Human IFT52 mutations uncover a novel role for the protein in microtubule dynamics and centrosome cohesion

Abstract

Mutations in genes encoding components of the intraflagellar transport (IFT) complexes have previously been associated with a spectrum of diseases collectively termed ciliopathies. Ciliopathies relate to defects in the formation or function of the cilium, a sensory or motile organelle present on the surface of most cell types. IFT52 is a key component of the IFT-B complex and ensures the interaction of the two subcomplexes, IFT-B1 and IFT-B2. Here, we report novel IFT52 biallelic mutations in cases with a short-rib thoracic dysplasia (SRTD) or a congenital anomaly of kidney and urinary tract (CAKUT). Combining in vitro and in vivo studies in zebrafish, we showed that SRTD-associated missense mutation impairs IFT-B complex assembly and IFT-B2 ciliary localization, resulting in decreased cilia length. In comparison, CAKUT-associated missense mutation has a mild pathogenicity, thus explaining the lack of skeletal defects in CAKUT case. In parallel, we demonstrated that the previously reported homozygous nonsense IFT52 mutation associated with Sensenbrenner syndrome [Girisha et al. (2016) A homozygous nonsense variant in IFT52 is associated with a human skeletal ciliopathy. Clin. Genet., 90, 536–539] leads to exon skipping and results in a partially functional protein. Finally, our work uncovered a novel role for IFT52 in microtubule network regulation. We showed that IFT52 interacts and partially co-localized with centrin at the distal end of centrioles where it is involved in its recruitment and/or maintenance. Alteration of this function likely contributes to centriole splitting observed in Ift52−/− cells. Altogether, our findings allow a better comprehensive genotype–phenotype correlation among IFT52-related cases and revealed a novel, extra-ciliary role for IFT52, i.e. disruption may contribute to pathophysiological mechanisms.

Bi-allelic Mutations in TTC29 Cause Male Subfertility with Asthenoteratospermia in Humans and Mice

“…Additionally, the analysis on TTC30A (also known as IFT70A, a component of IFT complex B), which is essential for anterograde IFT and ciliogenesis, 43,44 revealed a significantly reduced TTC30A staining in the spermatozoa from men harboring TTC29 mutations (Figures 4A and S4). Furthermore, IFT52 (a key component of IFT complex B), which plays a crucial role in microtubule anchorage and centrosome cohesion, 45,46 showed an atypical localization on the sperm flagella of men harboring TTC29 mutations in comparison with the control. IFT52 staining was found mainly at the flagellar base and faintly along flagella in the control, but it was weak and only aggregated at the base of sperm flagella in men harboring TTC29 mutations (Figures 4B and S5).…”

Characterization of primary cilia features reveal cell-type specific variability in in vitro models of osteogenic and chondrogenic differentiation

“…All cell-lines evaluated here have been extensively utilized to study molecular processes underlying osteoblast, chondrocyte differentiation and bone disorders, for example, osteoporosis and ciliopathies. It is noteworthy that skeletal ciliopathies such as short-rib thoracic dysplasias and cranioectodermal dysplasias are characterized by changes in primary cilia length and frequencies (Dupont et al, 2019;Walczak-Sztulpa et al, 2010). Moreover, degenerative conditions such as bone aging and osteoporosis are marked by the suppression of autophagy in osteocytes owing to their susceptibility to hypoxia and oxidative stress (Onal et al, 2013).…”

Principles and Practical Considerations for the Analysis of Disease-Associated Alternative Splicing Events Using the Gateway Cloning-Based Minigene Vectors pDESTsplice and pSpliceExpress

“…Depending on the objectives of the study, different experimental settings and laboratory protocols can be used. To give an overview of the potential applications of the pDESTsplice and pSpliceExpress vectors, we have compiled 25 published studies [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ], in which these minigene systems were used ( Table 1 and Table 2 ). In most of the works, the usage of pSpliceExpress has been described ( n = 18).…”