1
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Tingey M, Ruba A, Jiang Z, Yang W. Deciphering vesicle-assisted transport mechanisms in cytoplasm to cilium trafficking. Front Cell Neurosci 2024; 18:1379976. [PMID: 38860265 PMCID: PMC11163138 DOI: 10.3389/fncel.2024.1379976] [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: 01/31/2024] [Accepted: 05/13/2024] [Indexed: 06/12/2024] Open
Abstract
The cilium, a pivotal organelle crucial for cell signaling and proper cell function, relies on meticulous macromolecular transport from the cytoplasm for its formation and maintenance. While the intraflagellar transport (IFT) pathway has traditionally been the focus of extensive study concerning ciliogenesis and ciliary maintenance, recent research highlights a complementary and alternative mechanism-vesicle-assisted transport (VAT) in cytoplasm to cilium trafficking. Despite its potential significance, the VAT pathway remains largely uncharacterized. This review explores recent studies providing evidence for the dynamics of vesicle-related diffusion and transport within the live primary cilium, employing high-speed super-resolution light microscopy. Additionally, we analyze the spatial distribution of vesicles in the cilium, mainly relying on electron microscopy data. By scrutinizing the VAT pathways that facilitate cargo transport into the cilium, with a specific emphasis on recent advancements and imaging data, our objective is to synthesize a comprehensive model of ciliary transport through the integration of IFT-VAT mechanisms.
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Affiliation(s)
| | | | | | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA, United States
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2
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Rao VG, Subramanianbalachandar V, Magaj MM, Redemann S, Kulkarni SS. Mechanisms of cilia regeneration in Xenopus multiciliated epithelium in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.14.544972. [PMID: 37398226 PMCID: PMC10312767 DOI: 10.1101/2023.06.14.544972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cilia regeneration is a physiological event, and while studied extensively in unicellular organisms, it remains poorly understood in vertebrates. In this study, using Xenopus multiciliated cells (MCCs) as a model, we demonstrate that, unlike unicellular organisms, deciliation removes the transition zone (TZ) and the ciliary axoneme. While MCCs immediately begin the regeneration of the ciliary axoneme, surprisingly, the assembly of TZ is delayed. However, ciliary tip proteins, Sentan and Clamp, localize to regenerating cilia without delay. Using cycloheximide (CHX) to block new protein synthesis, we show that the TZ protein B9d1 is not a component of the cilia precursor pool and requires new transcription/translation, providing insights into the delayed repair of TZ. Moreover, MCCs in CHX treatment assemble fewer (∼ 10 vs. ∼150 in controls) but near wild-type length (ranging between 60 to 90%) cilia by gradually concentrating ciliogenesis proteins like IFTs at a select few basal bodies. Using mathematical modeling, we show that cilia length compared to cilia number influences the force generated by MCCs more. In summary, our results question the requirement of TZ in motile cilia assembly and provide insights into how cells determine organelle size and number.
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3
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Brody SL, Pan J, Huang T, Xu J, Xu H, Koenitizer J, Brennan SK, Nanjundappa R, Saba TG, Berical A, Hawkins FJ, Wang X, Zhang R, Mahjoub MR, Horani A, Dutcher SK. Loss of an extensive ciliary connectome induces proteostasis and cell fate switching in a severe motile ciliopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585965. [PMID: 38562900 PMCID: PMC10983967 DOI: 10.1101/2024.03.20.585965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Motile cilia have essential cellular functions in development, reproduction, and homeostasis. Genetic causes for motile ciliopathies have been identified, but the consequences on cellular functions beyond impaired motility remain unknown. Variants in CCDC39 and CCDC40 cause severe disease not explained by loss of motility. Using human cells with pathological variants in these genes, Chlamydomonas genetics, cryo-electron microscopy, single cell RNA transcriptomics, and proteomics, we identified perturbations in multiple cilia-independent pathways. Absence of the axonemal CCDC39/CCDC40 heterodimer results in loss of a connectome of over 90 proteins. The undocked connectome activates cell quality control pathways, switches multiciliated cell fate, impairs microtubule architecture, and creates a defective periciliary barrier. Both cilia-dependent and independent defects are likely responsible for the disease severity. Our findings provide a foundation for reconsidering the broad cellular impact of pathologic variants in ciliopathies and suggest new directions for therapies.
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Affiliation(s)
- Steven L Brody
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Jiehong Pan
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Tao Huang
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Jian Xu
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Huihui Xu
- Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Jeffrey Koenitizer
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Steven K Brennan
- Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Rashmi Nanjundappa
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Thomas G Saba
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, 48108, USA
| | - Andrew Berical
- Center for Regenerative Medicine, Boston University, Boston, MA, 02118, USA
| | - Finn J Hawkins
- Center for Regenerative Medicine, Boston University, Boston, MA, 02118, USA
| | - Xiangli Wang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Moe R Mahjoub
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
- Department of Cell Biology and Physisology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Amjad Horani
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, 48108, USA
- Department of Cell Biology and Physisology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Susan K Dutcher
- Department of Cell Biology and Physisology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
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4
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Moran AL, Louzao-Martinez L, Norris DP, Peters DJM, Blacque OE. Transport and barrier mechanisms that regulate ciliary compartmentalization and ciliopathies. Nat Rev Nephrol 2024; 20:83-100. [PMID: 37872350 DOI: 10.1038/s41581-023-00773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2023] [Indexed: 10/25/2023]
Abstract
Primary cilia act as cell surface antennae, coordinating cellular responses to sensory inputs and signalling molecules that regulate developmental and homeostatic pathways. Cilia are therefore critical to physiological processes, and defects in ciliary components are associated with a large group of inherited pleiotropic disorders - known collectively as ciliopathies - that have a broad spectrum of phenotypes and affect many or most tissues, including the kidney. A central feature of the cilium is its compartmentalized structure, which imparts its unique molecular composition and signalling environment despite its membrane and cytosol being contiguous with those of the cell. Such compartmentalization is achieved via active transport pathways that bring protein cargoes to and from the cilium, as well as gating pathways at the ciliary base that establish diffusion barriers to protein exchange into and out of the organelle. Many ciliopathy-linked proteins, including those involved in kidney development and homeostasis, are components of the compartmentalizing machinery. New insights into the major compartmentalizing pathways at the cilium, namely, ciliary gating, intraflagellar transport, lipidated protein flagellar transport and ciliary extracellular vesicle release pathways, have improved our understanding of the mechanisms that underpin ciliary disease and associated renal disorders.
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Affiliation(s)
- Ailis L Moran
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Laura Louzao-Martinez
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.
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5
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Chatzifrangkeskou M, Kouis P, Skourides PA. JNK regulates ciliogenesis through the interflagellar transport complex and actin networks. J Cell Biol 2023; 222:e202303052. [PMID: 37851005 PMCID: PMC10585068 DOI: 10.1083/jcb.202303052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/16/2023] [Accepted: 08/29/2023] [Indexed: 10/19/2023] Open
Abstract
The c-Jun N-terminal kinase (JNK) regulates various important physiological processes. Although the JNK pathway has been under intense investigation for over 20 yr, its complexity is still perplexing, with multiple protein partners underlying the diversity of its activity. We show that JNK is associated with the basal bodies in both primary and motile cilia. Loss of JNK disrupts basal body migration and docking and leads to severe ciliogenesis defects. JNK's involvement in ciliogenesis stems from a dual role in the regulation of the actin networks of multiciliated cells (MCCs) and the establishment of the intraflagellar transport-B core complex. JNK signaling is also critical for the maintenance of the actin networks and ciliary function in mature MCCs. JNK is implicated in the development of diabetes, neurodegeneration, and liver disease, all of which have been linked to ciliary dysfunction. Our work uncovers a novel role of JNK in ciliogenesis and ciliary function that could have important implications for JNK's role in the disease.
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Affiliation(s)
| | - Panayiotis Kouis
- Respiratory Physiology Laboratory, Medical School, University of Cyprus, Nicosia, Cyprus
| | - Paris A. Skourides
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
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6
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Dougherty LL, Dutta S, Avasthi P. The ERK activator, BCI, inhibits ciliogenesis and causes defects in motor behavior, ciliary gating, and cytoskeletal rearrangement. Life Sci Alliance 2023; 6:e202301899. [PMID: 36914265 PMCID: PMC10011610 DOI: 10.26508/lsa.202301899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023] Open
Abstract
MAPK pathways are well-known regulators of the cell cycle, but they have also been found to control ciliary length in a wide variety of organisms and cell types from Caenorhabditis elegans neurons to mammalian photoreceptors through unknown mechanisms. ERK1/2 is a MAP kinase in human cells that is predominantly phosphorylated by MEK1/2 and dephosphorylated by the phosphatase DUSP6. We have found that the ERK1/2 activator/DUSP6 inhibitor, (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI), inhibits ciliary maintenance in Chlamydomonas and hTERT-RPE1 cells and assembly in Chlamydomonas These effects involve inhibition of total protein synthesis, microtubule organization, membrane trafficking, and KAP-GFP motor dynamics. Our data provide evidence for various avenues for BCI-induced ciliary shortening and impaired ciliogenesis that gives mechanistic insight into how MAP kinases can regulate ciliary length.
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Affiliation(s)
- Larissa L Dougherty
- Biochemistry and Cell Biology Department, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
- Anatomy and Cell Biology Department, University of Kansas Medical Center, Kansas City, KS, USA
| | - Soumita Dutta
- Anatomy and Cell Biology Department, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Prachee Avasthi
- Biochemistry and Cell Biology Department, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA
- Anatomy and Cell Biology Department, University of Kansas Medical Center, Kansas City, KS, USA
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7
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Saravanan S, Trischler D, Bower R, Porter M, Lechtreck K. In vivo imaging reveals independent intraflagellar transport of the nexin-dynein regulatory complex subunits DRC2 and DRC4. Mol Biol Cell 2023; 34:br2. [PMID: 36598807 PMCID: PMC9930527 DOI: 10.1091/mbc.e22-11-0524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/19/2022] [Accepted: 12/23/2022] [Indexed: 01/05/2023] Open
Abstract
Many axonemal proteins enter cilia and flagella on intraflagellar transport (IFT) trains, which move bidirectionally along the axonemal microtubules. Certain axonemal substructures including the radial spokes and outer dynein arms are preassembled in the cell body and transported as multisubunit complexes into flagella by IFT. Here, we used in vivo imaging to analyze the transport and assembly of DRC2 and DRC4, two core subunits of the nexin-dynein regulatory complex (N-DRC). Tagged DRC2 moved by IFT in mutants lacking DRC4 and vice versa, showing that they do not depend on each other for IFT. Simultaneous imaging of tagged DRC2 and DRC4, expressed from transgenes that rescue a corresponding double mutant, mostly showed transport on separate IFT trains, but occasional cotransports were also observed. The results demonstrate that DRC2 and DRC4 are transported largely independently of each other into flagella. These studies suggest that the N-DRC assembles onto the axoneme by the stepwise addition of subunits.
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Affiliation(s)
- Sahana Saravanan
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Douglas Trischler
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Raqual Bower
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Mary Porter
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
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8
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Arora S, Rana M, Sachdev A, D'Souza JS. Appearing and disappearing acts of cilia. J Biosci 2023; 48:8. [PMID: 36924208 PMCID: PMC10005925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The past few decades have seen a rise in research on vertebrate cilia and ciliopathy, with interesting collaborations between basic and clinical scientists. This work includes studies on ciliary architecture, composition, evolution, and organelle generation and its biological role. The human body has cells that harbour any of the following four types of cilia: 9+0 motile, 9+0 immotile, 9+2 motile, and 9+2 immotile. Depending on the type, cilia play an important role in cell/fluid movement, mating, sensory perception, and development. Defects in cilia are associated with a wide range of human diseases afflicting the brain, heart, kidneys, respiratory tract, and reproductive system. These are commonly known as ciliopathies and affect millions of people worldwide. Due to their complex genetic etiology, diagnosis and therapy have remained elusive. Although model organisms like Chlamydomonas reinhardtii have been a useful source for ciliary research, reports of a fascinating and rewarding translation of this research into mammalian systems, especially humans, are seen. The current review peeks into one of the complex features of this organelle, namely its birth, the common denominators across the formation of both 9+0 and 9+2 ciliary types, the molecules involved in ciliogenesis, and the steps that go towards regulating their assembly and disassembly.
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Affiliation(s)
- Shashank Arora
- School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (E), Mumbai 400098, India
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9
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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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10
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Wang L, Wen X, Wang Z, Lin Z, Li C, Zhou H, Yu H, Li Y, Cheng Y, Chen Y, Lou G, Pan J, Cao M. Ciliary transition zone proteins coordinate ciliary protein composition and ectosome shedding. Nat Commun 2022; 13:3997. [PMID: 35810181 PMCID: PMC9271036 DOI: 10.1038/s41467-022-31751-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 06/30/2022] [Indexed: 11/09/2022] Open
Abstract
The transition zone (TZ) of the cilium/flagellum serves as a diffusion barrier that controls the entry/exit of ciliary proteins. Mutations of the TZ proteins disrupt barrier function and lead to multiple human diseases. However, the systematic regulation of ciliary composition and signaling-related processes by different TZ proteins is not completely understood. Here, we reveal that loss of TCTN1 in Chlamydomonas reinhardtii disrupts the assembly of wedge-shaped structures in the TZ. Proteomic analysis of cilia from WT and three TZ mutants, tctn1, cep290, and nphp4, shows a unique role of each TZ subunit in the regulation of ciliary composition, explaining the phenotypic diversity of different TZ mutants. Interestingly, we find that defects in the TZ impair the formation and biological activity of ciliary ectosomes. Collectively, our findings provide systematic insights into the regulation of ciliary composition by TZ proteins and reveal a link between the TZ and ciliary ectosomes. Cilia project from cells to serve sensory functions, and ciliary disruption can result in multiple disorders known as ciliopathies. Here the authors show that the ciliopathy gene TCTN1 functions to regulate the ciliary transition zone and ectosome formation.
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Affiliation(s)
- Liang Wang
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China.
| | - Xin Wen
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Zhengmao Wang
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266071, Qingdao, China.,MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Zaisheng Lin
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Chunhong Li
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Huilin Zhou
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Huimin Yu
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Yuhan Li
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Yifei Cheng
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Yuling Chen
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Geer Lou
- Shanghai Biotree Biotech Co. Ltd, 201815, Shanghai, China
| | - Junmin Pan
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266071, Qingdao, China.,MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Muqing Cao
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China.
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11
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Systematic characterization of gene function in the photosynthetic alga Chlamydomonas reinhardtii. Nat Genet 2022; 54:705-714. [PMID: 35513725 PMCID: PMC9110296 DOI: 10.1038/s41588-022-01052-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 03/15/2022] [Indexed: 12/12/2022]
Abstract
Most genes in photosynthetic organisms remain functionally uncharacterized. Here, using a barcoded mutant library of the model eukaryotic alga Chlamydomonas reinhardtii, we determined the phenotypes of more than 58,000 mutants under more than 121 different environmental growth conditions and chemical treatments. A total of 59% of genes are represented by at least one mutant that showed a phenotype, providing clues to the functions of thousands of genes. Mutant phenotypic profiles place uncharacterized genes into functional pathways such as DNA repair, photosynthesis, the CO2-concentrating mechanism and ciliogenesis. We illustrate the value of this resource by validating phenotypes and gene functions, including three new components of an actin cytoskeleton defense pathway. The data also inform phenotype discovery in land plants; mutants in Arabidopsis thaliana genes exhibit phenotypes similar to those we observed in their Chlamydomonas homologs. We anticipate that this resource will guide the functional characterization of genes across the tree of life. Systematic phenotyping of 58,101 mutants of the model eukaryotic alga Chlamydomonas reinhardtii under 121 environmental and chemical stress conditions provides a large resource for characterizing gene function.
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12
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De-Castro ARG, Rodrigues DRM, De-Castro MJG, Vieira N, Vieira C, Carvalho AX, Gassmann R, Abreu CMC, Dantas TJ. WDR60-mediated dynein-2 loading into cilia powers retrograde IFT and transition zone crossing. J Cell Biol 2022; 221:212746. [PMID: 34739033 PMCID: PMC8576871 DOI: 10.1083/jcb.202010178] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 09/20/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022] Open
Abstract
The dynein-2 motor complex drives retrograde intraflagellar transport (IFT), playing a pivotal role in the assembly and functions of cilia. However, the mechanisms that regulate dynein-2 motility remain poorly understood. Here, we identify the Caenorhabditis elegans WDR60 homologue, WDR-60, and dissect the roles of this intermediate chain using genome editing and live imaging of endogenous dynein-2/IFT components. We find that loss of WDR-60 impairs dynein-2 recruitment to cilia and its incorporation onto anterograde IFT trains, reducing retrograde motor availability at the ciliary tip. Consistent with this, we show that fewer dynein-2 motors power WDR-60–deficient retrograde IFT trains, which move at reduced velocities and fail to exit cilia, accumulating on the distal side of the transition zone. Remarkably, disrupting the transition zone’s NPHP module almost fully restores ciliary exit of underpowered retrograde trains in wdr-60 mutants. This work establishes WDR-60 as a major contributor to IFT, and the NPHP module as a roadblock to dynein-2 passage through the transition zone.
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Affiliation(s)
- Ana R G De-Castro
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Diogo R M Rodrigues
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Maria J G De-Castro
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Neide Vieira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Cármen Vieira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Ana X Carvalho
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Reto Gassmann
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Carla M C Abreu
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Tiago J Dantas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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13
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Potter VL, Moye AR, Robichaux MA, Wensel TG. Super-resolution microscopy reveals photoreceptor-specific subciliary location and function of ciliopathy-associated protein CEP290. JCI Insight 2021; 6:e145256. [PMID: 34520396 PMCID: PMC8564900 DOI: 10.1172/jci.insight.145256] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 09/08/2021] [Indexed: 01/19/2023] Open
Abstract
Mutations in the cilium-associated protein CEP290 cause retinal degeneration as part of multiorgan ciliopathies or as retina-specific diseases. The precise location and the functional roles of CEP290 within cilia and, specifically, the connecting cilia (CC) of photoreceptors, remain unclear. We used super-resolution fluorescence microscopy and electron microscopy to localize CEP290 in the CC and in the primary cilia of cultured cells with subdiffraction resolution and to determine effects of CEP290 deficiency in 3 mutant models. Radially, CEP290 localizes in close proximity to the microtubule doublets in the region between the doublets and the ciliary membrane. Longitudinally, it is distributed throughout the length of the CC whereas it is confined to the very base of primary cilia in human retinal pigment epithelium-1 cells. We found Y-shaped links, ciliary substructures between microtubules and membrane, throughout the length of the CC. Severe CEP290 deficiencies in mouse models did not prevent assembly of cilia or cause obvious mislocalization of ciliary components in early stages of degeneration. There were fewer cilia and no normal outer segments in the mutants, but the Y-shaped links were clearly present. These results point to photoreceptor-specific functions of CEP290 essential for CC maturation and stability following the earliest stages of ciliogenesis.
