1
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Wolfram M, Greif A, Baidukova O, Voll H, Tauber S, Lindacher J, Hegemann P, Kreimer G. Insights into degradation and targeting of the photoreceptor channelrhodopsin-1. PLANT, CELL & ENVIRONMENT 2024; 47:4188-4211. [PMID: 38935876 DOI: 10.1111/pce.15017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/05/2024] [Accepted: 06/11/2024] [Indexed: 06/29/2024]
Abstract
In Chlamydomonas, the directly light-gated, plasma membrane-localized cation channels channelrhodopsins ChR1 and ChR2 are the primary photoreceptors for phototaxis. Their targeting and abundance is essential for optimal movement responses. However, our knowledge how Chlamydomonas achieves this is still at its infancy. Here we show that ChR1 internalization occurs via light-stimulated endocytosis. Prior or during endocytosis ChR1 is modified and forms high molecular mass complexes. These are the solely detectable ChR1 forms in extracellular vesicles and their abundance therein dynamically changes upon illumination. The ChR1-containing extracellular vesicles are secreted via the plasma membrane and/or the ciliary base. In line with this, ciliogenesis mutants exhibit increased ChR1 degradation rates. Further, we establish involvement of the cysteine protease CEP1, a member of the papain-type C1A subfamily. ΔCEP1-knockout strains lack light-induced ChR1 degradation, whereas ChR2 degradation was unaffected. Low light stimulates CEP1 expression, which is regulated via phototropin, a SPA1 E3 ubiquitin ligase and cyclic AMP. Further, mutant and inhibitor analyses revealed involvement of the small GTPase ARL11 and SUMOylation in ChR1 targeting to the eyespot and cilia. Our study thus defines the degradation pathway of this central photoreceptor of Chlamydomonas and identifies novel elements involved in its homoeostasis and targeting.
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Affiliation(s)
- Michaela Wolfram
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Arne Greif
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Olga Baidukova
- Institute of Biology, Experimental Biophysics, Humboldt Universität, Berlin, Germany
| | - Hildegard Voll
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Sandra Tauber
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Jana Lindacher
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt Universität, Berlin, Germany
| | - Georg Kreimer
- Department of Biology, Cell Biology, Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
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2
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Lewis TR, Castillo CM, Klementieva NV, Hsu Y, Hao Y, Spencer WJ, Drack AV, Pazour GJ, Arshavsky VY. Contribution of intraflagellar transport to compartmentalization and maintenance of the photoreceptor cell. Proc Natl Acad Sci U S A 2024; 121:e2408551121. [PMID: 39145934 PMCID: PMC11348033 DOI: 10.1073/pnas.2408551121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/15/2024] [Indexed: 08/16/2024] Open
Abstract
The first steps of vision take place in the ciliary outer segment compartment of photoreceptor cells. The protein composition of outer segments is uniquely suited to perform this function. The most abundant among these proteins is the visual pigment, rhodopsin, whose outer segment trafficking involves intraflagellar transport (IFT). Here, we report three major findings from the analysis of mice in which ciliary transport was acutely impaired by conditional knockouts of IFT-B subunits. First, we demonstrate the existence of a sorting mechanism whereby mislocalized rhodopsin is recruited to and concentrated in extracellular vesicles prior to their release, presumably to protect the cell from adverse effects of protein mislocalization. Second, reducing rhodopsin expression significantly delays photoreceptor degeneration caused by IFT disruption, suggesting that controlling rhodopsin levels may be an effective therapy for some cases of retinal degenerative disease. Last, the loss of IFT-B subunits does not recapitulate a phenotype observed in mutants of the BBSome (another ciliary transport protein complex relying on IFT) in which non-ciliary proteins accumulate in the outer segment. Whereas it is widely thought that the role of the BBSome is to primarily participate in ciliary transport, our data suggest that the BBSome has another major function independent of IFT and possibly related to maintaining the diffusion barrier of the ciliary transition zone.
