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Wensel TG, Zhang Z, Anastassov IA, Gilliam JC, He F, Schmid MF, Robichaux MA. Structural and molecular bases of rod photoreceptor morphogenesis and disease. Prog Retin Eye Res 2016; 55:32-51. [PMID: 27352937 PMCID: PMC5112133 DOI: 10.1016/j.preteyeres.2016.06.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 06/14/2016] [Accepted: 06/20/2016] [Indexed: 12/15/2022]
Abstract
The rod cell has an extraordinarily specialized structure that allows it to carry out its unique function of detecting individual photons of light. Both the structural features of the rod and the metabolic processes required for highly amplified light detection seem to have rendered the rod especially sensitive to structural and metabolic defects, so that a large number of gene defects are primarily associated with rod cell death and give rise to blinding retinal dystrophies. The structures of the rod, especially those of the sensory cilium known as the outer segment, have been the subject of structural, biochemical, and genetic analysis for many years, but the molecular bases for rod morphogenesis and for cell death in rod dystrophies are still poorly understood. Recent developments in imaging technology, such as cryo-electron tomography and super-resolution fluorescence microscopy, in gene sequencing technology, and in gene editing technology are rapidly leading to new breakthroughs in our understanding of these questions. A summary is presented of our current understanding of selected aspects of these questions, highlighting areas of uncertainty and contention as well as recent discoveries that provide new insights. Examples of structural data from emerging imaging technologies are presented.
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Affiliation(s)
- Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Zhixian Zhang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ivan A Anastassov
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jared C Gilliam
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael F Schmid
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael A Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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52
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May-Simera HL, Gumerson JD, Gao C, Campos M, Cologna SM, Beyer T, Boldt K, Kaya KD, Patel N, Kretschmer F, Kelley MW, Petralia RS, Davey MG, Li T. Loss of MACF1 Abolishes Ciliogenesis and Disrupts Apicobasal Polarity Establishment in the Retina. Cell Rep 2016; 17:1399-1413. [PMID: 27783952 PMCID: PMC5123820 DOI: 10.1016/j.celrep.2016.09.089] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 09/10/2016] [Accepted: 09/27/2016] [Indexed: 12/26/2022] Open
Abstract
Microtubule actin crosslinking factor 1 (MACF1) plays a role in the coordination of microtubules and actin in multiple cellular processes. Here, we show that MACF1 is also critical for ciliogenesis in multiple cell types. Ablation of Macf1 in the developing retina abolishes ciliogenesis, and basal bodies fail to dock to ciliary vesicles or migrate apically. Photoreceptor polarity is randomized, while inner retinal cells laminate correctly, suggesting that photoreceptor maturation is guided by polarity cues provided by cilia. Deletion of MACF1 in adult photoreceptors causes reversal of basal body docking and loss of outer segments, reflecting a continuous requirement for MACF1 function. MACF1 also interacts with the ciliary proteins MKKS and TALPID3. We propose that a disruption of trafficking across microtubles to actin filaments underlies the ciliogenesis defect in cells lacking MACF1 and that MKKS and TALPID3 are involved in the coordination of microtubule and actin interactions.
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Affiliation(s)
| | | | - Chun Gao
- National Eye Institute, Bethesda, MD 20892, USA
| | | | - Stephanie M Cologna
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Tina Beyer
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Karsten Boldt
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | | | - Nisha Patel
- National Eye Institute, Bethesda, MD 20892, USA
| | | | - Matthew W Kelley
- National Institute on Deafness and Other Communication Disorders, Bethesda, MD 20892, USA
| | - Ronald S Petralia
- National Institute on Deafness and Other Communication Disorders, Bethesda, MD 20892, USA
| | - Megan G Davey
- The Roslin Institute, University of Edinburgh, Roslin, Midlothian EH25 9RG, UK
| | - Tiansen Li
- National Eye Institute, Bethesda, MD 20892, USA.
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53
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Rhee S, Kirschen GW, Gu Y, Ge S. Depletion of primary cilia from mature dentate granule cells impairs hippocampus-dependent contextual memory. Sci Rep 2016; 6:34370. [PMID: 27678193 PMCID: PMC5039642 DOI: 10.1038/srep34370] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 09/13/2016] [Indexed: 11/17/2022] Open
Abstract
The primary cilium, a sensory organelle, regulates cell proliferation and neuronal development of dentate granule cells in the hippocampus. However, its role in the function of mature dentate granule cells remains unknown. Here we specifically depleted and disrupted ciliary proteins IFT20 and Kif3A (respectively) in mature dentate granule cells and investigated hippocampus-dependent contextual memory and long-term plasticity at mossy fiber synapses. We found that depletion of IFT20 in these cells significantly impaired context-dependent fear-related memory. Furthermore, we tested synaptic plasticity of mossy fiber synapses in area CA3 and found increased long-term potentiation upon depletion of IFT20 or disruption of Kif3A. Our findings suggest a role of primary cilia in the memory function of mature dentate granule cells, which may result from abnormal mossy fiber synaptic plasticity. A direct link between the primary cilia of mature dentate granule cells and behavior will require further investigation using independent approaches to manipulate primary cilia.
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Affiliation(s)
- Soyoung Rhee
- Program in Molecular and Cellular Pharmacology, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Gregory W. Kirschen
- Program in Molecular and Cellular Pharmacology, State University of New York at Stony Brook, Stony Brook, New York, USA
- Medical Scientist Training Program, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Yan Gu
- Center of Stem Cell and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, China
- Department of Neurobiology and Behavior, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Shaoyu Ge
- Department of Neurobiology and Behavior, State University of New York at Stony Brook, Stony Brook, New York, USA
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54
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Siller SS, Burke MC, Li FQ, Takemaru KI. Chibby functions to preserve normal ciliary morphology through the regulation of intraflagellar transport in airway ciliated cells. Cell Cycle 2016; 14:3163-72. [PMID: 26266958 DOI: 10.1080/15384101.2015.1080396] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Airway cilia provide the coordinated motive force for mucociliary transport, which prevents the accumulation of mucus, debris, pollutants, and bacteria in our respiratory tracts. As airway cilia are constantly exposed to the environment and, hence, are an integral component of the pathogenesis of several congenital and chronic pulmonary disorders, it is necessary to understand the molecular mechanisms that control ciliated cell differentiation and ciliogenesis. We have previously reported that loss of the basal body protein Chibby (Cby) results in chronic upper airway infection in mice due to a significant reduction in the number of airway cilia. In the present work, we demonstrate that Cby is required for normal ciliary structure and proper distribution of proteins involved in the bidirectional intraflagellar transport (IFT) system, which consists of 2 distinct sub-complexes, IFT-A and IFT-B, and is essential for ciliary biogenesis and maintenance. In fully differentiated ciliated cells, abnormal paddle-like cilia with dilated ciliary tips are observed in Cby-/- airways and primary cultures of mouse tracheal epithelial cells (MTECs). In addition, IFT88, an IFT-B sub-complex protein, robustly accumulates within the dilated tips of both multicilia in Cby-/- MTECs and primary cilia in Cby-/- mouse embryonic fibroblasts (MEFs). Furthermore, we show that only IFT-B components, including IFT20 and IFT57, but not IFT-A and Bardet-Biedl syndrome (BBS) proteins, amass with IFT88 in these distended tips in Cby-/- ciliated cells. Taken together, our findings suggest that Cby plays a role in the proper distribution of IFT particles to preserve normal ciliary morphology in airway ciliated cells.
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Affiliation(s)
- Saul S Siller
- a Medical Scientist Training Program; Stony Brook University; Stony Brook , NY USA.,b Graduate Program in Molecular and Cellular Pharmacology; Stony Brook University; Stony Brook , NY USA.,c Department of Pharmacological Sciences ; Stony Brook University; Stony Brook , NY USA
| | - Michael C Burke
- a Medical Scientist Training Program; Stony Brook University; Stony Brook , NY USA.,d Graduate Program in Genetics; Stony Brook University; Stony Brook , NY USA
| | - Feng-Qian Li
- b Graduate Program in Molecular and Cellular Pharmacology; Stony Brook University; Stony Brook , NY USA.,c Department of Pharmacological Sciences ; Stony Brook University; Stony Brook , NY USA
| | - Ken-Ichi Takemaru
- a Medical Scientist Training Program; Stony Brook University; Stony Brook , NY USA.,b Graduate Program in Molecular and Cellular Pharmacology; Stony Brook University; Stony Brook , NY USA.,c Department of Pharmacological Sciences ; Stony Brook University; Stony Brook , NY USA.,d Graduate Program in Genetics; Stony Brook University; Stony Brook , NY USA
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55
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Boldt K, van Reeuwijk J, Lu Q, Koutroumpas K, Nguyen TMT, Texier Y, van Beersum SEC, Horn N, Willer JR, Mans DA, Dougherty G, Lamers IJC, Coene KLM, Arts HH, Betts MJ, Beyer T, Bolat E, Gloeckner CJ, Haidari K, Hetterschijt L, Iaconis D, Jenkins D, Klose F, Knapp B, Latour B, Letteboer SJF, Marcelis CL, Mitic D, Morleo M, Oud MM, Riemersma M, Rix S, Terhal PA, Toedt G, van Dam TJP, de Vrieze E, Wissinger Y, Wu KM, Apic G, Beales PL, Blacque OE, Gibson TJ, Huynen MA, Katsanis N, Kremer H, Omran H, van Wijk E, Wolfrum U, Kepes F, Davis EE, Franco B, Giles RH, Ueffing M, Russell RB, Roepman R. An organelle-specific protein landscape identifies novel diseases and molecular mechanisms. Nat Commun 2016; 7:11491. [PMID: 27173435 PMCID: PMC4869170 DOI: 10.1038/ncomms11491] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/01/2016] [Indexed: 01/12/2023] Open
Abstract
Cellular organelles provide opportunities to relate biological mechanisms to disease. Here we use affinity proteomics, genetics and cell biology to interrogate cilia: poorly understood organelles, where defects cause genetic diseases. Two hundred and seventeen tagged human ciliary proteins create a final landscape of 1,319 proteins, 4,905 interactions and 52 complexes. Reverse tagging, repetition of purifications and statistical analyses, produce a high-resolution network that reveals organelle-specific interactions and complexes not apparent in larger studies, and links vesicle transport, the cytoskeleton, signalling and ubiquitination to ciliary signalling and proteostasis. We observe sub-complexes in exocyst and intraflagellar transport complexes, which we validate biochemically, and by probing structurally predicted, disruptive, genetic variants from ciliary disease patients. The landscape suggests other genetic diseases could be ciliary including 3M syndrome. We show that 3M genes are involved in ciliogenesis, and that patient fibroblasts lack cilia. Overall, this organelle-specific targeting strategy shows considerable promise for Systems Medicine. Mutations in proteins that localize to primary cilia cause devastating diseases, yet the primary cilium is a poorly understood organelle. Here the authors use interaction proteomics to identify a network of human ciliary proteins that provides new insights into several biological processes and diseases.
