Cell-Specific ?-Tubulin Isotype Regulates Ciliary Microtubule Ultrastructure, Intraflagellar Transport, and Extracellular Vesicle Biology.

ABSTRACT: Cilia are found on most non-dividing cells in the human body and, when faulty, cause a wide range of pathologies called ciliopathies. Ciliary specialization in form and function is observed throughout the animal kingdom, yet mechanisms generating ciliary diversity are poorly understood. The "tubulin code"-a combination of tubulin isotypes and tubulin post-translational modifications-can generate microtubule diversity. Using C. elegans, we show that ?-tubulin isotype TBA-6 sculpts 18 A- and B-tubule singlets from nine ciliary A-B doublet microtubules in cephalic male (CEM) neurons. In CEM cilia, tba-6 regulates velocities and cargoes of intraflagellar transport (IFT) kinesin-2 motors kinesin-II and OSM-3/KIF17 without affecting kinesin-3 KLP-6 motility. In addition to their unique ultrastructure and accessory kinesin-3 motor, CEM cilia are specialized to produce extracellular vesicles. tba-6 also influences several aspects of extracellular vesicle biology, including cargo sorting, release, and bioactivity. We conclude that this cell-specific ?-tubulin isotype dictates the hallmarks of CEM cilia specialization. These findings provide insight into mechanisms generating ciliary diversity and lay a foundation for further understanding the tubulin code.

SUBMITTER: Silva M 

PROVIDER: S-EPMC5688951 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature