1
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Hjeij R, Leslie J, Rizk H, Dworniczak B, Olbrich H, Raidt J, Bode SFN, Gardham A, Stals K, Al-Haggar M, Osman E, Crosby A, Eldesoky T, Baple E, Omran H. Biallelic Variants in MNS1 Are Associated with Laterality Defects and Respiratory Involvement. Cells 2024; 13:1017. [PMID: 38920647 PMCID: PMC11202006 DOI: 10.3390/cells13121017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/27/2024] [Accepted: 06/06/2024] [Indexed: 06/27/2024] Open
Abstract
Defects in motile cilia, termed motile ciliopathies, result in clinical manifestations affecting the respiratory and reproductive system, as well as laterality defects and hydrocephalus. We previously defined biallelic MNS1 variants causing situs inversus and male infertility, mirroring the findings in Mns1-/- mice. Here, we present clinical and genomic findings in five newly identified individuals from four unrelated families affected by MNS1-related disorder. Ciliopathy panel testing and whole exome sequencing identified one previously reported and two novel MNS1 variants extending the genotypic spectrum of disease. A broad spectrum of laterality defects including situs inversus totalis and heterotaxia was confirmed. Interestingly, a single affected six-year-old girl homozygous for an MNS1 nonsense variant presented with a history of neonatal respiratory distress syndrome, recurrent respiratory tract infections, chronic rhinitis, and wet cough. Accordingly, immunofluorescence analysis showed the absence of MNS1 from the respiratory epithelial cells of this individual. Two other individuals with hypomorphic variants showed laterality defects and mild respiratory phenotype. This study represents the first observation of heterotaxia and respiratory disease in individuals with biallelic MNS1 variants, an important extension of the phenotype associated with MNS1-related motile ciliopathy disorder.
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Grants
- HJ 7/1-1, HJ 7/1-3, OM6/7, OM6/8, OM6/10, OM6/14, OM6/16, CRU 326, OM6/11, RA3522/1-1, OL 450/1 Deutsche Forschungsgemeinschaft
- Om2/009/12, Om2/015/16, Om2/010/20 Institute for Interdisciplinary Medicine
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Affiliation(s)
- Rim Hjeij
- Department of General Pediatrics, University Hospital Muenster, 48149 Muenster, Germany; (B.D.); (H.O.); (J.R.); (H.O.)
| | - Joseph Leslie
- Institute of Biomedical and Clinical Science, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK; (J.L.); (A.C.); (E.B.)
| | - Hoda Rizk
- Department of Pediatrics, Faculty of Medicine, University of Mansoura, Mansoura 35516, Egypt; (H.R.); (E.O.); (T.E.)
| | - Bernd Dworniczak
- Department of General Pediatrics, University Hospital Muenster, 48149 Muenster, Germany; (B.D.); (H.O.); (J.R.); (H.O.)
| | - Heike Olbrich
- Department of General Pediatrics, University Hospital Muenster, 48149 Muenster, Germany; (B.D.); (H.O.); (J.R.); (H.O.)
| | - Johanna Raidt
- Department of General Pediatrics, University Hospital Muenster, 48149 Muenster, Germany; (B.D.); (H.O.); (J.R.); (H.O.)
| | | | - Alice Gardham
- North West Thames Regional Genetic Service, North West London Hospitals, London HA1 2UJ, UK;
| | - Karen Stals
- Exeter Genomics Laboratory (NHS South West Genomic Laboratory Hub), Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK;
| | - Mohammad Al-Haggar
- Genetics Unit, Pediatrics Department, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt;
| | - Engy Osman
- Department of Pediatrics, Faculty of Medicine, University of Mansoura, Mansoura 35516, Egypt; (H.R.); (E.O.); (T.E.)
| | - Andrew Crosby
- Institute of Biomedical and Clinical Science, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK; (J.L.); (A.C.); (E.B.)
| | - Tarek Eldesoky
- Department of Pediatrics, Faculty of Medicine, University of Mansoura, Mansoura 35516, Egypt; (H.R.); (E.O.); (T.E.)
| | - Emma Baple
- Institute of Biomedical and Clinical Science, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK; (J.L.); (A.C.); (E.B.)
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter EX1 2ED, UK
| | - Heymut Omran
- Department of General Pediatrics, University Hospital Muenster, 48149 Muenster, Germany; (B.D.); (H.O.); (J.R.); (H.O.)
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2
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Lai B, Jiang H, Gao Y, Zhou X. Skeletal ciliopathy: pathogenesis and related signaling pathways. Mol Cell Biochem 2024; 479:811-823. [PMID: 37188988 DOI: 10.1007/s11010-023-04765-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/09/2023] [Indexed: 05/17/2023]
Abstract
Cilia are tiny organelles with conserved structures and components in eukaryotic cells. Ciliopathy is a set of diseases resulting from cilium dysfunction classified into first-order and second-order ciliopathy. With the advancement of clinical diagnosis and radiography, numerous skeletal phenotypes, including polydactyly, short limbs, short ribs, scoliosis, a narrow thorax, and numerous anomalies in bone and cartilage, have been discovered in ciliopathies. Mutation in genes encoding cilia core components or other cilia-related molecules have been found in skeletal ciliopathies. Meanwhile, various signaling pathways associated with cilia and skeleton development have been deemed to be significant for the occurrence and progression of diseases. Herein, we review the structure and key components of the cilium and summarize several skeletal ciliopathies with their presumable pathology. We also emphasize the signaling pathways involved in skeletal ciliopathies, which may assist in developing potential therapies for these diseases.
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Affiliation(s)
- Bowen Lai
- Department of Orthopedics, Changzheng Hospital, Second Military Medical University, Fengyang Road 415, Shanghai, 200003, China
| | - Heng Jiang
- Department of Orthopedics, Changzheng Hospital, Second Military Medical University, Fengyang Road 415, Shanghai, 200003, China
| | - Yuan Gao
- Department of Orthopedics, Changzheng Hospital, Second Military Medical University, Fengyang Road 415, Shanghai, 200003, China
| | - Xuhui Zhou
- Department of Orthopedics, Changzheng Hospital, Second Military Medical University, Fengyang Road 415, Shanghai, 200003, China.
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3
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Kalot R, Sentell Z, Kitzler TM, Torban E. Primary cilia and actin regulatory pathways in renal ciliopathies. FRONTIERS IN NEPHROLOGY 2024; 3:1331847. [PMID: 38292052 PMCID: PMC10824913 DOI: 10.3389/fneph.2023.1331847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024]
Abstract
Ciliopathies are a group of rare genetic disorders caused by defects to the structure or function of the primary cilium. They often affect multiple organs, leading to brain malformations, congenital heart defects, and anomalies of the retina or skeletal system. Kidney abnormalities are among the most frequent ciliopathic phenotypes manifesting as smaller, dysplastic, and cystic kidneys that are often accompanied by renal fibrosis. Many renal ciliopathies cause chronic kidney disease and often progress to end-stage renal disease, necessitating replacing therapies. There are more than 35 known ciliopathies; each is a rare hereditary condition, yet collectively they account for a significant proportion of chronic kidney disease worldwide. The primary cilium is a tiny microtubule-based organelle at the apex of almost all vertebrate cells. It serves as a "cellular antenna" surveying environment outside the cell and transducing this information inside the cell to trigger multiple signaling responses crucial for tissue morphogenesis and homeostasis. Hundreds of proteins and unique cellular mechanisms are involved in cilia formation. Recent evidence suggests that actin remodeling and regulation at the base of the primary cilium strongly impacts ciliogenesis. In this review, we provide an overview of the structure and function of the primary cilium, focusing on the role of actin cytoskeleton and its regulators in ciliogenesis. We then describe the key clinical, genetic, and molecular aspects of renal ciliopathies. We highlight what is known about actin regulation in the pathogenesis of these diseases with the aim to consider these recent molecular findings as potential therapeutic targets for renal ciliopathies.
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Affiliation(s)
- Rita Kalot
- Department of Medicine and Department of Physiology, McGill University, Montreal, QC, Canada
- The Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Zachary Sentell
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Thomas M. Kitzler
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- McGill University Health Center, Montreal, QC, Canada
| | - Elena Torban
- Department of Medicine and Department of Physiology, McGill University, Montreal, QC, Canada
- The Research Institute of the McGill University Health Center, Montreal, QC, Canada
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4
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Park S, Shi X. Expansion Microscopy of Ciliary Proteins. Methods Mol Biol 2024; 2725:79-88. [PMID: 37856018 DOI: 10.1007/978-1-0716-3507-0_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Label-retention expansion microscopy (LR-ExM) is a sample preparation technique, which embeds the cells or tissues in a swellable hydrogel and expands the sample so that one can achieve a high resolution with any conventional fluorescence microscopes. Fluorescence loss during polymerization and protein denaturation have been a major limitation of standard expansion microscopy. To minimize fluorescence loss, LR-ExM uses trifunctional anchors, which can survive from polymerization and denaturation, and then introduce fluorophores after expansion. By using LR-ExM, one can study the structure of primary cilia at molecular-scale resolution with a much higher signal-to-noise ratio, compared with previously introduced expansion microscopy methods. In this chapter, we describe a detailed procedure showing how LR-ExM is used to study ciliary proteins.
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Affiliation(s)
- Sohyeon Park
- Center for Complex Biological Systems, University of California Irvine, Irvine, CA, USA
| | - Xiaoyu Shi
- Center for Complex Biological Systems, University of California Irvine, Irvine, CA, USA.
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, USA.
- Department of Chemistry, University of California Irvine, Irvine, CA, USA.
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5
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Liu J, Xie H, Wu M, Hu Y, Kang Y. The role of cilia during organogenesis in zebrafish. Open Biol 2023; 13:230228. [PMID: 38086423 PMCID: PMC10715920 DOI: 10.1098/rsob.230228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023] Open
Abstract
Cilia are hair-like organelles that protrude from the surface of eukaryotic cells and are present on the surface of nearly all human cells. Cilia play a crucial role in signal transduction, organ development and tissue homeostasis. Abnormalities in the structure and function of cilia can lead to a group of human diseases known as ciliopathies. Currently, zebrafish serves as an ideal model for studying ciliary function and ciliopathies due to its relatively conserved structure and function of cilia compared to humans. In this review, we will summarize the different types of cilia that present in embryonic and adult zebrafish, and provide an overview of the advantages of using zebrafish as a vertebrate model for cilia research. We will specifically focus on the roles of cilia during zebrafish organogenesis based on recent studies. Additionally, we will highlight future prospects for ciliary research in zebrafish.
