1
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Heiman MG, Bülow HE. Dendrite morphogenesis in Caenorhabditis elegans. Genetics 2024; 227:iyae056. [PMID: 38785371 PMCID: PMC11151937 DOI: 10.1093/genetics/iyae056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 04/02/2024] [Indexed: 05/25/2024] Open
Abstract
Since the days of Ramón y Cajal, the vast diversity of neuronal and particularly dendrite morphology has been used to catalog neurons into different classes. Dendrite morphology varies greatly and reflects the different functions performed by different types of neurons. Significant progress has been made in our understanding of how dendrites form and the molecular factors and forces that shape these often elaborately sculpted structures. Here, we review work in the nematode Caenorhabditis elegans that has shed light on the developmental mechanisms that mediate dendrite morphogenesis with a focus on studies investigating ciliated sensory neurons and the highly elaborated dendritic trees of somatosensory neurons. These studies, which combine time-lapse imaging, genetics, and biochemistry, reveal an intricate network of factors that function both intrinsically in dendrites and extrinsically from surrounding tissues. Therefore, dendrite morphogenesis is the result of multiple tissue interactions, which ultimately determine the shape of dendritic arbors.
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Affiliation(s)
- Maxwell G Heiman
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Hannes E Bülow
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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2
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Chen Y, Zhang Y, Zhou X. Non-classical functions of nuclear pore proteins in ciliopathy. Front Mol Biosci 2023; 10:1278976. [PMID: 37908226 PMCID: PMC10614291 DOI: 10.3389/fmolb.2023.1278976] [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: 08/17/2023] [Accepted: 10/02/2023] [Indexed: 11/02/2023] Open
Abstract
Nucleoporins (NUPs) constitute integral nuclear pore protein (NPC) elements. Although traditional NUP functions have been extensively researched, evidence of additional vital non-NPC roles, referred to herein as non-classical NUP functions, is also emerging. Several NUPs localise at the ciliary base. Indeed, Nup188, Nup93 or Nup205 knockdown results in cilia loss, impacting cardiac left-right patterning in models and cell lines. Genetic variants of Nup205 and Nup188 have been identified in patients with congenital heart disease and situs inversus totalis or heterotaxy, a prevalent human ciliopathy. These findings link non-classical NUP functions to human diseases. This mini-review summarises pivotal NUP interactions with NIMA-related kinases or nephronophthisis proteins that regulate ciliary function and explores other NUPs potentially implicated in cilia-related disorders. Overall, elucidating the non-classical roles of NUPs will enhance comprehension of ciliopathy aetiology.
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Affiliation(s)
- Yan Chen
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University Shanghai Medical College, Shanghai, China
| | - Yuan Zhang
- Department of Assisted Reproduction, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiangyu Zhou
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University Shanghai Medical College, Shanghai, China
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3
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Truong HM, Cruz-Colón KO, Martínez-Márquez JY, Willer JR, Travis AM, Biswas SK, Lo WK, Bolz HJ, Pearring JN. The tectonic complex regulates membrane protein composition in the photoreceptor cilium. Nat Commun 2023; 14:5671. [PMID: 37704658 PMCID: PMC10500017 DOI: 10.1038/s41467-023-41450-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 08/30/2023] [Indexed: 09/15/2023] Open
Abstract
The primary cilium is a signaling organelle with a unique membrane composition maintained by a diffusional barrier residing at the transition zone. Many transition zone proteins, such as the tectonic complex, are linked to preserving ciliary composition but the mechanism remains unknown. To understand tectonic's role, we generate a photoreceptor-specific Tctn1 knockout mouse. Loss of Tctn1 results in the absence of the entire tectonic complex and associated MKS proteins yet has minimal effects on the transition zone structure of rod photoreceptors. We find that the protein composition of the photoreceptor cilium is disrupted as non-resident membrane proteins accumulate in the cilium over time, ultimately resulting in photoreceptor degeneration. We further show that fluorescent rhodopsin moves faster through the transition zone in photoreceptors lacking tectonic, which suggests that the tectonic complex acts as a physical barrier to slow down membrane protein diffusion in the photoreceptor transition zone to ensure proper removal of non-resident membrane proteins.
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Affiliation(s)
- Hanh M Truong
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | - Kevin O Cruz-Colón
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Jason R Willer
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Amanda M Travis
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Sondip K Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Hanno J Bolz
- Senckenberg Centre for Human Genetics, Frankfurt am Main, Germany
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Jillian N Pearring
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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4
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Tian X, Zhao H, Zhou J. Organization, functions, and mechanisms of the BBSome in development, ciliopathies, and beyond. eLife 2023; 12:e87623. [PMID: 37466224 DOI: 10.7554/elife.87623] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
The BBSome is an octameric protein complex that regulates ciliary transport and signaling. Mutations in BBSome subunits are closely associated with ciliary defects and lead to ciliopathies, notably Bardet-Biedl syndrome. Over the past few years, there has been significant progress in elucidating the molecular organization and functions of the BBSome complex. An improved understanding of BBSome-mediated biological events and molecular mechanisms is expected to help advance the development of diagnostic and therapeutic approaches for BBSome-related diseases. Here, we review the current literature on the structural assembly, transport regulation, and molecular functions of the BBSome, emphasizing its roles in cilium-related processes. We also provide perspectives on the pathological role of the BBSome in ciliopathies as well as how these can be exploited for therapeutic benefit.
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Affiliation(s)
- Xiaoyu Tian
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Huijie Zhao
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, College of Life Sciences, Nankai University, Tianjin, China
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5
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Reed R, Park K, Waddell B, Timbers TA, Li C, Baxi K, Giacomin RM, Leroux MR, Carvalho CE. The Caenorhabditis elegans Shugoshin regulates TAC-1 in cilia. Sci Rep 2023; 13:9410. [PMID: 37296204 PMCID: PMC10256747 DOI: 10.1038/s41598-023-36430-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 06/03/2023] [Indexed: 06/12/2023] Open
Abstract
The conserved Shugoshin (SGO) protein family is essential for mediating proper chromosome segregation from yeast to humans but has also been implicated in diverse roles outside of the nucleus. SGO's roles include inhibiting incorrect spindle attachment in the kinetochore, regulating the spindle assembly checkpoint (SAC), and ensuring centriole cohesion in the centrosome, all functions that involve different microtubule scaffolding structures in the cell. In Caenorhabditis elegans, a species with holocentric chromosomes, SGO-1 is not required for cohesin protection or spindle attachment but appears important for licensing meiotic recombination. Here we provide the first functional evidence that in C. elegans, Shugoshin functions in another extranuclear, microtubule-based structure, the primary cilium. We identify the centrosomal and microtubule-regulating transforming acidic coiled-coil protein, TACC/TAC-1, which also localizes to the basal body, as an SGO-1 binding protein. Genetic analyses indicate that TAC-1 activity must be maintained below a threshold at the ciliary base for correct cilia function, and that SGO-1 likely participates in constraining TAC-1 to the basal body by influencing the function of the transition zone 'ciliary gate'. This research expands our understanding of cellular functions of Shugoshin proteins and contributes to the growing examples of overlap between kinetochore, centrosome and cilia proteomes.
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Affiliation(s)
- R Reed
- Department of Biology, University of Saskatchewan, Saskatoon, Canada
| | - K Park
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- Terry Fox Laboratory, BC Cancer, Vancouver, BC, V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - B Waddell
- Department of Biology, University of Saskatchewan, Saskatoon, Canada
| | - T A Timbers
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - C Li
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - K Baxi
- Department of Biology, University of Saskatchewan, Saskatoon, Canada
| | - R M Giacomin
- Department of Biology, University of Saskatchewan, Saskatoon, Canada
| | - M R Leroux
- Department of Molecular Biology & Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
| | - C E Carvalho
- Department of Biology, University of Saskatchewan, Saskatoon, Canada.
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6
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Stubbs T, Bingman JI, Besse J, Mykytyn K. Ciliary signaling proteins are mislocalized in the brains of Bardet-Biedl syndrome 1-null mice. Front Cell Dev Biol 2023; 10:1092161. [PMID: 36699005 PMCID: PMC9868275 DOI: 10.3389/fcell.2022.1092161] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/22/2022] [Indexed: 01/11/2023] Open
Abstract
In the brain, primary cilia are found on most, if not all, central neurons. The importance of neuronal cilia is underscored by the fact that human diseases caused by primary cilia dysfunction, which are known as ciliopathies, are associated with neuropathologies, including neuropsychiatric disorders and learning and memory deficits. Neuronal cilia are enriched for certain G protein-coupled receptors and their downstream effectors, suggesting they sense and respond to neuromodulators in the extracellular milieu. GPCR ciliary localization is disrupted in neurons from mouse models of the ciliopathy Bardet-Biedl syndrome, with GPCRs failing to localize to cilia, indicating the Bardet-Biedl syndrome proteins are required for trafficking of G protein-coupled receptors into neuronal cilia. Yet, dopamine receptor 1 accumulates in cilia in the absence of Bardet-Biedl syndrome proteins, suggesting Bardet-Biedl syndrome proteins are required for normal ciliary import and export. To further explore the roles of the Bardet-Biedl syndrome proteins in neuronal cilia, we examined localization of ciliary signaling proteins in a new constitutive Bbs1 knockout mouse model. Interestingly, we find that two additional ciliary G protein-coupled receptors (Gpr161 and Gpr19) abnormally accumulate in cilia on Bardet-Biedl syndrome neurons. In addition, we find that the GPCR signaling protein β-arrestin accumulates in a subset of cilia in the brain, suggesting the presence of additional unidentified ciliary G protein-coupled receptors. These results confirm the importance of the Bardet-Biedl syndrome proteins in establishing ciliary GPCR pathways and indicate that loss of Bbs1 leads to complex changes in the localization of signaling proteins in the brain.