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Affiliation(s)
- Valencia L Potter
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology.,Program in Developmental Biology, Graduate School of Biomedical Sciences, and.,Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, USA
| | - Abigail R Moye
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
| | - Michael A Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology.,Departments of Ophthalmology and Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
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14
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Wiegering A, Dildrop R, Vesque C, Khanna H, Schneider-Maunoury S, Gerhardt C. Rpgrip1l controls ciliary gating by ensuring the proper amount of Cep290 at the vertebrate transition zone. Mol Biol Cell 2021; 32:675-689. [PMID: 33625872 PMCID: PMC8108517 DOI: 10.1091/mbc.e20-03-0190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A range of severe human diseases called ciliopathies is caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme, and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localize to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.,Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Renate Dildrop
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Christine Vesque
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Hemant Khanna
- Department of Ophthalmology and Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany
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15
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Barnes CL, Malhotra H, Calvert PD. Compartmentalization of Photoreceptor Sensory Cilia. Front Cell Dev Biol 2021; 9:636737. [PMID: 33614665 PMCID: PMC7889997 DOI: 10.3389/fcell.2021.636737] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/07/2021] [Indexed: 12/12/2022] Open
Abstract
Functional compartmentalization of cells is a universal strategy for segregating processes that require specific components, undergo regulation by modulating concentrations of those components, or that would be detrimental to other processes. Primary cilia are hair-like organelles that project from the apical plasma membranes of epithelial cells where they serve as exclusive compartments for sensing physical and chemical signals in the environment. As such, molecules involved in signal transduction are enriched within cilia and regulating their ciliary concentrations allows adaptation to the environmental stimuli. The highly efficient organization of primary cilia has been co-opted by major sensory neurons, olfactory cells and the photoreceptor neurons that underlie vision. The mechanisms underlying compartmentalization of cilia are an area of intense current research. Recent findings have revealed similarities and differences in molecular mechanisms of ciliary protein enrichment and its regulation among primary cilia and sensory cilia. Here we discuss the physiological demands on photoreceptors that have driven their evolution into neurons that rely on a highly specialized cilium for signaling changes in light intensity. We explore what is known and what is not known about how that specialization appears to have driven unique mechanisms for photoreceptor protein and membrane compartmentalization.
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Affiliation(s)
| | | | - Peter D. Calvert
- Department of Ophthalmology and Visual Sciences, Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, United States
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16
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Ning K, Song E, Sendayen BE, Prosseda PP, Chang KC, Ghaffarieh A, Alvarado JA, Wang B, Haider KM, Berbari NF, Hu Y, Sun Y. Defective INPP5E distribution in NPHP1-related Senior-Loken syndrome. Mol Genet Genomic Med 2020; 9:e1566. [PMID: 33306870 PMCID: PMC7963418 DOI: 10.1002/mgg3.1566] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/06/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022] Open
Abstract
Background Senior–Loken syndrome is a rare genetic disorder that presents with nephronophthisis and retinal degeneration, leading to end‐stage renal disease and progressive blindness. The most frequent cause of juvenile nephronophthisis is a mutation in the nephronophthisis type 1 (NPHP1) gene. NPHP1 encodes the protein nephrocystin‐1, which functions at the transition zone (TZ) of primary cilia. Methods We report a 9‐year‐old Senior–Loken syndrome boy with NPHP1 deletion, who presents with bilateral vision decrease and cystic renal disease. Renal function deteriorated to require bilateral nephrectomy and renal transplant. We performed immunohistochemistry, H&E staining, and electron microscopy on the renal sample to determine the subcellular distribution of ciliary proteins in the absence of NPHP1. Results Immunohistochemistry and electron microscopy of the resected kidney showed disorganized cystic structures with loss of cilia in renal tubules. Phosphoinositides have been recently recognized as critical components of the ciliary membrane and immunostaining of kidney sections for phosphoinositide 5‐phosphatase, INPP5E, showed loss of staining compared to healthy control. Ophthalmic examination showed decreased electroretinogram consistent with early retinal degeneration. Conclusion The decreased expression of INPP5E specifically in the primary cilium, coupled with disorganized cilia morphology, suggests a novel role of NPHP1 that it is involved in regulating ciliary phosphoinositide composition in the ciliary membrane of renal tubular cells. In this study, we report a 9‐year‐old Senior‐Loken syndrome patient with NPHP1 deletion. We found the decreased expression of INPP5E specifically in the primary cilium, coupled with disorganized cilia morphology, suggests a novel role of NPHP1 in regulating ciliary phosphoinositide composition in the ciliary membrane of renal tubular cells.
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Affiliation(s)
- Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Emilie Song
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Brent E Sendayen
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Philipp P Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kun-Che Chang
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Jorge A Alvarado
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Biao Wang
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kathryn M Haider
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University Purdue University in Indianapolis, Indianapolis, IN, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Stanford, CA, USA.,Palo Alto Veterans Administration Palo Alto, CA, USA
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17
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Craft Van De Weghe J, Harris JA, Kubo T, Witman GB, Lechtreck KF. Diffusion rather than intraflagellar transport likely provides most of the tubulin required for axonemal assembly in Chlamydomonas. J Cell Sci 2020; 133:jcs.249805. [PMID: 32801124 DOI: 10.1242/jcs.249805] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/31/2020] [Indexed: 12/18/2022] Open
Abstract
Tubulin enters the cilium by diffusion and motor-based intraflagellar transport (IFT). However, the respective contribution of each route in providing tubulin for axonemal assembly remains unknown. Using Chlamydomonas, we attenuated IFT-based tubulin transport of GFP-β-tubulin by altering the IFT74N-IFT81N tubulin-binding module and the C-terminal E-hook of tubulin. E-hook-deficient GFP-β-tubulin was incorporated into the axonemal microtubules, but its transport frequency by IFT was reduced by ∼90% in control cells and essentially abolished when the tubulin-binding site of IFT81 was incapacitated. Despite the strong reduction in IFT, the proportion of E-hook-deficient GFP-β-tubulin in the axoneme was only moderately reduced. In vivo imaging showed more GFP-β-tubulin particles entering cilia by diffusion than by IFT. Extrapolated to endogenous tubulin, the data indicate that diffusion provides most of the tubulin required for axonemal assembly. We propose that IFT of tubulin is nevertheless needed for ciliogenesis, because it augments the tubulin pool supplied to the ciliary tip by diffusion, thus ensuring that free tubulin there is maintained at the critical concentration for plus-end microtubule assembly during rapid ciliary growth.
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Affiliation(s)
| | - J Aaron Harris
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Tomohiro Kubo
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - George B Witman
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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18
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Bustamante-Marin XM, Horani A, Stoyanova M, Charng WL, Bottier M, Sears PR, Yin WN, Daniels LA, Bowen H, Conrad DF, Knowles MR, Ostrowski LE, Zariwala MA, Dutcher SK. Mutation of CFAP57, a protein required for the asymmetric targeting of a subset of inner dynein arms in Chlamydomonas, causes primary ciliary dyskinesia. PLoS Genet 2020; 16:e1008691. [PMID: 32764743 PMCID: PMC7444499 DOI: 10.1371/journal.pgen.1008691] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 08/19/2020] [Accepted: 02/22/2020] [Indexed: 01/10/2023] Open
Abstract
Primary ciliary dyskinesia (PCD) is characterized by chronic airway disease, reduced fertility, and randomization of the left/right body axis. It is caused by defects of motile cilia and sperm flagella. We screened a cohort of affected individuals that lack an obvious axonemal defect for pathogenic variants using whole exome capture, next generation sequencing, and bioinformatic analysis assuming an autosomal recessive trait. We identified one subject with an apparently homozygous nonsense variant [(c.1762C>T), p.(Arg588*)] in the uncharacterized CFAP57 gene. Interestingly, the variant results in the skipping of exon 11 (58 amino acids), which may be due to disruption of an exonic splicing enhancer. In normal human nasal epithelial cells, CFAP57 localizes throughout the ciliary axoneme. Nasal cells from the PCD patient express a shorter, mutant version of CFAP57 and the protein is not incorporated into the axoneme. The missing 58 amino acids include portions of WD repeats that may be important for loading onto the intraflagellar transport (IFT) complexes for transport or docking onto the axoneme. A reduced beat frequency and an alteration in ciliary waveform was observed. Knockdown of CFAP57 in human tracheobronchial epithelial cells (hTECs) recapitulates these findings. Phylogenetic analysis showed that CFAP57 is highly conserved in organisms that assemble motile cilia. CFAP57 is allelic with the BOP2/IDA8/FAP57 gene identified previously in Chlamydomonas reinhardtii. Two independent, insertional fap57 Chlamydomonas mutant strains show reduced swimming velocity and altered waveforms. Tandem mass tag (TMT) mass spectroscopy shows that FAP57 is missing, and the "g" inner dyneins (DHC7 and DHC3) and the "d" inner dynein (DHC2) are reduced, but the FAP57 paralog FBB7 is increased. Together, our data identify a homozygous variant in CFAP57 that causes PCD that is likely due to a defect in the inner dynein arm assembly process.