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Affiliation(s)
- Tylor R. Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | - Carson M. Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | | | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA52242
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | - William J. Spencer
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA52242
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA01605
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC27710
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3
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Zhang X, Yao S, Zhang L, Yang L, Yang M, Guo Q, Li Y, Wang Z, Lei B, Jin X. Mechanisms underlying morphological and functional changes of cilia in fibroblasts derived from patients bearing ARL3 T31A and ARL3 T31A/C118F mutations. FASEB J 2024; 38:e23519. [PMID: 38457249 DOI: 10.1096/fj.202301906r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/31/2024] [Accepted: 02/15/2024] [Indexed: 03/10/2024]
Abstract
ARL3 is essential for cilia development, and mutations in ARL3 are closely associated with ciliopathies. In a previous study, we observed distinct phenotypes of retinal dystrophy in patients with heterozygous ARL3T31A and compound heterozygous ARL3T31A/C118F mutations, indicating that different mutation types may exert diverse effects on their functions. Here, we generated transformed immortal fibroblast cells from patients carrying heterozygous ARL3T31A and compound heterozygous ARL3T31A/C118F mutations, and systematically evaluated their cilia morphology and function, which were further validated in ARPE-19 cells. Results showed that both ARL3T31A and ARL3T31A/C118F mutations led to a decrease in cilium formation. The ARL3T31A/C118F mutations caused significantly elongated cilia and impaired retrograde transport, whereas the ARL3T31A mutation did not induce significant changes in fibroblasts. RNA-sequencing results indicated that compared to ARL3T31A , ARL3T31A/C118F fibroblasts exhibited a higher enrichment of biological processes related to neuron projection development, tissue morphogenesis, and extracellular matrix (ECM) organization, with noticeable alterations in pathways such as ECM-receptor interaction, focal adhesion, and TGF-β signaling. Similar changes were observed in the proteomic results in ARPE-19 cells. Core regulated genes including IQUB, UNC13D, RAB3IP, and GRIP1 were specifically downregulated in the ARL3T31A/C118F group, and expressions of IQUB, NPM2, and SLC38A4 were further validated. Additionally, IQUB showed a rescuing effect on the overlong cilia observed in ARL3T31A/C118F fibroblasts. Our results not only enhance our understanding of ARL3-related diseases but also provide new insights into the analysis of heterozygous and compound heterozygous mutations in genetics.
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Affiliation(s)
- Xiaoli Zhang
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
- Institute of Neuroscience and The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Eye Institute, Henan Academy of Innovations in Medical Science, Zhengzhou, Henan, China
| | - Shun Yao
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Lujia Zhang
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
- Institute of Neuroscience and The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Lin Yang
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Mingzhu Yang
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Qingge Guo
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Yan Li
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Zhongfeng Wang
- Institute of Neuroscience and The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Bo Lei
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
- Eye Institute, Henan Academy of Innovations in Medical Science, Zhengzhou, Henan, China
| | - Xiuxiu Jin
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, Henan, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
- Eye Institute, Henan Academy of Innovations in Medical Science, Zhengzhou, Henan, China
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4
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Haggerty KN, Eshelman SC, Sexton LA, Frimpong E, Rogers LM, Agosto MA, Robichaux MA. Super-resolution mapping in rod photoreceptors identifies rhodopsin trafficking through the inner segment plasma membrane as an essential subcellular pathway. PLoS Biol 2024; 22:e3002467. [PMID: 38190419 PMCID: PMC10773939 DOI: 10.1371/journal.pbio.3002467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 12/10/2023] [Indexed: 01/10/2024] Open
Abstract
Photoreceptor cells in the vertebrate retina have a highly compartmentalized morphology for efficient phototransduction and vision. Rhodopsin, the visual pigment in rod photoreceptors, is densely packaged into the rod outer segment sensory cilium and continuously renewed through essential synthesis and trafficking pathways housed in the rod inner segment. Despite the importance of this region for rod health and maintenance, the subcellular organization of rhodopsin and its trafficking regulators in the mammalian rod inner segment remain undefined. We used super-resolution fluorescence microscopy with optimized retinal immunolabeling techniques to perform a single molecule localization analysis of rhodopsin in the inner segments of mouse rods. We found that a significant fraction of rhodopsin molecules was localized at the plasma membrane, at the surface, in an even distribution along the entire length of the inner segment, where markers of transport vesicles also colocalized. Thus, our results collectively establish a model of rhodopsin trafficking through the inner segment plasma membrane as an essential subcellular pathway in mouse rod photoreceptors.
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Affiliation(s)
- Kristen N. Haggerty
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Shannon C. Eshelman
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Lauren A. Sexton
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Emmanuel Frimpong
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Leah M. Rogers
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, West Virginia, United States of America
| | - Melina A. Agosto
- Retina and Optic Nerve Research Laboratory, Department of Physiology and Biophysics, and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michael A. Robichaux
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, West Virginia, United States of America
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5
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Gupta M, Pazour GJ. Intraflagellar transport: A critical player in photoreceptor development and the pathogenesis of retinal degenerative diseases. Cytoskeleton (Hoboken) 2023:10.1002/cm.21823. [PMID: 38140908 PMCID: PMC11193844 DOI: 10.1002/cm.21823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
In vertebrate vision, photons are detected by highly specialized sensory cilia called outer segments. Photoreceptor outer segments form by remodeling the membrane of a primary cilium into a stack of flattened disks. Intraflagellar transport (IFT) is critical to the formation of most types of eukaryotic cilia including the outer segments. This review covers the state of knowledge of the role of IFT in the formation and maintenance of outer segments and the human diseases that result from mutations in genes encoding the IFT complex and associated motors.