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7
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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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8
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Wang J, Thomas HR, Thompson RG, Waldrep SC, Fogerty J, Song P, Li Z, Ma Y, Santra P, Hoover JD, Yeo NC, Drummond IA, Yoder BK, Amack JD, Perkins B, Parant JM. Variable phenotypes and penetrance between and within different zebrafish ciliary transition zone mutants. Dis Model Mech 2022; 15:dmm049568. [PMID: 36533556 PMCID: PMC9844136 DOI: 10.1242/dmm.049568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 11/04/2022] [Indexed: 12/23/2022] Open
Abstract
Meckel syndrome, nephronophthisis, Joubert syndrome and Bardet-Biedl syndrome are caused by mutations in proteins that localize to the ciliary transition zone (TZ). The phenotypically distinct syndromes suggest that these TZ proteins have differing functions. However, mutations in a single TZ gene can result in multiple syndromes, suggesting that the phenotype is influenced by modifier genes. We performed a comprehensive analysis of ten zebrafish TZ mutants, including mks1, tmem216, tmem67, rpgrip1l, cc2d2a, b9d2, cep290, tctn1, nphp1 and nphp4, as well as mutants in ift88 and ift172. Our data indicate that variations in phenotypes exist between different TZ mutants, supporting different tissue-specific functions of these TZ genes. Further, we observed phenotypic variations within progeny of a single TZ mutant, reminiscent of multiple disease syndromes being associated with mutations in one gene. In some mutants, the dynamics of the phenotype became complex with transitory phenotypes that are corrected over time. We also demonstrated that multiple-guide-derived CRISPR/Cas9 F0 'crispant' embryos recapitulate zygotic null phenotypes, and rapidly identified ciliary phenotypes in 11 cilia-associated gene candidates (ankfn1, ccdc65, cfap57, fhad1, nme7, pacrg, saxo2, c1orf194, ttc26, zmynd12 and cfap52).
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Affiliation(s)
- Jun Wang
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Holly R. Thomas
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Robert G. Thompson
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Stephanie C. Waldrep
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Joseph Fogerty
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - Ping Song
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - Zhang Li
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, AL 35294, USA
| | - Yongjie Ma
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Peu Santra
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Jonathan D. Hoover
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Nan Cher Yeo
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Iain A. Drummond
- Davis Center for Aging and Regeneration, Mount Desert Island Biological Laboratory, 159 Old Bar Harbor Road, Bar Harbor, ME 04609, USA
| | - Bradley K. Yoder
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, AL 35294, USA
| | - Jeffrey D. Amack
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Brian Perkins
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - John M. Parant
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
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9
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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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10
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Xie C, Habif JC, Ukhanov K, Uytingco CR, Zhang L, Campbell RJ, Martens JR. Reversal of ciliary mechanisms of disassembly rescues olfactory dysfunction in ciliopathies. JCI Insight 2022; 7:158736. [PMID: 35771640 PMCID: PMC9462494 DOI: 10.1172/jci.insight.158736] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022] Open
Abstract
Ciliopathies are a class of genetic diseases resulting in cilia dysfunction in multiple organ systems, including the olfactory system. Currently, there are no available curative treatments for olfactory dysfunction and other symptoms in ciliopathies. The loss or shortening of olfactory cilia, as seen in multiple mouse models of the ciliopathy Bardet–Biedl syndrome (BBS), results in olfactory dysfunction. However, the underlying mechanism of the olfactory cilia reduction is unknown, thus limiting the development of therapeutic approaches for BBS and other ciliopathies. Here, we demonstrated that phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], a phosphoinositide typically excluded from olfactory cilia, aberrantly redistributed into the residual cilia of BBS mouse models, which caused F-actin ciliary infiltration. Importantly, PI(4,5)P2 and F-actin were necessary for olfactory cilia shortening. Using a gene therapeutic approach, the hydrolyzation of PI(4,5)P2 by overexpression of inositol polyphosphate-5-phosphatase E (INPP5E) restored cilia length and rescued odor detection and odor perception in BBS. Together, our data indicate that PI(4,5)P2/F-actin–dependent cilia disassembly is a common mechanism contributing to the loss of olfactory cilia in BBS and provide valuable pan-therapeutic intervention targets for the treatment of ciliopathies.
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Affiliation(s)
- Chao Xie
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Julien C Habif
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Kirill Ukhanov
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Cedric R Uytingco
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Lian Zhang
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Robert J Campbell
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
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11
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Van De Weghe JC, Gomez A, Doherty D. The Joubert-Meckel-Nephronophthisis Spectrum of Ciliopathies. Annu Rev Genomics Hum Genet 2022; 23:301-329. [PMID: 35655331 DOI: 10.1146/annurev-genom-121321-093528] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Joubert syndrome (JS), Meckel syndrome (MKS), and nephronophthisis (NPH) ciliopathy spectrum could be the poster child for advances and challenges in Mendelian human genetics over the past half century. Progress in understanding these conditions illustrates many core concepts of human genetics. The JS phenotype alone is caused by pathogenic variants in more than 40 genes; remarkably, all of the associated proteins function in and around the primary cilium. Primary cilia are near-ubiquitous, microtubule-based organelles that play crucial roles in development and homeostasis. Protruding from the cell, these cellular antennae sense diverse signals and mediate Hedgehog and other critical signaling pathways. Ciliary dysfunction causes many human conditions termed ciliopathies, which range from multiple congenital malformations to adult-onset single-organ failure. Research on the genetics of the JS-MKS-NPH spectrum has spurred extensive functional work exploring the broadly important role of primary cilia in health and disease. This functional work promises to illuminate the mechanisms underlying JS-MKS-NPH in humans, identify therapeutic targets across genetic causes, and generate future precision treatments. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
| | - Arianna Gomez
- Department of Pediatrics, University of Washington, Seattle, Washington, USA; .,Molecular Medicine and Mechanisms of Disease Program, Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA;
| | - Dan Doherty
- Department of Pediatrics, University of Washington, Seattle, Washington, USA; .,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA;
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12
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Lange KI, Best S, Tsiropoulou S, Berry I, Johnson CA, Blacque OE. Interpreting ciliopathy-associated missense variants of uncertain significance (VUS) in Caenorhabditis elegans. Hum Mol Genet 2022; 31:1574-1587. [PMID: 34964473 PMCID: PMC9122650 DOI: 10.1093/hmg/ddab344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 12/26/2022] Open
Abstract
Better methods are required to interpret the pathogenicity of disease-associated variants of uncertain significance (VUS), which cannot be actioned clinically. In this study, we explore the use of an animal model (Caenorhabditis elegans) for in vivo interpretation of missense VUS alleles of TMEM67, a cilia gene associated with ciliopathies. CRISPR/Cas9 gene editing was used to generate homozygous knock-in C. elegans worm strains carrying TMEM67 patient variants engineered into the orthologous gene (mks-3). Quantitative phenotypic assays of sensory cilia structure and function (neuronal dye filling, roaming and chemotaxis assays) measured how the variants impacted mks-3 gene function. Effects of the variants on mks-3 function were further investigated by looking at MKS-3::GFP localization and cilia ultrastructure. The quantitative assays in C. elegans accurately distinguished between known benign (Asp359Glu, Thr360Ala) and known pathogenic (Glu361Ter, Gln376Pro) variants. Analysis of eight missense VUS generated evidence that three are benign (Cys173Arg, Thr176Ile and Gly979Arg) and five are pathogenic (Cys170Tyr, His782Arg, Gly786Glu, His790Arg and Ser961Tyr). Results from worms were validated by a genetic complementation assay in a human TMEM67 knock-out hTERT-RPE1 cell line that tests a TMEM67 signalling function. We conclude that efficient genome editing and quantitative functional assays in C. elegans make it a tractable in vivo animal model for rapid, cost-effective interpretation of ciliopathy-associated missense VUS alleles.
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Affiliation(s)
- Karen I Lange
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sunayna Best
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, West Yorkshire, UK
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ian Berry
- Bristol Genetics Laboratory, Pathology Sciences, Southmead Hospital, Bristol BS10 5NB, UK
| | - Colin A Johnson
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, West Yorkshire, UK
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
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13
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OUP accepted manuscript. Hum Mol Genet 2022; 31:2295-2306. [DOI: 10.1093/hmg/ddac027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
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14
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Bentley-Ford MR, LaBonty M, Thomas HR, Haycraft CJ, Scott M, LaFayette C, Croyle MJ, Andersen RS, Parant JM, Yoder BK. Evolutionarily conserved genetic interactions between nphp-4 and bbs-5 mutations exacerbate ciliopathy phenotypes. Genetics 2021; 220:6433160. [PMID: 34850872 DOI: 10.1093/genetics/iyab209] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/08/2021] [Indexed: 12/13/2022] Open
Abstract
Primary cilia are sensory and signaling hubs with a protein composition that is distinct from the rest of the cell due to the barrier function of the transition zone (TZ) at the base of the cilium. Protein transport across the TZ is mediated in part by the BBSome, and mutations disrupting TZ and BBSome proteins cause human ciliopathy syndromes. Ciliopathies have phenotypic variability even among patients with identical genetic variants, suggesting a role for modifier loci. To identify potential ciliopathy modifiers, we performed a mutagenesis screen on nphp-4 mutant Caenorhabditis elegans and uncovered a novel allele of bbs-5. Nphp-4;bbs-5 double mutant worms have phenotypes not observed in either individual mutant strain. To test whether this genetic interaction is conserved, we also analyzed zebrafish and mouse mutants. While Nphp4 mutant zebrafish appeared overtly normal, Bbs5 mutants exhibited scoliosis. When combined, Nphp4;Bbs5 double mutant zebrafish did not exhibit synergistic effects, but the lack of a phenotype in Nphp4 mutants makes interpreting these data difficult. In contrast, Nphp4;Bbs5 double mutant mice were not viable and there were fewer mice than expected carrying three mutant alleles. In addition, postnatal loss of Bbs5 in mice using a conditional allele compromised survival when combined with an Nphp4 allele. As cilia are still formed in the double mutant mice, the exacerbated phenotype is likely a consequence of disrupted ciliary signaling. Collectively, these data support an evolutionarily conserved genetic interaction between Bbs5 and Nphp4 alleles that may contribute to the variability in ciliopathy phenotypes.
