SPEF1 mediates assembly of central pair microtubule complexes in cilia of Tetrahymena
SPEF1 is a conserved calponin-homology domain protein that decorates the seam of central pair microtubules in the distal segment of motile cilia. Here, we show that in the ciliate Tetrahymena, loss of SPEF1 disrupts the central pair throughout the middle segment, which comprises most of the cilium, producing gaps in the microtubule lattice, truncations of proximal microtubule regions, and loss of lateral projections. Although visible structural defects were restricted to the central microtubules, SPEF1 also localized to the ciliary outer doublets and to all classes of non-ciliary cortical microtubules. Within cilia, SPEF1 was strongly enriched near the distal tip but was also present throughout the middle segment, where it was more abundant on the central than on the outer doublet microtubules. In live cilia, most SPEF1 particles were stationary and turned over slowly; some underwent diffusion, but none moved by intraflagellar transport. Central pair defects arose early during ciliary assembly. We propose that SPEF1 functions as a general microtubule stabilizer whose activity is particularly important for the assembly of central pair microtubules within the middle ciliary segment.
Authors
- Thomas M. Kitzler (ORCID: https://orcid.org/0009-0006-1537-5237)
- Heymut Omran (ORCID: https://orcid.org/0000-0003-0282-6765)
- Dorota Włoga (ORCID: https://orcid.org/0000-0003-3314-7773)
- Yu‐Yang Jiang (ORCID: https://orcid.org/0000-0002-0338-4252)
- Zachary W. Nurcombe
- Lina Mougharbel (ORCID: https://orcid.org/0009-0009-9121-2853)
- Courtney Ozzello (ORCID: https://orcid.org/0000-0001-7172-7926)
- Krishna Kumar Vasudevan
- Corbin Black (ORCID: https://orcid.org/0000-0003-2777-6434)
- Khanh Huy Bui (ORCID: https://orcid.org/0000-0003-2814-9889)
- Mireya Parra (ORCID: https://orcid.org/0009-0002-2025-6372)
- Chad G. Pearson (ORCID: https://orcid.org/0000-0003-1915-6593)
- Mayukh Guha (ORCID: https://orcid.org/0000-0003-1323-6015)
- Panagiota Louka (ORCID: https://orcid.org/0000-0002-5847-5258)
- Raphaël F.-X. Tomasi
- Ewa Joachimiak (ORCID: https://orcid.org/0000-0003-3185-7923)
- Jacek Gaertig (ORCID: https://orcid.org/0000-0003-4420-4630)
- Charles N. Baroud (ORCID: https://orcid.org/0000-0001-5414-2010)
- Gerard W. Dougherty (ORCID: https://orcid.org/0000-0001-6905-8110)
- Pascale Dupuis‐Williams (ORCID: https://orcid.org/0000-0003-2070-1042)
- Karl F. Lechtreck (ORCID: https://orcid.org/0000-0002-6219-6470)
- Avrin Ghanaeian (ORCID: https://orcid.org/0009-0004-3554-4830)
- Neeraj Sharma (ORCID: https://orcid.org/0000-0002-6965-4833)
Institutions
- École Polytechnique (FR)
- Inserm (FR)
- Institut Pasteur (FR)
- University of Georgia (US)
- Instytut Biologii Doświadczalnej im. Marcelego Nenckiego (PL)
- University of Colorado Boulder (US)
- Université Paris Cité (FR)
- Université Paris-Saclay (FR)
- McGill University Health Centre (CA)
- Augenstern (DE)
- Laboratoire d'Hydrodynamique de l'École polytechnique (FR)
- University Hospital Münster (DE)
- McGill Genome Centre (CA)
- Cytoskeleton (United States) (US)
- McGill University (CA)
- University of Colorado Anschutz Medical Campus (US)
- ESPCI Paris (FR)
- Polish Academy of Sciences (PL)
Publication Details
- Journal
- Journal of Cell Science
- Published
- 2026-09-14
- DOI
- https://doi.org/10.1242/jcs.264648
- Citations
- 1
- Primary Topic
- Genetic and Kidney Cyst Diseases
- Type
- article
- Field-Weighted Citation Impact
- 5.10
Funders
- Deutsche Forschungsgemeinschaft
- Narodowe Centrum Nauki
- Narodowym Centrum Nauki
- Sickkids Research Institute
- Canadian Institutes of Health Research
- Natural Sciences and Engineering Research Council of Canada
- Fonds de Recherche du Québec - Santé
- National Institute of General Medical Sciences
- FP7 Ideas: European Research Council