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Affiliation(s)
- Mohona Gupta
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Suite 213 Biotech II, 373 Plantation Street, Worcester MA USA 01605
- Morningside Graduate School of Biological Sciences, University of Massachusetts Chan Medical School, 55 Lake Avenue North, Worcester MA USA 01655
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Suite 213 Biotech II, 373 Plantation Street, Worcester MA USA 01605
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6
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Kretschmer V, Schneider S, Matthiessen PA, Reichert D, Hotaling N, Glasßer G, Lieberwirth I, Bharti K, De Cegli R, Conte I, Nandrot EF, May-Simera HL. Deletion of IFT20 exclusively in the RPE ablates primary cilia and leads to retinal degeneration. PLoS Biol 2023; 21:e3002402. [PMID: 38048369 PMCID: PMC10721183 DOI: 10.1371/journal.pbio.3002402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/14/2023] [Accepted: 10/26/2023] [Indexed: 12/06/2023] Open
Abstract
Vision impairment places a serious burden on the aging society, affecting the lives of millions of people. Many retinal diseases are of genetic origin, of which over 50% are due to mutations in cilia-associated genes. Most research on retinal degeneration has focused on the ciliated photoreceptor cells of the retina. However, the contribution of primary cilia in other ocular cell types has largely been ignored. The retinal pigment epithelium (RPE) is a monolayer epithelium at the back of the eye intricately associated with photoreceptors and essential for visual function. It is already known that primary cilia in the RPE are critical for its development and maturation; however, it remains unclear whether this affects RPE function and retinal tissue homeostasis. We generated a conditional knockout mouse model, in which IFT20 is exclusively deleted in the RPE, ablating primary cilia. This leads to defective RPE function, followed by photoreceptor degeneration and, ultimately, vision impairment. Transcriptomic analysis offers insights into mechanisms underlying pathogenic changes, which include transcripts related to epithelial homeostasis, the visual cycle, and phagocytosis. Due to the loss of cilia exclusively in the RPE, this mouse model enables us to tease out the functional role of RPE cilia and their contribution to retinal degeneration, providing a powerful tool for basic and translational research in syndromic and non-syndromic retinal degeneration. Non-ciliary mechanisms of IFT20 in the RPE may also contribute to pathogenesis and cannot be excluded, especially considering the increasing evidence of non-ciliary functions of ciliary proteins.
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Affiliation(s)
- Viola Kretschmer
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
| | - Sandra Schneider
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
| | - Peter Andreas Matthiessen
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
| | - Dominik Reichert
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nathan Hotaling
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Gunnar Glasßer
- Max Planck Institute for Polymer Research, Mainz, Germany
| | | | - Kapil Bharti
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rossella De Cegli
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- University of Naples “Federico II”, Naples, Italy
| | | | - Helen Louise May-Simera
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
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7
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Masek M, Bachmann-Gagescu R. Control of protein and lipid composition of photoreceptor outer segments-Implications for retinal disease. Curr Top Dev Biol 2023; 155:165-225. [PMID: 38043951 DOI: 10.1016/bs.ctdb.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Vision is arguably our most important sense, and its loss brings substantial limitations to daily life for affected individuals. Light is perceived in retinal photoreceptors (PRs), which are highly specialized neurons subdivided into several compartments with distinct functions. The outer segments (OSs) of photoreceptors represent highly specialized primary ciliary compartments hosting the phototransduction cascade, which transforms incoming light into a neuronal signal. Retinal disease can result from various pathomechanisms originating in distinct subcompartments of the PR cell, or in the retinal pigment epithelium which supports the PRs. Dysfunction of primary cilia causes human disorders known as "ciliopathies", in which retinal disease is a common feature. This chapter focuses on PR OSs, discussing the mechanisms controlling their complex structure and composition. A sequence of tightly regulated sorting and trafficking events, both upstream of and within this ciliary compartment, ensures the establishment and maintenance of the adequate proteome and lipidome required for signaling in response to light. We discuss in particular our current understanding of the role of ciliopathy proteins involved in multi-protein complexes at the ciliary transition zone (CC2D2A) or BBSome (BBS1) and how their dysfunction causes retinal disease. While the loss of CC2D2A prevents the fusion of vesicles and delivery of the photopigment rhodopsin to the ciliary base, leading to early OS ultrastructural defects, BBS1 deficiency results in precocious accumulation of cholesterol in mutant OSs and decreased visual function preceding morphological changes. These distinct pathomechanisms underscore the central role of ciliary proteins involved in multiple processes controlling OS protein and lipid composition.