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Affiliation(s)
- Junjun Liu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Haibo Xie
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Mengfan Wu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Yidan Hu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Yunsi Kang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, People's Republic of China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, People's Republic of China
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6
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Legal T, Parra M, Tong M, Black CS, Joachimiak E, Valente-Paterno M, Lechtreck K, Gaertig J, Bui KH. CEP104/FAP256 and associated cap complex maintain stability of the ciliary tip. J Cell Biol 2023; 222:e202301129. [PMID: 37756660 PMCID: PMC10522465 DOI: 10.1083/jcb.202301129] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/13/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila. We show that the microtubules at the tip are highly crosslinked with each other and stabilized by luminal proteins, plugs, and cap proteins at the plus ends. In the tip region, the central pair lacks typical projections and twists significantly. By analyzing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explained the potential functions of CEP104/FAP256. These data provide new insights into the function of the ciliary tip and the mechanisms of ciliary assembly and length regulation.
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Affiliation(s)
- Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Mireya Parra
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Maxwell Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Corbin S. Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
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7
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Lee KH. Primary cilia: a novel research approach to overcome anticancer drug resistance. Front Mol Biosci 2023; 10:1270639. [PMID: 37900915 PMCID: PMC10602908 DOI: 10.3389/fmolb.2023.1270639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/11/2023] [Indexed: 10/31/2023] Open
Abstract
Primary cilia are cellular organelles that consist of a microtubule skeleton surrounded by a membrane filled with cell signaling receptors. Many studies have shown that primary cilia are cellular antennas, which serve as signaling hubs and their assembly and disassembly are dynamically regulated throughout the cell cycle, playing an important role in regulating cellular homeostasis. Aberrant control of primary cilia dynamics causes a number of genetic disorders known as ciliopathies and is closely associated with tumorigenesis. Anticancer drug resistance is a primary cause of chemotherapy failure, although there is no apparent remedy. The recent identification of a relationship between anticancer drug resistance and primary ciliary dynamics has made primary cilia an important target subcellular organelle for overcoming anticancer drug resistance. Therefore, the research on primary ciliary dynamics may provide new strategies to overcome anticancer drug resistance, which is urgently needed. This review aims to summarize research on the relevance of primary cilia and anticancer drug resistance, as well as future possibilities for research on overcoming anticancer drug resistance utilizing primary cilia dynamics.
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Affiliation(s)
- Kyung Ho Lee
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang-eup, Republic of Korea
- Department of Bio-Molecular Science, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon, Republic of Korea
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8
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Otto M, Hoyer-Fender S. ODF2 Negatively Regulates CP110 Levels at the Centrioles/Basal Bodies to Control the Biogenesis of Primary Cilia. Cells 2023; 12:2194. [PMID: 37681926 PMCID: PMC10486571 DOI: 10.3390/cells12172194] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023] Open
Abstract
Primary cilia are essential sensory organelles that develop when an inhibitory cap consisting of CP110 and other proteins is eliminated. The degradation of CP110 by the ubiquitin-dependent proteasome pathway mediated by NEURL4 and HYLS1 removes the inhibitory cap. Here, we investigated the suitability of rapamycin-mediated dimerization for centriolar recruitment and asked whether the induced recruitment of NEURL4 or HYLS1 to the centriole promotes primary cilia development and CP110 degradation. We used rapamycin-mediated dimerization with ODF2 to induce their targeted recruitment to the centriole. We found decreased CP110 levels in the transfected cells, but independent of rapamycin-mediated dimerization. By knocking down ODF2, we showed that ODF2 controls CP110 levels. The overexpression of ODF2 is not sufficient to promote the formation of primary cilia, but the overexpression of NEURL4 or HYLS1 is. The co-expression of ODF2 and HYLS1 resulted in the formation of tube-like structures, indicating an interaction. Thus, ODF2 controls primary cilia formation by negatively regulating the concentration of CP110 levels. Our data suggest that ODF2 most likely acts as a scaffold for the binding of proteins such as NEURL4 or HYLS1 to mediate CP110 degradation.
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Affiliation(s)
| | - Sigrid Hoyer-Fender
- Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology—Developmental Biology, GZMB, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
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9
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Clearman KR, Haycraft CJ, Croyle MJ, Collawn JF, Yoder BK. Functions of the primary cilium in the kidney and its connection with renal diseases. Curr Top Dev Biol 2023; 155:39-94. [PMID: 38043952 DOI: 10.1016/bs.ctdb.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The nonmotile primary cilium is a sensory structure found on most mammalian cell types that integrates multiple signaling pathways involved in tissue development and postnatal function. As such, mutations disrupting cilia activities cause a group of disorders referred to as ciliopathies. These disorders exhibit a wide spectrum of phenotypes impacting nearly every tissue. In the kidney, primary cilia dysfunction caused by mutations in polycystin 1 (Pkd1), polycystin 2 (Pkd2), or polycystic kidney and hepatic disease 1 (Pkhd1), result in polycystic kidney disease (PKD), a progressive disorder causing renal functional decline and end-stage renal disease. PKD affects nearly 1 in 1000 individuals and as there is no cure for PKD, patients frequently require dialysis or renal transplantation. Pkd1, Pkd2, and Pkhd1 encode membrane proteins that all localize in the cilium. Pkd1 and Pkd2 function as a nonselective cation channel complex while Pkhd1 protein function remains uncertain. Data indicate that the cilium may act as a mechanosensor to detect fluid movement through renal tubules. Other functions proposed for the cilium and PKD proteins in cyst development involve regulation of cell cycle and oriented division, regulation of renal inflammation and repair processes, maintenance of epithelial cell differentiation, and regulation of mitochondrial structure and metabolism. However, how loss of cilia or cilia function leads to cyst development remains elusive. Studies directed at understanding the roles of Pkd1, Pkd2, and Pkhd1 in the cilium and other locations within the cell will be important for developing therapeutic strategies to slow cyst progression.
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Affiliation(s)
- Kelsey R Clearman
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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10
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Mill P, Christensen ST, Pedersen LB. Primary cilia as dynamic and diverse signalling hubs in development and disease. Nat Rev Genet 2023; 24:421-441. [PMID: 37072495 PMCID: PMC7615029 DOI: 10.1038/s41576-023-00587-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 67.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 04/20/2023]
Abstract
Primary cilia, antenna-like sensory organelles protruding from the surface of most vertebrate cell types, are essential for regulating signalling pathways during development and adult homeostasis. Mutations in genes affecting cilia cause an overlapping spectrum of >30 human diseases and syndromes, the ciliopathies. Given the immense structural and functional diversity of the mammalian cilia repertoire, there is a growing disconnect between patient genotype and associated phenotypes, with variable severity and expressivity characteristic of the ciliopathies as a group. Recent technological developments are rapidly advancing our understanding of the complex mechanisms that control biogenesis and function of primary cilia across a range of cell types and are starting to tackle this diversity. Here, we examine the structural and functional diversity of primary cilia, their dynamic regulation in different cellular and developmental contexts and their disruption in disease.
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Affiliation(s)
- Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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11
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Gottardo M, Riparbelli MG, Callaini G, Megraw TL. Evidence for intraflagellar transport in butterfly spermatocyte cilia. Cytoskeleton (Hoboken) 2023; 80:112-122. [PMID: 37036073 PMCID: PMC10330035 DOI: 10.1002/cm.21755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/04/2023] [Accepted: 03/22/2023] [Indexed: 04/11/2023]
Abstract
In the model organism insect Drosophila melanogaster short cilia assemble on spermatocytes that elaborate into 1.8 mm long flagella during spermatid differentiation. A unique feature of these cilia/flagella is their lack of dependence on intraflagellar transport (IFT) for their assembly. Here, we show that in the common butterfly Pieris brassicae, the spermatocyte cilia are exceptionally long: about 40 μm compared to less than 1 μm in Drosophila. By transmission electron microscopy, we show that P. brassicae spermatocytes display several features not found in melanogaster, including compelling evidence of IFT structures and features of motile cilia.
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Affiliation(s)
- Marco Gottardo
- Department of Life Sciences, University of Siena, Italy
- These Authors contributed equally to this work
| | - Maria Giovanna Riparbelli
- Department of Life Sciences, University of Siena, Italy
- These Authors contributed equally to this work
| | | | - Timothy L. Megraw
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL USA
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12
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Ferreira JL, Pražák V, Vasishtan D, Siggel M, Hentzschel F, Binder AM, Pietsch E, Kosinski J, Frischknecht F, Gilberger TW, Grünewald K. Variable microtubule architecture in the malaria parasite. Nat Commun 2023; 14:1216. [PMID: 36869034 PMCID: PMC9984467 DOI: 10.1038/s41467-023-36627-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/09/2023] [Indexed: 03/05/2023] Open
Abstract
Microtubules are a ubiquitous eukaryotic cytoskeletal element typically consisting of 13 protofilaments arranged in a hollow cylinder. This arrangement is considered the canonical form and is adopted by most organisms, with rare exceptions. Here, we use in situ electron cryo-tomography and subvolume averaging to analyse the changing microtubule cytoskeleton of Plasmodium falciparum, the causative agent of malaria, throughout its life cycle. Unexpectedly, different parasite forms have distinct microtubule structures coordinated by unique organising centres. In merozoites, the most widely studied form, we observe canonical microtubules. In migrating mosquito forms, the 13 protofilament structure is further reinforced by interrupted luminal helices. Surprisingly, gametocytes contain a wide distribution of microtubule structures ranging from 13 to 18 protofilaments, doublets and triplets. Such a diversity of microtubule structures has not been observed in any other organism to date and is likely evidence of a distinct role in each life cycle form. This data provides a unique view into an unusual microtubule cytoskeleton of a relevant human pathogen.