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Affiliation(s)
- Karsten Boldt
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany
| | - Jeroen van Reeuwijk
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Qianhao Lu
- Biochemie Zentrum Heidelberg (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.,Cell Networks, Bioquant, Ruprecht-Karl University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Konstantinos Koutroumpas
- Institute of Systems and Synthetic Biology, Genopole, CNRS, Université d'Evry, 91030 Evry, France
| | - Thanh-Minh T Nguyen
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Yves Texier
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany.,Department of Molecular Epigenetics, Helmholtz Center Munich, Center for Integrated Protein Science, 81377 Munich, Germany
| | - Sylvia E C van Beersum
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Nicola Horn
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany
| | - Jason R Willer
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27701, USA
| | - Dorus A Mans
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Gerard Dougherty
- Department of General Pediatrics, University Children's Hospital Muenster, 48149 Muenster, Germany
| | - Ideke J C Lamers
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Karlien L M Coene
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Heleen H Arts
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Matthew J Betts
- Biochemie Zentrum Heidelberg (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.,Cell Networks, Bioquant, Ruprecht-Karl University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Tina Beyer
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany
| | - Emine Bolat
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Christian Johannes Gloeckner
- German Center for Neurodegenerative Diseases (DZNE) within the Helmholz Association, Otfried-Müller Strasse 23, 72076 Tuebingen, Germany
| | - Khatera Haidari
- Department of Nephrology and Hypertension, Regenerative Medicine Center, University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Lisette Hetterschijt
- Department of Otorhinolaryngology and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Daniela Iaconis
- Telethon Institute of Genetics and Medicine, TIGEM 80078, Italy
| | - Dagan Jenkins
- Molecular Medicine Unit and Birth Defects Research Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Franziska Klose
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany
| | - Barbara Knapp
- Cell and Matrix Biology, Inst. of Zoology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
| | - Brooke Latour
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Stef J F Letteboer
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Carlo L Marcelis
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Dragana Mitic
- Cambridge Cell Networks Ltd, St John's Innovation Centre, Cowley Road, Cambridge, CB4 0WS, UK
| | - Manuela Morleo
- Telethon Institute of Genetics and Medicine, TIGEM 80078, Italy.,Department of Translational Medicine Federico II University, 80131 Naples, Italy
| | - Machteld M Oud
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Moniek Riemersma
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Susan Rix
- Molecular Medicine Unit and Birth Defects Research Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Paulien A Terhal
- Department of Genetics, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Grischa Toedt
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Teunis J P van Dam
- Centre for Molecular and Biomolecular Informatics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, The Netherlands
| | - Erik de Vrieze
- Department of Otorhinolaryngology and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Yasmin Wissinger
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany
| | - Ka Man Wu
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Gordana Apic
- Cambridge Cell Networks Ltd, St John's Innovation Centre, Cowley Road, Cambridge, CB4 0WS, UK
| | - Philip L Beales
- Molecular Medicine Unit and Birth Defects Research Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Oliver E Blacque
- School of Biomolecular &Biomed Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, The Netherlands
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27701, USA
| | - Hannie Kremer
- Department of Otorhinolaryngology and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Heymut Omran
- Department of General Pediatrics, University Children's Hospital Muenster, 48149 Muenster, Germany
| | - Erwin van Wijk
- Department of Otorhinolaryngology and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
| | - Uwe Wolfrum
- Cell and Matrix Biology, Inst. of Zoology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
| | - François Kepes
- Institute of Systems and Synthetic Biology, Genopole, CNRS, Université d'Evry, 91030 Evry, France
| | - Erica E Davis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27701, USA
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine, TIGEM 80078, Italy.,Department of Translational Medicine Federico II University, 80131 Naples, Italy
| | - Rachel H Giles
- Department of Nephrology and Hypertension, Regenerative Medicine Center, University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Marius Ueffing
- Medical Proteome Center, Institute for Ophthalmic Research, University of Tuebingen, 72074 Tuebingen, Germany
| | - Robert B Russell
- Biochemie Zentrum Heidelberg (BZH), University of Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.,Cell Networks, Bioquant, Ruprecht-Karl University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Ronald Roepman
- Department of Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands
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56
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Unexpected Roles for Ciliary Kinesins and Intraflagellar Transport Proteins. Genetics 2016; 203:771-85. [PMID: 27038111 DOI: 10.1534/genetics.115.180943] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 03/22/2016] [Indexed: 11/18/2022] Open
Abstract
Transport of proteins in the ciliary shaft is driven by microtubule-dependent motors, kinesins. Prior studies suggested that the heterotrimeric ciliary kinesin may be dispensable for certain aspects of transport in specialized cilia of vertebrate photoreceptor cells. To test this possibility further, we analyzed the mutant phenotype of the zebrafish kif3a gene, which encodes the common motor subunit of heterotrimeric ciliary kinesins. Cilia are absent in all organs examined, leading to the conclusion that kif3a is indispensable for ciliogenesis in all cells, including photoreceptors. Unexpectedly, kif3a function precedes ciliogenesis as ciliary basal bodies are mispositioned in mutant photoreceptors. This phenotype is much less pronounced in intraflagellar transport (IFT) mutants and reveals that kif3a has a much broader role than previously assumed. Despite the severity of their basal body phenotype, kif3a mutant photoreceptors survive longer compared to those in IFT mutants, which display much weaker basal body mispositioning. This effect is absent in kif3a;IFT double mutants, indicating that IFT proteins have ciliary transport-independent roles, which add to the severity of their photoreceptor phenotype. kif3a is dispensable for basal body docking in otic vesicle sensory epithelia and, surprisingly, short cilia form in mechanosensory cristae even in the absence of kif3a In contrast to Kif3a, the functions of the Kif3c-related protein, encoded by the kif3c-like (kif3cl) gene, and the homodimeric ciliary kinesin, kif17, are dispensable for photoreceptor morphogenesis. These studies demonstrate unexpected new roles for both ciliary heterotrimeric kinesins and IFT particle genes and clarify the function of kif17, the homodimeric ciliary kinesin gene.
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57
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May-Simera H. Evaluation of Planar-Cell-Polarity Phenotypes in Ciliopathy Mouse Mutant Cochlea. J Vis Exp 2016:53559. [PMID: 26966880 DOI: 10.3791/53559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In recent years, primary cilia have emerged as key regulators in development and disease by influencing numerous signaling pathways. One of the earliest signaling pathways shown to be associated with ciliary function was the non-canonical Wnt signaling pathway, also referred to as planar cell polarity (PCP) signaling. One of the best places in which to study the effects of planar cell polarity (PCP) signaling during vertebrate development is the mammalian cochlea. PCP signaling disruption in the mouse cochlea disrupts cochlear outgrowth, cellular patterning and hair cell orientation, all of which are affected by cilia dysfunction. The goal of this protocol is to describe the analysis of PCP signaling in the developing mammalian cochlea via phenotypic analysis, immunohistochemistry and scanning electron microscopy. Defects in convergence and extension are manifested as a shortening of the cochlear duct and/or changes in cellular patterning, which can be quantified following dissection from developing mouse mutants. Changes in stereociliary bundle orientation and kinocilia length or positioning can be observed and quantitated using either immunofluorescence or scanning electron microscopy (SEM). A deeper insight into the role of ciliary proteins in cellular signaling pathways and other biological phenomena is crucial for our understanding of cellular and developmental biology, as well as for the development of targeted treatment strategies.
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Affiliation(s)
- Helen May-Simera
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-Universität Mainz;
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58
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Balmer S, Dussert A, Collu GM, Benitez E, Iomini C, Mlodzik M. Components of Intraflagellar Transport Complex A Function Independently of the Cilium to Regulate Canonical Wnt Signaling in Drosophila. Dev Cell 2015; 34:705-18. [PMID: 26364750 PMCID: PMC4610147 DOI: 10.1016/j.devcel.2015.07.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/17/2015] [Accepted: 07/29/2015] [Indexed: 12/28/2022]
Abstract
The development of multicellular organisms requires the precisely coordinated regulation of an evolutionarily conserved group of signaling pathways. Temporal and spatial control of these signaling cascades is achieved through networks of regulatory proteins, segregation of pathway components in specific subcellular compartments, or both. In vertebrates, dysregulation of primary cilia function has been strongly linked to developmental signaling defects, yet it remains unclear whether cilia sequester pathway components to regulate their activation or cilia-associated proteins directly modulate developmental signaling events. To elucidate this question, we conducted an RNAi-based screen in Drosophila non-ciliated cells to test for cilium-independent loss-of-function phenotypes of ciliary proteins in developmental signaling pathways. Our results show no effect on Hedgehog signaling. In contrast, our screen identified several cilia-associated proteins as functioning in canonical Wnt signaling. Further characterization of specific components of Intraflagellar Transport complex A uncovered a cilia-independent function in potentiating Wnt signals by promoting β-catenin/Armadillo activity.
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Affiliation(s)
- Sophie Balmer
- Department of Developmental & Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Aurore Dussert
- Department of Developmental & Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Giovanna M Collu
- Department of Developmental & Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Elvira Benitez
- Department of Developmental & Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Carlo Iomini
- Department of Developmental & Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Marek Mlodzik
- Department of Developmental & Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA; Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA.
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Stephen LA, Tawamie H, Davis GM, Tebbe L, Nürnberg P, Nürnberg G, Thiele H, Thoenes M, Boltshauser E, Uebe S, Rompel O, Reis A, Ekici AB, McTeir L, Fraser AM, Hall EA, Mill P, Daudet N, Cross C, Wolfrum U, Jamra RA, Davey MG, Bolz HJ. TALPID3 controls centrosome and cell polarity and the human ortholog KIAA0586 is mutated in Joubert syndrome (JBTS23). eLife 2015; 4. [PMID: 26386247 PMCID: PMC4641851 DOI: 10.7554/elife.08077] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/19/2015] [Indexed: 12/30/2022] Open
Abstract
Joubert syndrome (JBTS) is a severe recessive neurodevelopmental ciliopathy which can affect several organ systems. Mutations in known JBTS genes account for approximately half of the cases. By homozygosity mapping and whole-exome sequencing, we identified a novel locus, JBTS23, with a homozygous splice site mutation in KIAA0586 (alias TALPID3), a known lethal ciliopathy locus in model organisms. Truncating KIAA0586 mutations were identified in two additional patients with JBTS. One mutation, c.428delG (p.Arg143Lysfs*4), is unexpectedly common in the general population and may be a major contributor to JBTS. We demonstrate KIAA0586 protein localization at the basal body in human and mouse photoreceptors, as is common for JBTS proteins, and also in pericentriolar locations. We show that loss of TALPID3 (KIAA0586) function in animal models causes abnormal tissue polarity, centrosome length and orientation, and centriolar satellites. We propose that JBTS and other ciliopathies may in part result from cell polarity defects. DOI:http://dx.doi.org/10.7554/eLife.08077.001 Joubert syndrome is a rare and severe neurodevelopmental disease in which two parts of the brain called the cerebellar vermis and brainstem do not develop properly. The disease is caused by defects in the formation of small projections from the surface of cells, called cilia, which are essential for signalling processes inside cells. Mutations in at least 25 genes are known to cause Joubert syndrome, and all encode proteins that create or maintain cilia. However, these mutations account for only half of the cases that have been studied, which indicates that mutations in other genes may also cause Joubert syndrome. Here, Stephen et al. used genetic techniques called ‘homozygosity mapping’ and ‘whole-exome sequencing’ to search for other mutations that might cause the disease. They found that mutations in a gene encoding a protein called KIAA0586 also cause Joubert syndrome in humans. One of these mutations (c.428delG) is unexpectedly common in the healthy human population. It might be a major contributor to Joubert syndrome, and the manifestation of Joubert syndrome in individuals with this mutation might depend on the presence and nature of other mutations in KIAA0586 and in other genes. The TALPID3 protein in chickens and other ‘model’ animals is the equivalent of human KIAA0586. A loss of TALPID3 protein in animals has been shown to stop cilia from forming. This protein is found in a structure called the basal body, which is part of a larger structure called the centrosome that anchors cilia to the cell. Here, Stephen et al. show that this is also true in mouse and human eye cells. Further experiments using chicken embryos show that a loss of the TALPID3 protein alters the location of centrosomes inside cells. TALPID3 is also required for cells and organs to develop the correct polarity, that is, directional differences in their structure and shape. The centrosomes of chicken brain cells that lacked TALPID3 were poorly positioned at the cell surface and abnormally long, which is likely responsible for the cilia failing to form. Stephen et al.'s findings suggest that KIAA0586 is also important for human development through its ability to control the centrosome. Defects in TALPID3 have a more severe effect on animal models than many of the identified KIAA0586 mutations have on humans. Therefore, the next step in this research is to find a more suitable animal in which to study the role of this protein, which may inform efforts to develop treatments for Joubert syndrome. DOI:http://dx.doi.org/10.7554/eLife.08077.002
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Affiliation(s)
- Louise A Stephen
- Division of Developmental Biology, The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Hasan Tawamie
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Gemma M Davis
- Division of Developmental Biology, The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Lars Tebbe
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence, University of Cologne, Cologne, Germany
| | - Gudrun Nürnberg
- Cologne Center for Genomics, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Michaela Thoenes
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Eugen Boltshauser
- Department of Paediatric Neurology, University Children's Hospital Zurich, Zurich, Switzerland
| | - Steffen Uebe
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Oliver Rompel
- Institute of Radiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Arif B Ekici
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Lynn McTeir
- Division of Developmental Biology, The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Amy M Fraser
- Division of Developmental Biology, The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Emma A Hall
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Pleasantine Mill
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Nicolas Daudet
- UCL Ear Institute, University College London, London, United Kingdom
| | - Courtney Cross
- School of Osteopathic Medicine, A.T. Still University, Mesa, United States
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Centogene, Rostock, Germany.,Institute of Human Genetics, Leipzig University, Leipzig, Germany
| | - Megan G Davey
- Division of Developmental Biology, The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Hanno J Bolz
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany.,Bioscientia Center for Human Genetics, Bioscientia International Business, Ingelheim am Rhein, Germany
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60
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Falk N, Lösl M, Schröder N, Gießl A. Specialized Cilia in Mammalian Sensory Systems. Cells 2015; 4:500-19. [PMID: 26378583 PMCID: PMC4588048 DOI: 10.3390/cells4030500] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/04/2015] [Accepted: 09/09/2015] [Indexed: 02/01/2023] Open
Abstract
Cilia and flagella are highly conserved and important microtubule-based organelles that project from the surface of eukaryotic cells and act as antennae to sense extracellular signals. Moreover, cilia have emerged as key players in numerous physiological, developmental, and sensory processes such as hearing, olfaction, and photoreception. Genetic defects in ciliary proteins responsible for cilia formation, maintenance, or function underlie a wide array of human diseases like deafness, anosmia, and retinal degeneration in sensory systems. Impairment of more than one sensory organ results in numerous syndromic ciliary disorders like the autosomal recessive genetic diseases Bardet-Biedl and Usher syndrome. Here we describe the structure and distinct functional roles of cilia in sensory organs like the inner ear, the olfactory epithelium, and the retina of the mouse. The spectrum of ciliary function in fundamental cellular processes highlights the importance of elucidating ciliopathy-related proteins in order to find novel potential therapies.