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Affiliation(s)
- Markus Masek
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Zurich, Switzerland; Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland; University Research Priority Program AdaBD, University of Zurich, Zurich, Switzerland.
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8
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Li L, Li J, Yuan L. A direct interaction between CENTLEIN and RABIN8 is required for primary cilium formation. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1434-1444. [PMID: 37475549 PMCID: PMC10520482 DOI: 10.3724/abbs.2023064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 03/23/2023] [Indexed: 04/05/2023] Open
Abstract
Primary cilia are formed in nearly all growth-arrested cells and are essential for mammalian development and tissue homeostasis. Defects in primary cilia result in a range of disorders in humans, named ciliopathies. The spatiotemporal localization of RABIN8 on the pericentrosome is an early step in ciliogenesis. Here, we show that CENTLEIN depletion causes the persistent accumulation of RABIN8 on the pericentrosome and primary cilium loss in hTERT-immortalized retinal pigment epithelial cells and murine embryonic fibroblasts. CENTLEIN interacts with RABIN8 directly. A stretch of a 31-amino acid sequence located in the 200‒230 region of the RABIN8 GEF domain is responsible for its physical interaction with CENTLEIN, while expression of the full-length but not the internal deletion lacking the RABIN8-binding site of CENTLEIN largely rescues the ciliogenesis defect provoked by CENTLEIN depletion. Expression of activated RAB8A partially reverses cilium loss in CENTLEIN-null RPE1 cells, so the functional importance of the CENTLEIN-RABIN8 interaction is defined.
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Affiliation(s)
- Liansheng Li
- />Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijing101408China
| | - Junlin Li
- />Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijing101408China
| | - Li Yuan
- />Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijing101408China
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9
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Haggerty KN, Eshelman SC, Sexton LA, Frimpong E, Rogers LM, Agosto MA, Robichaux MA. Mapping rhodopsin trafficking in rod photoreceptors with quantitative super-resolution microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.20.537413. [PMID: 37131638 PMCID: PMC10153271 DOI: 10.1101/2023.04.20.537413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Photoreceptor cells in the vertebrate retina have a highly compartmentalized morphology for efficient long-term phototransduction. Rhodopsin, the visual pigment in rod photoreceptors, is densely packaged into the rod outer segment sensory cilium and continuously renewed through essential synthesis and trafficking pathways housed in the rod inner segment. Despite the importance of this region for rod health and maintenance, the subcellular organization of rhodopsin and its trafficking regulators in the mammalian rod inner segment remain undefined. We used super-resolution fluorescence microscopy with optimized retinal immunolabeling techniques to perform a single molecule localization analysis of rhodopsin in the inner segments of mouse rods. We found that a significant fraction of rhodopsin molecules was localized at the plasma membrane in an even distribution along the entire length of the inner segment, where markers of transport vesicles also colocalized. Thus, our results collectively establish a model of rhodopsin trafficking through the inner segment plasma membrane as an essential subcellular pathway in mouse rod photoreceptors.
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Affiliation(s)
- Kristen N. Haggerty
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, WV, 26506
| | - Shannon C. Eshelman
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, WV, 26506
| | - Lauren A. Sexton
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, WV, 26506
| | - Emmanuel Frimpong
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, WV, 26506
| | - Leah M. Rogers
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, WV, 26506
| | - Melina A. Agosto
- Retina and Optic Nerve Research Laboratory, Department of Physiology and Biophysics, and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Michael A. Robichaux
- Department of Ophthalmology & Visual Sciences and Department of Biochemistry & Molecular Medicine, West Virginia University, Morgantown, WV, 26506
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10
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Jeong J, Kang I, Kim Y, Ku KB, Park JH, Kim HJ, Kim CW, La J, Jung HE, Kim HC, Choi YJ, Kim J, Kim J, Lee HK. Regulation of c-SMAC formation and AKT-mTOR signaling by the TSG101-IFT20 axis in CD4 + T cells. Cell Mol Immunol 2023; 20:525-539. [PMID: 37029318 DOI: 10.1038/s41423-023-01008-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/14/2023] [Indexed: 04/09/2023] Open
Abstract
CD4+ T cells play major roles in the adaptive immune system, which requires antigen recognition, costimulation, and cytokines for its elaborate orchestration. Recent studies have provided new insight into the importance of the supramolecular activation cluster (SMAC), which comprises concentric circles and is involved in the amplification of CD4+ T cell activation. However, the underlying mechanism of SMAC formation remains poorly understood. Here, we performed single-cell RNA sequencing of CD4+ T cells left unstimulated and stimulated with anti-CD3 and anti-CD28 antibodies to identify novel proteins involved in their regulation. We found that intraflagellar transport 20 (IFT20), previously known as cilia-forming protein, was upregulated in antibody-stimulated CD4+ T cells compared to unstimulated CD4+ T cells. We also found that IFT20 interacted with tumor susceptibility gene 101 (TSG101), a protein that endocytoses ubiquitinated T-cell receptors. The interaction between IFT20 and TSG101 promoted SMAC formation, which led to amplification of AKT-mTOR signaling. However, IFT20-deficient CD4+ T cells showed SMAC malformation, resulting in reduced CD4+ T cell proliferation, aerobic glycolysis, and cellular respiration. Finally, mice with T-cell-specific IFT20 deficiency exhibited reduced allergen-induced airway inflammation. Thus, our data suggest that the IFT20-TSG101 axis regulates AKT-mTOR signaling via SMAC formation.