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Affiliation(s)
- Melissa R Bentley-Ford
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Melissa LaBonty
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Holly R Thomas
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL35294, USA
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mikyla Scott
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Cameron LaFayette
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Reagan S Andersen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John M Parant
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL35294, USA
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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15
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Datta P, Cribbs JT, Seo S. Differential requirement of NPHP1 for compartmentalized protein localization during photoreceptor outer segment development and maintenance. PLoS One 2021; 16:e0246358. [PMID: 33961633 PMCID: PMC8104407 DOI: 10.1371/journal.pone.0246358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
Nephrocystin (NPHP1) is a ciliary transition zone protein and its ablation causes nephronophthisis (NPHP) with partially penetrant retinal dystrophy. However, the precise requirements of NPHP1 in photoreceptors are not well understood. Here, we characterize retinal degeneration in a mouse model of NPHP1 and show that NPHP1 is required to prevent infiltration of inner segment plasma membrane proteins into the outer segment during the photoreceptor maturation. We demonstrate that Nphp1 gene-trap mutant mice, which were previously described as null, are likely hypomorphs due to the production of a small quantity of functional mRNAs derived from nonsense-associated altered splicing and skipping of two exons including the one harboring the gene-trap. In homozygous mutant animals, inner segment plasma membrane proteins such as syntaxin-3 (STX3), synaptosomal-associated protein 25 (SNAP25), and interphotoreceptor matrix proteoglycan 2 (IMPG2) accumulate in the outer segment when outer segments are actively elongating. This phenotype, however, is spontaneously ameliorated after the outer segment elongation is completed. Consistent with this, some photoreceptor cell loss (~30%) occurs during the photoreceptor maturation period but it stops afterward. We further show that Nphp1 genetically interacts with Cep290, another NPHP gene, and that a reduction of Cep290 gene dose results in retinal degeneration that continues until adulthood in Nphp1 mutant mice. These findings demonstrate that NPHP1 is required for the confinement of inner segment plasma membrane proteins during the outer segment development, but its requirement diminishes as photoreceptors mature. Our study also suggests that additional mutations in other NPHP genes may influence the penetrance of retinopathy in human NPHP1 patients.
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Affiliation(s)
- Poppy Datta
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
| | - J. Thomas Cribbs
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States of America
- Institute for Vision Research, The University of Iowa, Iowa City, IA, United States of America
- * E-mail:
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16
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Hazime KS, Zhou Z, Joachimiak E, Bulgakova NA, Wloga D, Malicki JJ. STORM imaging reveals the spatial arrangement of transition zone components and IFT particles at the ciliary base in Tetrahymena. Sci Rep 2021; 11:7899. [PMID: 33846423 PMCID: PMC8041816 DOI: 10.1038/s41598-021-86909-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 03/22/2021] [Indexed: 11/17/2022] Open
Abstract
The base of the cilium comprising the transition zone (TZ) and transition fibers (TF) acts as a selecting gate to regulate the intraflagellar transport (IFT)-dependent trafficking of proteins to and from cilia. Before entering the ciliary compartment, IFT complexes and transported cargoes accumulate at or near the base of the cilium. The spatial organization of IFT proteins at the cilia base is key for understanding cilia formation and function. Using stochastic optical reconstruction microscopy (STORM) and computational averaging, we show that seven TZ, nine IFT, three Bardet–Biedl syndrome (BBS), and one centrosomal protein, form 9-clustered rings at the cilium base of a ciliate Tetrahymena thermophila. In the axial dimension, analyzed TZ proteins localize to a narrow region of about 30 nm while IFT proteins dock approximately 80 nm proximal to TZ. Moreover, the IFT-A subcomplex is positioned peripheral to the IFT-B subcomplex and the investigated BBS proteins localize near the ciliary membrane. The positioning of the HA-tagged N- and C-termini of the selected proteins enabled the prediction of the spatial orientation of protein particles and likely cargo interaction sites. Based on the obtained data, we built a comprehensive 3D-model showing the arrangement of the investigated ciliary proteins.
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Affiliation(s)
- Khodor S Hazime
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
| | - Zhu Zhou
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Natalia A Bulgakova
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, 3 Pasteur Street, 02-093, Warsaw, Poland.
| | - Jarema J Malicki
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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17
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Akella JS, Barr MM. The tubulin code specializes neuronal cilia for extracellular vesicle release. Dev Neurobiol 2021; 81:231-252. [PMID: 33068333 PMCID: PMC8052387 DOI: 10.1002/dneu.22787] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/07/2020] [Accepted: 09/23/2020] [Indexed: 12/17/2022]
Abstract
Cilia are microtubule-based organelles that display diversity in morphology, ultrastructure, protein composition, and function. The ciliary microtubules of C. elegans sensory neurons exemplify this diversity and provide a paradigm to understand mechanisms driving ciliary specialization. Only a subset of ciliated neurons in C. elegans are specialized to make and release bioactive extracellular vesicles (EVs) into the environment. The cilia of extracellular vesicle releasing neurons have distinct axonemal features and specialized intraflagellar transport that are important for releasing EVs. In this review, we discuss the role of the tubulin code in the specialization of microtubules in cilia of EV releasing neurons.
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Affiliation(s)
- Jyothi S Akella
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
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18
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Xie C, Martens JR. Potential Therapeutic Targets for Olfactory Dysfunction in Ciliopathies Beyond Single-Gene Replacement. Chem Senses 2021; 46:6159785. [PMID: 33690843 DOI: 10.1093/chemse/bjab010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Olfactory dysfunction is a common disorder in the general population. There are multiple causes, one of which being ciliopathies, an emerging class of human hereditary genetic disorders characterized by multiple symptoms due to defects in ciliary biogenesis, maintenance, and/or function. Mutations/deletions in a wide spectrum of ciliary genes have been identified to cause ciliopathies. Currently, besides symptomatic therapy, there is no available therapeutic treatment option for olfactory dysfunction caused by ciliopathies. Multiple studies have demonstrated that targeted gene replacement can restore the morphology and function of olfactory cilia in olfactory sensory neurons and further re-establish the odor-guided behaviors in animals. Therefore, targeted gene replacement could be potentially used to treat olfactory dysfunction in ciliopathies. However, due to the potential limitations of single-gene therapy for polygenic mutation-induced diseases, alternative therapeutic targets for broader curative measures need to be developed for olfactory dysfunction, and also for other symptoms in ciliopathies. Here we review the current understanding of ciliogenesis and maintenance of olfactory cilia. Furthermore, we emphasize signaling mechanisms that may be involved in the regulation of olfactory ciliary length and highlight potential alternative therapeutic targets for the treatment of ciliopathy-induced dysfunction in the olfactory system and even in other ciliated organ systems.
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Affiliation(s)
- Chao Xie
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA.,Center for Smell and Taste, University of Florida College of Medicine, 1149 Newell Drive, Gainesville, FL 32610, USA
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA.,Center for Smell and Taste, University of Florida College of Medicine, 1149 Newell Drive, Gainesville, FL 32610, USA
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19
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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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20
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HTR6 and SSTR3 targeting to primary cilia. Biochem Soc Trans 2021; 49:79-91. [PMID: 33599752 DOI: 10.1042/bst20191005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 12/25/2020] [Accepted: 01/20/2021] [Indexed: 12/30/2022]
Abstract
Primary cilia are hair-like projections of the cell membrane supported by an inner microtubule scaffold, the axoneme, which polymerizes out of a membrane-docked centriole at the ciliary base. By working as specialized signaling compartments, primary cilia provide an optimal environment for many G protein-coupled receptors (GPCRs) and their effectors to efficiently transmit their signals to the rest of the cell. For this to occur, however, all necessary receptors and signal transducers must first accumulate at the ciliary membrane. Serotonin receptor 6 (HTR6) and Somatostatin receptor 3 (SSTR3) are two GPCRs whose signaling in brain neuronal cilia affects cognition and is implicated in psychiatric, neurodegenerative, and oncologic diseases. Over a decade ago, the third intracellular loops (IC3s) of HTR6 and SSTR3 were shown to contain ciliary localization sequences (CLSs) that, when grafted onto non-ciliary GPCRs, could drive their ciliary accumulation. Nevertheless, these CLSs were dispensable for ciliary targeting of HTR6 and SSTR3, suggesting the presence of additional CLSs, which we have recently identified in their C-terminal tails. Herein, we review the discovery and mapping of these CLSs, as well as the state of the art regarding how these CLSs may orchestrate ciliary accumulation of these GPCRs by controlling when and where they interact with the ciliary entry and exit machinery via adaptors such as TULP3, RABL2 and the BBSome.
