Ciliopathy patient variants reveal organelle-specific functions for TUBB4B in axonemal microtubules
Daniel O Dodd, Sabrina Méchaussier, Patricia L. Yeyati, Fraser McPhie, Jacob R. Anderson, Chen Jing Khoo, Amelia Shoemark, Deepesh Kumar Gupta, Thomas Attard, Maimoona A. Zariwala, Marie Legendre, Diana Bracht, Julia Wallmeier, Miao Gui, Mahmoud R. Fassad, David Parry, Peter A. Tennant, Alison Meynert, Gabrielle Wheway, Lucas Fares‐Taie, Holly A. Black, Rana Mitri-Frangieh, Catherine Faucon, Josseline Kaplan, Mitali Patel, Lisa McKie, Roly Megaw, Christos Gatsogiannis, Mai A. Mohamed, Stuart Aitken, Philippe Gautier, Finn R. Reinholt, Robert A. Hirst, Chris O’Callaghan, Ketil Heimdal, Mathieu Bottier, Estelle Escudier, Suzanne Crowley, Maria Descartes, Ethylin Wang Jabs, Priti Kenia, Jeanne Amiel, Giacomo Maria Bacci, Claudia Calogero, Viviana Palazzo, Lucia Tiberi, Ulrike Blümlein, Andrew Rogers, Jennifer Wambach, Daniel J. Wegner, Anne B. Fulton, Margaret A. Kenna, Margaret Rosenfeld, Ingrid A. Holm, Alan J. Quigley, Emma A. Hall, Laura C. Murphy, Diane Cassidy, Alex von Kriegsheim, Diane M. Cassidy, Alex von Kriegsheim, Jean‐François Papon, Laurent Pasquier, Marlène Murris, James D. Chalmers, Claire Hogg, Kenneth Macleod, Don S. Urquhart, Stefan Unger, Timothy J. Aitman, Serge Amselem, Margaret W. Leigh, Michael R. Knowles, Heymut Omran, Hannah M. Mitchison, Alan Brown, Joseph A. Marsh, Julie P. I. Welburn, Shih-Chieh Ti, Amjad Horani, Jean‐Michel Rozet, Isabelle Perrault, Pleasantine Mill, Isabelle Perrault, Pleasantine Mill
Abstract
Tubulin, one of the most abundant cytoskeletal building blocks, has numerous isotypes in metazoans encoded by different conserved genes. Whether these distinct isotypes form cell type– and context-specific microtubule structures is poorly understood. Based on a cohort of 12 patients with primary ciliary dyskinesia as well as mouse mutants, we identified and characterized variants in the TUBB4B isotype that specifically perturbed centriole and cilium biogenesis. Distinct TUBB4B variants differentially affected microtubule dynamics and cilia formation in a dominant-negative manner. Structure-function studies revealed that different TUBB4B variants disrupted distinct tubulin interfaces, thereby enabling stratification of patients into three classes of ciliopathic diseases. These findings show that specific tubulin isotypes have distinct and nonredundant subcellular functions and establish a link between tubulinopathies and ciliopathies.