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Affiliation(s)
- Josie L Ferreira
- Centre for Structural Systems Biology, Hamburg, Germany
- Leibniz Institute for Virology (LIV), Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London, UK
| | - Vojtěch Pražák
- Centre for Structural Systems Biology, Hamburg, Germany
- Leibniz Institute for Virology (LIV), Hamburg, Germany
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Daven Vasishtan
- Centre for Structural Systems Biology, Hamburg, Germany
- Leibniz Institute for Virology (LIV), Hamburg, Germany
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Marc Siggel
- Centre for Structural Systems Biology, Hamburg, Germany
- European Molecular Biology Laboratory, Hamburg, Germany
| | - Franziska Hentzschel
- Integrative Parasitology, Centre for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- German Center for Infection Research, DZIF Partner Site Heidelberg, Heidelberg, Germany
| | - Annika M Binder
- Integrative Parasitology, Centre for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
| | - Emma Pietsch
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Jan Kosinski
- Centre for Structural Systems Biology, Hamburg, Germany
- European Molecular Biology Laboratory, Hamburg, Germany
- Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Centre for Infectious Diseases, Heidelberg University Medical School, Heidelberg, Germany
- German Center for Infection Research, DZIF Partner Site Heidelberg, Heidelberg, Germany
| | - Tim W Gilberger
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- University of Hamburg, Hamburg, Germany
| | - Kay Grünewald
- Centre for Structural Systems Biology, Hamburg, Germany.
- Leibniz Institute for Virology (LIV), Hamburg, Germany.
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- University of Hamburg, Hamburg, Germany.
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13
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Legal T, Tong M, Black C, Valente Paterno M, Gaertig J, Bui KH. Molecular architecture of the ciliary tip revealed by cryo-electron tomography. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.03.522627. [PMID: 36711791 PMCID: PMC9881849 DOI: 10.1101/2023.01.03.522627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila. We show the microtubules in the tip are highly cross-linked with each other and stabilised by luminal proteins, plugs and cap proteins at the plus ends. In the tip region, the central pair lacks the typical projections and twists significantly. By analysing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explain potential functions of CEP104/FAP256. These data provide new insights into the function of the ciliary tip and inform about the mechanisms of ciliary assembly and length regulation.
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Affiliation(s)
- T Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - M Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - C Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - M Valente Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - J Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, United States of America
| | - K H Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
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14
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Kretschmar C, Hernández-Cáceres MP, Reyes M, Peña-Oyarzún D, García-Navarrete C, Troncoso R, Díaz-Castro F, Budini M, Morselli E, Riquelme JA, Hill JA, Lavandero S, Criollo A. Methods for studying primary cilia in heart tissue after ischemia-reperfusion injury. Methods Cell Biol 2023; 176:85-101. [PMID: 37164544 DOI: 10.1016/bs.mcb.2022.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Cardiovascular diseases are the leading cause of death and disability worldwide. After heart injury triggered by myocardial ischemia or myocardial infarction, extensive zones of tissue are damaged and some of the tissue dies by necrosis and/or apoptosis. The loss of contractile mass activates a series of biochemical mechanisms that allow, through cardiac remodeling, the replacement of the dysfunctional heart tissue by fibrotic material. Our previous studies have shown that primary cilia, non-motile antenna-like structures at the cell surface required for the activation of specific signaling pathways, are present in cardiac fibroblasts and required for cardiac fibrosis induced by ischemia/reperfusion (I/R) in mice. I/R-induced myocardial fibrosis promotes the enrichment of ciliated cardiac fibroblasts where the myocardial injury occurs. Given discussions about the existence of cilia in specific cardiac cell types, as well as the functional relevance of studying cilia-dependent signaling in cardiac fibrosis after I/R, here we describe our methods to evaluate the presence and roles of primary cilia in cardiac fibrosis after I/R in mice.
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15
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Czerny CC, Borschel A, Cai M, Otto M, Hoyer-Fender S. FOXA1 is a transcriptional activator of Odf2/Cenexin and regulates primary ciliation. Sci Rep 2022; 12:21468. [PMID: 36509813 PMCID: PMC9744847 DOI: 10.1038/s41598-022-25966-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Primary cilia are sensory organelles essential for embryonic and postnatal development, and tissue homeostasis in adulthood. They are generated in a cell cycle-dependent manner and found on most cells of the body. Although cilia formation is intensively investigated virtually nothing is known about the transcriptional regulation of primary ciliation. We used here Odf2/Cenexin, encoding a protein of the mother centriole and the basal body that is mandatory for primary cilia formation, as the target gene for the identification of transcriptional activators. We identified a consensus binding site for Fox transcription factors (TFs) in its promoter region and focused here on the Fox family. We found transcriptional activation of Odf2 neither by FOXO TFs nor by the core TF for multiciliation, FOXJ1. However, we identified FOXA1 as a transcriptional activator of Odf2 by reporter gene assays and qRT-PCR, and showed by qWB that Foxa1 knockdown caused a decrease in ODF2 and CP110 proteins. We verified the binding sequence of FOXA1 in the Odf2 promoter by ChIP. Finally, we demonstrated that knockdown of FOXA1 affected primary cilia formation. We, thus, showed for the first time, that FOXA1 regulates primary ciliation by transcriptional activation of ciliary genes.
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Affiliation(s)
- Christian Carl Czerny
- grid.7450.60000 0001 2364 4210Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology – Developmental Biology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität, Justus-von-Liebig-Weg 11, Göttingen, Germany
| | - Anett Borschel
- grid.7450.60000 0001 2364 4210Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology – Developmental Biology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität, Justus-von-Liebig-Weg 11, Göttingen, Germany
| | - Mingfang Cai
- grid.7450.60000 0001 2364 4210Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology – Developmental Biology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität, Justus-von-Liebig-Weg 11, Göttingen, Germany
| | - Madeline Otto
- grid.7450.60000 0001 2364 4210Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology – Developmental Biology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität, Justus-von-Liebig-Weg 11, Göttingen, Germany ,grid.424957.90000 0004 0624 9165Present Address: Thermo Fisher Scientific GENEART, Regensburg, Germany
| | - Sigrid Hoyer-Fender
- grid.7450.60000 0001 2364 4210Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology – Developmental Biology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität, Justus-von-Liebig-Weg 11, Göttingen, Germany
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16
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Life-Saver or Undertaker: The Relationship between Primary Cilia and Cell Death in Vertebrate Embryonic Development. J Dev Biol 2022; 10:jdb10040052. [PMID: 36547474 PMCID: PMC9783631 DOI: 10.3390/jdb10040052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
The development of multicellular organisms requires a tightly coordinated network of cellular processes and intercellular signalling. For more than 20 years, it has been known that primary cilia are deeply involved in the mediation of intercellular signalling and that ciliary dysfunction results in severe developmental defects. Cilia-mediated signalling regulates cellular processes such as proliferation, differentiation, migration, etc. Another cellular process ensuring proper embryonic development is cell death. While the effect of cilia-mediated signalling on many cellular processes has been extensively studied, the relationship between primary cilia and cell death remains largely unknown. This article provides a short review on the current knowledge about this relationship.
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17
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Park K, Leroux MR. Composition, organization and mechanisms of the transition zone, a gate for the cilium. EMBO Rep 2022; 23:e55420. [PMID: 36408840 PMCID: PMC9724682 DOI: 10.15252/embr.202255420] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/08/2022] [Accepted: 10/31/2022] [Indexed: 11/22/2022] Open
Abstract
The cilium evolved to provide the ancestral eukaryote with the ability to move and sense its environment. Acquiring these functions required the compartmentalization of a dynein-based motility apparatus and signaling proteins within a discrete subcellular organelle contiguous with the cytosol. Here, we explore the potential molecular mechanisms for how the proximal-most region of the cilium, termed transition zone (TZ), acts as a diffusion barrier for both membrane and soluble proteins and helps to ensure ciliary autonomy and homeostasis. These include a unique complement and spatial organization of proteins that span from the microtubule-based axoneme to the ciliary membrane; a protein picket fence; a specialized lipid microdomain; differential membrane curvature and thickness; and lastly, a size-selective molecular sieve. In addition, the TZ must be permissive for, and functionally integrates with, ciliary trafficking systems (including intraflagellar transport) that cross the barrier and make the ciliary compartment dynamic. The quest to understand the TZ continues and promises to not only illuminate essential aspects of human cell signaling, physiology, and development, but also to unravel how TZ dysfunction contributes to ciliopathies that affect multiple organ systems, including eyes, kidney, and brain.
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Affiliation(s)
- Kwangjin Park
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
- Present address:
Terry Fox LaboratoryBC CancerVancouverBCCanada
- Present address:
Department of Medical GeneticsUniversity of British ColumbiaVancouverBCCanada
| | - Michel R Leroux
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
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18
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Primary Cilia Influence Progenitor Function during Cortical Development. Cells 2022; 11:cells11182895. [PMID: 36139475 PMCID: PMC9496791 DOI: 10.3390/cells11182895] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/29/2022] [Accepted: 09/13/2022] [Indexed: 11/29/2022] Open
Abstract
Corticogenesis is an intricate process controlled temporally and spatially by many intrinsic and extrinsic factors. Alterations during this important process can lead to severe cortical malformations. Apical neuronal progenitors are essential cells able to self-amplify and also generate basal progenitors and/or neurons. Apical radial glia (aRG) are neuronal progenitors with a unique morphology. They have a long basal process acting as a support for neuronal migration to the cortical plate and a short apical process directed towards the ventricle from which protrudes a primary cilium. This antenna-like structure allows aRG to sense cues from the embryonic cerebrospinal fluid (eCSF) helping to maintain cell shape and to influence several key functions of aRG such as proliferation and differentiation. Centrosomes, major microtubule organising centres, are crucial for cilia formation. In this review, we focus on how primary cilia influence aRG function during cortical development and pathologies which may arise due to defects in this structure. Reporting and cataloguing a number of ciliary mutant models, we discuss the importance of primary cilia for aRG function and cortical development.