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Affiliation(s)
- Ximena M. Bustamante-Marin
- Department of Medicine, Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Amjad Horani
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Mihaela Stoyanova
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Wu-Lin Charng
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Mathieu Bottier
- Department of Mechanical Engineering, Washington University, St. Louis, Missouri, United States of America
| | - Patrick R. Sears
- Department of Medicine, Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Wei-Ning Yin
- Department of Medicine, Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Leigh Anne Daniels
- Department of Medicine, Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Hailey Bowen
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Donald F. Conrad
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Michael R. Knowles
- Department of Medicine, Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Lawrence E. Ostrowski
- Department of Medicine, Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Maimoona A. Zariwala
- Department of Pathology and Laboratory Medicine and the Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Susan K. Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
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19
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Vuolo L, Stevenson NL, Mukhopadhyay AG, Roberts AJ, Stephens DJ. Cytoplasmic dynein-2 at a glance. J Cell Sci 2020; 133:133/6/jcs240614. [DOI: 10.1242/jcs.240614] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
ABSTRACT
Cytoplasmic dynein-2 is a motor protein complex that drives the movement of cargoes along microtubules within cilia, facilitating the assembly of these organelles on the surface of nearly all mammalian cells. Dynein-2 is crucial for ciliary function, as evidenced by deleterious mutations in patients with skeletal abnormalities. Long-standing questions include how the dynein-2 complex is assembled, regulated, and switched between active and inactive states. A combination of model organisms, in vitro cell biology, live-cell imaging, structural biology and biochemistry has advanced our understanding of the dynein-2 motor. In this Cell Science at a Glance article and the accompanying poster, we discuss the current understanding of dynein-2 and its roles in ciliary assembly and function.
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Affiliation(s)
- Laura Vuolo
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Nicola L. Stevenson
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Aakash G. Mukhopadhyay
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK
| | - Anthony J. Roberts
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK
| | - David J. Stephens
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
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20
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Gogendeau D, Lemullois M, Le Borgne P, Castelli M, Aubusson-Fleury A, Arnaiz O, Cohen J, Vesque C, Schneider-Maunoury S, Bouhouche K, Koll F, Tassin AM. MKS-NPHP module proteins control ciliary shedding at the transition zone. PLoS Biol 2020; 18:e3000640. [PMID: 32163404 PMCID: PMC7093003 DOI: 10.1371/journal.pbio.3000640] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/24/2020] [Accepted: 02/24/2020] [Indexed: 12/21/2022] Open
Abstract
Ciliary shedding occurs from unicellular organisms to metazoans. Although required during the cell cycle and during neurogenesis, the process remains poorly understood. In all cellular models, this phenomenon occurs distal to the transition zone (TZ), suggesting conserved molecular mechanisms. The TZ module proteins (Meckel Gruber syndrome [MKS]/Nephronophtysis [NPHP]/Centrosomal protein of 290 kDa [CEP290]/Retinitis pigmentosa GTPase regulator-Interacting Protein 1-Like Protein [RPGRIP1L]) are known to cooperate to establish TZ formation and function. To determine whether they control deciliation, we studied the function of 5 of them (Transmembrane protein 107 [TMEM107], Transmembrane protein 216 [TMEM216], CEP290, RPGRIP1L, and NPHP4) in Paramecium. All proteins are recruited to the TZ of growing cilia and localize with 9-fold symmetry at the level of the most distal part of the TZ. We demonstrate that depletion of the MKS2/TMEM216 and TMEM107 proteins induces constant deciliation of some cilia, while depletion of either NPHP4, CEP290, or RPGRIP1L prevents Ca2+/EtOH deciliation. Our results constitute the first evidence for a role of conserved TZ proteins in deciliation and open new directions for understanding motile cilia physiology. Functional analysis and subcellular localisation of the conserved transition zone proteins in the ciliate Paramecium tetraurelia demonstrates their involvement in the ciliary shedding process, opening new avenues fir understanding the molecular mechanism of deciliation.
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Affiliation(s)
- Delphine Gogendeau
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Michel Lemullois
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Pierrick Le Borgne
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Manon Castelli
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anne Aubusson-Fleury
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Olivier Arnaiz
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Jean Cohen
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Christine Vesque
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Developmental Biology Laboratory-Institut de Biologie Paris-Seine (IBPS), Paris, France
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Developmental Biology Laboratory-Institut de Biologie Paris-Seine (IBPS), Paris, France
| | - Khaled Bouhouche
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - France Koll
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anne-Marie Tassin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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21
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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: 226] [Impact Index Per Article: 56.5] [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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22
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Long H, Huang K. Transport of Ciliary Membrane Proteins. Front Cell Dev Biol 2020; 7:381. [PMID: 31998723 PMCID: PMC6970386 DOI: 10.3389/fcell.2019.00381] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 12/17/2019] [Indexed: 12/24/2022] Open
Abstract
Cilia and flagella are highly conserved organelles in eukaryotic cells that drive cell movement and act as cell antennae that receive and transmit signals. In addition to receiving and transducing external signals that activate signal cascades, cilia also secrete ciliary ectosomes that send signals to recipient cells, and thereby mediate cell–cell communication. Abnormal ciliary function leads to various ciliopathies, and the precise transport and localization of ciliary membrane proteins are essential for cilium function. This review summarizes current knowledge about the transport processes of ciliary membrane proteins after their synthesis at the endoplasmic reticulum: modification and sorting in the Golgi apparatus, transport through vesicles to the ciliary base, entrance into cilia through the diffusion barrier, and turnover by ectosome secretion. The molecular mechanisms and regulation involved in each step are also discussed. Transport of ciliary membrane proteins is a complex, precise cellular process coordinated among multiple organelles. By systematically analyzing the existing research, we identify topics that should be further investigated to promote progress in this field of research.
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Affiliation(s)
- Huan Long
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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23
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Garcia G, Raleigh DR, Reiter JF. How the Ciliary Membrane Is Organized Inside-Out to Communicate Outside-In. Curr Biol 2019; 28:R421-R434. [PMID: 29689227 DOI: 10.1016/j.cub.2018.03.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cilia, organelles that move to execute functions like fertilization and signal to execute functions like photoreception and embryonic patterning, are composed of a core of nine-fold doublet microtubules overlain by a membrane. Distinct types of cilia display distinct membrane morphologies, ranging from simple domed cylinders to the highly ornate invaginations and membrane disks of photoreceptor outer segments. Critical for the ability of cilia to signal, both the protein and the lipid compositions of ciliary membranes are different from those of other cellular membranes. This specialization presents a unique challenge for the cell as, unlike membrane-bounded organelles, the ciliary membrane is contiguous with the surrounding plasma membrane. This distinct ciliary membrane is generated in concert with multiple membrane remodeling events that comprise the process of ciliogenesis. Once the cilium is formed, control of ciliary membrane composition relies on discrete molecular machines, including a barrier to membrane proteins entering the cilium at a specialized region of the base of the cilium called the transition zone and a trafficking adaptor that controls G protein-coupled receptor (GPCR) localization to the cilium called the BBSome. The ciliary membrane can be further remodeled by the removal of membrane proteins by the release of ciliary extracellular vesicles that may function in intercellular communication, removal of unneeded proteins or ciliary disassembly. Here, we review the structures and transport mechanisms that control ciliary membrane composition, and discuss how membrane specialization enables the cilium to function as the antenna of the cell.
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Affiliation(s)
- Galo Garcia
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - David R Raleigh
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Department of Radiation Oncology, University of California, San Francisco, CA 94143, USA; Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.
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24
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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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Lodh S. Primary Cilium, An Unsung Hero in Maintaining Functional β-cell Population. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:471-480. [PMID: 31543709 PMCID: PMC6747938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
A primary challenge in type 2 diabetes (T2D) is the preservation of a functional population of β-cells, which play a central role in regulating blood glucose levels. Two congenital disorders, Bardet-Biedl syndrome (BBS) and Alström syndrome (ALMS), can serve as useful models to understand how β-cells are normally produced and regenerated. Both are characterized by obesity, loss of β-cells, and defects in primary cilia - the sensory center of cells. Primary cilia are cellular protrusions present in almost every vertebrate cell. This antenna-like organelle plays a crucial role in regulating several signaling pathways that direct proper development, proliferation, and homeostasis. Mutations in genes expressing ciliary proteins or proteins present at or near the base of the cilium lead to disorders, collectively called ciliopathies. BBS and Alström syndrome are such disorders. Though both BBS and Alström patients are obese, their childhood diabetes rates are vastly different, suggesting distinct pathogenesis underlying these two ciliopathies. Clinical studies suggest that BBS patients are protected against early onset diabetes by sustained or enhanced β-cell function. In contrast, Alström patients are more prone to develop diabetes. They have hyperinsulinemia, yet their β-cells fail to sense glucose and to regulate insulin secretion accordingly. These data suggest a potential role for primary cilia in maintaining a functional β-cell population and that defects in cilia or in ciliary proteins impair development and function of β-cells. Identifying the respective roles of primary cilia and ciliary proteins, such as BBS and ALMS1 may shed light on β-cell biology and uncover potentially novel targets for diabetes therapy.
