Cilia are versatile, microtubule-based organelles that facilitate cellular signaling, motility, and environmental sensing in eukaryotic cells. These dynamic structures act as hubs for key developmental signaling pathways, while their assembly and disassembly are intricately regulated along cell cycle transitions. Recent findings show that factors regulating ciliogenesis and cilia dynamics often integrate their roles across other cellular processes, including cell cycle regulation, cytoskeletal organization, and intracellular trafficking, ensuring multilevel crosstalk of mechanisms controlling organogenesis. Disruptions in these shared regulators lead to broad defects associated with both ciliopathies and cancer. This review explores the crosstalk of regulatory mechanisms governing cilia assembly, disassembly, and maintenance during ciliary signaling and the cell cycle, along with the broader implications for development, tissue homeostasis, and disease.

• Klíčová slova
• Cancer, Cell cycle regulation, Cilia, Ciliary dynamics, Ciliary signaling, Ciliopathies, Tissue development,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Bardet-Biedl syndrome (BBS) is a pleiotropic ciliopathy caused by dysfunction of the BBSome, a cargo adaptor essential for export of transmembrane receptors from cilia. Although actin-dependent ectocytosis has been proposed to compensate defective cargo retrieval, its molecular basis remains unclear, especially in relation to BBS pathology. In this study, we investigated how actin polymerization and ectocytosis are regulated within the cilium. Our findings reveal that ciliary CDC42, a RHO-family GTPase triggers in situ actin polymerization, ciliary ectocytosis, and cilia shortening in BBSome-deficient cells. Activation of the Sonic Hedgehog pathway further enhances CDC42 activity specifically in BBSome-deficient cilia. Inhibition of CDC42 in BBSome-deficient cells decreases the frequency and duration of ciliary actin polymerization events, causing buildup of G protein coupled receptor 161 (GPR161) in bulges along the axoneme during Sonic Hedgehog signaling. Overall, our study identifies CDC42 as a key trigger of ciliary ectocytosis. Hyperactive ciliary CDC42 and ectocytosis and the resulting loss of ciliary material might contribute to BBS disease severity.

• Klíčová slova
• Actin, Bardet-Biedl Syndrome, CDC42, Cilium, Ectocytosis,
• MeSH
• aktiny * metabolismus   MeSH
• Bardetův-Biedlův syndrom * metabolismus   genetika   patologie   MeSH
• cdc42 protein vázající GTP * metabolismus   genetika   MeSH
• cilie * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• proteiny hedgehog metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   genetika   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aktiny * MeSH
• cdc42 protein vázající GTP * MeSH
• proteiny hedgehog MeSH
• receptory spřažené s G-proteiny MeSH

Microtubule doublets (MTDs) comprise an incomplete microtubule (B-tubule) attached to the side of a complete cylindrical microtubule. These compound microtubules are conserved in cilia across the tree of life; however, the mechanisms by which MTDs form and are maintained in vivo remain poorly understood. Here, we identify microtubule-associated protein 9 (MAP9) as an MTD-associated protein. We demonstrate that C. elegans MAPH-9, a MAP9 homolog, is present during MTD assembly and localizes exclusively to MTDs, a preference that is in part mediated by tubulin polyglutamylation. We find that loss of MAPH-9 causes ultrastructural MTD defects, including shortened and/or squashed B-tubules with reduced numbers of protofilaments, dysregulated axonemal motor velocity, and perturbed cilia function. Because we find that the mammalian ortholog MAP9 localizes to axonemes in cultured mammalian cells and mouse tissues, we propose that MAP9/MAPH-9 plays a conserved role in regulating ciliary motors and supporting the structure of axonemal MTDs.

• Klíčová slova
• C. elegans, MAP9, axoneme, cilia, dynein, kinesin, microtubule, microtubule doublet, microtubule-associated protein, polyglutamylation,
• MeSH
• axonema * metabolismus   ultrastruktura   MeSH
• Caenorhabditis elegans * metabolismus   MeSH
• cilie metabolismus   MeSH
• mikrotubuly metabolismus   MeSH
• myši MeSH
• pohyb MeSH
• savci MeSH
• tubulin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• Map9 protein, mouse MeSH Prohlížeč
• tubulin MeSH

Usher syndrome (USH) is the most common form of monogenic deaf-blindness. Loss of vision is untreatable and there are no suitable animal models for testing therapeutic strategies of the ocular constituent of USH, so far. By introducing a human mutation into the harmonin-encoding USH1C gene in pigs, we generated the first translational animal model for USH type 1 with characteristic hearing defect, vestibular dysfunction, and visual impairment. Changes in photoreceptor architecture, quantitative motion analysis, and electroretinography were characteristics of the reduced retinal virtue in USH1C pigs. Fibroblasts from USH1C pigs or USH1C patients showed significantly elongated primary cilia, confirming USH as a true and general ciliopathy. Primary cells also proved their capacity for assessing the therapeutic potential of CRISPR/Cas-mediated gene repair or gene therapy in vitro. AAV-based delivery of harmonin into the eye of USH1C pigs indicated therapeutic efficacy in vivo.

• Klíčová slova
• Usher syndrome, gene therapy, impaired vision, photoreceptor morphology, pig model,
• MeSH
• cytoskeletální proteiny MeSH
• fotoreceptory MeSH
• lidé MeSH
• prasata MeSH
• proteiny buněčného cyklu genetika   MeSH
• Usherovy syndromy * genetika   metabolismus   terapie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytoskeletální proteiny MeSH
• proteiny buněčného cyklu MeSH

Primary cilia are hair-like sensory organelles protruding from the surface of most human cells. As cilia are dynamic, several aspects of their biology can only be revealed by real-time analysis in living cells. Here we describe the generation of primary cilia reporter cell lines. Furthermore, we provide a detailed protocol of how to use the reporter cell lines for live-cell imaging microscopy analysis of primary cilia to study their growth as well as intraciliary transport. For complete details on the use and execution of this protocol, please refer to Bernatik et al. (2020) and Pejskova et al. (2020).

• Klíčová slova
• Cell Biology, Cell culture, Microscopy, Molecular Biology,
• MeSH
• buněčné linie MeSH
• cilie * metabolismus   MeSH
• lidé MeSH
• mikroskopie metody   MeSH
• počítačové zpracování obrazu * metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH