Distinct spectrum of ciliopathic diseases results from de novoTUBB4B variants through differential effects on organelle-specific microtubules

ABSTRACT: Microtubules are ancient and highly conserved polymers composed of alpha and beta tubulin heterodimers. Their dynamic remodelling drives diverse cellular processes from organelle trafficking and chromosome segregation to templating more stable structures like those of centrioles and ciliary axonemes. While organisms like Chlamydomonas reinhardtii only have a single - and -tubulin gene, TUBB4B, is one of 10 human -tubulin isotypes which can pair with one of the 9 isotypes of -tubulin. Whether this diversification permits discrete transcriptional units for cell type specific expression, or whether additional functional differences exist between isotypes remains unclear. Here, using human disease genetics, we reveal three distinct classes of ciliopathic disease in human patients carrying de novo mutations in TUBB4B. Using structure-function studies, we demonstrate these mutations differentially affect microtubule dynamics and cilia formation in a dominant negative manner. Importantly, using patient-modelled mutant as well as knockout Tubb4b mice we establish a necessary and non-redundant function for TUBB4B in building centrioles and axonemes of multiciliated cells. Our results suggest that a functional difference in TUBB4B is required to support the unique microtubule architecture in motile ciliated cells. It places primary ciliary dyskinesia and the ciliopathies more broadly into an expanding phenotypic and clinical spectrum of human tubulinopathies.

INSTRUMENT(S): Orbitrap Fusion Lumos, Q Exactive

ORGANISM(S): Homo Sapiens (human) Mus Musculus (mouse)

TISSUE(S): Epithelial Cell

SUBMITTER: Alex von kriegsheim  

LAB HEAD: Alex von Kriegsheim

PROVIDER: PXD036304 | Pride | 2024-01-30

REPOSITORIES: Pride