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21
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Lange KI, Tsiropoulou S, Kucharska K, Blacque OE. Interpreting the pathogenicity of Joubert syndrome missense variants in Caenorhabditis elegans. Dis Model Mech 2021; 14:dmm.046631. [PMID: 33234550 PMCID: PMC7859701 DOI: 10.1242/dmm.046631] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/13/2020] [Indexed: 12/26/2022] Open
Abstract
Ciliopathies are inherited disorders caused by defects in motile and non-motile (primary) cilia. Ciliopathy syndromes and associated gene variants are often highly pleiotropic and represent exemplars for interrogating genotype-phenotype correlations. Towards understanding disease mechanisms in the context of ciliopathy mutations, we have used a leading model organism for cilia and ciliopathy research, Caenorhabditis elegans, together with gene editing, to characterise two missense variants (P74S and G155S) in mksr-2/B9D2 associated with Joubert syndrome (JBTS). B9D2 functions within the Meckel syndrome (MKS) module at the ciliary base transition zone (TZ) compartment and regulates the molecular composition and sensory/signalling functions of the cilium. Quantitative assays of cilium/TZ structure and function, together with knock-in reporters, confirm that both variant alleles are pathogenic in worms. G155S causes a more severe overall phenotype and disrupts endogenous MKSR-2 organisation at the TZ. Recapitulation of the patient biallelic genotype shows that compound heterozygous worms phenocopy worms homozygous for P74S. The P74S and G155S alleles also reveal evidence of a very close functional association between the B9D2-associated B9 complex and MKS-2/TMEM216. Together, these data establish C. elegans as a model for interpreting JBTS mutations and provide further insight into MKS module organisation. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Karen I Lange
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Katarzyna Kucharska
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
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22
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McConnachie DJ, Stow JL, Mallett AJ. Ciliopathies and the Kidney: A Review. Am J Kidney Dis 2020; 77:410-419. [PMID: 33039432 DOI: 10.1053/j.ajkd.2020.08.012] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/11/2020] [Indexed: 12/19/2022]
Abstract
Primary cilia are specialized sensory organelles that protrude from the apical surface of most cell types. During the past 2 decades, they have been found to play important roles in tissue development and signal transduction, with mutations in ciliary-associated proteins resulting in a group of diseases collectively known as ciliopathies. Many of these mutations manifest as renal ciliopathies, characterized by kidney dysfunction resulting from aberrant cilia or ciliary functions. This group of overlapping and genetically heterogeneous diseases includes polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome as the main focus of this review. Renal ciliopathies are characterized by the presence of kidney cysts that develop due to uncontrolled epithelial cell proliferation, growth, and polarity, downstream of dysregulated ciliary-dependent signaling. Due to cystic-associated kidney injury and systemic inflammation, cases result in kidney failure requiring dialysis and transplantation. Of the handful of pharmacologic treatments available, none are curative. It is important to determine the molecular mechanisms that underlie the involvement of the primary cilium in cyst initiation, expansion, and progression for the development of novel and efficacious treatments. This review updates research progress in defining key genes and molecules central to ciliogenesis and renal ciliopathies.
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Affiliation(s)
- Dominique J McConnachie
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation Disease and Research, The University of Queensland, Brisbane, QLD, Australia
| | - Jennifer L Stow
- Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Andrew J Mallett
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation Disease and Research, The University of Queensland, Brisbane, QLD, Australia; Kidney Health Service, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia; Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, VIC, Australia.
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23
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Hasenpusch-Theil K, Laclef C, Colligan M, Fitzgerald E, Howe K, Carroll E, Abrams SR, Reiter JF, Schneider-Maunoury S, Theil T. A transient role of the ciliary gene Inpp5e in controlling direct versus indirect neurogenesis in cortical development. eLife 2020; 9:e58162. [PMID: 32840212 PMCID: PMC7481005 DOI: 10.7554/elife.58162] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 08/24/2020] [Indexed: 01/13/2023] Open
Abstract
During the development of the cerebral cortex, neurons are generated directly from radial glial cells or indirectly via basal progenitors. The balance between these division modes determines the number and types of neurons formed in the cortex thereby affecting cortical functioning. Here, we investigate the role of primary cilia in controlling the decision between forming neurons directly or indirectly. We show that a mutation in the ciliary gene Inpp5e leads to a transient increase in direct neurogenesis and subsequently to an overproduction of layer V neurons in newborn mice. Loss of Inpp5e also affects ciliary structure coinciding with reduced Gli3 repressor levels. Genetically restoring Gli3 repressor rescues the decreased indirect neurogenesis in Inpp5e mutants. Overall, our analyses reveal how primary cilia determine neuronal subtype composition of the cortex by controlling direct versus indirect neurogenesis. These findings have implications for understanding cortical malformations in ciliopathies with INPP5E mutations.
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Affiliation(s)
- Kerstin Hasenpusch-Theil
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
- Simons Initiative for the Developing Brain, University of EdinburghEdinburghUnited Kingdom
| | - Christine Laclef
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology UnitParisFrance
| | - Matt Colligan
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Eamon Fitzgerald
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Katherine Howe
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Emily Carroll
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Shaun R Abrams
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology UnitParisFrance
| | - Thomas Theil
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
- Simons Initiative for the Developing Brain, University of EdinburghEdinburghUnited Kingdom
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24
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Hu J, Harris PC. Regulation of polycystin expression, maturation and trafficking. Cell Signal 2020; 72:109630. [PMID: 32275942 PMCID: PMC7269868 DOI: 10.1016/j.cellsig.2020.109630] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The major autosomal dominant polycystic kidney disease (ADPKD) genes, PKD1 and PKD2, are wildly expressed at the organ and tissue level. PKD1 encodes polycystin 1 (PC1), a large membrane associated receptor-like protein that can complex with the PKD2 product, PC2. Various cellular locations have been described for both PC1, including the plasma membrane and extracellular vesicles, and PC2, especially the endoplasmic reticulum (ER), but compelling evidence indicates that the primary cilium, a sensory organelle, is the key site for the polycystin complex to prevent PKD. As with other membrane proteins, the ER biogenesis pathway is key to appropriately folding, performing quality control, and exporting fully folded PC1 to the Golgi apparatus. There is a requirement for binding with PC2 and cleavage of PC1 at the GPS for this folding and export to occur. Six different monogenic defects in this pathway lead to cystic disease development, with PC1 apparently particularly sensitive to defects in this general protein processing pathway. Trafficking of membrane proteins, and the polycystins in particular, through the Golgi to the primary cilium have been analyzed in detail, but at this time, there is no clear consensus on a ciliary targeting sequence required to export proteins to the cilium. After transitioning though the trans-Golgi network, polycystin-bearing vesicles are likely sorted to early or recycling endosomes and then transported to the ciliary base, possibly via docking to transition fibers (TF). The membrane-bound polycystin complex then undergoes facilitated trafficking through the transition zone, the diffusion barrier at the base of the cilium, before entering the cilium. Intraflagellar transport (IFT) may be involved in moving the polycystins along the cilia, but data also indicates other mechanisms. The ciliary polycystin complex can be ubiquitinated and removed from cilia by internalization at the ciliary base and may be sent back to the plasma membrane for recycling or to lysosomes for degradation. Monogenic defects in processes regulating the protein composition of cilia are associated with syndromic disorders involving many organ systems, reflecting the pleotropic role of cilia during development and for tissue maintenance. Many of these ciliopathies have renal involvement, likely because of faulty polycystin signaling from cilia. Understanding the expression, maturation and trafficking of the polycystins helps understand PKD pathogenesis and suggests opportunities for therapeutic intervention.
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Affiliation(s)
- Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
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25
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Zhang M, Chang Z, Tian Y, Wang L, Lu Y. Two novel TCTN2 mutations cause Meckel-Gruber syndrome. J Hum Genet 2020; 65:1039-1043. [PMID: 32655147 DOI: 10.1038/s10038-020-0804-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/26/2020] [Indexed: 11/09/2022]
Abstract
Meckel-Gruber syndrome (MKS) is a clinically and genetically heterogeneous ciliopathy characterized by a triad of occipital encephalocele, polycystic kidneys, and postaxial polydactyly. Pathogenesis of MKS is related to dysfunction of primary cilia. However, reports on MKS caused by Tectonic2 (TCTN2) mutations are scanty whilst. There is no direct evidence of ciliogenesis in such MKS patients. Here, we identified two novel nonsense variants of TCTN2 (c.343G > T, p.E115*; c.1540C > T, p.Q514*) in a Chinese MKS fetus. Compared to reported TCTN2-causing MKS patients, our case represented an endocardial pad defect, which was not reported previously. We also found primary cilia protruded normally from the surface of epithelial cells in the affected fetal kidney tubules compared to controls, indicating TCTN2 is not necessary for ciliogenesis in the kidney. To our knowledge, this is the first case of MKS fetus caused by TCTN2 mutations from China.
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Affiliation(s)
- Manli Zhang
- Translational Medicine Center, Chinese PLA General Hospital, 28 Fuxing Road, 100853, Beijing, People's Republic of China
| | - Zhijie Chang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Medicine, School of Life Sciences, Tsinghua University, 30 Shuangqing Road, 100084, Beijing, People's Republic of China
| | - Yaping Tian
- Translational Medicine Center, Chinese PLA General Hospital, 28 Fuxing Road, 100853, Beijing, People's Republic of China
| | - Longxia Wang
- Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, 100853, Beijing, People's Republic of China.
| | - Yanping Lu
- Department of Gynaecology and Obstetrics, Chinese PLA General Hospital, 28 Fuxing Road, 100853, Beijing, People's Republic of China.
