The Ultrastructure of Olfactory and Nasal Respiratory Epithelium Surfaces
D. V. M. Gerd Reznik, Sherman F. Stinson in Nasal Tumors in Animals and Man, 2017
Ciliogenesis apparently occurs for several cilia at the time, both in the case of olfactory (Figure 26) and respiratory cilia (Figure 27). Besides ciliary stubs, Figure 27 shows microvilli with high P-face particle densities. Necklace formation precedes formation of cilia (Figures 23, 25A, and 27).35,149,258 During outgrowth, and apparently also in later stages, olfactory cilia terminate club-shaped or vesicular (Figures 26 and 38 A).8,23,69,154
Meckel Gruber and Joubert Syndrome Diagnosed Prenatally: Allelism between the Two Ciliopathies, Complexities of Mutation Types and Digenic Inheritance
Published in Fetal and Pediatric Pathology, 2022
Somya Srivastava, Rani Manisha, Aradhana Dwivedi, Harshita Agarwal, Deepti Saxena, Vinita Agrawal, Kausik Mandal
Ciliopathies are a diverse group of disorders which occur due to dysfunction of motile or immotile cilia. They have 2 important functions-motility and cell signaling. Impaired ciliary motility exclusively results in primary ciliary dyskinesia which gives rise to disorders encompassing infertility, situs inversus, bronchiectasis and atelectasis. Impaired signaling and sensory function of motile or immotile cilia results in disorders of multiple organs (brain, eye, ear, kidney, liver, nose, skeleton). Ciliogenesis starts from a mother centriole which matures into a basal body, docks on the plasma membrane and further gives rise to the ciliary shaft. In between the shaft and the basal body lies the transition zone which controls the trafficking of molecules into and out of the cell [1].
PLK4: a link between centriole biogenesis and cancer
Published in Expert Opinion on Therapeutic Targets, 2018
Radhika Radha Maniswami, Seema Prashanth, Archana Venkataramana Karanth, Sindhu Koushik, Hemalatha Govindaraj, Ramesh Mullangi, Sriram Rajagopal, Sooriya Kumar Jegatheesan
Ciliogenesis begins with the nucleation of the mother centriole that functions as a basal body to template primary cilia [84]. PLK4-dependent phosphorylation of PCM1 is necessary for ciliogenesis. PLK4 phosphorylates PCM1 at a conserved S372 position and promotes dimerization/oligomerization. It also stimulates interaction of PCM1 with other centriolar satellite components such as hMsd1/SSX2IP, BBS4, and CEP290 resulting in increased aggregation and localization of centriolar satellites. Integrity of centriolar satellite components is an important prerequisite for ciliogenesis. It has been observed that depletion of PLK4 results in dispersion of centriolar satellites and perturbed ciliogenesis leading to loss of primary cilia [103]. This result in defective signaling since primary cilia coordinates a series of pathways that include Hedgehog, Wnt, PDGFRα, integrin and cell differentiation signaling pathways [104,105].
A homozygous POC1B variant causes recessive cone-rod dystrophy
Published in Ophthalmic Genetics, 2021
Ann-Marie C. Peturson, Nicole C. L. Noel, Ian M. MacDonald
POC1A, the paralog of POC1B, also encodes a centriolar protein. POC1A and POC1B proteins localize to the centrosome and contribute to centriole stability (4). There appears to be partially redundant functions of POC1A and POC1B in the centrosome of some cells, as co-knockdown is required to impair centrosome structure in HeLa cells (4). However, knockdown of POC1B alone negatively impacts HeLa cell proliferation (4); this indicates that while POC1A and POC1B may have similar functions within the centrosome, POC1B may play a unique, more integral role than POC1A in specific cell types. Potential divergences in POC1A and POC1B function between tissue or cell types are further highlighted by functional studies and disease manifestation. There is conflicting data surrounding whether POC1A is required for cilia formation (2,15), suggesting that there may be a tissue or cell type-specific influence of POC1A on ciliogenesis. Pathogenic POC1A variants have been reported in a form of primordial dwarfism (15,16), but POC1B has not been associated with short stature conditions – this may be due to a lack of POC1B requirement in cells related to long bone growth, lethality of POC1B variants that would otherwise cause short stature, or inadequate investigation of POC1B in patients with primordial dwarfism. No ocular conditions or retinal dystrophies are associated with POC1A and whether POC1A plays a role in basal body stability within photoreceptor cells is currently unknown.