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Affiliation(s)
- Sukanya Lodh
- To whom all correspondence should be addressed: Sukanya Lodh, Department of Biological sciences, Marquette University, 1428 W. Clybourn St., Milwaukee, WI 53233; Tel: 802-881-6221, Email address:
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Leigh MW, Horani A, Kinghorn B, O'Connor MG, Zariwala MA, Knowles MR. Primary Ciliary Dyskinesia (PCD): A genetic disorder of motile cilia. ACTA ACUST UNITED AC 2019; 4:51-75. [PMID: 31572664 DOI: 10.3233/trd-190036] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Margaret W Leigh
- Department of Pediatrics and Marsico Lung Institute, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Amjad Horani
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - BreAnna Kinghorn
- Seattle Children's Hospital, Department of Pediatrics, University of Washington School of Medicine; Seattle, Washington
| | - Michael G O'Connor
- Department of Pediatrics, Vanderbilt University Medical Center and Monroe Carell Jr Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Maimoona A Zariwala
- Department of Pathology/Lab Medicine and Marsico Lung Institute, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Michael R Knowles
- Department of Medicine and Marsico Lung Institute, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Jack B, Mueller DM, Fee AC, Tetlow AL, Avasthi P. Partially Redundant Actin Genes in Chlamydomonas Control Transition Zone Organization and Flagellum-Directed Traffic. Cell Rep 2019; 27:2459-2467.e3. [PMID: 31116988 PMCID: PMC6541019 DOI: 10.1016/j.celrep.2019.04.087] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/03/2018] [Accepted: 04/18/2019] [Indexed: 11/16/2022] Open
Abstract
The unicellular green alga Chlamydomonas reinhardtii is a biflagellated cell with two actin genes: one encoding a conventional actin (IDA5) and the other encoding a divergent novel actin-like protein (NAP1). Here, we probe how actin redundancy contributes to flagellar assembly. Disrupting a single actin allows complete flagellar assembly. However, when disrupting both actins using latrunculin B (LatB) treatment on the nap1 mutant background, we find that actins are necessary for flagellar growth from newly synthesized limiting flagellar proteins. Under total actin disruption, transmission electron microscopy identified an accumulation of Golgi-adjacent vesicles. We also find that there is a mislocalization of a key transition zone gating and ciliopathy protein, NPHP-4. Our experiments demonstrate that each stage of flagellar biogenesis requires redundant actin function to varying degrees, with an absolute requirement for these actins in transport of Golgi-adjacent vesicles and flagellar incorporation of newly synthesized proteins.
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Affiliation(s)
- Brittany Jack
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - David M Mueller
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Ann C Fee
- University of Missouri-Kansas City, School of Medicine, Kansas City, MO 64110, USA
| | - Ashley L Tetlow
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Prachee Avasthi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Ophthalmology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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Bottier M, Thomas KA, Dutcher SK, Bayly PV. How Does Cilium Length Affect Beating? Biophys J 2019; 116:1292-1304. [PMID: 30878201 PMCID: PMC6451027 DOI: 10.1016/j.bpj.2019.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/23/2019] [Accepted: 02/13/2019] [Indexed: 12/21/2022] Open
Abstract
The effects of cilium length on the dynamics of cilia motion were investigated by high-speed video microscopy of uniciliated mutants of the swimming alga, Chlamydomonas reinhardtii. Cells with short cilia were obtained by deciliating cells via pH shock and allowing cilia to reassemble for limited times. The frequency of cilia beating was estimated from the motion of the cell body and of the cilium. Key features of the ciliary waveform were quantified from polynomial curves fitted to the cilium in each image frame. Most notably, periodic beating did not emerge until the cilium reached a critical length between 2 and 4 μm. Surprisingly, in cells that exhibited periodic beating, the frequency of beating was similar for all lengths with only a slight decrease in frequency as length increased from 4 μm to the normal length of 10-12 μm. The waveform average curvature (rad/μm) was also conserved as the cilium grew. The mechanical metrics of ciliary propulsion (force, torque, and power) all increased in proportion to length. The mechanical efficiency of beating appeared to be maximal at the normal wild-type length of 10-12 μm. These quantitative features of ciliary behavior illuminate the biophysics of cilia motion and, in future studies, may help distinguish competing hypotheses of the underlying mechanism of oscillation.
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Affiliation(s)
- Mathieu Bottier
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri; Department of Genetics, Washington University in St. Louis, St. Louis, Missouri
| | - Kyle A Thomas
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri
| | - Susan K Dutcher
- Department of Genetics, Washington University in St. Louis, St. Louis, Missouri
| | - Philip V Bayly
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri.
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Lin H, Zhang Z, Iomini C, Dutcher SK. Identifying RNA splicing factors using IFT genes in Chlamydomonas reinhardtii. Open Biol 2019. [PMID: 29514868 PMCID: PMC5881031 DOI: 10.1098/rsob.170211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Intraflagellar transport moves proteins in and out of flagella/cilia and it is essential for the assembly of these organelles. Using whole-genome sequencing, we identified splice site mutations in two IFT genes, IFT81 (fla9) and IFT121 (ift121-2), which lead to flagellar assembly defects in the unicellular green alga Chlamydomonas reinhardtii. The splicing defects in these ift mutants are partially corrected by mutations in two conserved spliceosome proteins, DGR14 and FRA10. We identified a dgr14 deletion mutant, which suppresses the 3′ splice site mutation in IFT81, and a frameshift mutant of FRA10, which suppresses the 5′ splice site mutation in IFT121. Surprisingly, we found dgr14-1 and fra10 mutations suppress both splice site mutations. We suggest these two proteins are involved in facilitating splice site recognition/interaction; in their absence some splice site mutations are tolerated. Nonsense mutations in SMG1, which is involved in nonsense-mediated decay, lead to accumulation of aberrant transcripts and partial restoration of flagellar assembly in the ift mutants. The high density of introns and the conservation of noncore splicing factors, together with the ease of scoring the ift mutant phenotype, make Chlamydomonas an attractive organism to identify new proteins involved in splicing through suppressor screening.
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Affiliation(s)
- Huawen Lin
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Zhengyan Zhang
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Carlo Iomini
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
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Rapid and high efficiency transformation of Chlamydomonas reinhardtii by square-wave electroporation. Biosci Rep 2019; 39:BSR20181210. [PMID: 30530569 PMCID: PMC6328877 DOI: 10.1042/bsr20181210] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/04/2018] [Accepted: 12/07/2018] [Indexed: 11/17/2022] Open
Abstract
Chlamydomonas reinhardtii, the unicellular green algae, is the model organism for studies in various physiological processes and for bioindustrial applications. To explore the molecular mechanisms underlying physiological processes or to establish engineered cell lines, the exogenous DNA needs to be integrated into the genome for the insertional mutagenesis or transgene expression. However, the amount of selected marker DNA is not seriously considered in the existing electroporation methods for mutants library construction. Here, we reported a rapid-and-high-efficiency transformation technique for cell-walled strains using square-wave electroporation system. The final yield with this electroporation method was 2-6 × 103 transformants per μg exogenous DNA for cell-walled strains in a strain-dependent manner. In general, this electroporation technique was the easy and applicable way to build a mutant library for screening phenotypes of interest.
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Baehr W, Hanke-Gogokhia C, Sharif A, Reed M, Dahl T, Frederick JM, Ying G. Insights into photoreceptor ciliogenesis revealed by animal models. Prog Retin Eye Res 2018; 71:26-56. [PMID: 30590118 DOI: 10.1016/j.preteyeres.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/10/2018] [Accepted: 12/18/2018] [Indexed: 12/11/2022]
Abstract
Photoreceptors are polarized neurons, with very specific subcellular compartmentalization and unique requirements for protein expression and trafficking. Each photoreceptor contains an outer segment, the site of photon capture that initiates vision, an inner segment that houses the biosynthetic machinery and a synaptic terminal for signal transmission to downstream neurons. Outer segments and inner segments are connected by a connecting cilium (CC), the equivalent of a transition zone (TZ) of primary cilia. The connecting cilium is part of the basal body/axoneme backbone that stabilizes the outer segment. This report will update the reader on late developments in photoreceptor ciliogenesis and transition zone formation, specifically in mouse photoreceptors, focusing on early events in photoreceptor ciliogenesis. The connecting cilium, an elongated and narrow structure through which all outer segment proteins and membrane components must traffic, functions as a gate that controls access to the outer segment. Here we will review genes and their protein products essential for basal body maturation and for CC/TZ genesis, sorted by phenotype. Emphasis is given to naturally occurring mouse mutants and gene knockouts that interfere with CC/TZ formation and ciliogenesis.