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26
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Martin-Hurtado A, Lastres-Becker I, Cuadrado A, Garcia-Gonzalo FR. NRF2 and Primary Cilia: An Emerging Partnership. Antioxidants (Basel) 2020; 9:antiox9060475. [PMID: 32498260 PMCID: PMC7346227 DOI: 10.3390/antiox9060475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/30/2020] [Accepted: 05/31/2020] [Indexed: 02/07/2023] Open
Abstract
When not dividing, many cell types target their centrosome to the plasma membrane, where it nucleates assembly of a primary cilium, an antenna-like signaling structure consisting of nine concentric microtubule pairs surrounded by membrane. Primary cilia play important pathophysiological roles in many tissues, their dysfunction being associated with cancer and ciliopathies, a diverse group of congenital human diseases. Several recent studies have unveiled functional connections between primary cilia and NRF2 (nuclear factor erythroid 2-related factor 2), the master transcription factor orchestrating cytoprotective responses to oxidative and other cellular stresses. These NRF2-cilia relationships are reciprocal: primary cilia, by promoting autophagy, downregulate NRF2 activity. In turn, NRF2 transcriptionally regulates genes involved in ciliogenesis and Hedgehog (Hh) signaling, a cilia-dependent pathway with major roles in embryogenesis, stem cell function and tumorigenesis. Nevertheless, while we found that NRF2 stimulates ciliogenesis and Hh signaling, a more recent study reported that NRF2 negatively affects these processes. Herein, we review the available evidence linking NRF2 to primary cilia, suggest possible explanations to reconcile seemingly contradictory data, and discuss what the emerging interplay between primary cilia and NRF2 may mean for human health and disease.
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Affiliation(s)
- Ana Martin-Hurtado
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
| | - Isabel Lastres-Becker
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28013 Madrid, Spain
| | - Antonio Cuadrado
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28013 Madrid, Spain
| | - Francesc R. Garcia-Gonzalo
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
- Correspondence:
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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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28
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Actin-based regulation of ciliogenesis - The long and the short of it. Semin Cell Dev Biol 2019; 102:132-138. [PMID: 31862221 DOI: 10.1016/j.semcdb.2019.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/23/2019] [Accepted: 12/07/2019] [Indexed: 12/11/2022]
Abstract
The primary cilia is found on the mammalian cell surface where it serves as an antenna for the reception and transmission of a variety of cellular signaling pathways. At its core the cilium is a microtubule-based organelle, but it is clear that its assembly and function are dependent upon the coordinated regulation of both actin and microtubule dynamics. In particular, the discovery that the centrosome is able to act as both a microtubule and actin organizing centre implies that both cytoskeletal networks are acting directly on the process of cilia assembly. In this review, we set our recent results with the formin FHDC1 in the context of current reports that show each stage of ciliogenesis is impacted by changes in actin dynamics. These include direct effects of actin filament assembly on basal body positioning, vesicle trafficking to and entry into the cilium, cilia length, cilia membrane organization and cilia-dependent signaling.
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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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30
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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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Lessieur EM, Song P, Nivar GC, Piccillo EM, Fogerty J, Rozic R, Perkins BD. Ciliary genes arl13b, ahi1 and cc2d2a differentially modify expression of visual acuity phenotypes but do not enhance retinal degeneration due to mutation of cep290 in zebrafish. PLoS One 2019; 14:e0213960. [PMID: 30970040 PMCID: PMC6457629 DOI: 10.1371/journal.pone.0213960] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 03/28/2019] [Indexed: 01/11/2023] Open
Abstract
Mutations in the gene Centrosomal Protein 290 kDa (CEP290) result in multiple ciliopathies ranging from the neonatal lethal disorder Meckel-Gruber Syndrome to multi-systemic disorders such as Joubert Syndrome and Bardet-Biedl Syndrome to nonsyndromic diseases like Leber Congenital Amaurosis (LCA) and retinitis pigmentosa. Results from model organisms and human genetics studies, have suggest that mutations in genes encoding protein components of the transition zone (TZ) and other cilia-associated proteins can function as genetic modifiers and be a source for CEP290 pleiotropy. We investigated the zebrafish cep290fh297/fh297 mutant, which encodes a nonsense mutation (p.Q1217*). This mutant is viable as adults, exhibits scoliosis, and undergoes a slow, progressive cone degeneration. The cep290fh297/fh297 mutants showed partial mislocalization of the transmembrane protein rhodopsin but not of the prenylated proteins rhodopsin kinase (GRK1) or the rod transducin subunit GNB1. Surprisingly, photoreceptor degeneration did not trigger proliferation of Müller glia, but proliferation of rod progenitors in the outer nuclear layer was significantly increased. To determine if heterozygous mutations in other cilia genes could exacerbate retinal degeneration, we bred cep290fh297/fh297 mutants to arl13b, ahi1, and cc2d2a mutant zebrafish lines. While cep290fh297/fh297 mutants lacking a single allele of these genes did not exhibit accelerated photoreceptor degeneration, loss of one alleles of arl13b or ahi1 reduced visual performance in optokinetic response assays at 5 days post fertilization. Our results indicate that the cep290fh297/fh297 mutant is a useful model to study the role of genetic modifiers on photoreceptor degeneration in zebrafish and to explore how progressive photoreceptor degeneration influences regeneration in adult zebrafish.
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Affiliation(s)
- Emma M. Lessieur
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ping Song
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Gabrielle C. Nivar
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Ellen M. Piccillo
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Joseph Fogerty
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Richard Rozic
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Brian D. Perkins
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
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32
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Patowary A, Won SY, Oh SJ, Nesbitt RR, Archer M, Nickerson D, Raskind WH, Bernier R, Lee JE, Brkanac Z. Family-based exome sequencing and case-control analysis implicate CEP41 as an ASD gene. Transl Psychiatry 2019; 9:4. [PMID: 30664616 PMCID: PMC6341097 DOI: 10.1038/s41398-018-0343-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/13/2018] [Indexed: 12/03/2022] Open
Abstract
Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with a strong genetic component. Although next-generation sequencing (NGS) technologies have been successfully applied to gene identification in de novo ASD, the genetic architecture of familial ASD remains largely unexplored. Our approach, which leverages the high specificity and sensitivity of NGS technology, has focused on rare variants in familial autism. We used NGS exome sequencing in 26 families with distantly related affected individuals to identify genes with private gene disrupting and missense variants of interest (VOI). We found that the genes carrying VOIs were enriched for biological processes related to cell projection organization and neuron development, which is consistent with the neurodevelopmental hypothesis of ASD. For a subset of genes carrying VOIs, we then used targeted NGS sequencing and gene-based variant burden case-control analysis to test for association with ASD. Missense variants in one gene, CEP41, associated significantly with ASD (p = 6.185e-05). Homozygous gene-disrupting variants in CEP41 were initially found to be responsible for recessive Joubert syndrome. Using a zebrafish model, we evaluated the mechanism by which the CEP41 variants might contribute to ASD. We found that CEP41 missense variants affect development of the axonal tract, cranial neural crest migration and social behavior phenotype. Our work demonstrates the involvement of CEP41 heterozygous missense variants in ASD and that biological processes involved in cell projection organization and neuron development are enriched in ASD families we have studied.
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Affiliation(s)
- Ashok Patowary
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
| | - So Yeon Won
- 0000 0001 2181 989Xgrid.264381.aDepartment of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea
| | - Shin Ji Oh
- 0000 0001 2181 989Xgrid.264381.aDepartment of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea
| | - Ryan R Nesbitt
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
| | - Marilyn Archer
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
| | - Debbie Nickerson
- 0000000122986657grid.34477.33Department of Genome Sciences, University of Washington, Seattle, WA USA
| | - Wendy H. Raskind
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA ,0000000122986657grid.34477.33Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA USA
| | - Raphael Bernier
- 0000000122986657grid.34477.33Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA
| | - Ji Eun Lee
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Korea. .,Division of Medical Science Research, Samsung Medical Center, Seoul, Korea.
| | - Zoran Brkanac
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA.
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33
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Jensen VL, Lambacher NJ, Li C, Mohan S, Williams CL, Inglis PN, Yoder BK, Blacque OE, Leroux MR. Role for intraflagellar transport in building a functional transition zone. EMBO Rep 2018; 19:e45862. [PMID: 30429209 PMCID: PMC6280794 DOI: 10.15252/embr.201845862] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 10/22/2018] [Accepted: 10/26/2018] [Indexed: 12/21/2022] Open
Abstract
Genetic disorders caused by cilia dysfunction, termed ciliopathies, frequently involve the intraflagellar transport (IFT) system. Mutations in IFT subunits-including IFT-dynein motor DYNC2H1-impair ciliary structures and Hedgehog signalling, typically leading to "skeletal" ciliopathies such as Jeune asphyxiating thoracic dystrophy. Intriguingly, IFT gene mutations also cause eye, kidney and brain ciliopathies often linked to defects in the transition zone (TZ), a ciliary gate implicated in Hedgehog signalling. Here, we identify a C. elegans temperature-sensitive (ts) IFT-dynein mutant (che-3; human DYNC2H1) and use it to show a role for retrograde IFT in anterograde transport and ciliary maintenance. Unexpectedly, correct TZ assembly and gating function for periciliary proteins also require IFT-dynein. Using the reversibility of the novel ts-IFT-dynein, we show that restoring IFT in adults (post-developmentally) reverses defects in ciliary structure, TZ protein localisation and ciliary gating. Notably, this ability to reverse TZ defects declines as animals age. Together, our findings reveal a previously unknown role for IFT in TZ assembly in metazoans, providing new insights into the pathomechanism and potential phenotypic overlap between IFT- and TZ-associated ciliopathies.