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Affiliation(s)
- Nathalie Falk
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Marlene Lösl
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Nadja Schröder
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Andreas Gießl
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
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61
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Whole-exome sequencing reveals a novel frameshift mutation in the FAM161A gene causing autosomal recessive retinitis pigmentosa in the Indian population. J Hum Genet 2015; 60:625-30. [PMID: 26246154 DOI: 10.1038/jhg.2015.92] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/18/2015] [Accepted: 06/30/2015] [Indexed: 11/08/2022]
Abstract
Retinitis pigmentosa (RP) is a heterogenous group of inherited retinal degenerations caused by mutations in at least 50 genes. To identify genetic mutations underlying autosomal recessive RP (arRP), we performed whole-exome sequencing study on two consanguineous marriage Indian families (RP-252 and RP-182) and 100 sporadic RP patients. Here we reported novel mutation in FAM161A in RP-252 and RP-182 with two patients affected with RP in each family. The FAM161A gene was identified as the causative gene for RP28, an autosomal recessive form of RP. By whole-exome sequencing we identified several homozygous genomic regions, one of which included the recently identified FAM161A gene mutated in RP28-linked arRP. Sequencing analysis revealed the presence of a novel homozygous frameshift mutation p.R592FsX2 in both patients of family RP-252 and family RP-182. In 100 sporadic Indian RP patients, this novel homozygous frameshift mutation p.R592FsX2 was identified in one sporadic patient ARRP-S-I-46 by whole-exome sequencing and validated by Sanger sequencing. Meanwhile, this homozygous frameshift mutation was absent in 1000 ethnicity-matched control samples screened by direct Sanger sequencing. In conclusion, we identified a novel homozygous frameshift mutations of RP28-linked RP gene FAM161A in Indian population.
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62
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Guo J, Higginbotham H, Li J, Nichols J, Hirt J, Ghukasyan V, Anton ES. Developmental disruptions underlying brain abnormalities in ciliopathies. Nat Commun 2015. [PMID: 26206566 PMCID: PMC4515781 DOI: 10.1038/ncomms8857] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Primary cilia are essential conveyors of signals underlying major cell functions. Cerebral cortical progenitors and neurons have a primary cilium. The significance of cilia function for brain development and function is evident in the plethora of developmental brain disorders associated with human ciliopathies. Nevertheless, the role of primary cilia function in corticogenesis remains largely unknown. Here we delineate the functions of primary cilia in the construction of cerebral cortex and their relevance to ciliopathies, using an shRNA library targeting ciliopathy genes known to cause brain disorders, but whose roles in brain development are unclear. We used the library to query how ciliopathy genes affect distinct stages of mouse cortical development, in particular neural progenitor development, neuronal migration, neuronal differentiation and early neuronal connectivity. Our results define the developmental functions of ciliopathy genes and delineate disrupted developmental events that are integrally related to the emergence of brain abnormalities in ciliopathies. Primary cilia are essential conveyors of signals underlying major cellular functions but their role in brain development is not completely understood. Here the authors compiled a shRNA library targeting ciliopathy genes known to cause brain disorders, and used it to query how ciliopathy genes affect distinct stages of mouse cortical development.
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Affiliation(s)
- Jiami Guo
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Holden Higginbotham
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Jingjun Li
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Jackie Nichols
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Josua Hirt
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Vladimir Ghukasyan
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - E S Anton
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
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63
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Karam A, Tebbe L, Weber C, Messaddeq N, Morlé L, Kessler P, Wolfrum U, Trottier Y. A novel function of Huntingtin in the cilium and retinal ciliopathy in Huntington's disease mice. Neurobiol Dis 2015; 80:15-28. [PMID: 25989602 DOI: 10.1016/j.nbd.2015.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 05/08/2015] [Indexed: 10/23/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the toxic expansion of polyglutamine in the Huntingtin (HTT) protein. The pathomechanism is complex and not fully understood. Increasing evidence indicates that the loss of normal protein function also contributes to the pathogenesis, pointing out the importance of understanding the physiological roles of HTT. We provide evidence for a novel function of HTT in the cilium. HTT localizes in diverse types of cilia--including 9 + 0 non-motile sensory cilia of neurons and 9 + 2 motile multicilia of trachea and ependymal cells--which exert various functions during tissue development and homeostasis. In the photoreceptor cilium, HTT is present in all subciliary compartments from the base of the cilium and adjacent centriole to the tip of the axoneme. In HD mice, photoreceptor cilia are abnormally elongated, have hyperacetylated alpha-tubulin and show mislocalization of the intraflagellar transport proteins IFT57 and IFT88. As a consequence, intraflagellar transport function is perturbed and leads to aberrant accumulation of outer segment proteins in the photoreceptor cell bodies and disruption of outer segment integrity, all of which precede overt cell death. Strikingly, endogenous mouse HTT is strongly reduced in cilia and accumulates in photoreceptor cell bodies, suggesting that HTT loss function contributes to structural and functional defects of photoreceptor cilia in HD mouse. Our results indicate that cilia pathology participates in HD physiopathology and may represent a therapeutic target.
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Affiliation(s)
- Alice Karam
- Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Lars Tebbe
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
| | - Chantal Weber
- Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Nadia Messaddeq
- Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Laurette Morlé
- Centre de Génétique et de Physiologie Moléculaires et Cellulaires, CNRS UMR 5534, Université Claude Bernard Lyon 1, Villeurbanne, Lyon, 69622, France
| | - Pascal Kessler
- Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg University of Mainz, 55122 Mainz, Germany; Focus Program Translational Neurosciences (FTN), Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
| | - Yvon Trottier
- Institute of Genetics and Molecular and Cellular Biology, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France.
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64
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Stinchcombe JC, Griffiths GM. Communication, the centrosome and the immunological synapse. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0463. [PMID: 25047617 PMCID: PMC4113107 DOI: 10.1098/rstb.2013.0463] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Recent findings on the behaviour of the centrosome at the immunological synapse suggest a critical role for centrosome polarization in controlling the communication between immune cells required to generate an effective immune response. The features observed at the immunological synapse show parallels to centrosome (basal body) polarization seen in cilia and flagella, and the cellular communication that is now known to occur at all of these sites.
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Affiliation(s)
- Jane C Stinchcombe
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK
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65
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May-Simera HL, Petralia RS, Montcouquiol M, Wang YX, Szarama KB, Liu Y, Lin W, Deans MR, Pazour GJ, Kelley MW. Ciliary proteins Bbs8 and Ift20 promote planar cell polarity in the cochlea. Development 2015; 142:555-66. [PMID: 25605782 DOI: 10.1242/dev.113696] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Primary cilia have been implicated in the generation of planar cell polarity (PCP). However, variations in the severity of polarity defects in different cilia mutants, coupled with recent demonstrations of non-cilia-related actions of some cilia genes, make it difficult to determine the basis of these polarity defects. To address this issue, we evaluated PCP defects in cochlea from a selection of mice with mutations in cilia-related genes. Results indicated notable PCP defects, including mis-oriented hair cell stereociliary bundles, in Bbs8 and Ift20 single mutants that are more severe than in other cilia gene knockouts. In addition, deletion of either Bbs8 or Ift20 results in disruptions in asymmetric accumulation of the core PCP molecule Vangl2 in cochlear cells, suggesting a role for Bbs8 and/or Ift20, possibly upstream of core PCP asymmetry. Consistent with this, co-immunoprecipitation experiments indicate direct interactions of Bbs8 and Ift20 with Vangl2. We observed localization of Bbs and Ift proteins to filamentous actin as well as microtubules. This could implicate these molecules in selective trafficking of membrane proteins upstream of cytoskeletal reorganization, and identifies new roles for cilia-related proteins in cochlear PCP.