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19
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Vinay L, Belleannée C. EV duty vehicles: Features and functions of ciliary extracellular vesicles. Front Genet 2022; 13:916233. [PMID: 36061180 PMCID: PMC9438925 DOI: 10.3389/fgene.2022.916233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/08/2022] [Indexed: 12/12/2022] Open
Abstract
The primary cilium is a microtubule-based organelle that extends from a basal body at the surface of most cells. This antenna is an efficient sensor of the cell micro-environment and is instrumental to the proper development and homeostatic control of organs. Recent compelling studies indicate that, in addition to its role as a sensor, the primary cilium also emits signals through the release of bioactive extracellular vesicles (EVs). While some primary-cilium derived EVs are released through an actin-dependent ectocytosis and are called ectosomes (or large EVs, 350–500 nm), others originate from the exocytosis of multivesicular bodies and are smaller (small EVs, 50–100 nm). Ciliary EVs carry unique signaling factors, including protein markers and microRNAs (miRNAs), and participate in intercellular communication in different organism models. This review discusses the mechanism of release, the molecular features, and functions of EVs deriving from cilia, based on the existing literature.
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20
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Conversion of anterograde into retrograde trains is an intrinsic property of intraflagellar transport. Curr Biol 2022; 32:4071-4078.e4. [PMID: 35926510 PMCID: PMC9521741 DOI: 10.1016/j.cub.2022.07.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 06/06/2022] [Accepted: 07/14/2022] [Indexed: 12/30/2022]
Abstract
Cilia or eukaryotic flagella are microtubule-based organelles found across the eukaryotic tree of life. Their very high aspect ratio and crowded interior are unfavorable to diffusive transport of most components required for their assembly and maintenance. Instead, a system of intraflagellar transport (IFT) trains moves cargo rapidly up and down the cilium (Figure 1A).1-3 Anterograde IFT, from the cell body to the ciliary tip, is driven by kinesin-II motors, whereas retrograde IFT is powered by cytoplasmic dynein-1b motors.4 Both motors are associated with long chains of IFT protein complexes, known as IFT trains, and their cargoes.5-8 The conversion from anterograde to retrograde motility at the ciliary tip involves (1) the dissociation of kinesin motors from trains,9 (2) a fundamental restructuring of the train from the anterograde to the retrograde architecture,8,10,11 (3) the unloading and reloading of cargo,2 and (4) the activation of the dynein motors.8,12 A prominent hypothesis is that there is dedicated calcium-dependent protein-based machinery at the ciliary tip to mediate these processes.4,13 However, the mechanisms of IFT turnaround have remained elusive. In this study, we use mechanical and chemical methods to block IFT at intermediate positions along the cilia of the green algae Chlamydomonas reinhardtii, in normal and calcium-depleted conditions. We show that IFT turnaround, kinesin dissociation, and dynein-1b activation can consistently be induced at arbitrary distances from the ciliary tip, with no stationary tip machinery being required. Instead, we demonstrate that the anterograde-to-retrograde conversion is a calcium-independent intrinsic ability of IFT.
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21
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Harkins D, Harvey TJ, Atterton C, Miller I, Currey L, Oishi S, Kasherman M, Davila RA, Harris L, Green K, Piper H, Parton RG, Thor S, Cooper HM, Piper M. Hydrocephalus in Nfix−/− Mice Is Underpinned by Changes in Ependymal Cell Physiology. Cells 2022; 11:cells11152377. [PMID: 35954220 PMCID: PMC9368351 DOI: 10.3390/cells11152377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 02/04/2023] Open
Abstract
Nuclear factor one X (NFIX) is a transcription factor required for normal ependymal development. Constitutive loss of Nfix in mice (Nfix−/−) is associated with hydrocephalus and sloughing of the dorsal ependyma within the lateral ventricles. Previous studies have implicated NFIX in the transcriptional regulation of genes encoding for factors essential to ependymal development. However, the cellular and molecular mechanisms underpinning hydrocephalus in Nfix−/− mice are unknown. To investigate the role of NFIX in hydrocephalus, we examined ependymal cells in brains from postnatal Nfix−/− and control (Nfix+/+) mice using a combination of confocal and electron microscopy. This revealed that the ependymal cells in Nfix−/− mice exhibited abnormal cilia structure and disrupted localisation of adhesion proteins. Furthermore, we modelled ependymal cell adhesion using epithelial cell culture and revealed changes in extracellular matrix and adherens junction gene expression following knockdown of NFIX. Finally, the ablation of Nfix from ependymal cells in the adult brain using a conditional approach culminated in enlarged ventricles, sloughing of ependymal cells from the lateral ventricles and abnormal localisation of adhesion proteins, which are phenotypes observed during development. Collectively, these data demonstrate a pivotal role for NFIX in the regulation of cell adhesion within ependymal cells of the lateral ventricles.
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Affiliation(s)
- Danyon Harkins
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Tracey J. Harvey
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Cooper Atterton
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Ingrid Miller
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Laura Currey
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Sabrina Oishi
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Maria Kasherman
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Raul Ayala Davila
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Lucy Harris
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane 4072, Australia; (L.H.); (K.G.); (R.G.P.)
| | - Kathryn Green
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane 4072, Australia; (L.H.); (K.G.); (R.G.P.)
| | - Hannah Piper
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Robert G. Parton
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane 4072, Australia; (L.H.); (K.G.); (R.G.P.)
- Institute for Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Stefan Thor
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
| | - Helen M. Cooper
- Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia;
| | - Michael Piper
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia; (D.H.); (T.J.H.); (C.A.); (I.M.); (L.C.); (S.O.); (M.K.); (R.A.D.); (H.P.); (S.T.)
- Queensland Brain Institute, The University of Queensland, Brisbane 4072, Australia;
- Correspondence:
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22
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Shibata D, Morita M, Sato Y, Shiba K, Kitanobo S, Yokoya R, Inaba K. Axonemal Growth and Alignment During Paraspermatogenesis in the Marine Gastropod Strombus luhuanus. Front Cell Dev Biol 2022; 10:905748. [PMID: 35832793 PMCID: PMC9271582 DOI: 10.3389/fcell.2022.905748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
Parasperm are non-fertilizing sperm that are produced simultaneously with fertile eusperm. They occur in several animal species and show considerable morphological diversity. We investigated the dynamics of axonemes during paraspermatogenesis in the marine snail S. luhuanus. Mature parasperm were characterized by two lateral undulating membranes for motility and many globular vesicles. Axonemes were first observed as brush-like structures that extruded from the anterior region. Multiple axonemes longer than the brush then started to extend inside the cytoplasm towards the posterior region. The mass of the axonemes separated into two lateral rows and formed an undulating membrane that drives bidirectional swimming in the mature parasperm. The central pair of axonemes was aligned in the undulating membrane, resulting in cooperative bend propagation. During paraspermatogenesis, centrioles were largely diminished and localized to the anterior region. CEP290, a major component of the transition zone, showed a broad distribution in the anterior area. Axonemes in the posterior region showed a 9 + 0 structure with both outer and inner arm dyneins. These observations provide a structural basis for understanding the physiological functions of parasperm in marine reproductive strategies.
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Affiliation(s)
- Daisuke Shibata
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Masaya Morita
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
| | - Yu Sato
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Seiya Kitanobo
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Ryo Yokoya
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
- *Correspondence: Kazuo Inaba,
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23
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Cavalier-Smith T. Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi. PROTOPLASMA 2022; 259:487-593. [PMID: 34940909 PMCID: PMC9010356 DOI: 10.1007/s00709-021-01665-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/03/2021] [Indexed: 05/19/2023]
Abstract
I thoroughly discuss ciliary transition zone (TZ) evolution, highlighting many overlooked evolutionarily significant ultrastructural details. I establish fundamental principles of TZ ultrastructure and evolution throughout eukaryotes, inferring unrecognised ancestral TZ patterns for Fungi, opisthokonts, and Corticata (i.e., kingdoms Plantae and Chromista). Typical TZs have a dense transitional plate (TP), with a previously overlooked complex lattice as skeleton. I show most eukaryotes have centriole/TZ junction acorn-V filaments (whose ancestral function was arguably supporting central pair microtubule-nucleating sites; I discuss their role in centriole growth). Uniquely simple malawimonad TZs (without TP, simpler acorn) pinpoint the eukaryote tree's root between them and TP-bearers, highlighting novel superclades. I integrate TZ/ciliary evolution with the best multiprotein trees, naming newly recognised major eukaryote clades and revise megaclassification of basal kingdom Protozoa. Recent discovery of non-photosynthetic phagotrophic flagellates with genome-free plastids (Rhodelphis), the sister group to phylum Rhodophyta (red algae), illuminates plant and chromist early evolution. I show previously overlooked marked similarities in cell ultrastructure between Rhodelphis and Picomonas, formerly considered an early diverging chromist. In both a nonagonal tube lies between their TP and an annular septum surrounding their 9+2 ciliary axoneme. Mitochondrial dense condensations and mitochondrion-linked smooth endomembrane cytoplasmic partitioning cisternae further support grouping Picomonadea and Rhodelphea as new plant phylum Pararhoda. As Pararhoda/Rhodophyta form a robust clade on site-heterogeneous multiprotein trees, I group Pararhoda and Rhodophyta as new infrakingdom Rhodaria of Plantae within subkingdom Biliphyta, which also includes Glaucophyta with fundamentally similar TZ, uniquely in eukaryotes. I explain how biliphyte TZs generated viridiplant stellate-structures.
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24
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Transmission Electron Microscopy Tilt-Series Data from In-Situ Chondrocyte Primary Cilia. DATA 2021. [DOI: 10.3390/data6110118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The primary cilium has recently become the focus of intensive investigations into understanding the physical structure and processes of eukaryotic cells. This paper describes two tilt-series image datasets, acquired by transmission electron microscopy, of in situ chick-embryo sternal-cartilage primary cilia. These data have been released under an open-access licence, and are well suited to tomographic reconstruction and modelling of the cilium.
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25
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Hilgendorf KI. Primary Cilia Are Critical Regulators of White Adipose Tissue Expansion. Front Physiol 2021; 12:769367. [PMID: 34759842 PMCID: PMC8573240 DOI: 10.3389/fphys.2021.769367] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/04/2021] [Indexed: 12/14/2022] Open
Abstract
The primary cilium is a microtubule-based cellular protrusion found on most mammalian cell types in diverse tissues. It functions as a cellular antenna to sense and transduce a broad range of signals, including odorants, light, mechanical stimuli, and chemical ligands. This diversity in signals requires cilia to display a context and cell type-specific repertoire of receptors. Recently, primary cilia have emerged as critical regulators of metabolism. The importance of primary cilia in metabolic disease is highlighted by the clinical features of human genetic disorders with dysfunctional ciliary signaling, which include obesity and diabetes. This review summarizes the current literature on the role of primary cilia in metabolic disease, focusing on the importance of primary cilia in directing white adipose tissue expansion during obesity.