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Affiliation(s)
- Victor L Jensen
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Nils J Lambacher
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Chunmei Li
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Swetha Mohan
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Corey L Williams
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham Medical School, Birmingham, AL, USA
| | - Peter N Inglis
- Department of Biology, Kwantlen Polytechnic University, Surrey, BC, Canada
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham Medical School, Birmingham, AL, USA
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michel R Leroux
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
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34
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Weng RR, Yang TT, Huang CE, Chang CW, Wang WJ, Liao JC. Super-Resolution Imaging Reveals TCTN2 Depletion-Induced IFT88 Lumen Leakage and Ciliary Weakening. Biophys J 2018; 115:263-275. [PMID: 29866362 DOI: 10.1016/j.bpj.2018.04.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/07/2018] [Accepted: 04/23/2018] [Indexed: 11/28/2022] Open
Abstract
The primary cilium is an essential organelle mediating key signaling activities, such as sonic hedgehog signaling. The molecular composition of the ciliary compartment is distinct from that of the cytosol, with the transition zone (TZ) gated the ciliary base. The TZ is a packed and organized protein complex containing multiple ciliopathy-associated protein species. Tectonic 2 (TCTN2) is one of the TZ proteins in the vicinity of the ciliary membrane, and its mutation is associated with Meckel syndrome. Despite its importance in ciliopathies, the role of TCTN2 in ciliary structure and molecules remains unclear. Here, we created a CRISPR/Cas9 TCTN2 knockout human retinal pigment epithelial cell line and conducted quantitative analysis of geometric localization using both wide-field and super-resolution microscopy techniques. We found that TCTN2 depletion resulted in partial TZ damage, loss of ciliary membrane proteins, leakage of intraflagellar transport protein IFT88 toward the basal body lumen, and cilium shortening and curving. The basal body lumen occupancy of IFT88 was also observed in si-RPGRIP1L cells and cytochalasin-D-treated wild-type cells, suggesting varying lumen accessibility for intraflagellar transport proteins under different perturbed conditions. Our findings support two possible models for the lumen leakage of IFT88, i.e., a tip leakage model and a misregulation model. Together, our quantitative image analysis augmented by super-resolution microscopy facilitates the observation of structural destruction and molecular redistribution in TCTN2-/- cilia, shedding light on mechanistic understanding of TZ-protein-associated ciliopathies.
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Affiliation(s)
- Rueyhung Roc Weng
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - T Tony Yang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - Chia-En Huang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - Chih-Wei Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - Won-Jing Wang
- Institute of Biochemistry and Molecular Biology, National Yang Ming University, Taipei, Taiwan
| | - Jung-Chi Liao
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan; Genome and Systems Biology Degree Program, National Taiwan University, Taipei, Taiwan.
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35
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Ye F, Nager AR, Nachury MV. BBSome trains remove activated GPCRs from cilia by enabling passage through the transition zone. J Cell Biol 2018; 217:1847-1868. [PMID: 29483145 PMCID: PMC5940304 DOI: 10.1083/jcb.201709041] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/27/2017] [Accepted: 01/29/2018] [Indexed: 02/08/2023] Open
Abstract
A diffusion barrier at the transition zone enables the compartmentalization of signaling molecules by cilia. The BBSome and the small guanosine triphosphatase Arl6, which triggers BBSome coat polymerization, are required for the exit of activated signaling receptors from cilia, but how diffusion barriers are crossed when membrane proteins exit cilia remains to be determined. In this study, we found that activation of the ciliary G protein-coupled receptors (GPCRs) Smoothened and SSTR3 drove the Arl6-dependent assembly of large, highly processive, and cargo-laden retrograde BBSome trains. Single-molecule imaging revealed that the assembly of BBSome trains enables the lateral transport of ciliary GPCRs across the transition zone. However, the removal of activated GPCRs from cilia was inefficient because a second periciliary diffusion barrier was infrequently crossed. We conclude that exit from cilia is a two-step process in which BBSome/Arl6 trains first move activated GPCRs through the transition zone before a periciliary barrier can be crossed.
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Affiliation(s)
- Fan Ye
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
| | - Andrew R Nager
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
| | - Maxence V Nachury
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
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36
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Wang B, Zhang Y, Dong H, Gong S, Wei B, Luo M, Wang H, Wu X, Liu W, Xu X, Zheng Y, Sun M. Loss of Tctn3 causes neuronal apoptosis and neural tube defects in mice. Cell Death Dis 2018; 9:520. [PMID: 29725084 PMCID: PMC5938703 DOI: 10.1038/s41419-018-0563-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/23/2018] [Accepted: 04/03/2018] [Indexed: 12/18/2022]
Abstract
Tctn3 belongs to the Tectonic (Tctn) family and is a single-pass membrane protein localized at the transition zone of primary cilia as an important component of ciliopathy-related protein complexes. Previous studies showed that mutations in Tctn1 and Tctn2, two members of the tectonic family, have been reported to disrupt neural tube development in humans and mice, but the functions of Tctn3 in brain development remain elusive. In this study, Tctn3 knockout (KO) mice were generated by utilizing the piggyBac (PB) transposon system. We found that Tctn3 KO mice exhibited abnormal global development, including prenatal lethality, microphthalmia, polysyndactyly, and abnormal head, sternum, and neural tube, whereas Tctn3 heterozygous KO mice did not show abnormal development or behaviors. Further, we found that the mRNA levels of Gli1 and Ptch1, downstream signaling components of the Shh pathway, were significantly reduced. Likewise, neural tube patterning-related proteins, such as Shh, Foxa2, and Nkx2.2, were altered in their distribution. Interestingly, Tctn3 KO led to significant changes in apoptosis-related proteins, including Bcl-2, Bax, and cleaved PARP1, resulting in reduced numbers of neuronal cells in embryonic brains. Tctn3 KO inhibited the PI3K/Akt signaling pathway but not the mTOR-dependent pathway. The small molecule SC79, a specific Akt activator, blocked apoptotic cell death in primary mouse embryonic fibroblasts from Tctn3 KO mice. Finally, NPHP1, a protein with anti-apoptotic ability, was found to form a complex with Tctn3, and its levels were decreased in Tctn3 KO mice. In conclusion, our results show that Tctn3 KO disrupts the Shh signaling pathway and neural tube patterning, resulting in abnormal embryonic development, cellular apoptosis, and prenatal death in mice.
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Affiliation(s)
- Bin Wang
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou City, 215006, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou City, 215123, Jiangsu, China
| | - Yingying Zhang
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou City, 215006, Jiangsu, China
| | - Hongli Dong
- Department of Neurology, Suzhou Hospital of Traditional Chinese Medicine, Suzhou City, 215123, Jiangsu, China
| | - Siyi Gong
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou City, 215006, Jiangsu, China.,Institute of Neuroscience, Soochow University, Suzhou City, 215123, Jiangsu, China
| | - Bin Wei
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou City, 215006, Jiangsu, China
| | - Man Luo
- Institute of Neuroscience, Soochow University, Suzhou City, 215123, Jiangsu, China
| | - Hongyan Wang
- Obstetrics and Gynecology Hospital Research Center, Institute of Reproduction and Development, Fudan University, Shanghai, 200433, China.,State Key Laboratory of Genetic Engineering, MOE Key Laboratory of Contemporary Anthropology, and Collaborative Innovation Center for Genetics & Development, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Xiaohui Wu
- State Key Laboratory of Genetic Engineering, MOE Key Laboratory of Contemporary Anthropology, and Collaborative Innovation Center for Genetics & Development, School of Life Sciences, Fudan University, Shanghai, 200438, China.,Institute of Developmental Biology & Molecular Medicine, Fudan University, Shanghai, 200433, China
| | - Wei Liu
- Department of Pathology, the First Affiliated Hospital of Soochow University, Suzhou City, 215006, Jiangsu, China
| | - Xingshun Xu
- Institute of Neuroscience, Soochow University, Suzhou City, 215123, Jiangsu, China.
| | - Yufang Zheng
- Obstetrics and Gynecology Hospital Research Center, Institute of Reproduction and Development, Fudan University, Shanghai, 200433, China. .,State Key Laboratory of Genetic Engineering, MOE Key Laboratory of Contemporary Anthropology, and Collaborative Innovation Center for Genetics & Development, School of Life Sciences, Fudan University, Shanghai, 200438, China. .,Institute of Developmental Biology & Molecular Medicine, Fudan University, Shanghai, 200433, China.
| | - Miao Sun
- Institute for Fetology, the First Affiliated Hospital of Soochow University, Suzhou City, 215006, Jiangsu, China.