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Affiliation(s)
- Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA.
| | - Christin Hanke-Gogokhia
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Ali Sharif
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Michelle Reed
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Tiffanie Dahl
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Jeanne M Frederick
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Guoxin Ying
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
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Lin H, Guo S, Dutcher SK. RPGRIP1L helps to establish the ciliary gate for entry of proteins. J Cell Sci 2018; 131:jcs220905. [PMID: 30237221 PMCID: PMC6215392 DOI: 10.1242/jcs.220905] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 09/10/2018] [Indexed: 12/12/2022] Open
Abstract
Mutations in transition zone genes change the composition of the ciliary proteome. We isolated new mutations in RPGRIP1L (denotated as RPG1 in algae) that affect the localization of the transition zone protein NPHP4 in the model organism Chlamydomonas reinhardtii NPHP4 localization is not affected in multiple new intraflagellar transport (IFT) mutants. We compared the proteome of cilia from wild-type and mutants that affect the transition zone (RPGRIP1L) or IFT (IFT172 and DHC1b) by mass spectrometry. The rpg1-1 mutant cilia show the most dramatic increase in cytoplasmic proteins. These nonciliary proteins function in translation, membrane remodeling, ATP production and as chaperonins. These proteins are excluded in isolated cilia from fla11-1 (IFT172) and fla24-1 (DHC1b). Our data support the idea that RPGRIP1L, but not IFT proteins, acts as part of the gate for cytoplasmic proteins. The rpg1-1 cilia lack only a few proteins, which suggests that RPGRIP1L only has a minor role of in the retention of ciliary proteins. The fla11-1 mutant shows the greatest loss/reduction of proteins, and one-third of these proteins have a transmembrane domain. Hence, IFT172 may play a role in the retention of proteins.
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Affiliation(s)
- Huawen Lin
- Department of Genetics, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Suyang Guo
- Department of Genetics, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University in St. Louis, St. Louis, MO 63110, USA
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Lewis WR, Bales KL, Revell DZ, Croyle MJ, Engle SE, Song CJ, Malarkey EB, Uytingco CR, Shan D, Antonellis PJ, Nagy TR, Kesterson RA, Mrug MM, Martens JR, Berbari NF, Gross AK, Yoder BK. Mks6 mutations reveal tissue- and cell type-specific roles for the cilia transition zone. FASEB J 2018; 33:1440-1455. [PMID: 30133325 PMCID: PMC6355093 DOI: 10.1096/fj.201801149r] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The transition zone (TZ) is a domain at the base of the cilium that is involved in maintaining ciliary compartment-specific sensory and signaling activity by regulating cilia protein composition. Mutations in TZ proteins result in cilia dysfunction, often causing pleiotropic effects observed in a group of human diseases classified as ciliopathies. The purpose of this study is to describe the importance of the TZ component Meckel-Grüber syndrome 6 ( Mks6) in several organ systems and tissues regarding ciliogenesis and cilia maintenance using congenital and conditional mutant mouse models. Similar to MKS, congenital loss of Mks6 is embryonic lethal, displaying cilia loss and altered cytoskeletal microtubule modifications but only in specific cell types. Conditional Mks6 mutants have a variable cystic kidney phenotype along with severe retinal degeneration with mislocalization of phototransduction cascade proteins. However, other phenotypes, such as anosmia and obesity, which are typically associated with cilia and TZ dysfunction, were not evident. These data indicate that despite Mks6 being a core TZ component, it has tissue- or cell type-specific functions important for cilia formation and cilia sensory and signaling activities. Lewis, W. R., Bales, K. L., Revell, D. Z., Croyle, M. J., Engle, S. E., Song, C. J., Malarkey, E. B., Uytingco, C. R., Shan, D., Antonellis, P. J., Nagy, T. R., Kesterson, R. A., Mrug, M. M., Martens, J. R., Berbari, N. F., Gross, A. K., Yoder, B. K. Mks6 mutations reveal tissue- and cell type-specific roles for the cilia transition zone.
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Affiliation(s)
- Wesley R Lewis
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Katie L Bales
- Department of Optometry and Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Dustin Z Revell
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Staci E Engle
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, USA
| | - Cheng Jack Song
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Erik B Malarkey
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Cedric R Uytingco
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Dan Shan
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Patrick J Antonellis
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, USA
| | - Tim R Nagy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA; and
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Michal M Mrug
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, USA
| | - Alecia K Gross
- Department of Optometry and Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Abstract
Although tumours initiate from oncogenic changes in a cancer cell, subsequent tumour progression and therapeutic response depend on interactions between the cancer cells and the tumour microenvironment (TME). The primary monocilium, or cilium, provides a spatially localized platform for signalling by Hedgehog, Notch, WNT and some receptor tyrosine kinase pathways and mechanosensation. Changes in ciliation of cancer cells and/or cells of the TME during tumour development enforce asymmetric intercellular signalling in the TME. Growing evidence indicates that some oncogenic signalling pathways as well as some targeted anticancer therapies induce ciliation, while others repress it. The links between the genomic profile of cancer cells, drug treatment and ciliary signalling in the TME likely affect tumour growth and therapeutic response.
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Affiliation(s)
- Hanqing Liu
- School of Pharmacy, Jiangsu University, Jiangsu, China
| | - Anna A Kiseleva
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA, USA
- Kazan Federal University, Kazan, Russia
| | - Erica A Golemis
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA, USA.
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Chlamydomonas Basal Bodies as Flagella Organizing Centers. Cells 2018; 7:cells7070079. [PMID: 30018231 PMCID: PMC6070942 DOI: 10.3390/cells7070079] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 11/17/2022] Open
Abstract
During ciliogenesis, centrioles convert to membrane-docked basal bodies, which initiate the formation of cilia/flagella and template the nine doublet microtubules of the flagellar axoneme. The discovery that many human diseases and developmental disorders result from defects in flagella has fueled a strong interest in the analysis of flagellar assembly. Here, we will review the structure, function, and development of basal bodies in the unicellular green alga Chlamydomonas reinhardtii, a widely used model for the analysis of basal bodies and flagella. Intraflagellar transport (IFT), a flagella-specific protein shuttle critical for ciliogenesis, was first described in C. reinhardtii. A focus of this review will be on the role of the basal bodies in organizing the IFT machinery.
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Morthorst SK, Christensen ST, Pedersen LB. Regulation of ciliary membrane protein trafficking and signalling by kinesin motor proteins. FEBS J 2018; 285:4535-4564. [PMID: 29894023 DOI: 10.1111/febs.14583] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/09/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022]
Abstract
Primary cilia are antenna-like sensory organelles that regulate a substantial number of cellular signalling pathways in vertebrates, both during embryonic development as well as in adulthood, and mutations in genes coding for ciliary proteins are causative of an expanding group of pleiotropic diseases known as ciliopathies. Cilia consist of a microtubule-based axoneme core, which is subtended by a basal body and covered by a bilayer lipid membrane of unique protein and lipid composition. Cilia are dynamic organelles, and the ability of cells to regulate ciliary protein and lipid content in response to specific cellular and environmental cues is crucial for balancing ciliary signalling output. Here we discuss mechanisms involved in regulation of ciliary membrane protein trafficking and signalling, with main focus on kinesin-2 and kinesin-3 family members.
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Cell-Type Transcriptomes of the Multicellular Green Alga Volvox carteri Yield Insights into the Evolutionary Origins of Germ and Somatic Differentiation Programs. G3-GENES GENOMES GENETICS 2018; 8:531-550. [PMID: 29208647 PMCID: PMC5919742 DOI: 10.1534/g3.117.300253] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Germ-soma differentiation is a hallmark of complex multicellular organisms, yet its origins are not well understood. Volvox carteri is a simple multicellular green alga that has recently evolved a simple germ-soma dichotomy with only two cell-types: large germ cells called gonidia and small terminally differentiated somatic cells. Here, we provide a comprehensive characterization of the gonidial and somatic transcriptomes of V. carteri to uncover fundamental differences between the molecular and metabolic programming of these cell-types. We found extensive transcriptome differentiation between cell-types, with somatic cells expressing a more specialized program overrepresented in younger, lineage-specific genes, and gonidial cells expressing a more generalist program overrepresented in more ancient genes that shared striking overlap with stem cell-specific genes from animals and land plants. Directed analyses of different pathways revealed a strong dichotomy between cell-types with gonidial cells expressing growth-related genes and somatic cells expressing an altruistic metabolic program geared toward the assembly of flagella, which support organismal motility, and the conversion of storage carbon to sugars, which act as donors for production of extracellular matrix (ECM) glycoproteins whose secretion enables massive organismal expansion. V. carteri orthologs of diurnally controlled genes from C. reinhardtii, a single-celled relative, were analyzed for cell-type distribution and found to be strongly partitioned, with expression of dark-phase genes overrepresented in somatic cells and light-phase genes overrepresented in gonidial cells- a result that is consistent with cell-type programs in V. carteri arising by cooption of temporal regulons in a unicellular ancestor. Together, our findings reveal fundamental molecular, metabolic, and evolutionary mechanisms that underlie the origins of germ-soma differentiation in V. carteri and provide a template for understanding the acquisition of germ-soma differentiation in other multicellular lineages.
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Ruba A, Luo W, Yang W. Application of High-speed Super-resolution SPEED Microscopy in Live Primary Cilium. J Vis Exp 2018. [PMID: 29364223 DOI: 10.3791/56475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The primary cilium is a microtubule-based protrusion on the surface of many eukaryotic cells and contains a unique complement of proteins that function critically in cell motility and signaling. Since cilia are incapable of synthesizing their own protein, nearly 200 unique ciliary proteins need to be trafficked between the cytosol and primary cilia. However, it is still a technical challenge to map three-dimensional (3D) locations of transport pathways for these proteins in live primary cilia due to the limitations of currently existing techniques. To conquer the challenge, recently we have developed and employed a high-speed virtual 3D super-resolution microscopy, termed single-point edge-excitation sub-diffraction (SPEED) microscopy, to determine the 3D spatial location of transport pathways for both cytosolic and membrane proteins in primary cilia of live cells. In this article, we will demonstrate the detailed setup of SPEED microscopy, the preparation of cells expressing fluorescence-protein-labeled ciliary proteins, the real-time single-molecule tracking of individual proteins in live cilium and the achievement of 3D spatial probability density maps of transport routes for ciliary proteins.