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Affiliation(s)
- Keren I Hilgendorf
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
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26
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Wood BM, Baena V, Huang H, Jorgens DM, Terasaki M, Kornberg TB. Cytonemes with complex geometries and composition extend into invaginations of target cells. J Cell Biol 2021; 220:211896. [PMID: 33734293 PMCID: PMC7980254 DOI: 10.1083/jcb.202101116] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/13/2021] [Accepted: 02/23/2021] [Indexed: 12/16/2022] Open
Abstract
Cytonemes are specialized filopodia that mediate paracrine signaling in Drosophila and other animals. Studies using fluorescence confocal microscopy (CM) established their general paths, cell targets, and essential roles in signaling. To investigate details unresolvable by CM, we used high-pressure freezing and EM to visualize cytoneme structures, paths, contents, and contacts. We observed cytonemes previously seen by CM in the Drosophila wing imaginal disc system, including disc, tracheal air sac primordium (ASP), and myoblast cytonemes, and identified cytonemes extending into invaginations of target cells, and cytonemes connecting ASP cells and connecting myoblasts. Diameters of cytoneme shafts vary between repeating wide (206 ± 51.8 nm) and thin (55.9 ± 16.2 nm) segments. Actin, ribosomes, and membranous compartments are present throughout; rough ER and mitochondria are in wider proximal sections. These results reveal novel structural features of filopodia and provide a basis for understanding cytoneme cell biology and function.
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Affiliation(s)
- Brent M Wood
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Valentina Baena
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT
| | - Hai Huang
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
| | - Danielle M Jorgens
- Electron Microscope Laboratory, University of California, Berkeley, Berkeley, CA
| | - Mark Terasaki
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT
| | - Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA
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Singh AV, Romeo A, Scott K, Wagener S, Leibrock L, Laux P, Luch A, Kerkar P, Balakrishnan S, Dakua SP, Park B. Emerging Technologies for In Vitro Inhalation Toxicology. Adv Healthc Mater 2021; 10:e2100633. [PMID: 34292676 DOI: 10.1002/adhm.202100633] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/04/2021] [Indexed: 12/20/2022]
Abstract
Respiratory toxicology remains a major research area in the 21st century since current scenario of airborne viral infection transmission and pollutant inhalation is expected to raise the annual morbidity beyond 2 million. Clinical and epidemiological research connecting human exposure to air contaminants to understand adverse pulmonary health outcomes is, therefore, an immediate subject of human health assessment. Important observations in defining systemic effects of environmental contaminants on inhalation metabolic dysfunction, liver health, and gastrointestinal tract have been well explored with in vivo models. In this review, a framework is provided, a paradigm is established about inhalation toxicity testing in vitro, and a brief overview of breathing Lungs-on-Chip (LoC) as design concepts is given. The optimized bioengineering approaches and microfluidics with their fundamental pros, and cons are presented. There are different strategies that researchers apply to inhalation toxicity studies to assess a variety of inhalable substances and relevant LoC approaches. A case study from published literature and frame arguments about reproducibility as well as in vitro/in vivo correlations are discussed. Finally, the opportunities and challenges in soft robotics, systems inhalation toxicology approach integrating bioengineering, machine learning, and artificial intelligence to address a multitude model for future toxicology are discussed.
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Affiliation(s)
- Ajay Vikram Singh
- Department of Chemical and Product Safety German Federal Institute for Risk Assessment (BfR) Max‐Dohrn‐Strasse 8‐10 Berlin 10589 Germany
| | - Anthony Romeo
- Department of Chemical Engineering Rayen School of Engineering Youngstown State University Youngstown OH 44555 USA
| | - Kassandra Scott
- Department of Chemical Engineering Rayen School of Engineering Youngstown State University Youngstown OH 44555 USA
| | - Sandra Wagener
- Department of Chemical and Product Safety German Federal Institute for Risk Assessment (BfR) Max‐Dohrn‐Strasse 8‐10 Berlin 10589 Germany
| | - Lars Leibrock
- Department of Chemical and Product Safety German Federal Institute for Risk Assessment (BfR) Max‐Dohrn‐Strasse 8‐10 Berlin 10589 Germany
| | - Peter Laux
- Department of Chemical and Product Safety German Federal Institute for Risk Assessment (BfR) Max‐Dohrn‐Strasse 8‐10 Berlin 10589 Germany
| | - Andreas Luch
- Department of Chemical and Product Safety German Federal Institute for Risk Assessment (BfR) Max‐Dohrn‐Strasse 8‐10 Berlin 10589 Germany
| | - Pranali Kerkar
- ICMR – National AIDS Research Institute (NARI) Pune Maharashtra 411026 India
| | - Shidin Balakrishnan
- Department of Surgery Hamad Medical Corporation (HMC) PO Box 3050 Doha Qatar
| | - Sarada Prasad Dakua
- Department of Surgery Hamad Medical Corporation (HMC) PO Box 3050 Doha Qatar
| | - Byung‐Wook Park
- Department of Chemical Engineering Rayen School of Engineering Youngstown State University Youngstown OH 44555 USA
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28
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Focșa IO, Budișteanu M, Bălgrădean M. Clinical and genetic heterogeneity of primary ciliopathies (Review). Int J Mol Med 2021; 48:176. [PMID: 34278440 PMCID: PMC8354309 DOI: 10.3892/ijmm.2021.5009] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 06/28/2021] [Indexed: 01/11/2023] Open
Abstract
Ciliopathies comprise a group of complex disorders, with involvement of the majority of organs and systems. In total, >180 causal genes have been identified and, in addition to Mendelian inheritance, oligogenicity, genetic modifications, epistatic interactions and retrotransposon insertions have all been described when defining the ciliopathic phenotype. It is remarkable how the structural and functional impairment of a single, minuscule organelle may lead to the pathogenesis of highly pleiotropic diseases. Thus, combined efforts have been made to identify the genetic substratum and to determine the pathophysiological mechanism underlying the clinical presentation, in order to diagnose and classify ciliopathies. Yet, predicting the phenotype, given the intricacy of the genetic cause and overlapping clinical characteristics, represents a major challenge. In the future, advances in proteomics, cell biology and model organisms may provide new insights that could remodel the field of ciliopathies.
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Affiliation(s)
- Ina Ofelia Focșa
- Department of Medical Genetics, University of Medicine and Pharmacy 'Carol Davila', 021901 Bucharest, Romania
| | - Magdalena Budișteanu
- Department of Pediatric Neurology, 'Prof. Dr. Alexandru Obregia' Clinical Hospital of Psychiatry, 041914 Bucharest, Romania
| | - Mihaela Bălgrădean
- Department of Pediatrics and Pediatric Nephrology, Emergency Clinical Hospital for Children 'Maria Skłodowska Curie', 077120 Bucharest, Romania
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29
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Role of DZIP1-CBY-FAM92 transition zone complex in the basal body to membrane attachment and ciliary budding. Biochem Soc Trans 2021; 48:1067-1075. [PMID: 32491167 DOI: 10.1042/bst20191007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/20/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023]
Abstract
Cilia play important signaling or motile functions in various organisms. In Human, cilia dysfunctions are responsible for a wide range of diseases, called ciliopathies. Cilia assembly is a tightly controlled process, which starts with the conversion of the centriole into a basal body, leading to the formation of the ciliary bud that protrudes inside a ciliary vesicle and/or ultimately at the cell surface. Ciliary bud formation is associated with the assembly of the transition zone (TZ), a complex architecture of proteins of the ciliary base which plays critical functions in gating proteins in and out of the ciliary compartment. Many proteins are involved in the assembly of the TZ, which shows structural and functional variations in different cell types or organisms. In this review, we discuss how a particular complex, composed of members of the DZIP1, CBY and FAM92 families of proteins, is required for the initial stages of cilia assembly leading to ciliary bud formation and how their functional hierarchy contributes to TZ assembly. Moreover, we summarize how evidences in Drosophila reveal functional differences of the DZIP1-CBY-FAM92 complex in the different ciliated tissues of this organism. Whereas it is essential for proper TZ assembly in the two types of ciliated tissues, it is involved in stable anchoring of basal bodies to the plasma membrane in male germ cells. Overall, the DZIP1-CBY-FAM92 complex reveals a molecular assembly pathway required for the initial stages of ciliary bud formation and that is conserved from Drosophila to Human.
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Expression of α-Tubulin Acetyltransferase 1 and Tubulin Acetylation as Selective Forces in Cell Competition. Cells 2021; 10:cells10020390. [PMID: 33672816 PMCID: PMC7918103 DOI: 10.3390/cells10020390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 02/09/2021] [Indexed: 12/23/2022] Open
Abstract
The wound healing response of fibroblasts critically depends on the primary cilium, a sensory organelle protruding into the environment and comprising a stable axonemal structure. A characteristic marker for primary cilia is acetylation of axonemal tubulin. Although formation of primary cilia is under cell cycle control, the environmental cues affecting ciliation are not fully understood. Our purpose was, therefore, to study the impact of culture conditions on cilia formation in NIH3T3 fibroblasts. We quantified ciliation in different NIH3T3 sub-cell lines and culture conditions by immunodetection of primary cilia and counting. Quantitative Western blotting, qRT-PCR, and proliferation assays completed our investigation. We observed large differences between NIH3T3 sub-cell lines in their ability to generate acetylated primary cilia that correlated with cytoplasmic tubulin acetylation. We found no increased activity of the major tubulin deacetylase, HDAC6, but instead reduced expression of the α-tubulin acetyltransferase 1 (Atat1) as being causative. Our observations demonstrate that cells with reduced expression of Atat1 and tubulin acetylation proliferate faster, eventually displacing all other cells in the population. Expression of Atat1 and tubulin acetylation are therefore selective forces in cell competition.