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Affiliation(s)
- Jiung Jeong
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital, Seoul, 03080, Republic of Korea
| | - In Kang
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yumin Kim
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea
| | - Keun Bon Ku
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- Department of Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea
| | - Jang Hyun Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hyun-Jin Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Chae Won Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jeongwoo La
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hi Eun Jung
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hyeon Cheol Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Young Joon Choi
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jaeho Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Joon Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Heung Kyu Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea.
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11
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Stevenson NL. The factory, the antenna and the scaffold: the three-way interplay between the Golgi, cilium and extracellular matrix underlying tissue function. Biol Open 2023; 12:287059. [PMID: 36802341 PMCID: PMC9986613 DOI: 10.1242/bio.059719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
The growth and development of healthy tissues is dependent on the construction of a highly specialised extracellular matrix (ECM) to provide support for cell growth and migration and to determine the biomechanical properties of the tissue. These scaffolds are composed of extensively glycosylated proteins which are secreted and assembled into well-ordered structures that can hydrate, mineralise, and store growth factors as required. The proteolytic processing and glycosylation of ECM components is vital to their function. These modifications are under the control of the Golgi apparatus, an intracellular factory hosting spatially organised, protein-modifying enzymes. Regulation also requires a cellular antenna, the cilium, which integrates extracellular growth signals and mechanical cues to inform ECM production. Consequently, mutations in either Golgi or ciliary genes frequently lead to connective tissue disorders. The individual importance of each of these organelles to ECM function is well-studied. However, emerging evidence points towards a more tightly linked system of interdependence between the Golgi, cilium and ECM. This review examines how the interplay between all three compartments underpins healthy tissue. As an example, it will look at several members of the golgin family of Golgi-resident proteins whose loss is detrimental to connective tissue function. This perspective will be important for many future studies looking to dissect the cause and effect of mutations impacting tissue integrity.
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Affiliation(s)
- Nicola L Stevenson
- Cell Biology Laboratories, School of Biochemistry, Faculty of Biomedical Sciences University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
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12
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Zhu T, Zhang Y, Sheng X, Zhang X, Chen Y, Zhu H, Guo Y, Qi Y, Zhao Y, Zhou Q, Chen X, Guo X, Zhao C. Absence of CEP78 causes photoreceptor and sperm flagella impairments in mice and a human individual. eLife 2023; 12:76157. [PMID: 36756949 PMCID: PMC9984195 DOI: 10.7554/elife.76157] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/07/2023] [Indexed: 02/10/2023] Open
Abstract
Cone-rod dystrophy (CRD) is a genetically inherited retinal disease that can be associated with male infertility, while the specific genetic mechanisms are not well known. Here, we report CEP78 as a causative gene of a particular syndrome including CRD and male infertility with multiple morphological abnormalities of sperm flagella (MMAF) both in human and mouse. Cep78 knockout mice exhibited impaired function and morphology of photoreceptors, typified by reduced ERG amplitudes, disrupted translocation of cone arrestin, attenuated and disorganized photoreceptor outer segments (OS) disks and widen OS bases, as well as interrupted connecting cilia elongation and abnormal structures. Cep78 deletion also caused male infertility and MMAF, with disordered '9+2' structure and triplet microtubules in sperm flagella. Intraflagellar transport (IFT) proteins IFT20 and TTC21A are identified as interacting proteins of CEP78. Furthermore, CEP78 regulated the interaction, stability, and centriolar localization of its interacting protein. Insufficiency of CEP78 or its interacting protein causes abnormal centriole elongation and cilia shortening. Absence of CEP78 protein in human caused similar phenotypes in vision and MMAF as Cep78-/- mice. Collectively, our study supports the important roles of CEP78 defects in centriole and ciliary dysfunctions and molecular pathogenesis of such multi-system syndrome.