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Affiliation(s)
- Helen L May-Simera
- Section on Developmental Neuroscience, Laboratory of Cochlear Development, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ronald S Petralia
- Advanced Imaging Core, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mireille Montcouquiol
- Planar Polarity and Plasticity Group, Institut National de la Santé et de la Recherche Médicale U862, Neurocenter Magendie, 33077 Bordeaux, France
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Katherine B Szarama
- Section on Developmental Neuroscience, Laboratory of Cochlear Development, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Yun Liu
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Weichun Lin
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75235, USA
| | - Michael R Deans
- Division of Otolaryngology-Head and Neck Surgery and Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Matthew W Kelley
- Section on Developmental Neuroscience, Laboratory of Cochlear Development, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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66
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Chuang JZ, Hsu YC, Sung CH. Ultrastructural visualization of trans-ciliary rhodopsin cargoes in mammalian rods. Cilia 2015; 4:4. [PMID: 25664179 PMCID: PMC4320831 DOI: 10.1186/s13630-015-0013-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/15/2015] [Indexed: 11/28/2022] Open
Abstract
Background Cilia are vital to various cellular and sensory functions. The pathway by which ciliary membrane proteins translocate through the transition zone is not well understood. Direct morphological characterization of ciliary cargoes in transit remains lacking. In the vertebrate photoreceptor, rhodopsin is synthesized and transported from the inner segment to the disc membranes of the outer segment (OS), which is a modified cilium. To date, the membrane topology of the basal OS and the mechanisms by which rhodopsin is transported through the transition zone (i.e., connecting cilium) and by which nascent disc membranes are formed remain controversial. Results Using an antibody recognizing its cytoplasmic C-terminus, we localize rhodopsin on both the plasma membrane and lumen of the connecting cilium by immuno-electron microscopy (EM). We also use transmission EM to visualize the electron-dense enzymatic products derived from the rhodopsin-horseradish peroxidase (HRP) fusion in transfected rodent rods. In the connecting cilium, rhodopsin is not only expressed in the plasma membrane but also in the lumen on two types of membranous carriers, long smooth tubules and small, coated, filament-bound vesicles. Additionally, membrane-bound rhodopsin carriers are also found in close proximity to the nascent discs at the basal OS axoneme and in the distal inner segment. This topology-indicative HRP-rhodopsin reporter shows that the nascent basalmost discs and the mature discs have the same membrane topology, with no indication of evagination or invagination from the basal OS plasma membranes. Serial block face and focus ion beam scanning EM analyses both indicate that the transport carriers enter the connecting cilium lumen from either the basal body lumen or cytoplasmic space between the axonemal microtubules and the ciliary plasma membrane. Conclusions Our results suggest the existence of multiple ciliary gate entry pathways in rod photoreceptors. Rhodopsin is likely transported across the connecting cilium on the plasma membrane and through the lumens on two types of tubulovesicular carriers produced in the inner segment. Our findings agree with a previous model that rhodopsin carriers derived from the cell body may fuse directly onto nascent discs as they grow and mature. Electronic supplementary material The online version of this article (doi:10.1186/s13630-015-0013-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jen-Zen Chuang
- Department of Ophthalmology, Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY 10065 USA
| | - Ya-Chu Hsu
- Department of Ophthalmology, Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY 10065 USA
| | - Ching-Hwa Sung
- Department of Ophthalmology, Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY 10065 USA ; Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY 10067 USA ; The Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, 1300 York Avenue, LC313, New York, NY 10065 USA
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Ferraro S, Gomez-Montalvo AI, Olmos R, Ramirez M, Lamas M. Primary cilia in rat mature Müller glia: downregulation of IFT20 expression reduces sonic hedgehog-mediated proliferation and dedifferentiation potential of Müller glia primary cultures. Cell Mol Neurobiol 2014; 35:533-42. [PMID: 25504432 DOI: 10.1007/s10571-014-0149-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/08/2014] [Indexed: 11/26/2022]
Abstract
Primary cilia are specialized organelles that extend from the cell surface and concentrate signal transduction components. In the nervous system, primary cilia-associated signals, such as sonic hedgehog (Shh), regulate cell proliferation and neuronal fate. Primary cilia assembly and maintenance require a multi-subunit intraflagellar transport (IFT) protein complex. Defects in primary cilia and IFT proteins are associated to severe pathological phenotypes. In the retina, the study of primary cilia has been mainly restricted to the specialized photoreceptor outer segment. The presence and physiological role of primary cilia in other retinal cells have not been clearly elucidated. Müller cells are the main glia of the retina where they exert distinct functions to maintain homeostasis. In pathological conditions, Müller cells mount a unique regenerative response through the processes of dedifferentiation, proliferation, and differentiation into neuronal lineages. The involvement of IFT proteins or a primary cilium in these processes has not been explored. In this study, we used mature Müller glia primary cultures to reveal the presence of the primary cilia by immunoreactivity to acetylated α-tubulin and γ-tubulin, which localize to the axoneme and ciliar basal body, respectively. We demonstrate that si-RNA-mediated downregulation of IFT20 gene expression, a main component of the IFT machinery, blocks Shh-induced Müller cell proliferation. We present evidence that IFT20 ablation impairs the dedifferentiation capacity of Müller cells induced by Shh and by glutamate. Our demonstration that Müller glia expresses IFT20 and harbors primary cilia, and opens new venues of research on the role of primary cilia in the retina.
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Affiliation(s)
- Silene Ferraro
- Departamento de Farmacobiología, CINVESTAV Sede Sur, Calzada de los Tenorios 235, Mexico, DF, Mexico
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Umberger NL, Caspary T. Ciliary transport regulates PDGF-AA/αα signaling via elevated mammalian target of rapamycin signaling and diminished PP2A activity. Mol Biol Cell 2014; 26:350-8. [PMID: 25392303 PMCID: PMC4294681 DOI: 10.1091/mbc.e14-05-0952] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Primary cilia are built and maintained by intraflagellar transport (IFT), whereby the two IFT complexes, IFTA and IFTB, carry cargo via kinesin and dynein motors for anterograde and retrograde transport, respectively. Many signaling pathways, including platelet- derived growth factor (PDGF)-AA/αα, are linked to primary cilia. Active PDGF-AA/αα signaling results in phosphorylation of Akt at two residues: P-Akt(T308) and P-Akt(S473), and previous work showed decreased P-Akt(S473) in response to PDGF-AA upon anterograde transport disruption. In this study, we investigated PDGF-AA/αα signaling via P-Akt(T308) and P-Akt(S473) in distinct ciliary transport mutants. We found increased Akt phosphorylation in the absence of PDGF-AA stimulation, which we show is due to impaired dephosphorylation resulting from diminished PP2A activity toward P-Akt(T308). Anterograde transport mutants display low platelet-derived growth factor receptor (PDGFR)α levels, whereas retrograde mutants exhibit normal PDGFRα levels. Despite this, neither shows an increase in P-Akt(S473) or P-Akt(T308) upon PDGF-AA stimulation. Because mammalian target of rapamycin complex 1 (mTORC1) signaling is increased in ciliary transport mutant cells and mTOR signaling inhibits PDGFRα levels, we demonstrate that inhibition of mTORC1 rescues PDGFRα levels as well as PDGF-AA-dependent phosphorylation of Akt(S473) and Akt(T308) in ciliary transport mutant MEFs. Taken together, our data indicate that the regulation of mTORC1 signaling and PP2A activity by ciliary transport plays key roles in PDGF-AA/αα signaling.
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Affiliation(s)
- Nicole L Umberger
- Genetics and Molecular Biology Graduate Programs, Emory University School of Medicine, Atlanta, GA 30322 Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
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Abstract
Cilia proteins have long been characterized for their role in cilia formation and function, and their implications in ciliopathies. However, several cellular defects induced by cilia proteins deregulation suggest that they could have non-ciliary roles. Indeed, several non-ciliary functions have been recently characterized for cilia proteins including roles in intra-cellular and in vesicular transport, in spindle orientation or in the maintenance of genomic stability. These observations thus raise the crucial question of the contribution of non-ciliary functions of cilia proteins to the pathological manifestations associated with ciliopathies such as polycystic kidney disease.
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Affiliation(s)
- Nicolas Taulet
- CNRS-CRBM (centre de recherche en biochimie macromoléculaire), équipe centrosome, cil et pathologies, université de Montpellier, 1919, route de Mende, 34293 Montpellier, France
| | - Bénédicte Delaval
- CNRS-CRBM (centre de recherche en biochimie macromoléculaire), équipe centrosome, cil et pathologies, université de Montpellier, 1919, route de Mende, 34293 Montpellier, France
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70
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Beck BB, Phillips JB, Bartram MP, Wegner J, Thoenes M, Pannes A, Sampson J, Heller R, Göbel H, Koerber F, Neugebauer A, Hedergott A, Nürnberg G, Nürnberg P, Thiele H, Altmüller J, Toliat MR, Staubach S, Boycott KM, Valente EM, Janecke AR, Eisenberger T, Bergmann C, Tebbe L, Wang Y, Wu Y, Fry AM, Westerfield M, Wolfrum U, Bolz HJ. Mutation of POC1B in a severe syndromic retinal ciliopathy. Hum Mutat 2014; 35:1153-62. [PMID: 25044745 PMCID: PMC4425427 DOI: 10.1002/humu.22618] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/12/2014] [Indexed: 12/20/2022]
Abstract
We describe a consanguineous Iraqi family with Leber congenital amaurosis (LCA), Joubert syndrome (JBTS), and polycystic kidney disease (PKD). Targeted next-generation sequencing for excluding mutations in known LCA and JBTS genes, homozygosity mapping, and whole-exome sequencing identified a homozygous missense variant, c.317G>C (p.Arg106Pro), in POC1B, a gene essential for ciliogenesis, basal body, and centrosome integrity. In silico modeling suggested a requirement of p.Arg106 for the formation of the third WD40 repeat and a protein interaction interface. In human and mouse retina, POC1B localized to the basal body and centriole adjacent to the connecting cilium of photoreceptors and in synapses of the outer plexiform layer. Knockdown of Poc1b in zebrafish caused cystic kidneys and retinal degeneration with shortened and reduced photoreceptor connecting cilia, compatible with the human syndromic ciliopathy. A recent study describes homozygosity for p.Arg106ProPOC1B in a family with nonsyndromic cone-rod dystrophy. The phenotype associated with homozygous p.Arg106ProPOC1B may thus be highly variable, analogous to homozygous p.Leu710Ser in WDR19 causing either isolated retinitis pigmentosa or Jeune syndrome. Our study indicates that POC1B is required for retinal integrity, and we propose POC1B mutations as a probable cause for JBTS with severe PKD.