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37
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Wiegering A, Dildrop R, Kalfhues L, Spychala A, Kuschel S, Lier JM, Zobel T, Dahmen S, Leu T, Struchtrup A, Legendre F, Vesque C, Schneider-Maunoury S, Saunier S, Rüther U, Gerhardt C. Cell type-specific regulation of ciliary transition zone assembly in vertebrates. EMBO J 2018; 37:embj.201797791. [PMID: 29650680 PMCID: PMC5978567 DOI: 10.15252/embj.201797791] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 01/07/2023] Open
Abstract
Ciliopathies are life-threatening human diseases caused by defective cilia. They can often be traced back to mutations of genes encoding transition zone (TZ) proteins demonstrating that the understanding of TZ organisation is of paramount importance. The TZ consists of multimeric protein modules that are subject to a stringent assembly hierarchy. Previous reports place Rpgrip1l at the top of the TZ assembly hierarchy in Caenorhabditis elegans By performing quantitative immunofluorescence studies in RPGRIP1L-/- mouse embryos and human embryonic cells, we recognise a different situation in vertebrates in which Rpgrip1l deficiency affects TZ assembly in a cell type-specific manner. In cell types in which the loss of Rpgrip1l alone does not affect all modules, additional truncation or removal of vertebrate-specific Rpgrip1 results in an impairment of all modules. Consequently, Rpgrip1l and Rpgrip1 synergistically ensure the TZ composition in several vertebrate cell types, revealing a higher complexity of TZ assembly in vertebrates than in invertebrates.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Renate Dildrop
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Lisa Kalfhues
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - André Spychala
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Stefanie Kuschel
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Johanna Maria Lier
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Thomas Zobel
- Center for Advanced Imaging (CAi), Heinrich Heine University, Düsseldorf, Germany
| | - Stefanie Dahmen
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Tristan Leu
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Andreas Struchtrup
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Flora Legendre
- INSERM, U983, Hôpital Necker-Enfants Malades, Paris, France.,Sorbonne Paris Cité, Faculté de Médecine, Université Paris-Descartes, Paris, France
| | - Christine Vesque
- Paris-Seine (IBPS) - Developmental Biology Laboratory, Institut de Biologie, CNRS, UMR7622, INSERM U1156, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France
| | - Sylvie Schneider-Maunoury
- Paris-Seine (IBPS) - Developmental Biology Laboratory, Institut de Biologie, CNRS, UMR7622, INSERM U1156, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France
| | - Sophie Saunier
- INSERM, U983, Hôpital Necker-Enfants Malades, Paris, France.,Sorbonne Paris Cité, Faculté de Médecine, Université Paris-Descartes, Paris, France
| | - Ulrich Rüther
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, Düsseldorf, Germany
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38
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Nachury MV. The molecular machines that traffic signaling receptors into and out of cilia. Curr Opin Cell Biol 2018; 51:124-131. [PMID: 29579578 PMCID: PMC5949257 DOI: 10.1016/j.ceb.2018.03.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 12/12/2022]
Abstract
Cilia are surface-exposed organelles that dynamically concentrate signaling molecules to organize sensory, developmental and homeostatic pathways. Entry and exit of signaling receptors is germane to the processing of signals and the molecular machines for entry and exit have started to emerge. The IFT-A complex and its membrane recruitment factor Tulp3 complex promotes the entry of signaling receptors into cilia while the BBSome and its membrane recruitment factor Arl6GTP ferry activated signaling receptors out of cilia. Ciliary exit is a surprisingly complex process entailing passage through a first diffusion barrier at the transition zone, diffusion inside an intermediate compartment and crossing of a periciliary diffusion barrier. The two barriers may organize a privileged compartment where activated signaling receptors transiently reside.
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Affiliation(s)
- Maxence V Nachury
- UCSF School of Medicine, Department of Ophthalmology, United States.
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39
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Phelps IG, Dempsey JC, Grout ME, Isabella CR, Tully HM, Doherty D, Bachmann-Gagescu R. Interpreting the clinical significance of combined variants in multiple recessive disease genes: systematic investigation of Joubert syndrome yields little support for oligogenicity. Genet Med 2018; 20:223-233. [PMID: 28771248 PMCID: PMC5797514 DOI: 10.1038/gim.2017.94] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 05/19/2017] [Indexed: 01/11/2023] Open
Abstract
PurposeNext-generation sequencing (NGS) often identifies multiple rare predicted-deleterious variants (RDVs) in different genes associated with a recessive disorder in a given patient. Such variants have been proposed to contribute to digenicity/oligogenicity or "triallelism" or to act as genetic modifiers.MethodsUsing the recessive ciliopathy Joubert syndrome (JBTS) as a model, we investigated these possibilities systematically, relying on NGS of known JBTS genes in a large JBTS and two control cohorts.Results65% of affected individuals had a recessive genetic cause, while 4.9% were candidates for di-/oligogenicity, harboring heterozygous RDVs in two or more genes, compared with 4.2-8% in controls (P = 0.66-0.21). Based on Exome Aggregation Consortium (ExAC) allele frequencies, the probability of cumulating RDVs in any two JBTS genes is 9.3%. We found no support for triallelism, as no unaffected siblings carried the same biallelic RDVs as their affected relative. Sixty percent of individuals sharing identical causal RDVs displayed phenotypic discordance. Although 38% of affected individuals harbored RDVs in addition to the causal mutations, their presence did not correlate with phenotypic severity.ConclusionOur data offer little support for triallelism or digenicity/oligogenicity as clinically relevant inheritance modes in JBTS. While phenotypic discordance supports the existence of genetic modifiers, identifying clinically relevant modifiers remains challenging.
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Affiliation(s)
- Ian G. Phelps
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Megan E. Grout
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Hannah M. Tully
- Department of Neurology, University of Washington, Seattle, Washington
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington
| | - Dan Doherty
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, Washington
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Switzerland
- Institute of Molecular Life Sciences, University of Zurich, Switzerland
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40
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Bernabé-Rubio M, Alonso MA. Routes and machinery of primary cilium biogenesis. Cell Mol Life Sci 2017; 74:4077-4095. [PMID: 28624967 PMCID: PMC11107551 DOI: 10.1007/s00018-017-2570-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/01/2017] [Accepted: 06/13/2017] [Indexed: 02/06/2023]
Abstract
Primary cilia are solitary, microtubule-based protrusions of the cell surface that play fundamental roles as photosensors, mechanosensors and biochemical sensors. Primary cilia dysfunction results in a long list of developmental and degenerative disorders that combine to give rise to a large spectrum of human diseases affecting almost any major body organ. Depending on the cell type, primary ciliogenesis is initiated intracellularly, as in fibroblasts, or at the cell surface, as in renal polarized epithelial cells. In this review, we have focused on the routes of primary ciliogenesis placing particular emphasis on the recently described pathway in renal polarized epithelial cells by which the midbody remnant resulting from a previous cell division event enables the centrosome for initiation of primary cilium assembly. The protein machinery implicated in primary cilium formation in epithelial cells, including the machinery best known for its involvement in establishing cell polarity and polarized membrane trafficking, is also discussed.
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Affiliation(s)
- Miguel Bernabé-Rubio
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Nicolás Cabrera 1, Cantoblanco, 28049, Madrid, Spain
| | - Miguel A Alonso
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Nicolás Cabrera 1, Cantoblanco, 28049, Madrid, Spain.
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41
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Prosseda PP, Luo N, Wang B, Alvarado JA, Hu Y, Sun Y. Loss of OCRL increases ciliary PI(4,5)P 2 in Lowe oculocerebrorenal syndrome. J Cell Sci 2017; 130:3447-3454. [PMID: 28871046 DOI: 10.1242/jcs.200857] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 08/29/2017] [Indexed: 12/24/2022] Open
Abstract
Lowe syndrome is a rare X-linked disorder characterized by bilateral congenital cataracts and glaucoma, mental retardation, and proximal renal tubular dysfunction. Mutations in OCRL, an inositol polyphosphate 5-phosphatase that dephosphorylates PI(4,5)P2, cause Lowe syndrome. Previously we showed that OCRL localizes to the primary cilium, which has a distinct membrane phospholipid composition, but disruption of phosphoinositides in the ciliary membrane is poorly understood. Here, we demonstrate that cilia from Lowe syndrome patient fibroblasts exhibit increased levels of PI(4,5)P2 and decreased levels of PI4P. In particular, subcellular distribution of PI(4,5)P2 build-up was observed at the transition zone. Accumulation of ciliary PI(4,5)P2 was pronounced in mouse embryonic fibroblasts (MEFs) derived from Lowe syndrome mouse model as well as in Ocrl-null MEFs, which was reversed by reintroduction of OCRL. Similarly, expression of wild-type OCRL reversed the elevated PI(4,5)P2 in Lowe patient cells. Accumulation of sonic hedgehog protein in response to hedgehog agonist was decreased in MEFs derived from a Lowe syndrome mouse model. Together, our findings show for the first time an abnormality in ciliary phosphoinositides of both human and mouse cell models of Lowe syndrome.