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Affiliation(s)
- Tianyu Zhu
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Yuxin Zhang
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Shanghai Medical College, Fudan UniversityShanghaiChina
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical UniversityNanjingChina
| | - Xunlun Sheng
- Gansu Aier Ophthalmiology and Optometry HospitalLanzhouChina
- Ningxia Eye Hospital, People’s Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical UniversityYinchuanChina
| | - Xiangzheng Zhang
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Yu Chen
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Hongjing Zhu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical UniversityNanjingChina
| | - Yueshuai Guo
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Yaling Qi
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Yichen Zhao
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Qi Zhou
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Xue Chen
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing Medical UniversityNanjingChina
| | - Xuejiang Guo
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Gusu School, Nanjing Medical UniversityNanjingChina
| | - Chen Zhao
- Department of Ophthalmology and Vision Science, Eye & ENT Hospital, Shanghai Medical College, Fudan UniversityShanghaiChina
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13
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Mdm1 ablation results in retinal degeneration by specific intraflagellar transport defects of photoreceptor cells. Cell Death Dis 2022; 13:833. [PMID: 36171205 PMCID: PMC9519634 DOI: 10.1038/s41419-022-05237-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 01/23/2023]
Abstract
Mouse double minute 1 (Mdm1) might be involved in the function and structure of centrioles and age-related retinal degeneration. However, the mechanism by which Mdm1 deficiency causes retinal degeneration remains unknown. We confirmed that the Mdm1 protein is localized at the connecting cilium (CC) of photoreceptor cells in the retina. The electroretinograms of 6-week-old Mdm1-/- mice revealed decreased vision, which was eventually lost, and outer segment (OS) photoreceptor degeneration was evident on postnatal day 7, with complete loss of the outer nuclear layer (ONL) observed at 35 weeks. Mdm1-/- mouse retinas showed mislocalization of opsins in the photoreceptor cells, indicating particular intraflagellar transport (IFT) defects, and entrapment of the nuclei in the ONL by microvilli of retinal pigment epithelial cells, leading to apoptosis in the ONL. These results suggest that Mdm1 ablation causes specific IFT defects, which prevents the OS from continuously replenishing new discs, resulting in retinal degeneration.
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14
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Golgi Dysfunctions in Ciliopathies. Cells 2022; 11:cells11182773. [PMID: 36139347 PMCID: PMC9496873 DOI: 10.3390/cells11182773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
The Golgi apparatus (GA) is essential for intracellular sorting, trafficking and the targeting of proteins to specific cellular compartments. Anatomically, the GA spreads all over the cell but is also particularly enriched close to the base of the primary cilium. This peculiar organelle protrudes at the surface of almost all cells and fulfills many cellular functions, in particular during development, when a dysfunction of the primary cilium can lead to disorders called ciliopathies. While ciliopathies caused by loss of ciliated proteins have been extensively documented, several studies suggest that alterations of GA and GA-associated proteins can also affect ciliogenesis. Here, we aim to discuss how the loss-of-function of genes coding these proteins induces ciliary defects and results in ciliopathies.
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15
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Reed M, Takemaru KI, Ying G, Frederick JM, Baehr W. Deletion of CEP164 in mouse photoreceptors post-ciliogenesis interrupts ciliary intraflagellar transport (IFT). PLoS Genet 2022; 18:e1010154. [PMID: 36074756 PMCID: PMC9488791 DOI: 10.1371/journal.pgen.1010154] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 09/20/2022] [Accepted: 07/20/2022] [Indexed: 11/18/2022] Open
Abstract
Centrosomal protein of 164 kDa (CEP164) is located at distal appendages of primary cilia and is necessary for basal body (BB) docking to the apical membrane. To investigate the function of photoreceptor CEP164 before and after BB docking, we deleted CEP164 during retina embryonic development (Six3Cre), in postnatal rod photoreceptors (iCre75) and in mature retina using tamoxifen induction (Prom1-ETCre). BBs dock to the cell cortex during postnatal day 6 (P6) to extend a connecting cilium (CC) and an axoneme. P6 retina-specific knockouts (retCep164-/-) are unable to dock BBs, thereby preventing formation of CC or outer segments (OSs). In rod-specific knockouts (rodCep164-/-), Cre expression starts after P7 and CC/OS form. P16 rodCep164-/- rods have nearly normal OS lengths, and maintain OS attachment through P21 despite loss of CEP164. Intraflagellar transport components (IFT88, IFT57 and IFT140) were reduced at P16 rodCep164-/- BBs and CC tips and nearly absent at P21, indicating impaired intraflagellar transport. Nascent OS discs, labeled with a fluorescent dye on P14 and P18 and harvested on P19, showed continued rodCep164-/- disc morphogenesis but absence of P14 discs mid-distally, indicating OS instability. Tamoxifen induction with PROM1ETCre;Cep164F/F (tamCep164-/-) adult mice affected maintenance of both rod and cone OSs. The results suggest that CEP164 is key towards recruitment and stabilization of IFT-B particles at the BB/CC. IFT impairment may be the main driver of ciliary malfunction observed with hypomorphic CEP164 mutations.