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Affiliation(s)
- Bodo B. Beck
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
| | | | - Malte P. Bartram
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University Hospital of Cologne, 50931 Cologne, Germany
| | - Jeremy Wegner
- Institute of Neuroscience, University of Oregon, 97401 Eugene, Oregon, USA
| | - Michaela Thoenes
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
| | - Andrea Pannes
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
| | - Josephina Sampson
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom, LE7 9HN
| | - Raoul Heller
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
| | - Heike Göbel
- Department of Pathology, University Hospital of Cologne, 50931 Cologne, Germany
| | - Friederike Koerber
- Department of Radiology, University Hospital of Cologne, 50931 Cologne, Germany
| | - Antje Neugebauer
- Department of Ophthalmology, University Hospital of Cologne, 50931 Cologne, Germany
| | - Andrea Hedergott
- Department of Ophthalmology, University Hospital of Cologne, 50931 Cologne, Germany
| | - Gudrun Nürnberg
- Cologne Center for Genomics (CCG) and Centre for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG) and Centre for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG) and Centre for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Janine Altmüller
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
- Cologne Center for Genomics (CCG) and Centre for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Mohammad R. Toliat
- Cologne Center for Genomics (CCG) and Centre for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Simon Staubach
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
| | - Kym M. Boycott
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, K1H 8L1 Ottawa, Canada
| | - Enza Maria Valente
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza Institute, 71013 San Giovanni Rotondo, Italy
- Department of Medicine and Surgery, University of Salerno, 84080 Salerno, Italy
| | - Andreas R. Janecke
- Department of Pediatrics I, and Division of Human Genetics, Innsbruck Medical University, 6020 Innsbruck, Austria
| | | | - Carsten Bergmann
- Center for Human Genetics, Bioscientia, 55218 Ingelheim, Germany
- Department of Medicine, Renal Division, University of Freiburg Medical Center, 79095 Freiburg, Germany
| | - Lars Tebbe
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg, University of Mainz, 55099 Mainz, Germany
| | - Yang Wang
- Lab of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, 518000 Shenzhen, P. R. China
| | - Yundong Wu
- Lab of Computational Chemistry and Drug Design, Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, 518000 Shenzhen, P. R. China
- College of Chemistry, Peking University, 100871 Beijing, P. R. China
| | - Andrew M. Fry
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom, LE7 9HN
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, 97401 Eugene, Oregon, USA
| | - Uwe Wolfrum
- Department of Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg, University of Mainz, 55099 Mainz, Germany
- Focus Program Translational Neurosciences (FTN), Johannes Gutenberg University of Mainz, 55122 Mainz, Germany
| | - Hanno J. Bolz
- Institute of Human Genetics, University Hospital of Cologne, 50931 Cologne, Germany
- Center for Human Genetics, Bioscientia, 55218 Ingelheim, Germany
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71
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Bujakowska KM, Zhang Q, Siemiatkowska AM, Liu Q, Place E, Falk MJ, Consugar M, Lancelot ME, Antonio A, Lonjou C, Carpentier W, Mohand-Saïd S, den Hollander AI, Cremers FPM, Leroy BP, Gai X, Sahel JA, van den Born LI, Collin RWJ, Zeitz C, Audo I, Pierce EA. Mutations in IFT172 cause isolated retinal degeneration and Bardet-Biedl syndrome. Hum Mol Genet 2014; 24:230-42. [PMID: 25168386 DOI: 10.1093/hmg/ddu441] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Primary cilia are sensory organelles present on most mammalian cells. The assembly and maintenance of primary cilia are facilitated by intraflagellar transport (IFT), a bidirectional protein trafficking along the cilium. Mutations in genes coding for IFT components have been associated with a group of diseases called ciliopathies. These genetic disorders can affect a variety of organs including the retina. Using whole exome sequencing in three families, we identified mutations in Intraflagellar Transport 172 Homolog [IFT172 (Chlamydomonas)] that underlie an isolated retinal degeneration and Bardet-Biedl syndrome. Extensive functional analyses of the identified mutations in cell culture, rat retina and in zebrafish demonstrated their hypomorphic or null nature. It has recently been reported that mutations in IFT172 cause a severe ciliopathy syndrome involving skeletal, renal, hepatic and retinal abnormalities (Jeune and Mainzer-Saldino syndromes). Here, we report for the first time that mutations in this gene can also lead to an isolated form of retinal degeneration. The functional data for the mutations can partially explain milder phenotypes; however, the involvement of modifying alleles in the IFT172-associated phenotypes cannot be excluded. These findings expand the spectrum of disease associated with mutations in IFT172 and suggest that mutations in genes originally reported to be associated with syndromic ciliopathies should also be considered in subjects with non-syndromic retinal dystrophy.
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Affiliation(s)
- Kinga M Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France
| | - Qi Zhang
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | | | - Qin Liu
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Emily Place
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Marni J Falk
- Department of Pediatrics, Division of Human Genetics, The Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Mark Consugar
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Marie-Elise Lancelot
- Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France
| | - Aline Antonio
- Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France
| | - Christine Lonjou
- Plateforme Post-génomique P3S, Hôpital Pitié Salpêtrière, Paris 75013, France
| | - Wassila Carpentier
- Plateforme Post-génomique P3S, Hôpital Pitié Salpêtrière, Paris 75013, France
| | - Saddek Mohand-Saïd
- Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France Institut National de la Santé et de la Recherche Médicale and Direction de L'Hospitalisation et de L'Organisation des Soins Centre D'Investigation Clinique 1423, Centre Hospitalier National D'Ophtalmologie des Quinze-Vingts, Paris 75012, France
| | - Anneke I den Hollander
- Department of Human Genetics Radboud Institute for Molecular Life Sciences, and Department of Ophthalmology, Radboud University Medical Center, Nijmegen 6500 HB, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics Radboud Institute for Molecular Life Sciences, and
| | - Bart P Leroy
- Department of Ophthalmology and Center for Medical Genetics, Ghent University Hospital and Ghent University, Ghent 9000, Belgium Ophthalmic Genetics and Visual Electrophysiology, Division of Ophthalmology, The Children's Hospital of Philadelphia, PA 19104, USA
| | - Xiaowu Gai
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - José-Alain Sahel
- Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France Institut National de la Santé et de la Recherche Médicale and Direction de L'Hospitalisation et de L'Organisation des Soins Centre D'Investigation Clinique 1423, Centre Hospitalier National D'Ophtalmologie des Quinze-Vingts, Paris 75012, France Fondation Ophtalmologique Adolphe de Rothschild, Paris 75019, France Academie des Sciences, Institut de France, Paris 75006, France University College London, Institute of Ophthalmology, London EC1V 9EL, UK and
| | | | - Rob W J Collin
- Department of Human Genetics Radboud Institute for Molecular Life Sciences, and
| | - Christina Zeitz
- Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France
| | - Isabelle Audo
- Institut National de la Santé et de la Recherche Médicale U968, Paris 75012, France Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris 75012, France Centre National de la Recherche Scientifique, UMR_7210, Paris 75012, France Institut National de la Santé et de la Recherche Médicale and Direction de L'Hospitalisation et de L'Organisation des Soins Centre D'Investigation Clinique 1423, Centre Hospitalier National D'Ophtalmologie des Quinze-Vingts, Paris 75012, France University College London, Institute of Ophthalmology, London EC1V 9EL, UK and
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
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72
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Usher syndrome protein network functions in the retina and their relation to other retinal ciliopathies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:527-33. [PMID: 24664740 DOI: 10.1007/978-1-4614-3209-8_67] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human Usher syndrome (USH) is the most frequent cause of combined hereditary deaf-blindness. USH is genetically and clinically heterogeneous: 15 chromosomal loci assigned to 3 clinical types, USH1-3. All USH1 and 2 proteins are organized into protein networks by the scaffold proteins harmonin (USH1C), whirlin (USH2D) and SANS (USH1G). This has contributed essentially to our current understanding of the USH protein function in the eye and the ear and explains why defects in proteins of different families cause very similar phenotypes. Ongoing in depth analyses of USH protein networks in the eye indicated cytoskeletal functions as well as roles in molecular transport processes and ciliary cargo delivery in photoreceptor cells. The analysis of USH protein networks revealed molecular links of USH to other ciliopathies, including non-syndromic inner ear defects and isolated retinal dystrophies but also to kidney diseases and syndromes like the Bardet-Biedl syndrome. These findings provide emerging evidence that USH is a ciliopathy molecularly related to other ciliopathies, which opens an avenue for common therapy strategies to treat these diseases.
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73
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Abstract
While the presence of a primary cilium on neural progenitors and on post-mitotic neurons was noted long ago, a primary cilium has been observed on migrating cortical interneurons only recently. As in fibroblasts, the cilium of interneurons controls the directionality of migration. It plays an important role in the reorientation of cortical interneurons toward the cortical plate. The morphogen Shh, which is expressed in the migratory pathway of interneurons, is one of the signals that control this reorientation. After a short description of the migratory pathways of cortical interneurons, we focus on cellular mechanisms that allow interneurons to reorient their trajectory during their long-distance migration. Then we examine the role of the primary cilium in cell migration and how ciliogenesis might be related to the migration cycle in interneurons. Finally, we review the molecular mechanisms at the basis of the sensory function of the primary cilium and examine how Shh signals could influence the migratory behavior of cortical interneurons. These novel data provide a cellular basis to further understanding cognitive deficits associated with human ciliopathies.
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Affiliation(s)
- Christine Métin
- Institut du Fer à Moulin, INSERM UMRS-839, Université Pierre et Marie Curie Paris 6, Paris France
| | - Maria Pedraza
- Institut du Fer à Moulin, INSERM UMRS-839, Université Pierre et Marie Curie Paris 6, Paris France
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74
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Derivation of traceable and transplantable photoreceptors from mouse embryonic stem cells. Stem Cell Reports 2014; 2:853-65. [PMID: 24936471 PMCID: PMC4050344 DOI: 10.1016/j.stemcr.2014.04.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 01/12/2023] Open
Abstract
Retinal degenerative diseases resulting in the loss of photoreceptors are one of the major causes of blindness. Photoreceptor replacement therapy is a promising treatment because the transplantation of retina-derived photoreceptors can be applied now to different murine retinopathies to restore visual function. To have an unlimited source of photoreceptors, we derived a transgenic embryonic stem cell (ESC) line in which the Crx-GFP transgene is expressed in photoreceptors and assessed the capacity of a 3D culture protocol to produce integration-competent photoreceptors. This culture system allows the production of a large number of photoreceptors recapitulating the in vivo development. After transplantation, integrated cells showed the typical morphology of mature rods bearing external segments and ribbon synapses. We conclude that a 3D protocol coupled with ESCs provides a safe and renewable source of photoreceptors displaying a development and transplantation competence comparable to photoreceptors from age-matched retinas. De novo isolation of Crx-GFP embryonic stem cell lines to trace photoreceptors 3D culture system fine-tuning to generate many integration-competent photoreceptors Revealing in-vitro- and in-vivo-developing retina similarities Characterization of the most appropriate stage to transplant photoreceptors
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75
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Wood CR, Rosenbaum JL. Proteins of the ciliary axoneme are found on cytoplasmic membrane vesicles during growth of cilia. Curr Biol 2014; 24:1114-20. [PMID: 24814148 PMCID: PMC4096978 DOI: 10.1016/j.cub.2014.03.047] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/24/2014] [Accepted: 03/14/2014] [Indexed: 12/01/2022]
Abstract
The cilium is a specialized extension of the cell in which many specific proteins are admitted and retained, while many others are excluded or expelled. In order to maintain the organelle, the cell must possess mechanisms for the selective gating of protein entry, as well as for the targeted transport of proteins to the cilium from their sites of synthesis within the cell [1-4]. We hypothesized that the cell employs cytoplasmic vesicles as vehicles not only for the transport of proteins destined for the ciliary membrane but also for the transport of axonemal proteins to the cilium by means of peripheral association with vesicles. To test this hypothesis, we employed two different experimental strategies: (1) isolation and biochemical characterization of cytoplasmic vesicles that carry ciliary proteins, and (2) in situ localization of ciliary proteins on cytoplasmic vesicle surfaces using gold labeling and electron microscopy. Our findings indicate that structural proteins destined for the ciliary axoneme are attached to the outer surfaces of cytoplasmic vesicles that carry integral ciliary membrane proteins during the process of ciliary growth.
