul Guichard (ORCID: https://orcid.org/0000-0002-0363-1049)
- Florent Lemaître (ORCID: https://orcid.org/0000-0002-3787-038X)
- Souradip Mukherjee (ORCID: https://orcid.org/0000-0002-7037-1996)
- Umut Batman (ORCID: https://orcid.org/0000-0003-2591-6704)
- Carsten Janke (ORCID: https://orcid.org/0000-0001-7053-2000)
Institutions
- University of Geneva (CH)
- Centre National de la Recherche Scientifique (FR)
- Inserm (FR)
- Czech Academy of Sciences (CZ)
- Charles University (CZ)
- Université Paris Sciences et Lettres (FR)
- Université Paris-Saclay (FR)
- Czech Academy of Sciences, Institute of Biotechnology (CZ)
- Czech Academy of Sciences, Institute of Molecular Genetics (CZ)
- Institut Curie (FR)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-10-16
- DOI
- https://doi.org/10.1038/s41467-026-78500-1
- Primary Topic
- Genetic and Kidney Cyst Diseases
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Univerzita Karlova v Praze
- Grantová Agentura, Univerzita Karlova
- Agence Nationale de la Recherche
- Ministerstvo Školství, Mládeže a Tělovýchovy
- Grantová Agentura České Republiky
- Fondation pour la Recherche Médicale
- Staatssekretariat für Bildung, Forschung und Innovation