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APEX2 Proximity Proteomics Resolves Flagellum Subdomains and Identifies Flagellum Tip-Specific Proteins in Trypanosoma brucei. mSphere 2021; 6:6/1/e01090-20. [PMID: 33568455 PMCID: PMC8141408 DOI: 10.1128/msphere.01090-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Trypanosoma brucei is the protozoan parasite responsible for sleeping sickness, a lethal vector-borne disease. T. brucei has a single flagellum (cilium) that plays critical roles in transmission and pathogenesis. An emerging concept is that the flagellum is organized into subdomains, each having specialized composition and function. The overall flagellum proteome has been well studied, but a critical knowledge gap is the protein composition of individual subdomains. We have tested whether APEX-based proximity proteomics could be used to examine the protein composition of T. brucei flagellum subdomains. As APEX-based labeling has not previously been described in T. brucei, we first fused APEX2 to the DRC1 subunit of the nexin-dynein regulatory complex, a well-characterized axonemal complex. We found that DRC1-APEX2 directs flagellum-specific biotinylation, and purification of biotinylated proteins yields a DRC1 “proximity proteome” having good overlap with published proteomes obtained from purified axonemes. Having validated the use of APEX2 in T. brucei, we next attempted to distinguish flagellar subdomains by fusing APEX2 to a flagellar membrane protein that is restricted to the flagellum tip, AC1, and another one that is excluded from the tip, FS179. Fluorescence microscopy demonstrated subdomain-specific biotinylation, and principal-component analysis showed distinct profiles between AC1-APEX2 and FS179-APEX2. Comparing these two profiles allowed us to identify an AC1 proximity proteome that is enriched for tip proteins, including proteins involved in signaling. Our results demonstrate that APEX2-based proximity proteomics is effective in T. brucei and can be used to resolve the proteome composition of flagellum subdomains that cannot themselves be readily purified. IMPORTANCE Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Given the essential and multifunctional role of the T. brucei flagellum, there is need for approaches that enable proteomic analysis of individual subdomains. Our work establishes that APEX2 proximity labeling can, indeed, be implemented in the biochemical environment of T. brucei and has allowed identification of proximity proteomes for different flagellar subdomains that cannot be purified. This capacity opens the possibility to study the composition and function of other compartments. We expect this approach may be extended to other eukaryotic pathogens and will enhance the utility of T. brucei as a model organism to study ciliopathies, heritable human diseases in which cilium function is impaired.
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Hasenpusch-Theil K, Theil T. The Multifaceted Roles of Primary Cilia in the Development of the Cerebral Cortex. Front Cell Dev Biol 2021; 9:630161. [PMID: 33604340 PMCID: PMC7884624 DOI: 10.3389/fcell.2021.630161] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
The primary cilium, a microtubule based organelle protruding from the cell surface and acting as an antenna in multiple signaling pathways, takes center stage in the formation of the cerebral cortex, the part of the brain that performs highly complex neural tasks and confers humans with their unique cognitive capabilities. These activities require dozens of different types of neurons that are interconnected in complex ways. Due to this complexity, corticogenesis has been regarded as one of the most complex developmental processes and cortical malformations underlie a number of neurodevelopmental disorders such as intellectual disability, autism spectrum disorders, and epilepsy. Cortical development involves several steps controlled by cell–cell signaling. In fact, recent findings have implicated cilia in diverse processes such as neurogenesis, neuronal migration, axon pathfinding, and circuit formation in the developing cortex. Here, we will review recent advances on the multiple roles of cilia during cortex formation and will discuss the implications for a better understanding of the disease mechanisms underlying neurodevelopmental disorders.
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Affiliation(s)
- Kerstin Hasenpusch-Theil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas Theil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
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33
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Peng Z, Resnick A, Young YN. Primary cilium: a paradigm for integrating mathematical modeling with experiments and numerical simulations in mechanobiology. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:1215-1237. [PMID: 33757184 PMCID: PMC8552149 DOI: 10.3934/mbe.2021066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Primary cilia are non-motile, solitary (one per cell) microtubule-based organelles that emerge from the mother centriole after cells have exited the mitotic cycle. Identified as a mechanosensing organelle that responds to both mechanical and chemical stimuli, the primary cilium provides a fertile ground for integrative investigations of mathematical modeling, numerical simulations, and experiments. Recent experimental findings revealed considerable complexity to the underlying mechanosensory mechanisms that transmit extracellular stimuli to intracellular signaling many of which include primary cilia. In this invited review, we provide a brief survey of experimental findings on primary cilia and how these results lead to various mathematical models of the mechanics of the primary cilium bent under an external forcing such as a fluid flow or a trap. Mathematical modeling of the primary cilium as a fluid-structure interaction problem highlights the importance of basal anchorage and the anisotropic moduli of the microtubules. As theoretical modeling and numerical simulations progress, along with improved state-of-the-art experiments on primary cilia, we hope that details of ciliary regulated mechano-chemical signaling dynamics in cellular physiology will be understood in the near future.
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Affiliation(s)
- Zhangli Peng
- Department of Bioengineering, University of Illinois at Chicago, 851 S. Morgan St., Chicago, IL 60607, USA
| | - Andrew Resnick
- Department of Physics, Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH 44115, USA
| | - Y.-N. Young
- Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA
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34
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Kiesel P, Alvarez Viar G, Tsoy N, Maraspini R, Gorilak P, Varga V, Honigmann A, Pigino G. The molecular structure of mammalian primary cilia revealed by cryo-electron tomography. Nat Struct Mol Biol 2020; 27:1115-1124. [PMID: 32989303 PMCID: PMC7610599 DOI: 10.1038/s41594-020-0507-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 08/12/2020] [Indexed: 01/09/2023]
Abstract
Primary cilia are microtubule-based organelles that are important for signaling and sensing in eukaryotic cells. Unlike the thoroughly studied motile cilia, the three-dimensional architecture and molecular composition of primary cilia are largely unexplored. Yet, studying these aspects is necessary to understand how primary cilia function in health and disease. We developed an enabling method for investigating the structure of primary cilia isolated from MDCK-II cells at molecular resolution by cryo-electron tomography. We show that the textbook '9 + 0' arrangement of microtubule doublets is only present at the primary cilium base. A few microns out, the architecture changes into an unstructured bundle of EB1-decorated microtubules and actin filaments, putting an end to a long debate on the presence or absence of actin filaments in primary cilia. Our work provides a plethora of insights into the molecular structure of primary cilia and offers a methodological framework to study these important organelles.
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Affiliation(s)
- Petra Kiesel
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Nikolai Tsoy
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Riccardo Maraspini
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Peter Gorilak
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vladimir Varga
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
- Human Technopole, Milan, Italy.
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35
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Hosio M, Jaks V, Lagus H, Vuola J, Ogawa R, Kankuri E. Primary Ciliary Signaling in the Skin-Contribution to Wound Healing and Scarring. Front Cell Dev Biol 2020; 8:578384. [PMID: 33282860 PMCID: PMC7691485 DOI: 10.3389/fcell.2020.578384] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/08/2020] [Indexed: 12/21/2022] Open
Abstract
Primary cilia (PC) are solitary, post-mitotic, microtubule-based, and membrane-covered protrusions that are found on almost every mammalian cell. PC are specialized cellular sensory organelles that transmit environmental information to the cell. Signaling through PC is involved in the regulation of a variety of cellular processes, including proliferation, differentiation, and migration. Conversely, defective, or abnormal PC signaling can contribute to the development of various pathological conditions. Our knowledge of the role of PC in organ development and function is largely based on ciliopathies, a family of genetic disorders with mutations affecting the structure and function of PC. In this review, we focus on the role of PC in their major signaling pathways active in skin cells, and their contribution to wound healing and scarring. To provide comprehensive insights into the current understanding of PC functions, we have collected data available in the literature, including evidence across cell types, tissues, and animal species. We conclude that PC are underappreciated subcellular organelles that significantly contribute to both physiological and pathological processes of the skin development and wound healing. Thus, PC assembly and disassembly and PC signaling may serve as attractive targets for antifibrotic and antiscarring therapies.
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Affiliation(s)
- Mayu Hosio
- Faculty of Medicine, Department of Pharmacology, University of Helsinki, Helsinki, Finland
| | - Viljar Jaks
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- Dermatology Clinic, Tartu University Hospital, Tartu, Estonia
| | - Heli Lagus
- Department of Plastic Surgery and Wound Healing Centre, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Jyrki Vuola
- Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Rei Ogawa
- Department of Plastic, Reconstructive and Aesthetic Surgery, Nippon Medical School, Tokyo, Japan
| | - Esko Kankuri
- Faculty of Medicine, Department of Pharmacology, University of Helsinki, Helsinki, Finland
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36
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Lee KH. Involvement of Wnt signaling in primary cilia assembly and disassembly. FEBS J 2020; 287:5027-5038. [PMID: 33015954 DOI: 10.1111/febs.15579] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 09/29/2020] [Indexed: 11/28/2022]
Abstract
The primary cilium is a nonmotile microtubule-based structure, which functions as an antenna-like cellular sensing organelle. The primary cilium is assembled from the basal body, a mother centriole-based structure, during interphase or a quiescent cell stage, and rapidly disassembles before entering mitosis in a dynamic cycle. Defects in this ciliogenesis dynamics are associated with human diseases such as ciliopathy and cancer, but the molecular mechanisms of the ciliogenesis dynamics are still largely unknown. To date, various cellular signaling pathways associated with primary cilia have been proposed, but the main signaling pathways regulating primary cilia assembly/disassembly remain enigmatic. This review describes recent findings in Wnt-induced primary cilia assembly/disassembly and potential future directions for the study of the cellular signaling related to the primary ciliogenesis dynamics.
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Affiliation(s)
- Kyung Ho Lee
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang, Korea
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37
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Venard CM, Vasudevan KK, Stearns T. Cilium axoneme internalization and degradation in chytrid fungi. Cytoskeleton (Hoboken) 2020; 77:365-378. [PMID: 33103844 PMCID: PMC7944584 DOI: 10.1002/cm.21637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/16/2022]
Abstract
Loss of the cilium is important for cell cycle progression and certain developmental transitions. Chytrid fungi are a group of basal fungi that have retained centrioles and cilia, and they can disassemble their cilia via axoneme internalization as part of the transition from free-swimming spores to sessile sporangia. While this type of cilium disassembly has been observed in many single-celled eukaryotes, it has not been well characterized because it is not observed in common model organisms. To better characterize cilium disassembly via axoneme internalization, we focused on chytrids Rhizoclosmatium globosum and Spizellomyces punctatus to represent two lineages of chytrids with different motility characteristics. Our results show that each chytrid species can reel in its axoneme into the cell body along its cortex on the order of minutes, while S. punctatus has additional faster ciliary compartment loss and lash-around mechanisms. S. punctatus retraction can also occur away from the cell cortex and is partially actin dependent. Post-internalization, the tubulin of the axoneme is degraded in both chytrids over the course of about 2 hr. Axoneme disassembly and axonemal tubulin degradation are both partially proteasome dependent. Overall, chytrid cilium disassembly is a fast process that separates axoneme internalization and degradation.