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Affiliation(s)
- Christopher R Wood
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Joel L Rosenbaum
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
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76
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Karlstetter M, Sorusch N, Caramoy A, Dannhausen K, Aslanidis A, Fauser S, Boesl MR, Nagel-Wolfrum K, Tamm ER, Jägle H, Stoehr H, Wolfrum U, Langmann T. Disruption of the retinitis pigmentosa 28 gene Fam161a in mice affects photoreceptor ciliary structure and leads to progressive retinal degeneration. Hum Mol Genet 2014; 23:5197-210. [DOI: 10.1093/hmg/ddu242] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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77
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Crouse JA, Lopes VS, Sanagustin JT, Keady BT, Williams DS, Pazour GJ. Distinct functions for IFT140 and IFT20 in opsin transport. Cytoskeleton (Hoboken) 2014; 71:302-10. [PMID: 24619649 DOI: 10.1002/cm.21173] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/26/2014] [Accepted: 03/04/2014] [Indexed: 12/20/2022]
Abstract
In the vertebrate retina, light is detected by the outer segments of photoreceptor rods and cones, which are highly modified cilia. Like other cilia, outer segments have no protein synthetic capacity and depend on proteins made in the cell body for their formation and maintenance. The mechanism of transport into the outer segment is not fully understood but intraflagellar transport (IFT) is thought to be a major mechanism for moving protein from the cell body into the cilium. In the case of photoreceptor cells, the high density of receptors and the disk turnover that occurs daily necessitates much higher rates of transport than would be required in other cilia. In this work, we show that the IFT complex A protein IFT140 is required for development and maintenance of outer segments. In earlier work we found that acute deletion of Ift20 caused opsin to accumulate at the Golgi complex. In this work, we find that acute deletion of Ift140 does not cause opsin to accumulate at the Golgi complex but rather it accumulates in the plasma membrane of the inner segments. This work is a strong support of a model of opsin transport where IFT20 is involved in the movement from the Golgi complex to the base of the cilium. Then, once at the base, the opsin is carried through the connecting cilium by an IFT complex that includes IFT140. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Jacquelin A Crouse
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Worcester, Massachusetts
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78
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Finetti F, Patrussi L, Masi G, Onnis A, Galgano D, Lucherini OM, Pazour GJ, Baldari CT. Specific recycling receptors are targeted to the immune synapse by the intraflagellar transport system. J Cell Sci 2014; 127:1924-37. [PMID: 24554435 DOI: 10.1242/jcs.139337] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
T cell activation requires sustained signaling at the immune synapse, a specialized interface with the antigen-presenting cell (APC) that assembles following T cell antigen receptor (TCR) engagement by major histocompatibility complex (MHC)-bound peptide. Central to sustained signaling is the continuous recruitment of TCRs to the immune synapse. These TCRs are partly mobilized from an endosomal pool by polarized recycling. We have identified IFT20, a component of the intraflagellar transport (IFT) system that controls ciliogenesis, as a central regulator of TCR recycling to the immune synapse. Here, we have investigated the interplay of IFT20 with the Rab GTPase network that controls recycling. We found that IFT20 forms a complex with Rab5 and the TCR on early endosomes. IFT20 knockdown (IFT20KD) resulted in a block in the recycling pathway, leading to a build-up of recycling TCRs in Rab5(+) endosomes. Recycling of the transferrin receptor (TfR), but not of CXCR4, was disrupted by IFT20 deficiency. The IFT components IFT52 and IFT57 were found to act together with IFT20 to regulate TCR and TfR recycling. The results provide novel insights into the mechanisms that control TCR recycling and immune synapse assembly, and underscore the trafficking-related function of the IFT system beyond ciliogenesis.
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Affiliation(s)
- Francesca Finetti
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
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79
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Sung CH, Leroux MR. The roles of evolutionarily conserved functional modules in cilia-related trafficking. Nat Cell Biol 2014; 15:1387-97. [PMID: 24296415 DOI: 10.1038/ncb2888] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cilia are present across most eukaryotic phyla and have diverse sensory and motility roles in animal physiology, cell signalling and development. Their biogenesis and maintenance depend on vesicular and intraciliary (intraflagellar) trafficking pathways that share conserved structural and functional modules. The functional units of the interconnected pathways, which include proteins involved in membrane coating as well as small GTPases and their accessory factors, were first experimentally associated with canonical vesicular trafficking. These components are, however, ancient, having been co-opted by the ancestral eukaryote to establish the ciliary organelle, and their study can inform us about ciliary biology in higher organisms.
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Affiliation(s)
- Ching-Hwa Sung
- Margaret M. Dyson Vision Research Institute, Department of Ophthalmology, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, USA
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80
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Wheway G, Parry DA, Johnson CA. The role of primary cilia in the development and disease of the retina. Organogenesis 2014; 10:69-85. [PMID: 24162842 PMCID: PMC4049897 DOI: 10.4161/org.26710] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/01/2013] [Accepted: 10/04/2013] [Indexed: 02/07/2023] Open
Abstract
The normal development and function of photoreceptors is essential for eye health and visual acuity in vertebrates. Mutations in genes encoding proteins involved in photoreceptor development and function are associated with a suite of inherited retinal dystrophies, often as part of complex multi-organ syndromic conditions. In this review, we focus on the role of the photoreceptor outer segment, a highly modified and specialized primary cilium, in retinal health and disease. We discuss the many defects in the structure and function of the photoreceptor primary cilium that can cause a class of inherited conditions known as ciliopathies, often characterized by retinal dystrophy and degeneration, and highlight the recent insights into disease mechanisms.
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Affiliation(s)
- Gabrielle Wheway
- Section of Ophthalmology and Neurosciences; Leeds Institute of Molecular Medicine; The University of Leeds; Leeds, United Kingdom
| | - David A Parry
- Section of Genetics; Leeds Institute of Molecular Medicine; The University of Leeds; Leeds, United Kingdom
| | - Colin A Johnson
- Section of Ophthalmology and Neurosciences; Leeds Institute of Molecular Medicine; The University of Leeds; Leeds, United Kingdom
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81
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Wang J, Deretic D. Molecular complexes that direct rhodopsin transport to primary cilia. Prog Retin Eye Res 2013; 38:1-19. [PMID: 24135424 DOI: 10.1016/j.preteyeres.2013.08.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/13/2013] [Accepted: 08/19/2013] [Indexed: 11/27/2022]
Abstract
Rhodopsin is a key molecular constituent of photoreceptor cells, yet understanding of how it regulates photoreceptor membrane trafficking and biogenesis of light-sensing organelles, the rod outer segments (ROS) is only beginning to emerge. Recently identified sequence of well-orchestrated molecular interactions of rhodopsin with the functional networks of Arf and Rab GTPases at multiple stages of intracellular targeting fits well into the complex framework of the biogenesis and maintenance of primary cilia, of which the ROS is one example. This review will discuss the latest progress in dissecting the molecular complexes that coordinate rhodopsin incorporation into ciliary-targeted carriers with the recruitment and activation of membrane tethering complexes and regulators of fusion with the periciliary plasma membrane. In addition to revealing the fundamental principals of ciliary membrane renewal, recent advances also provide molecular insight into the ways by which disruptions of the exquisitely orchestrated interactions lead to cilia dysfunction and result in human retinal dystrophies and syndromic diseases that affect multiple organs, including the eyes.
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Affiliation(s)
- Jing Wang
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Dusanka Deretic
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM 87131, USA; Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM 87131, USA.
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82
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Localization of primary cilia in mouse retina. Acta Histochem 2013; 115:789-94. [PMID: 23608602 DOI: 10.1016/j.acthis.2013.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 03/04/2013] [Accepted: 03/06/2013] [Indexed: 12/22/2022]
Abstract
The primary cilia are considered as "cellular antennae" that sense and interchange information with the extracellular environment. Nearly all mammalian cells have a single primary cilium. In the retina, the outer segment of the photoreceptor is known to be a specialized form of primary cilium, but studies on cilia in other layers of the retina are scarce. In this study, we investigated the expression of primary cilia in the whole thickness of the mouse retina using immunofluorescence with three different ciliary markers: Arl13b, acetylated α-tubulin and adenylyl cyclase III. Our results show positive reactions in the photoreceptor layer, outer plexiform layer and ganglion cell layer, which might suggest the possible presence of primary cilia in these areas, but we could not directly prove the strand-like shape of cilia in those areas. In the outer plexiform layer, all three markers showed intense staining along the neuronal synapses, which suggests that the neuronal processes themselves might share the features of cilia.
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83
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Davidson AE, Schwarz N, Zelinger L, Stern-Schneider G, Shoemark A, Spitzbarth B, Gross M, Laxer U, Sosna J, Sergouniotis PI, Waseem NH, Wilson R, Kahn RA, Plagnol V, Wolfrum U, Banin E, Hardcastle AJ, Cheetham ME, Sharon D, Webster AR. Mutations in ARL2BP, encoding ADP-ribosylation-factor-like 2 binding protein, cause autosomal-recessive retinitis pigmentosa. Am J Hum Genet 2013; 93:321-9. [PMID: 23849777 DOI: 10.1016/j.ajhg.2013.06.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/03/2013] [Accepted: 06/04/2013] [Indexed: 01/01/2023] Open
Abstract
Retinitis pigmentosa (RP) is a genetically heterogeneous retinal degeneration characterized by photoreceptor death, which results in visual failure. Here, we used a combination of homozygosity mapping and exome sequencing to identify mutations in ARL2BP, which encodes an effector protein of the small GTPases ARL2 and ARL3, as causative for autosomal-recessive RP (RP66). In a family affected by RP and situs inversus, a homozygous, splice-acceptor mutation, c.101-1G>C, which alters pre-mRNA splicing of ARLBP2 in blood RNA, was identified. In another family, a homozygous c.134T>G (p.Met45Arg) mutation was identified. In the mouse retina, ARL2BP localized to the basal body and cilium-associated centriole of photoreceptors and the periciliary extension of the inner segment. Depletion of ARL2BP caused cilia shortening. Moreover, depletion of ARL2, but not ARL3, caused displacement of ARL2BP from the basal body, suggesting that ARL2 is vital for recruiting or anchoring ARL2BP at the base of the cilium. This hypothesis is supported by the finding that the p.Met45Arg amino acid substitution reduced binding to ARL2 and caused the loss of ARL2BP localization at the basal body in ciliated nasal epithelial cells. These data demonstrate a role for ARL2BP and ARL2 in primary cilia function and that this role is essential for normal photoreceptor maintenance and function.
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84
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Smith TS, Spitzbarth B, Li J, Dugger DR, Stern-Schneider G, Sehn E, Bolch SN, McDowell JH, Tipton J, Wolfrum U, Smith WC. Light-dependent phosphorylation of Bardet-Biedl syndrome 5 in photoreceptor cells modulates its interaction with arrestin1. Cell Mol Life Sci 2013; 70:4603-16. [PMID: 23817741 DOI: 10.1007/s00018-013-1403-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/04/2013] [Accepted: 06/10/2013] [Indexed: 01/14/2023]
Abstract
Arrestins are dynamic proteins that move between cell compartments triggered by stimulation of G-protein-coupled receptors. Even more dynamically in vertebrate photoreceptors, arrestin1 (Arr1) moves between the inner and outer segments according to the light conditions. Previous studies have shown that the light-driven translocation of Arr1 in rod photoreceptors is initiated by rhodopsin through a phospholipase C/protein kinase C (PKC) signaling cascade. The purpose of this study is to identify the PKC substrate that regulates the translocation of Arr1. Mass spectrometry was used to identify the primary phosphorylated proteins in extracts prepared from PKC-stimulated mouse eye cups, confirming the finding with in vitro phosphorylation assays. Our results show that Bardet-Biedl syndrome 5 (BBS5) is the principal protein phosphorylated either by phorbol ester stimulation or by light stimulation of PKC. Via immunoprecipitation of BBS5 in rod outer segments, Arr1 was pulled down; phosphorylation of BBS5 reduced this co-precipitation of Arr1. Immunofluorescence and immunoelectron microscopy showed that BBS5 principally localizes along the axonemes of rods and cones, but also in photoreceptor inner segments, and synaptic regions. Our principal findings in this study are threefold. First, we demonstrate that BBS5 is post-translationally regulated by phosphorylation via PKC, an event that is triggered by light in photoreceptor cells. Second, we find a direct interaction between BBS5 and Arr1, an interaction that is modulated by phosphorylation of BBS5. Finally, we show that BBS5 is distributed along the photoreceptor axoneme, co-localizing with Arr1 in the dark. These findings suggest a role for BBS5 in regulating light-dependent translocation of Arr1 and a model describing its role in Arr1 translocation is proposed.