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Affiliation(s)
- Michelle Reed
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Ken-Ichi Takemaru
- Stony Brook University, Department of Pharmacological Sciences, Stony Brook, New York, United States of America
| | - Guoxin Ying
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Jeanne M. Frederick
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
| | - Wolfgang Baehr
- Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah, United States of America
- Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biology, University of Utah, Salt Lake City, Utah, United States of America
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16
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Tmem138 is localized to the connecting cilium essential for rhodopsin localization and outer segment biogenesis. Proc Natl Acad Sci U S A 2022; 119:e2109934119. [PMID: 35394880 PMCID: PMC9169668 DOI: 10.1073/pnas.2109934119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The connecting cilium (CC) of the photoreceptor provides the only route for the trafficking of the outer segment (OS) proteins. Failure of OS protein transport causes degenerative photoreceptor diseases, including retinitis pigmentosa. We demonstrate that Tmem138, a protein linked to ciliopathy, is localized to the photoreceptor CC. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 interacts with rhodopsin and two additional CC compartment proteins, Ahi1 and Tmem231, likely forming a membrane complex to facilitate trafficking of rhodopsin and other OS-bound proteins across the CC. The study thus implicates a new line of regulation on the delivery of OS proteins through interactions with CC membrane complex(es) and provides insights into photoreceptor ciliopathy diseases. Photoreceptor connecting cilium (CC) is structurally analogous to the transition zone (TZ) of primary cilia and gates the molecular trafficking between the inner and the outer segment (OS). Retinal dystrophies with underlying CC defects are manifested in a broad array of syndromic conditions known as ciliopathies as well as nonsyndromic retinal degenerations. Despite extensive studies, many questions remain in the mechanism of protein trafficking across the photoreceptor CC. Here, we genetically inactivated mouse Tmem138, a gene encoding a putative transmembrane protein localized to the ciliary TZ and linked to ciliopathies. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 was found localized to the photoreceptor CC and was required for localization of Ahi1 to the distal subdomain of the CC. Among the examined set of OS proteins, rhodopsin was mislocalized throughout the mutant cell body prior to OS morphogenesis. Ablation of Tmem138 in mature rods recapitulated the molecular changes in the germline mutants, causing failure of disc renewal and disintegration of the OS. Furthermore, Tmem138 interacts reciprocally with rhodopsin and a related protein Tmem231, and the ciliary localization of the latter was also altered in the mutant photoreceptors. Taken together, these results suggest a crucial role of Tmem138 in the functional organization of the CC, which is essential for rhodopsin localization and OS biogenesis.
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17
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Dewees SI, Vargová R, Hardin KR, Turn RE, Devi S, Linnert J, Wolfrum U, Caspary T, Eliáš M, Kahn RA. Phylogenetic profiling and cellular analyses of ARL16 reveal roles in traffic of IFT140 and INPP5E. Mol Biol Cell 2022; 33:ar33. [PMID: 35196065 PMCID: PMC9250359 DOI: 10.1091/mbc.e21-10-0509-t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/11/2022] [Accepted: 02/18/2022] [Indexed: 12/14/2022] Open
Abstract
The ARF family of regulatory GTPases is ancient, with 16 members predicted to have been present in the last eukaryotic common ancestor. Our phylogenetic profiling of paralogues in diverse species identified four family members whose presence correlates with that of a cilium/flagellum: ARL3, ARL6, ARL13, and ARL16. No prior evidence links ARL16 to cilia or other cell functions, despite its presence throughout eukaryotes. Deletion of ARL16 in mouse embryonic fibroblasts (MEFs) results in decreased ciliogenesis yet increased ciliary length. We also found Arl16 knockout (KO) in MEFs to alter ciliary protein content, including loss of ARL13B, ARL3, INPP5E, and the IFT-A core component IFT140. Instead, both INPP5E and IFT140 accumulate at the Golgi in Arl16 KO lines, while other intraflagellar transport (IFT) proteins do not, suggesting a specific defect in traffic from Golgi to cilia. We propose that ARL16 regulates a Golgi-cilia traffic pathway and is required specifically in the export of IFT140 and INPP5E from the Golgi.