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Affiliation(s)
| | - Wangxi Luo
- Department of Biology, Temple University
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39
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Seo S, Datta P. Photoreceptor outer segment as a sink for membrane proteins: hypothesis and implications in retinal ciliopathies. Hum Mol Genet 2017; 26:R75-R82. [PMID: 28453661 DOI: 10.1093/hmg/ddx163] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/24/2017] [Indexed: 12/28/2022] Open
Abstract
The photoreceptor outer segment (OS) is a unique modification of the primary cilium, specialized for light perception. Being homologous organelles, the primary cilium and the OS share common building blocks and molecular machinery to construct and maintain them. The OS, however, has several unique structural features that are not seen in primary cilia. Although these unique features of the OS have been well documented, their implications in protein localization have been under-appreciated. In this review, we compare the structural properties of the primary cilium and the OS, and propose a hypothesis that the OS can act as a sink for membrane proteins. We further discuss the implications of this hypothesis in polarized protein localization in photoreceptors and mechanisms of photoreceptor degeneration in retinal ciliopathies.
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Affiliation(s)
- Seongjin Seo
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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40
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Shi X, Garcia G, Van De Weghe JC, McGorty R, Pazour GJ, Doherty D, Huang B, Reiter JF. Super-resolution microscopy reveals that disruption of ciliary transition-zone architecture causes Joubert syndrome. Nat Cell Biol 2017; 19:1178-1188. [PMID: 28846093 DOI: 10.1038/ncb3599] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 07/25/2017] [Indexed: 12/16/2022]
Abstract
Ciliopathies, including nephronophthisis (NPHP), Meckel syndrome (MKS) and Joubert syndrome (JBTS), can be caused by mutations affecting components of the transition zone, a domain near the base of the cilium that controls the protein composition of its membrane. We defined the three-dimensional arrangement of key proteins in the transition zone using two-colour stochastic optical reconstruction microscopy (STORM). NPHP and MKS complex components form nested rings comprised of nine-fold doublets. JBTS-associated mutations in RPGRIP1L or TCTN2 displace certain transition-zone proteins. Diverse ciliary proteins accumulate at the transition zone in wild-type cells, suggesting that the transition zone is a waypoint for proteins entering and exiting the cilium. JBTS-associated mutations in RPGRIP1L disrupt SMO accumulation at the transition zone and the ciliary localization of SMO. We propose that the disruption of transition-zone architecture in JBTS leads to a failure of SMO to accumulate at the transition zone and cilium, disrupting developmental signalling in JBTS.
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Affiliation(s)
- Xiaoyu Shi
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, USA
| | - Galo Garcia
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California 94143, USA.,Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California 94143, USA
| | - Julie C Van De Weghe
- Department of Pediatrics, University of Washington Medical Center, Seattle, Washington 98195, USA
| | - Ryan McGorty
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, USA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, Massachusetts 01605, USA
| | - Dan Doherty
- Department of Pediatrics, University of Washington Medical Center, Seattle, Washington 98195, USA
| | - Bo Huang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, USA.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California 94143, USA.,Chan Zuckerberg Biohub, San Francisco, California 94158, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California 94143, USA.,Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California 94143, USA
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41
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Takao D, Wang L, Boss A, Verhey KJ. Protein Interaction Analysis Provides a Map of the Spatial and Temporal Organization of the Ciliary Gating Zone. Curr Biol 2017; 27:2296-2306.e3. [PMID: 28736169 DOI: 10.1016/j.cub.2017.06.044] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/09/2017] [Accepted: 06/16/2017] [Indexed: 11/19/2022]
Abstract
The motility and signaling functions of the primary cilium require a unique protein and lipid composition that is determined by gating mechanisms localized at the base of the cilium. Several protein complexes localize to the gating zone and may regulate ciliary protein composition; however, the mechanisms of ciliary gating and the dynamics of the gating components are largely unknown. Here, we used the BiFC (bimolecular fluorescence complementation) assay and report for the first time on the protein-protein interactions that occur between ciliary gating components and transiting cargoes during ciliary entry. We find that the nucleoporin Nup62 and the C termini of the nephronophthisis (NPHP) proteins NPHP4 and NPHP5 interact with the axoneme-associated kinesin-2 motor KIF17 and thus spatially map to the inner region of the ciliary gating zone. Nup62 and NPHP4 exhibit rapid turnover at the transition zone and thus define dynamic components of the gate. We find that B9D1, AHI1, and the N termini of NPHP4 and NPHP5 interact with the transmembrane protein SSTR3 and thus spatially map to the outer region of the ciliary gating zone. B9D1, AHI1, and NPHP5 exhibit little to no turnover at the transition zone and thus define components of a stable gating structure. These data provide the first comprehensive map of the molecular orientations of gating zone components along the inner-to-outer axis of the ciliary gating zone. These results advance our understanding of the functional roles of gating zone components in regulating ciliary protein composition.
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Affiliation(s)
- Daisuke Takao
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Liang Wang
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Tongshan District, Xuzhou 221116, China
| | - Allison Boss
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA.
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42
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Abstract
Motile and non-motile (primary) cilia are nearly ubiquitous cellular organelles. The dysfunction of cilia causes diseases known as ciliopathies. The number of reported ciliopathies (currently 35) is increasing, as is the number of established (187) and candidate (241) ciliopathy-associated genes. The characterization of ciliopathy-associated proteins and phenotypes has improved our knowledge of ciliary functions. In particular, investigating ciliopathies has helped us to understand the molecular mechanisms by which the cilium-associated basal body functions in early ciliogenesis, as well as how the transition zone functions in ciliary gating, and how intraflagellar transport enables cargo trafficking and signalling. Both basic biological and clinical studies are uncovering novel ciliopathies and the ciliary proteins involved. The assignment of these proteins to different ciliary structures, processes and ciliopathy subclasses (first order and second order) provides insights into how this versatile organelle is built, compartmentalized and functions in diverse ways that are essential for human health.
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43
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Hou Y, Witman GB. The N-terminus of IFT46 mediates intraflagellar transport of outer arm dynein and its cargo-adaptor ODA16. Mol Biol Cell 2017; 28:2420-2433. [PMID: 28701346 PMCID: PMC5576905 DOI: 10.1091/mbc.e17-03-0172] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 01/23/2023] Open
Abstract
A transposon event, resulting in partial suppression of a Chlamydomonas IFT46 null mutant, allowed the function of the N-terminus of IFT46 in flagellar assembly to be explored. The IFT46 N-terminus is not required for IFT complex assembly but is required for transport of outer arm dynein and its adaptor, ODA16, into the flagellum. Cilia are assembled via intraflagellar transport (IFT). The IFT machinery is composed of motors and multisubunit particles, termed IFT-A and IFT-B, that carry cargo into the cilium. Knowledge of how the IFT subunits interact with their cargo is of critical importance for understanding how the unique ciliary domain is established. We previously reported a Chlamydomonas mutant, ift46-1, that fails to express the IFT-B protein IFT46, has greatly reduced levels of other IFT-B proteins, and assembles only very short flagella. A spontaneous suppression of ift46-1 restored IFT-B levels and enabled growth of longer flagella, but the flagella lacked outer dynein arms. Here we show that the suppression is due to insertion of the transposon MRC1 into the ift46-1 allele, causing the expression of a fusion protein including the IFT46 C-terminal 240 amino acids. The IFT46 C-terminus can assemble into and stabilize IFT-B but does not support transport of outer arm dynein into flagella. ODA16, a cargo adaptor specific for outer arm dynein, also fails to be imported into the flagella in the absence of the IFT46 N-terminus. We conclude that the IFT46 N-terminus, ODA16, and outer arm dynein interact for IFT of the latter.
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Affiliation(s)
- Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
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44
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Kumar D, Strenkert D, Patel-King RS, Leonard MT, Merchant SS, Mains RE, King SM, Eipper BA. A bioactive peptide amidating enzyme is required for ciliogenesis. eLife 2017; 6. [PMID: 28513435 PMCID: PMC5461114 DOI: 10.7554/elife.25728] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/15/2017] [Indexed: 02/06/2023] Open
Abstract
The pathways controlling cilium biogenesis in different cell types have not been fully elucidated. We recently identified peptidylglycine α-amidating monooxygenase (PAM), an enzyme required for generating amidated bioactive signaling peptides, in Chlamydomonas and mammalian cilia. Here, we show that PAM is required for the normal assembly of motile and primary cilia in Chlamydomonas, planaria and mice. Chlamydomonas PAM knockdown lines failed to assemble cilia beyond the transition zone, had abnormal Golgi architecture and altered levels of cilia assembly components. Decreased PAM gene expression reduced motile ciliary density on the ventral surface of planaria and resulted in the appearance of cytosolic axonemes lacking a ciliary membrane. The architecture of primary cilia on neuroepithelial cells in Pam-/- mouse embryos was also aberrant. Our data suggest that PAM activity and alterations in post-Golgi trafficking contribute to the observed ciliogenesis defects and provide an unanticipated, highly conserved link between PAM, amidation and ciliary assembly.