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Affiliation(s)
- Tyler S Smith
- Department of Ophthalmology, University of Florida, Box 100284 JHMHC, Gainesville, FL, 32610-0284, USA
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85
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Finetti F, Baldari CT. Compartmentalization of signaling by vesicular trafficking: a shared building design for the immune synapse and the primary cilium. Immunol Rev 2013; 251:97-112. [PMID: 23278743 DOI: 10.1111/imr.12018] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Accumulating evidence underscores the immune synapse (IS) of naive T cells as a site of intense vesicular trafficking. At variance with helper and cytolytic effectors, which use the IS as a secretory platform to deliver cytokines and/or lytic granules to their cellular targets, this process is exploited by naive T cells as a means to regulate the assembly and maintenance of the IS, on which productive signaling and cell activation crucially depend. We have recently identified a role of the intraflagellar transport (IFT) system, which is responsible for the assembly of the primary cilium, in the non-ciliated T-cell, where it controls IS assembly by promoting polarized T-cell receptor recycling. This unexpected finding not only provides new insight into the mechanisms of IS assembly but also strongly supports the notion that the IS and the primary cilium, which are both characterized by a specialized membrane domain highly enriched in receptors and signaling mediators, share architectural similarities and are homologous structures. Here, we review our current understanding of vesicular trafficking in the regulation of the assembly and maintenance of the naive T-cell IS and the primary cilium, with a focus on the IFT system.
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Affiliation(s)
- Francesca Finetti
- Department of Evolutionary Biology, University of Siena, Siena, Italy
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86
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Papal S, Cortese M, Legendre K, Sorusch N, Dragavon J, Sahly I, Shorte S, Wolfrum U, Petit C, El-Amraoui A. The giant spectrin βV couples the molecular motors to phototransduction and Usher syndrome type I proteins along their trafficking route. Hum Mol Genet 2013; 22:3773-88. [PMID: 23704327 DOI: 10.1093/hmg/ddt228] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the myosin VIIa gene cause Usher syndrome type IB (USH1B), characterized by deaf-blindness. A delay of opsin trafficking has been observed in the retinal photoreceptor cells of myosin VIIa-deficient mice. We identified spectrin βV, the mammalian β-heavy spectrin, as a myosin VIIa- and rhodopsin-interacting partner in photoreceptor cells. Spectrin βV displays a polarized distribution from the Golgi apparatus to the base of the outer segment, which, unlike that of other β spectrins, matches the trafficking route of opsin and other phototransduction proteins. Formation of spectrin βV-rhodopsin complex could be detected in the differentiating photoreceptors as soon as their outer segment emerges. A failure of the spectrin βV-mediated coupling between myosin VIIa and opsin molecules thus probably accounts for the opsin transport delay in myosin VIIa-deficient mice. We showed that spectrin βV also associates with two USH1 proteins, sans (USH1G) and harmonin (USH1C). Spectrins are supposed to function as heteromers of α and β subunits, but fluorescence resonance energy transfer and in vitro binding experiments indicated that spectrin βV can also form homodimers, which likely supports its αII-independent βV functions. Finally, consistent with its distribution along the connecting cilia axonemes, spectrin βV binds to several subunits of the microtubule-based motor proteins, kinesin II and the dynein complex. We therefore suggest that spectrin βV homomers couple some USH1 proteins, opsin and other phototransduction proteins to both actin- and microtubule-based motors, thereby contributing to their transport towards the photoreceptor outer disks.
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Affiliation(s)
- Samantha Papal
- Institut Pasteur, Unité de génétique et physiologie de l'audition, Paris, France
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87
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Olivier-Mason A, Wojtyniak M, Bowie RV, Nechipurenko IV, Blacque OE, Sengupta P. Transmembrane protein OSTA-1 shapes sensory cilia morphology via regulation of intracellular membrane trafficking in C. elegans. Development 2013; 140:1560-72. [PMID: 23482491 DOI: 10.1242/dev.086249] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The structure and function of primary cilia are critically dependent on intracellular trafficking pathways that transport ciliary membrane and protein components. The mechanisms by which these trafficking pathways are regulated are not fully characterized. Here we identify the transmembrane protein OSTA-1 as a new regulator of the trafficking pathways that shape the morphology and protein composition of sensory cilia in C. elegans. osta-1 encodes an organic solute transporter alpha-like protein, mammalian homologs of which have been implicated in membrane trafficking and solute transport, although a role in regulating cilia structure has not previously been demonstrated. We show that mutations in osta-1 result in altered ciliary membrane volume, branch length and complexity, as well as defects in localization of a subset of ciliary transmembrane proteins in different sensory cilia types. OSTA-1 is associated with transport vesicles, localizes to a ciliary compartment shown to house trafficking proteins, and regulates both retrograde and anterograde flux of the endosome-associated RAB-5 small GTPase. Genetic epistasis experiments with sensory signaling, exocytic and endocytic proteins further implicate OSTA-1 as a crucial regulator of ciliary architecture via regulation of cilia-destined trafficking. Our findings suggest that regulation of transport pathways in a cell type-specific manner contributes to diversity in sensory cilia structure and might allow dynamic remodeling of ciliary architecture via multiple inputs.
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Affiliation(s)
- Anique Olivier-Mason
- Department of Biology and National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA
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88
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Pearring JN, Salinas RY, Baker SA, Arshavsky VY. Protein sorting, targeting and trafficking in photoreceptor cells. Prog Retin Eye Res 2013; 36:24-51. [PMID: 23562855 DOI: 10.1016/j.preteyeres.2013.03.002] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 03/22/2013] [Accepted: 03/26/2013] [Indexed: 01/24/2023]
Abstract
Vision is the most fundamental of our senses initiated when photons are absorbed by the rod and cone photoreceptor neurons of the retina. At the distal end of each photoreceptor resides a light-sensing organelle, called the outer segment, which is a modified primary cilium highly enriched with proteins involved in visual signal transduction. At the proximal end, each photoreceptor has a synaptic terminal, which connects this cell to the downstream neurons for further processing of the visual information. Understanding the mechanisms involved in creating and maintaining functional compartmentalization of photoreceptor cells remains among the most fascinating topics in ocular cell biology. This review will discuss how photoreceptor compartmentalization is supported by protein sorting, targeting and trafficking, with an emphasis on the best-studied cases of outer segment-resident proteins.
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Affiliation(s)
- Jillian N Pearring
- Department of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
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89
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Gilliam JC, Chang JT, Sandoval IM, Zhang Y, Li T, Pittler SJ, Chiu W, Wensel TG. Three-dimensional architecture of the rod sensory cilium and its disruption in retinal neurodegeneration. Cell 2013. [PMID: 23178122 DOI: 10.1016/j.cell.2012.10.038] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Defects in primary cilia lead to devastating disease because of their roles in sensation and developmental signaling but much is unknown about ciliary structure and mechanisms of their formation and maintenance. We used cryo-electron tomography to obtain 3D maps of the connecting cilium and adjacent cellular structures of a modified primary cilium, the rod outer segment, from wild-type and genetically defective mice. The results reveal the molecular architecture of the cilium and provide insights into protein functions. They suggest that the ciliary rootlet is involved in cellular transport and stabilizes the axoneme. A defect in the BBSome membrane coat caused defects in vesicle targeting near the base of the cilium. Loss of the proteins encoded by the Cngb1 gene disrupted links between the disk and plasma membranes. The structures of the outer segment membranes support a model for disk morphogenesis in which basal disks are enveloped by the plasma membrane.
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Affiliation(s)
- Jared C Gilliam
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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90
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Broekhuis JR, Leong WY, Jansen G. Regulation of cilium length and intraflagellar transport. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 303:101-38. [PMID: 23445809 DOI: 10.1016/b978-0-12-407697-6.00003-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Primary cilia are highly conserved sensory organelles that extend from the surface of almost all vertebrate cells. The importance of cilia is evident from their involvement in many diseases, called ciliopathies. Primary cilia contain a microtubular axoneme that is used as a railway for transport of both structural components and signaling proteins. This transport machinery is called intraflagellar transport (IFT). Cilia are dynamic organelles whose presence on the cell surface, morphology, length and function are highly regulated. It is clear that the IFT machinery plays an important role in this regulation. However, it is not clear how, for example environmental cues or cell fate decisions are relayed to modulate IFT and cilium morphology or function. This chapter presents an overview of molecules that have been shown to regulate cilium length and IFT. Several examples where signaling modulates IFT and cilium function are used to discuss the importance of these systems for the cell and for understanding of the etiology of ciliopathies.
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91
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Photoreceptor sensory cilia and ciliopathies: focus on CEP290, RPGR and their interacting proteins. Cilia 2012; 1:22. [PMID: 23351659 PMCID: PMC3563624 DOI: 10.1186/2046-2530-1-22] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 09/19/2012] [Indexed: 02/08/2023] Open
Abstract
Ciliopathies encompass a broad array of clinical findings associated with genetic defects in biogenesis and/or function of the primary cilium, a ubiquitous organelle involved in the transduction of diverse biological signals. Degeneration or dysfunction of retinal photoreceptors is frequently observed in diverse ciliopathies. The sensory cilium in a photoreceptor elaborates into unique outer segment discs that provide extensive surface area for maximal photon capture and efficient visual transduction. The daily renewal of approximately 10% of outer segments requires a precise control of ciliary transport. Here, we review the ciliopathies with associated retinal degeneration, describe the distinctive structure of the photoreceptor cilium, and discuss mouse models that allow investigations into molecular mechanisms of cilia biogenesis and defects. We have specifically focused on two ciliary proteins - CEP290 and RPGR - that underlie photoreceptor degeneration and syndromic ciliopathies. Mouse models of CEP290 and RPGR disease, and of their multiple interacting partners, have helped unravel new functional insights into cell type-specific phenotypic defects in distinct ciliary proteins. Elucidation of multifaceted ciliary functions and associated protein complexes will require concerted efforts to assimilate diverse datasets from in vivo and in vitro studies. We therefore discuss a possible framework for investigating genetic networks associated with photoreceptor cilia biogenesis and pathology.
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92
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Baudoin JP, Viou L, Launay PS, Luccardini C, Espeso Gil S, Kiyasova V, Irinopoulou T, Alvarez C, Rio JP, Boudier T, Lechaire JP, Kessaris N, Spassky N, Métin C. Tangentially Migrating Neurons Assemble a Primary Cilium that Promotes Their Reorientation to the Cortical Plate. Neuron 2012; 76:1108-22. [DOI: 10.1016/j.neuron.2012.10.027] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2012] [Indexed: 10/27/2022]
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93
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Herranz-Martín S, Jimeno D, Paniagua AE, Velasco A, Lara JM, Aijón J, Lillo C. Immunocytochemical evidence of the localization of the Crumbs homologue 3 protein (CRB3) in the developing and mature mouse retina. PLoS One 2012; 7:e50511. [PMID: 23226298 PMCID: PMC3511585 DOI: 10.1371/journal.pone.0050511] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/22/2012] [Indexed: 12/28/2022] Open
Abstract
CRB3 (Crumbs homologue 3), a member of the CRB protein family (homologous to the Drosophila Crumbs), is expressed in different epithelium-derived cell types in mammals, where it seems to be involved in regulating the establishment and stability of tight junctions and in ciliogenesis. This protein has been also detected in the retina, but little is known about its localization and function in this tissue. Our goal here was to perform an in-depth study of the presence of CRB3 protein in the mouse retina and to analyze its expression during photoreceptor ciliogenesis and the establishment of the plexiform retinal layers. Double immunofluorescence experiments for CRB3 and well-known markers for the different retinal cell types were performed to study the localization of the CRB3 protein. According to our results, CRB3 is present from postnatal day 0 (P0) until adulthood in the mouse retina. It is localized in the inner segments (IS) of photoreceptor cells, especially concentrated in the area where the connecting cilium is located, in their synaptic terminals in the outer plexiform layer (OPL), and in sub-populations of amacrine and bipolar cells in the inner plexiform layer (IPL).