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Affiliation(s)
- Philipp P Prosseda
- Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA
| | - Na Luo
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Biao Wang
- Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA
| | - Jorge A Alvarado
- Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA
| | - Yang Hu
- Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA
| | - Yang Sun
- Stanford University, Department of Ophthalmology, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94304, USA .,Palo Alto Veterans Administration, Palo Alto, CA 94304, USA
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42
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Grammatikopoulos T, Thompson RJ. Reply to: "Doublecortin domain containing protein 2 (DCDC2) genetic variants in primary sclerosing cholangitis". J Hepatol 2017; 67:652-653. [PMID: 28461131 DOI: 10.1016/j.jhep.2017.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 04/22/2017] [Indexed: 12/04/2022]
Affiliation(s)
- Tassos Grammatikopoulos
- Paediatric Liver, GI & Nutrition Centre, King's College Hospital, London, UK; Institute of Liver Studies, Division of Transplantation Immunology and Mucosal Biology, King's College London, London, UK.
| | - Richard J Thompson
- Paediatric Liver, GI & Nutrition Centre, King's College Hospital, London, UK; Institute of Liver Studies, Division of Transplantation Immunology and Mucosal Biology, King's College London, London, UK
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43
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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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44
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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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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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46
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Conduit SE, Ramaswamy V, Remke M, Watkins DN, Wainwright BJ, Taylor MD, Mitchell CA, Dyson JM. A compartmentalized phosphoinositide signaling axis at cilia is regulated by INPP5E to maintain cilia and promote Sonic Hedgehog medulloblastoma. Oncogene 2017. [PMID: 28650469 DOI: 10.1038/onc.2017.208] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sonic Hedgehog (SHH) signaling at primary cilia drives the proliferation and progression of a subset of medulloblastomas, the most common malignant paediatric brain tumor. Severe side effects associated with conventional treatments and resistance to targeted therapies has led to the need for new strategies. SHH signaling is dependent on primary cilia for signal transduction suggesting the potential for cilia destabilizing mechanisms as a therapeutic target. INPP5E is an inositol polyphosphate 5-phosphatase that hydrolyses PtdIns(4,5)P2 and more potently, the phosphoinositide (PI) 3-kinase product PtdIns(3,4,5)P3. INPP5E promotes SHH signaling during embryonic development via PtdIns(4,5)P2 hydrolysis at cilia, that in turn regulates the cilia recruitment of the SHH suppressor GPR161. However, the role INPP5E plays in cancer is unknown and the contribution of PI3-kinase signaling to cilia function is little characterized. Here, we reveal INPP5E promotes SHH signaling in SHH medulloblastoma by negatively regulating a cilia-compartmentalized PI3-kinase signaling axis that maintains primary cilia on tumor cells. Conditional deletion of Inpp5e in a murine model of constitutively active Smoothened-driven medulloblastoma slowed tumor progression, suppressed cell proliferation, reduced SHH signaling and promoted tumor cell cilia loss. PtdIns(3,4,5)P3, its effector pAKT and the target pGSK3β, which when non-phosphorylated promotes cilia assembly/stability, localized to tumor cell cilia. The number of PtdIns(3,4,5)P3/pAKT/pGSK3β-positive cilia was increased in cultured Inpp5e-null tumor cells relative to controls. PI3-kinase inhibition or expression of wild-type, but not catalytically inactive HA-INPP5E partially rescued cilia loss in Inpp5e-null tumor cells in vitro. INPP5E mRNA and copy number were reduced in human SHH medulloblastoma compared to other molecular subtypes and consistent with the murine model, reduced INPP5E was associated with improved overall survival. Therefore our study identifies a compartmentalized PtdIns(3,4,5)P3/AKT/GSK3β signaling axis at cilia in SHH-dependent medulloblastoma that is regulated by INPP5E to maintain tumor cell cilia, promote SHH signaling and thereby medulloblastoma progression.
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Affiliation(s)
- S E Conduit
- Department of Biochemistry and Molecular Biology, Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - V Ramaswamy
- Division of Haematology/Oncology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - M Remke
- The Arthur and Sonia Labatt Brain Tumor Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - D N Watkins
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia.,St. Vincent's Clinical School, Faculty of Medicine, UNSW, Darlinghurst, New South Wales, Australia.,Department of Thoracic Medicine, St Vincent's Hospital, Darlinghurst, New South Wales, Australia
| | - B J Wainwright
- Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - M D Taylor
- The Arthur and Sonia Labatt Brain Tumor Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - C A Mitchell
- Department of Biochemistry and Molecular Biology, Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - J M Dyson
- Department of Biochemistry and Molecular Biology, Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Lessieur EM, Fogerty J, Gaivin RJ, Song P, Perkins BD. The Ciliopathy Gene ahi1 Is Required for Zebrafish Cone Photoreceptor Outer Segment Morphogenesis and Survival. Invest Ophthalmol Vis Sci 2017; 58:448-460. [PMID: 28118669 PMCID: PMC5270624 DOI: 10.1167/iovs.16-20326] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose Joubert syndrome (JBTS) is an autosomal recessive ciliopathy with considerable phenotypic variability. In addition to central nervous system abnormalities, a subset of JBTS patients exhibit retinal dystrophy and/or kidney disease. Mutations in the AHI1 gene are causative for approximately 10% of all JBTS cases. The purpose of this study was to generate ahi1 mutant alleles in zebrafish and to characterize the retinal phenotypes. Methods Zebrafish ahi1 mutants were generated using transcription activator-like effector nucleases (TALENs). Expression analysis was performed by whole-mount in situ hybridization. Anatomic and molecular characterization of photoreceptors was investigated by histology, electron microscopy, and immunohistochemistry. The optokinetic response (OKR) behavior assay was used to assess visual function. Kidney cilia were evaluated by whole-mount immunostaining. Results The ahi1lri46 mutation in zebrafish resulted in shorter cone outer segments but did not affect visual behavior at 5 days after fertilization (dpf). No defects in rod morphology or rhodopsin localization were observed at 5 dpf. By 5 months of age, cone degeneration and rhodopsin mislocalization in rod photoreceptors was observed. The connecting cilium formed normally and Cc2d2a and Cep290 localized properly. Distal pronephric duct cilia were absent in mutant fish; however, only 9% of ahi1 mutants had kidney cysts by 5 dpf, suggesting that the pronephros remained largely functional. Conclusions The results indicate that Ahi1 is required for photoreceptor disc morphogenesis and outer segment maintenance in zebrafish.
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Affiliation(s)
- Emma M Lessieur
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
| | - Joseph Fogerty
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Robert J Gaivin
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Ping Song
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Brian D Perkins
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States 2Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
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Ganner A, Neumann-Haefelin E. Genetic kidney diseases: Caenorhabditis elegans as model system. Cell Tissue Res 2017; 369:105-118. [PMID: 28484847 DOI: 10.1007/s00441-017-2622-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/31/2017] [Indexed: 12/18/2022]
Abstract
Despite its apparent simplicity, the nematode Caenorhabditis elegans has a high rating as a model in molecular and developmental biology and biomedical research. C. elegans has no excretory system comparable with the mammalian kidney but many of the genes and molecular pathways involved in human kidney diseases are conserved in C. elegans. The plethora of genetic, molecular and imaging tools available in C. elegans has enabled major discoveries in renal research and advanced our understanding of the pathogenesis of genetic kidney diseases. In particular, studies in C. elegans have pioneered the fundamental role of cilia for cystic kidney diseases. In addition, proteins of the glomerular filtration barrier and podocytes are critical for cell recognition, assembly of functional neuronal circuits, mechanosensation and signal transduction in C. elegans. C. elegans has also proved tremendously valuable for aging research and the Von Hippel-Lindau tumor suppressor gene has been shown to modulate lifespan in the nematode. Further, studies of the excretory canal, membrane transport and ion channel function in C. elegans have provided insights into mechanisms of tubulogenesis and cellular homeostasis. This review recounts the way that C. elegans can be used to investigate various aspects of genetic and molecular nephrology. This model system opens up an exciting and new area of study of renal development and diseases.
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Affiliation(s)
- Athina Ganner
- Department of Nephrology, Medical Center, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
| | - Elke Neumann-Haefelin
- Department of Nephrology, Medical Center, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
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McInerney-Leo AM, Wheeler L, Marshall MS, Anderson LK, Zankl A, Brown MA, Leo PJ, Wicking C, Duncan EL. Homozygous variant in C21orf2 in a case of Jeune syndrome with severe thoracic involvement: Extending the phenotypic spectrum. Am J Med Genet A 2017; 173:1698-1704. [PMID: 28422394 DOI: 10.1002/ajmg.a.38215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 02/01/2017] [Indexed: 01/08/2023]
Abstract
We previously reported exome sequencing in a short-rib thoracic dystrophy (SRTD) cohort, in whom recessive mutations were identified in SRTD-associated genes in 10 of 11 cases. A heterozygous stop mutation in the known SRTD gene WDR60 was identified in the remaining case; no novel candidate gene/s were suggested by homozygous/compound heterozygous analysis. This case was thus considered unsolved. Re-analysis following an analysis pipeline update identified a homozygous mutation in C21orf2 (c.218G > C; p.Arg73Pro). This homozygous variant was previously removed at the quality control stage by the default GATK parameter "in-breeding co-efficient." C21orf2 was recently associated with both Jeune asphyxiating thoracic dystrophy (JATD) and axial spondylometaphyseal dysplasia (axial SMD); this particular mutation was reported in homozygous and compound heterozygous state in both conditions. Our case has phenotypic features of both JATD and axial SMD; and the extent of thoracic involvement appears more severe than in other C21orf2-positive cases. Identification of a homozygous C21orf2 mutation in this case emphasizes the value of exome sequencing for simultaneously screening known genes and identifying novel genes. Additionally, it highlights the importance of re-interrogating data both as novel gene associations are identified and as analysis pipelines are refined. Finally, the severity of thoracic restriction in this case adds to the phenotypic spectrum attributable to C21orf2 mutations.
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Affiliation(s)
- Aideen M McInerney-Leo
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia.,The University of Queensland Diamantina Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Lawrie Wheeler
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia
| | - Mhairi S Marshall
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia
| | - Lisa K Anderson
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia
| | - Andreas Zankl
- Discipline of Genetic Medicine, The University of Sydney, Sydney, Australia.,Academic Department of Medical Genetics, Sydney Children's Hospital Network (Westmead), Sydney, Australia
| | - Matthew A Brown
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia
| | - Paul J Leo
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia
| | - Carol Wicking
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Emma L Duncan
- Translational Genomics Group, Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology (QUT) at the Translational Research Institute, Brisbane, Queensland, Australia.,Department of Endocrinology, James Mayne Building, Royal Brisbane and Women's Hospital, Queensland, Australia.,School of Medicine, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia.,University of Queensland Diamantina Institute, University of Queensland, Brisbane, Queensland, Australia
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50
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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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