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Affiliation(s)
- Claire M Venard
- Department of Biology, Stanford University, Stanford, California
| | | | - Tim Stearns
- Department of Biology, Stanford University, Stanford, California
- Department of Genetics, Stanford University, Stanford, California
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38
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Ravi RT, Leung MR, Zeev-Ben-Mordehai T. Looking back and looking forward: contributions of electron microscopy to the structural cell biology of gametes and fertilization. Open Biol 2020; 10:200186. [PMID: 32931719 PMCID: PMC7536082 DOI: 10.1098/rsob.200186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/25/2020] [Indexed: 01/22/2023] Open
Abstract
Mammalian gametes-the sperm and the egg-represent opposite extremes of cellular organization and scale. Studying the ultrastructure of gametes is crucial to understanding their interactions, and how to manipulate them in order to either encourage or prevent their union. Here, we survey the prominent electron microscopy (EM) techniques, with an emphasis on considerations for applying them to study mammalian gametes. We review how conventional EM has provided significant insight into gamete ultrastructure, but also how the harsh sample preparation methods required preclude understanding at a truly molecular level. We present recent advancements in cryo-electron tomography that provide an opportunity to image cells in a near-native state and at unprecedented levels of detail. New and emerging cellular EM techniques are poised to rekindle exploration of fundamental questions in mammalian reproduction, especially phenomena that involve complex membrane remodelling and protein reorganization. These methods will also allow novel lines of enquiry into problems of practical significance, such as investigating unexplained causes of human infertility and improving assisted reproductive technologies for biodiversity conservation.
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Affiliation(s)
- Ravi Teja Ravi
- Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
| | - Miguel Ricardo Leung
- Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
- Division of Structural Biology, Wellcome Centre for Human Genetics, The University of Oxford, Oxford OX3 7BN, UK
| | - Tzviya Zeev-Ben-Mordehai
- Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584CH Utrecht, The Netherlands
- Division of Structural Biology, Wellcome Centre for Human Genetics, The University of Oxford, Oxford OX3 7BN, UK
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39
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Chen HY, Kelley RA, Li T, Swaroop A. Primary cilia biogenesis and associated retinal ciliopathies. Semin Cell Dev Biol 2020; 110:70-88. [PMID: 32747192 PMCID: PMC7855621 DOI: 10.1016/j.semcdb.2020.07.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/19/2022]
Abstract
The primary cilium is a ubiquitous microtubule-based organelle that senses external environment and modulates diverse signaling pathways in different cell types and tissues. The cilium originates from the mother centriole through a complex set of cellular events requiring hundreds of distinct components. Aberrant ciliogenesis or ciliary transport leads to a broad spectrum of clinical entities with overlapping yet highly variable phenotypes, collectively called ciliopathies, which include sensory defects and syndromic disorders with multi-organ pathologies. For efficient light detection, photoreceptors in the retina elaborate a modified cilium known as the outer segment, which is packed with membranous discs enriched for components of the phototransduction machinery. Retinopathy phenotype involves dysfunction and/or degeneration of the light sensing photoreceptors and is highly penetrant in ciliopathies. This review will discuss primary cilia biogenesis and ciliopathies, with a focus on the retina, and the role of CP110-CEP290-CC2D2A network. We will also explore how recent technologies can advance our understanding of cilia biology and discuss new paradigms for developing potential therapies of retinal ciliopathies.
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Affiliation(s)
- Holly Y Chen
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
| | - Ryan A Kelley
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Tiansen Li
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
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40
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Katoh Y, Chiba S, Nakayama K. Practical method for superresolution imaging of primary cilia and centrioles by expansion microscopy using an amplibody for fluorescence signal amplification. Mol Biol Cell 2020; 31:2195-2206. [PMID: 32726175 PMCID: PMC7550703 DOI: 10.1091/mbc.e20-04-0250] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Primary cilia are microtubule-based protrusions from the cell surface that are approximately 0.3 µm in diameter and 3 µm in length. Because size approximates the optical diffraction limit, ciliary structures at the subdiffraction level can be observed only by using a superresolution microscope or electron microscope. Expansion microscopy (ExM) is an alternative superresolution imaging technique that uses a swellable hydrogel that enables the physical expansion of specimens. However, the efficacy of ExM has not been fully verified, and further improvements in the method are anticipated. In this study, we applied ExM to the observation of primary cilia and centrioles and compared the acquired images with those obtained using conventional superresolution microscopy. Furthermore, we developed a new tool, called the amplibody, for fluorescence signal amplification, to compensate for the substantial decrease in fluorescence signal per unit volume inherent to physical expansion and for the partial proteolytic digestion of cellular proteins before expansion. We also demonstrate that the combinatorial use of the ExM protocol optimized for amplibodies and Airyscan superresolution microscopy enables the practical observation of cilia and centrioles with high brightness and resolution.
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Affiliation(s)
- Yohei Katoh
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shuhei Chiba
- Graduate School of Medicine, Osaka City University, Asahi-machi, 1-4-3 Abeno, Osaka 545-8585, Japan
| | - Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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41
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Greenan GA, Vale RD, Agard DA. Electron cryotomography of intact motile cilia defines the basal body to axoneme transition. J Cell Biol 2020; 219:133537. [PMID: 31874113 PMCID: PMC7039205 DOI: 10.1083/jcb.201907060] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/23/2019] [Accepted: 10/28/2019] [Indexed: 12/16/2022] Open
Abstract
Greenan et al. use electron cryotomography on intact motile cilia to elucidate how basal bodies template the formation of motile axonemes. Cells use motile cilia to generate force in the extracellular space. The structure of a cilium can be classified into three subdomains: the intracellular basal body (BB) that templates cilium formation, the extracellular axoneme that generates force, and the transition zone (TZ) that bridges them. While the BB is composed of triplet microtubules (TMTs), the axoneme is composed of doublet microtubules (DMTs), meaning the cilium must convert between different microtubule geometries. Here, we performed electron cryotomography to define this conversion, and our reconstructions reveal identifying structural features of the BB, TZ, and axoneme. Each region is distinct in terms of microtubule number and geometry, microtubule inner proteins, and microtubule linkers. TMT to DMT conversion occurs within the BB, and microtubule geometry changes to axonemal by the end of the TZ, followed by the addition of axoneme-specific components essential for cilium motility. Our results provide the highest-resolution images of the motile cilium to date and reveal how BBs template axonemes.
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Affiliation(s)
- Garrett A Greenan
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA.,The Howard Hughes Medical Institute, Chevy Chase, MD
| | - Ronald D Vale
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA.,The Howard Hughes Medical Institute, Chevy Chase, MD
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA.,The Howard Hughes Medical Institute, Chevy Chase, MD
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42
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Conkar D, Firat-Karalar EN. Microtubule-associated proteins and emerging links to primary cilium structure, assembly, maintenance, and disassembly. FEBS J 2020; 288:786-798. [PMID: 32627332 DOI: 10.1111/febs.15473] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/23/2020] [Accepted: 06/30/2020] [Indexed: 12/22/2022]
Abstract
The primary cilium is a microtubule-based structure that protrudes from the cell surface in diverse eukaryotic organisms. It functions as a key signaling center that decodes a variety of mechanical and chemical stimuli and plays fundamental roles in development and homeostasis. Accordingly, structural and functional defects of the primary cilium have profound effects on the physiology of multiple organ systems including kidney, retina, and central nervous system. At the core of the primary cilium is the microtubule-based axoneme, which supports the cilium shape and acts as the scaffold for bidirectional transport of cargoes into and out of cilium. Advances in imaging, proteomics, and structural biology have revealed new insights into the ultrastructural organization and composition of the primary cilium, the mechanisms that underlie its biogenesis and functions, and the pathologies that result from their deregulation termed ciliopathies. In this viewpoint, we first discuss the recent studies that identified the three-dimensional native architecture of the ciliary axoneme and revealed that it is considerably different from the well-known '9 + 0' paradigm. Moving forward, we explore emerging themes in the assembly and maintenance of the axoneme, with a focus on how microtubule-associated proteins regulate its structure, length, and stability. This far more complex picture of the primary cilium structure and composition, as well as the recent technological advances, open up new avenues for future research.
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Affiliation(s)
- Deniz Conkar
- Department of Molecular Biology and Genetics, Koc University, Istanbul, Turkey
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43
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Palaiologou E, Goggin P, Chatelet DS, Ribeiro de Souza R, Chiu W, Ashley B, Lofthouse EM, Sengers BG, Torrens C, Page AM, Cleal JK, Lewis RM. Serial block-face scanning electron microscopy reveals novel intercellular connections in human term placental microvasculature. J Anat 2020; 237:241-249. [PMID: 32242928 PMCID: PMC7369196 DOI: 10.1111/joa.13191] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 01/26/2023] Open
Abstract
The placental microvasculature is a conduit for fetal blood allowing solute exchange between the mother and the fetus. Serial block‐face scanning electron microscopy (SBF SEM) allows ultrastructure to be viewed in three dimensions and provides a new perspective on placental anatomy. This study used SBF SEM to study endothelial cells within the human placental microvasculature from uncomplicated pregnancies. Term human placental villi were aldehyde‐fixed and processed for imaging by SBF SEM. Manual segmentation was carried out on a terminal villous capillary and an intermediate villous arteriole and venule. Twenty‐seven SBF SEM stacks from terminal villi were analysed using stereological approaches to determine the volumes of microvascular components and the proportions of pericyte coverage. SBF SEM analysis of capillary endothelial cells revealed the presence of interendothelial protrusions (IEPs) originating from the donor cell at the endothelial junction and forming deep thin projections up to 7 μm into the adjacent endothelial cells. IEP density was estimated to be in the order of 35 million cm–3 placental tissue. Pericytes cover 15% of the fetal capillary surface area in terminal villi. In comparison, the cytotrophoblast covered 24% of the syncytiotrophoblast basal membrane. A trans‐endothelial channel was observed in a region of the vasculo‐syncytial capillary. Pericyte coverage was extensive in both arteriole and venule. Three‐dimensional imaging of the placental microvasculature identified novel ultrastructural features and provided an insight into factors that may influence capillary permeability and placental function. We hypothesise that the IEPs may allow mechanosensing between adjacent endothelial cells to assist in the maintenance of vessel integrity. The numbers of endothelial junctions, the presence of trans‐endothelial channels and the extent of pericyte coverage all provide an insight into the factors determining capillary permeability.