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Affiliation(s)
- Dhivya Kumar
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, United States
| | - Daniela Strenkert
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, United States
| | - Ramila S Patel-King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, United States
| | - Michael T Leonard
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, United States
| | - Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, United States.,Institute for Genomics and Proteomics, University of California, Los Angeles, Los Angeles, United States
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, United States
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, United States
| | - Betty A Eipper
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, United States.,Department of Neuroscience, University of Connecticut Health Center, Farmington, United States
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45
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Jensen VL, Leroux MR. Gates for soluble and membrane proteins, and two trafficking systems (IFT and LIFT), establish a dynamic ciliary signaling compartment. Curr Opin Cell Biol 2017; 47:83-91. [PMID: 28432921 DOI: 10.1016/j.ceb.2017.03.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/18/2017] [Accepted: 03/21/2017] [Indexed: 12/28/2022]
Abstract
Primary cilia are microtubule-based organelles found on most mammalian cell surfaces. They possess a soluble matrix and membrane contiguous with the cell body cytosol and plasma membrane, and yet, have distinct compositions that can be modulated to enable dynamic signal transduction. Here, we discuss how specialized ciliary compartments are established using a coordinated network of gating, trafficking and targeting activities. Cilium homeostasis is maintained by a size-selective molecular mesh that limits soluble protein entry, and by a membrane diffusion barrier localized at the transition zone. Bidirectional protein shuttling between the cell body and cilium uses IntraFlagellar Transport (IFT), and prenylated ciliary protein delivery is achieved through Lipidated protein IntraFlagellar Targeting (LIFT). Elucidating how these gates and transport systems function will help reveal the roles that cilia play in ciliary signaling and the growing spectrum of disorders termed ciliopathies.
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Affiliation(s)
- Victor L Jensen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada; Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, Canada
| | - Michel R Leroux
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada; Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, Canada.
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46
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Gonçalves J, Pelletier L. The Ciliary Transition Zone: Finding the Pieces and Assembling the Gate. Mol Cells 2017; 40:243-253. [PMID: 28401750 PMCID: PMC5424270 DOI: 10.14348/molcells.2017.0054] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/05/2017] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic cilia are organelles that project from the surface of cells to fulfill motility and sensory functions. In vertebrates, the functions of both motile and immotile cilia are critical for embryonic development and adult tissue homeostasis. Importantly, a multitude of human diseases is caused by abnormal cilia biogenesis and functions which rely on the compartmentalization of the cilium and the maintenance of its protein composition. The transition zone (TZ) is a specialized ciliary domain present at the base of the cilium and is part of a gate that controls protein entry and exit from this organelle. The relevance of the TZ is highlighted by the fact that several of its components are coded by ciliopathy genes. Here we review recent developments in the study of TZ proteomes, the mapping of individual components to the TZ structure and the establishment of the TZ as a lipid gate.
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Affiliation(s)
- João Gonçalves
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5,
Canada
| | - Laurence Pelletier
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5,
Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8,
Canada
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47
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Lechtreck KF, Van De Weghe JC, Harris JA, Liu P. Protein transport in growing and steady-state cilia. Traffic 2017; 18:277-286. [PMID: 28248449 DOI: 10.1111/tra.12474] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 12/18/2022]
Abstract
Cilia and eukaryotic flagella are threadlike cell extensions with motile and sensory functions. Their assembly requires intraflagellar transport (IFT), a bidirectional motor-driven transport of protein carriers along the axonemal microtubules. IFT moves ample amounts of structural proteins including tubulin into growing cilia likely explaining its critical role for assembly. IFT continues in non-growing cilia contributing to a variety of processes ranging from axonemal maintenance and the export of non-ciliary proteins to cell locomotion and ciliary signaling. Here, we discuss recent data on cues regulating the type, amount and timing of cargo transported by IFT. A regulation of IFT-cargo interactions is critical to establish, maintain and adjust ciliary length, protein composition and function.
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Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | | | | | - Peiwei Liu
- Department of Cellular Biology, University of Georgia, Athens, Georgia
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48
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Mizuno K, Sloboda RD. Protein arginine methyltransferases interact with intraflagellar transport particles and change location during flagellar growth and resorption. Mol Biol Cell 2017; 28:1208-1222. [PMID: 28298486 PMCID: PMC5415017 DOI: 10.1091/mbc.e16-11-0774] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/03/2017] [Accepted: 03/08/2017] [Indexed: 01/09/2023] Open
Abstract
Protein arginine methyl transferases are located at specific sites in the flagellum. They change location during changes in flagellar dynamics (i.e., resorption and regeneration) via interaction with intraflagellar transport trains. Changes in protein by posttranslational modifications comprise an important mechanism for the control of many cellular processes. Several flagellar proteins are methylated on arginine residues during flagellar resorption; however, the function is not understood. To learn more about the role of protein methylation during flagellar dynamics, we focused on protein arginine methyltransferases (PRMTs) 1, 3, 5, and 10. These PRMTs localize to the tip of flagella and in a punctate pattern along the length, very similar, but not identical, to that of intraflagellar transport (IFT) components. In addition, we found that PRMT 1 and 3 are also highly enriched at the base of the flagella, and the basal localization of these PRMTs changes during flagellar regeneration and resorption. Proteins with methyl arginine residues are also enriched at the tip and base of flagella, and their localization also changes during flagellar assembly and disassembly. PRMTs are lost from the flagella of fla10-1 cells, which carry a temperature-sensitive mutation in the anterograde motor for IFT. The data define the distribution of specific PRMTs and their target proteins in flagella and demonstrate that PRMTs are cargo for translocation within flagella by the process of IFT.
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Affiliation(s)
- Katsutoshi Mizuno
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Roger D Sloboda
- Marine Biological Laboratory, Woods Hole, MA 02543 .,Marine Biological Laboratory, Woods Hole, MA 02543
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49
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Brown JM, Mosley M, Montes-Berrueta D, Hou Y, Yang F, Scarbrough C, Witman GB, Wirschell M. Characterization of a new oda3 allele, oda3-6, defective in assembly of the outer dynein arm-docking complex in Chlamydomonas reinhardtii. PLoS One 2017; 12:e0173842. [PMID: 28291812 PMCID: PMC5349678 DOI: 10.1371/journal.pone.0173842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 02/27/2017] [Indexed: 12/17/2022] Open
Abstract
We have used an insertional mutagenesis approach to generate new C. reinhardtii motility mutants. Of 56 mutants isolated, one is a new allele at the ODA3 locus, called oda3-6. Similar to the previously characterized oda3 alleles, oda3-6 has a slow-jerky swimming phenotype and reduced swimming speed. The oda3-6 mutant fails to assemble the outer dynein arm motor and outer dynein arm—docking complex (ODA-DC) in the ciliary axoneme due to an insertion in the 5’ end of the DCC1 gene, which encodes the DC1 subunit of the ODA-DC. Transformation of oda3-6 with the wild-type DCC1 gene rescues the mutant swimming phenotype and restores assembly of the ODA-DC and the outer dynein arm in the cilium. This is the first oda3 mutant to be characterized at the molecular level and is likely to be very useful for further analysis of DC1 function.
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Affiliation(s)
- Jason M. Brown
- Department of Biology, Salem State University, Salem, Massachusetts, United States of America
| | - Matthew Mosley
- University of Mississippi Medical Center, Department of Biochemistry, Jackson, Mississippi, United States of America
| | - Daniela Montes-Berrueta
- Department of Biology, Salem State University, Salem, Massachusetts, United States of America
| | - Yuqing Hou
- University of Massachusetts Medical School, Department of Cell and Developmental Biology, Worcester, Massachusetts, United States of America
| | - Fan Yang
- University of Mississippi Medical Center, Department of Biochemistry, Jackson, Mississippi, United States of America
| | - Chasity Scarbrough
- University of Mississippi Medical Center, Department of Biochemistry, Jackson, Mississippi, United States of America
| | - George B. Witman
- University of Massachusetts Medical School, Department of Cell and Developmental Biology, Worcester, Massachusetts, United States of America
| | - Maureen Wirschell
- University of Mississippi Medical Center, Department of Biochemistry, Jackson, Mississippi, United States of America
- * E-mail:
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50
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KIF13B establishes a CAV1-enriched microdomain at the ciliary transition zone to promote Sonic hedgehog signalling. Nat Commun 2017; 8:14177. [PMID: 28134340 PMCID: PMC5290278 DOI: 10.1038/ncomms14177] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 12/06/2016] [Indexed: 12/20/2022] Open
Abstract
Ciliary membrane composition is controlled by transition zone (TZ) proteins such as RPGRIP1, RPGRIPL and NPHP4, which are vital for balanced coordination of diverse signalling systems like the Sonic hedgehog (Shh) pathway. Activation of this pathway involves Shh-induced ciliary accumulation of Smoothened (SMO), which is disrupted by disease-causing mutations in TZ components. Here we identify kinesin-3 motor protein KIF13B as a novel member of the RPGRIP1N-C2 domain-containing protein family and show that KIF13B regulates TZ membrane composition and ciliary SMO accumulation. KIF13B is upregulated during ciliogenesis and is recruited to the ciliary base by NPHP4, which binds to two distinct sites in the KIF13B tail region, including an RPGRIP1N-C2 domain. KIF13B and NPHP4 are both essential for establishment of a CAV1 membrane microdomain at the TZ, which in turn is required for Shh-induced ciliary SMO accumulation. Thus KIF13B is a novel regulator of ciliary TZ configuration, membrane composition and Shh signalling.
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