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Affiliation(s)
- Saúl Herranz-Martín
- Institute of Neurosciences of Castilla y León (INCyL), Institute of Biomedical Research of Salamanca (IBSAL), Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - David Jimeno
- Centro de Investigación del Cáncer-IBMCC (CSIC-USAL), University of Salamanca, Campus Unamuno, Salamanca, Spain
| | - Antonio E. Paniagua
- Institute of Neurosciences of Castilla y León (INCyL), Institute of Biomedical Research of Salamanca (IBSAL), Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Almudena Velasco
- Institute of Neurosciences of Castilla y León (INCyL), Institute of Biomedical Research of Salamanca (IBSAL), Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Juan M. Lara
- Institute of Neurosciences of Castilla y León (INCyL), Institute of Biomedical Research of Salamanca (IBSAL), Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - José Aijón
- Institute of Neurosciences of Castilla y León (INCyL), Institute of Biomedical Research of Salamanca (IBSAL), Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
| | - Concepción Lillo
- Institute of Neurosciences of Castilla y León (INCyL), Institute of Biomedical Research of Salamanca (IBSAL), Cell Biology and Pathology, University of Salamanca, Salamanca, Spain
- * E-mail:
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94
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Live-cell imaging evidence for the ciliary transport of rod photoreceptor opsin by heterotrimeric kinesin-2. J Neurosci 2012; 32:10587-93. [PMID: 22855808 DOI: 10.1523/jneurosci.0015-12.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Primary cilia detect extracellular signals through membrane receptors and channels. The outer segment of a vertebrate photoreceptor cell represents the most elaborate of all primary cilia, containing extraordinarily large amounts of the visual receptor protein, opsin. Because of its high abundance, opsin represents a potential model system for the study of ciliary membrane receptors, including their transport. Here, we have analyzed the movement of ciliary opsin to test whether the highly conserved intraflagellar transport (IFT), as driven by heterotrimeric kinesin-2, is required. Results show that opsin can enter and move along the primary cilium of a nonphotoreceptor cell (an hTERT-RPE1 epithelial cell), suggesting that it can co-opt the basic anterograde motor system of cilia. Fluorescence recovery after photobleaching analysis of cilia of hTERT-RPE1 cells showed that the movement of ciliary opsin was comparable to that of the IFT protein, IFT88. Moreover, the movement of opsin in these cilia, as well as in cilia of mouse rod photoreceptor cells, was reduced significantly when KIF3A, the obligate motor subunit of heterotrimeric kinesin-2, was deficient. These studies therefore provide evidence from live-cell analysis that the conserved heterotrimeric kinesin-2 is required for the normal transport of opsin along the ciliary plasma membrane.
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95
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Garcia-Gonzalo FR, Reiter JF. Scoring a backstage pass: mechanisms of ciliogenesis and ciliary access. ACTA ACUST UNITED AC 2012; 197:697-709. [PMID: 22689651 PMCID: PMC3373398 DOI: 10.1083/jcb.201111146] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cilia are conserved, microtubule-based cell surface projections that emanate from basal bodies, membrane-docked centrioles. The beating of motile cilia and flagella enables cells to swim and epithelia to displace fluids. In contrast, most primary cilia do not beat but instead detect environmental or intercellular stimuli. Inborn defects in both kinds of cilia cause human ciliopathies, diseases with diverse manifestations such as heterotaxia and kidney cysts. These diseases are caused by defects in ciliogenesis or ciliary function. The signaling functions of cilia require regulation of ciliary composition, which depends on the control of protein traffic into and out of cilia.
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Affiliation(s)
- Francesc R Garcia-Gonzalo
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
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96
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Zach F, Grassmann F, Langmann T, Sorusch N, Wolfrum U, Stöhr H. The retinitis pigmentosa 28 protein FAM161A is a novel ciliary protein involved in intermolecular protein interaction and microtubule association. Hum Mol Genet 2012; 21:4573-86. [PMID: 22791751 DOI: 10.1093/hmg/dds268] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Loss-of-function mutations in the gene encoding FAM161A were recently discovered as the cause for RP28, an autosomal recessive form of retinitis pigmentosa. To initiate the characterization of the cellular role of FAM161A in the retina, we focused on its subcellular localization and conducted in vitro studies to identify FAM161A-interacting proteins and associated cellular structures. Immunohistochemistry revealed the presence of mouse FAM161A in the photoreceptor inner segments, the synaptic regions of the outer and inner plexiform layers and the ganglion cells. In mouse and human retinal sections from unfixed eyes, FAM161A localized to the ciliary region linking photoreceptor outer and inner segments. High-resolution immunofluorescence and immunoelectron microscopy mapped FAM161A to the connecting cilium, the basal body region and the adjacent centriole. Ectopic FAM161A was found in the centrosome and concentrated at the base of primary cilia in cultured cells. In addition, overexpressed FAM161A was clearly associated with microtubules during interphase and mitosis. The presence of FAM161A increased microtubule acetylation and stabilization. We further show that the evolutionarily conserved UPF0564 domain of FAM161A is crucial for its binding to microtubules and mediates homo- and heterotypic FAM161A and FAM161B interaction. In conclusion, our study shows that FAM161A is a microtubule-associated ciliary protein presumably involved in microtubule stabilization to maintain the microtubule tracks and/or in transport processes along microtubules in photoreceptors and other retinal cell types.
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Affiliation(s)
- Frank Zach
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
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97
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The base of the cilium: roles for transition fibres and the transition zone in ciliary formation, maintenance and compartmentalization. EMBO Rep 2012; 13:608-18. [PMID: 22653444 DOI: 10.1038/embor.2012.73] [Citation(s) in RCA: 362] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 05/11/2012] [Indexed: 12/13/2022] Open
Abstract
Both the basal body and the microtubule-based axoneme it nucleates have evolutionarily conserved subdomains crucial for cilium biogenesis, function and maintenance. Here, we focus on two conspicuous but underappreciated regions of these structures that make membrane connections. One is the basal body distal end, which includes transition fibres of largely undefined composition that link to the base of the ciliary membrane. Transition fibres seem to serve as docking sites for intraflagellar transport particles, which move proteins within the ciliary compartment and are required for cilium biogenesis and sustained function. The other is the proximal-most region of the axoneme, termed the transition zone, which is characterized by Y-shaped linkers that span from the axoneme to the ciliary necklace on the membrane surface. The transition zone comprises a growing number of ciliopathy proteins that function as modular components of a ciliary gate. This gate, which forms early during ciliogenesis, might function in part by regulating intraflagellar transport. Together with a recently described septin ring diffusion barrier at the ciliary base, the transition fibres and transition zone deserve attention for their varied roles in forming functional ciliary compartments.
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98
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May-Simera HL, Kelley MW. Cilia, Wnt signaling, and the cytoskeleton. Cilia 2012; 1:7. [PMID: 23351924 PMCID: PMC3555707 DOI: 10.1186/2046-2530-1-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 05/02/2012] [Indexed: 12/14/2022] Open
Abstract
Primary cilia have recently been highlighted as key regulators in development and disease. This review focuses on current work demonstrating the broad role of cilia-related proteins in developmental signaling systems. Of particular consideration is the importance of the basal body region, located at the base of the cilium, in its role as a focal point for many signaling pathways and as a microtubule organizing center. As the cilium is effectively a microtubular extension of the cytoskeleton, investigating connections between the cilium and the cytoskeleton provides greater insight into signaling and cell function. Of the many signaling pathways associated with primary cilia, the most extensively studied in association with the cytoskeleton and cytoskeletal rearrangements are both canonical and non-canonical Wnt pathways. One of the key concepts currently emerging is a possible additional role for the traditionally 'cilia-related' proteins in other aspects of cellular processes. In many cases, disruption of such processes manifests at the level of the cilium. While the involvement of cilia and cilia-related proteins in signaling pathways is currently being unraveled, there is a growing body of evidence to support the notion that ciliary proteins are required not only for regulation of Wnt signaling, but also as downstream effectors of Wnt signaling. This review summarizes recent advances in our understanding of the involvement of cilia and basal body proteins in Wnt signaling pathways.
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Affiliation(s)
- Helen L May-Simera
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, NIH, 35 Convent Drive, Bethesda, MD 20892, USA.
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99
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Luo N, West CC, Murga-Zamalloa CA, Sun L, Anderson RM, Wells CD, Weinreb RN, Travers JB, Khanna H, Sun Y. OCRL localizes to the primary cilium: a new role for cilia in Lowe syndrome. Hum Mol Genet 2012; 21:3333-44. [PMID: 22543976 PMCID: PMC3392109 DOI: 10.1093/hmg/dds163] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Oculocerebral renal syndrome of Lowe (OCRL or Lowe syndrome), a severe X-linked congenital disorder characterized by congenital cataracts and glaucoma, mental retardation and kidney dysfunction, is caused by mutations in the OCRL gene. OCRL is a phosphoinositide 5-phosphatase that interacts with small GTPases and is involved in intracellular trafficking. Despite extensive studies, it is unclear how OCRL mutations result in a myriad of phenotypes found in Lowe syndrome. Our results show that OCRL localizes to the primary cilium of retinal pigment epithelial cells, fibroblasts and kidney tubular cells. Lowe syndrome-associated mutations in OCRL result in shortened cilia and this phenotype can be rescued by the introduction of wild-type OCRL; in vivo, knockdown of ocrl in zebrafish embryos results in defective cilia formation in Kupffer vesicles and cilia-dependent phenotypes. Cumulatively, our data provide evidence for a role of OCRL in cilia maintenance and suggest the involvement of ciliary dysfunction in the manifestation of Lowe syndrome.
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Affiliation(s)
- Na Luo
- Department of Ophthalmology, Glick Eye Institute, Indiana University, 1601 W Michigan St., Indianapolis, IN 46202, USA
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100
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Kersten FF, van Wijk E, Hetterschijt L, Bauβ K, Peters TA, Aslanyan MG, van der Zwaag B, Wolfrum U, Keunen JE, Roepman R, Kremer H. The mitotic spindle protein SPAG5/Astrin connects to the Usher protein network postmitotically. Cilia 2012; 1:2. [PMID: 23351521 PMCID: PMC3541543 DOI: 10.1186/2046-2530-1-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 04/25/2012] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED BACKGROUND Mutations in the gene for Usher syndrome 2A (USH2A) are causative for non-syndromic retinitis pigmentosa and Usher syndrome, a condition that is the most common cause of combined deaf-blindness. To gain insight into the molecular pathology underlying USH2A-associated retinal degeneration, we aimed to identify interacting proteins of USH2A isoform B (USH2AisoB) in the retina. RESULTS We identified the centrosomal and microtubule-associated protein sperm-associated antigen (SPAG)5 in the retina. SPAG5 was also found to interact with another previously described USH2AisoB interaction partner: the centrosomal ninein-like protein NINLisoB. Using In situ hybridization, we found that Spag5 was widely expressed during murine embryonic development, with prominent signals in the eye, cochlea, brain, kidney and liver. SPAG5 expression in adult human tissues was detected by quantitative PCR, which identified expression in the retina, brain, intestine, kidney and testis. In the retina, Spag5, Ush2aisoB and NinlisoB were present at several subcellular structures of photoreceptor cells, and colocalized at the basal bodies. CONCLUSIONS Based on these results and on the suggested roles for USH proteins in vesicle transport and providing structural support to both the inner ear and the retina, we hypothesize that SPAG5, USH2AisoB and NINLisoB may function together in microtubule-based cytoplasmic trafficking of proteins that are essential for cilium formation, maintenance and/or function.
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Affiliation(s)
- Ferry Fj Kersten
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
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