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Affiliation(s)
- Eleni Palaiologou
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Patricia Goggin
- Biomedical Imaging Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - David S Chatelet
- Biomedical Imaging Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | | | - Wendy Chiu
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Brogan Ashley
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Emma M Lofthouse
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Bram G Sengers
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK.,Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Christopher Torrens
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK.,Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Anton M Page
- Biomedical Imaging Unit, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Jane K Cleal
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK.,Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Rohan M Lewis
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK.,Institute for Life Sciences, University of Southampton, Southampton, UK
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Establishing and regulating the composition of cilia for signal transduction. Nat Rev Mol Cell Biol 2020; 20:389-405. [PMID: 30948801 DOI: 10.1038/s41580-019-0116-4] [Citation(s) in RCA: 246] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The primary cilium is a hair-like surface-exposed organelle of the eukaryotic cell that decodes a variety of signals - such as odorants, light and Hedgehog morphogens - by altering the local concentrations and activities of signalling proteins. Signalling within the cilium is conveyed through a diverse array of second messengers, including conventional signalling molecules (such as cAMP) and some unusual intermediates (such as sterols). Diffusion barriers at the ciliary base establish the unique composition of this signalling compartment, and cilia adapt their proteome to signalling demands through regulated protein trafficking. Much progress has been made on the molecular understanding of regulated ciliary trafficking, which encompasses not only exchanges between the cilium and the rest of the cell but also the shedding of signalling factors into extracellular vesicles.
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Kim YJ, Kim J. Therapeutic perspectives for structural and functional abnormalities of cilia. Cell Mol Life Sci 2019; 76:3695-3709. [PMID: 31147753 PMCID: PMC11105626 DOI: 10.1007/s00018-019-03158-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/17/2019] [Accepted: 05/22/2019] [Indexed: 12/15/2022]
Abstract
Ciliopathies are a group of hereditary disorders that result from structural or functional abnormalities of cilia. Recent intense research efforts have uncovered the genetic bases of ciliopathies, and our understanding of the assembly and functions of cilia has been improved significantly. Although mechanism-specific therapies for ciliopathies have not yet received regulatory approval, the use of innovative therapeutic modalities such as oligonucleotide therapy, gene replacement therapy, and gene editing in addition to symptomatic treatments are expected to provide valid treatment options in the near future. Moreover, candidate chemical compounds for developing small molecule drugs to treat ciliopathies have been identified. This review introduces the key features of cilia and ciliopathies, and summarizes the advances as well as the challenges that remain with the development of therapies for treating ciliopathies.
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Affiliation(s)
- Yong Joon Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Joon Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea.
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Persico V, Callaini G, Riparbelli MG. The Microtubule-Depolymerizing Kinesin-13 Klp10A Is Enriched in the Transition Zone of the Ciliary Structures of Drosophila melanogaster. Front Cell Dev Biol 2019; 7:173. [PMID: 31497602 PMCID: PMC6713071 DOI: 10.3389/fcell.2019.00173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/07/2019] [Indexed: 12/14/2022] Open
Abstract
The precursor of the flagellar axoneme is already present in the primary spermatocytes of Drosophila melanogaster. During spermatogenesis each primary spermatocyte shows a centriole pair that moves to the cell membrane and organizes an axoneme-based structure, the cilium-like region (CLR). The CLRs persist through the meiotic divisions and are inherited by young spermatids. During spermatid differentiation the ciliary caps elongate giving rise to the sperm axoneme. Mutations in Klp10A, a kinesin-13 of Drosophila, results in defects of centriole/CLR organization in spermatocytes and of ciliary cap assembly in elongating spermatids. Reduced Klp10A expression also results in strong structural defects of sensory type I neurons. We show, here, that this protein displays a peculiar localization during male gametogenesis. The Klp10A signal is first detected at the distal ends of the centrioles when they dock to the plasma membrane of young primary spermatocytes. At the onset of the first meiotic prometaphase, when the CLRs reach their full size, Klp10A is enriched in a distinct narrow area at the distal end of the centrioles and persists in elongating spermatids at the base of the ciliary cap. We conclude that Klp10A could be a core component of the ciliary transition zone in Drosophila.
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Affiliation(s)
| | - Giuliano Callaini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
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Characterization of Primary Cilia in Normal Fallopian Tube Epithelium and Serous Tubal Intraepithelial Carcinoma. Int J Gynecol Cancer 2019; 28:1535-1544. [PMID: 30095490 PMCID: PMC6166701 DOI: 10.1097/igc.0000000000001321] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Supplemental digital content is available in the text. Objectives The aim of this study was to investigate the distribution of primary cilia on secretory cells in normal fallopian tube (FT) and serous tubal intraepithelial carcinoma (STIC). Methods Fallopian tube tissue samples were obtained from 4 females undergoing prophylactic hysterectomies and 6 patients diagnosed with STIC. A mogp-TAg transgenic mouse STIC sample was also compared with a wild-type mouse FT sample. Serous tubal intraepithelial carcinoma was identified by hematoxylin and eosin staining and confirmed by positive Ki-67 and p53 immunohistochemical staining of tissue sections. We assessed the relative distribution of primary cilia on secretory cells and motile cilia on multiple ciliated cells by immunofluorescence and immunohistochemical staining. Ciliary function was assessed by immunofluorescence staining of specific ciliary marker proteins and responsiveness to Sonic Hedgehog signaling. Results Primary cilia are widespread on secretory cells in the ampulla, isthmus, and in particular, the fimbriae of human FT where they may appear to mediate ciliary-mediated Sonic Hedgehog signaling. A statistically significant reduction in the number of primary cilia on secretory cells was observed in human STIC samples compared with normal controls (P < 0.0002, Student t test), supported by similar findings in a mouse STIC sample. Immunohistochemical staining for dynein axonemal heavy chain 5 discriminated multiple motile cilia from primary cilia in human FT. Conclusions Primary cilia are widespread on secretory cells in the ampulla, isthmus, and in particular, the fimbriae of the human FT but are significantly reduced in both human and mouse STIC samples. Immunohistochemical staining for ciliary proteins may have clinical utility for early detection of STIC.
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48
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Mirvis M, Siemers KA, Nelson WJ, Stearns TP. Primary cilium loss in mammalian cells occurs predominantly by whole-cilium shedding. PLoS Biol 2019; 17:e3000381. [PMID: 31314751 PMCID: PMC6699714 DOI: 10.1371/journal.pbio.3000381] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 08/19/2019] [Accepted: 07/02/2019] [Indexed: 12/17/2022] Open
Abstract
The primary cilium is a central signaling hub in cell proliferation and differentiation and is built and disassembled every cell cycle in many animal cells. Disassembly is critically important, as misregulation or delay of cilia loss leads to cell cycle defects. The physical means by which cilia are lost are poorly understood but are thought to involve resorption of ciliary components into the cell body. To investigate cilium loss in mammalian cells, we used live-cell imaging to comprehensively characterize individual events. The predominant mode of cilium loss was rapid deciliation, in which the membrane and axoneme of the cilium was shed from the cell. Gradual resorption was also observed, as well as events in which a period of gradual resorption was followed by rapid deciliation. Deciliation resulted in intact shed cilia that could be recovered from culture medium and contained both membrane and axoneme proteins. We modulated levels of katanin and intracellular calcium, two putative regulators of deciliation, and found that excess katanin promotes cilia loss by deciliation, independently of calcium. Together, these results suggest that mammalian ciliary loss involves a tunable decision between deciliation and resorption.
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Affiliation(s)
- Mary Mirvis
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Kathleen A. Siemers
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - W. James Nelson
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Tim P. Stearns
- Department of Biology, Stanford University, Stanford, California, United States of America
- Department of Genetics, Stanford University, Stanford, California, United States of America
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49
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Cilia Distal Domain: Diversity in Evolutionarily Conserved Structures. Cells 2019; 8:cells8020160. [PMID: 30769894 PMCID: PMC6406257 DOI: 10.3390/cells8020160] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/25/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022] Open
Abstract
Eukaryotic cilia are microtubule-based organelles that protrude from the cell surface to fulfill sensory and motility functions. Their basic structure consists of an axoneme templated by a centriole/basal body. Striking differences in ciliary ultra-structures can be found at the ciliary base, the axoneme and the tip, not only throughout the eukaryotic tree of life, but within a single organism. Defects in cilia biogenesis and function are at the origin of human ciliopathies. This structural/functional diversity and its relationship with the etiology of these diseases is poorly understood. Some of the important events in cilia function occur at their distal domain, including cilia assembly/disassembly, IFT (intraflagellar transport) complexes' remodeling, and signal detection/transduction. How axonemal microtubules end at this domain varies with distinct cilia types, originating different tip architectures. Additionally, they show a high degree of dynamic behavior and are able to respond to different stimuli. The existence of microtubule-capping structures (caps) in certain types of cilia contributes to this diversity. It has been proposed that caps play a role in axoneme length control and stabilization, but their roles are still poorly understood. Here, we review the current knowledge on cilia structure diversity with a focus on the cilia distal domain and caps and discuss how they affect cilia structure and function.
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50
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Ijaz F, Ikegami K. Live cell imaging of dynamic behaviors of motile cilia and primary cilium. Microscopy (Oxf) 2019; 68:99-110. [DOI: 10.1093/jmicro/dfy147] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/17/2018] [Accepted: 12/27/2018] [Indexed: 12/17/2022] Open
Affiliation(s)
- Faryal Ijaz
- Department of Anatomy and Developmental Biology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-Ku, Hiroshima, Japan
| | - Koji Ikegami
- Department of Anatomy and Developmental Biology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-Ku, Hiroshima, Japan
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, Japan
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