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Affiliation(s)
- Skylar I. Dewees
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30307
| | - Romana Vargová
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, CZ-710 00, Ostrava, Czech Republic
| | - Katherine R. Hardin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30307
| | - Rachel E. Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30307
- Department of Microbiology and Immunology, Stanford University, Palo Alto, CA 94305-5124
| | - Saroja Devi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Joshua Linnert
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, CZ-710 00, Ostrava, Czech Republic
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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18
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Turn RE, Hu Y, Dewees SI, Devi N, East MP, Hardin KR, Khatib T, Linnert J, Wolfrum U, Lim MJ, Casanova JE, Caspary T, Kahn RA. The ARF GAPs ELMOD1 and ELMOD3 act at the Golgi and cilia to regulate ciliogenesis and ciliary protein traffic. Mol Biol Cell 2022; 33:ar13. [PMID: 34818063 PMCID: PMC9236152 DOI: 10.1091/mbc.e21-09-0443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/11/2022] Open
Abstract
ELMODs are a family of three mammalian paralogues that display GTPase-activating protein (GAP) activity toward a uniquely broad array of ADP-ribosylation factor (ARF) family GTPases that includes ARF-like (ARL) proteins. ELMODs are ubiquitously expressed in mammalian tissues, highly conserved across eukaryotes, and ancient in origin, being present in the last eukaryotic common ancestor. We described functions of ELMOD2 in immortalized mouse embryonic fibroblasts (MEFs) in the regulation of cell division, microtubules, ciliogenesis, and mitochondrial fusion. Here, using similar strategies with the paralogues ELMOD1 and ELMOD3, we identify novel functions and locations of these cell regulators and compare them to those of ELMOD2, allowing the determination of functional redundancy among the family members. We found strong similarities in phenotypes resulting from deletion of either Elmod1 or Elmod3 and marked differences from those arising in Elmod2 deletion lines. Deletion of either Elmod1 or Elmod3 results in the decreased ability of cells to form primary cilia, loss of a subset of proteins from cilia, and accumulation of some ciliary proteins at the Golgi, predicted to result from compromised traffic from the Golgi to cilia. These phenotypes are reversed upon activating mutant expression of either ARL3 or ARL16, linking their roles to ELMOD1/3 actions.
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Affiliation(s)
- Rachel E. Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
- Department of Microbiology and Immunology, Stanford University, Palo Alto, CA 94305
| | - Yihan Hu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan, China
| | - Skylar I. Dewees
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Narra Devi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Michael P. East
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Katherine R. Hardin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Tala Khatib
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Joshua Linnert
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Michael J. Lim
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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19
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Chandra B, Tung ML, Hsu Y, Scheetz T, Sheffield VC. Retinal ciliopathies through the lens of Bardet-Biedl Syndrome: Past, present and future. Prog Retin Eye Res 2021; 89:101035. [PMID: 34929400 DOI: 10.1016/j.preteyeres.2021.101035] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
The primary cilium is a highly specialized and evolutionary conserved organelle in eukaryotes that plays a significant role in cell signaling and trafficking. Over the past few decades tremendous progress has been made in understanding the physiology of cilia and the underlying pathomechanisms of various ciliopathies. Syndromic ciliopathies consist of a group of disorders caused by ciliary dysfunction or abnormal ciliogenesis. These disorders have multiorgan involvement in addition to retinal degeneration underscoring the ubiquitous distribution of primary cilia in different cell types. Genotype-phenotype correlation is often challenging due to the allelic heterogeneity and pleiotropy of these disorders. In this review, we discuss the clinical and genetic features of syndromic ciliopathies with a focus on Bardet-Biedl syndrome (BBS) as a representative disorder. We discuss the structure and function of primary cilia and their role in retinal photoreceptors. We describe the progress made thus far in understanding the functional and genetic characterization including expression quantitative trait locus (eQTL) analysis of BBS genes. In the future directions section, we discuss the emerging technologies, such as gene therapy, as well as anticipated challenges and their implications in therapeutic development for ciliopathies.
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Affiliation(s)
- Bharatendu Chandra
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Moon Ley Tung
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Todd Scheetz
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Val C Sheffield
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA.
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20
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Hong JJ, Kim KE, Park SY, Bok J, Seo JT, Moon SJ. Differential Roles of Tubby Family Proteins in Ciliary Formation and Trafficking. Mol Cells 2021; 44:591-601. [PMID: 34462398 PMCID: PMC8424140 DOI: 10.14348/molcells.2021.0082] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/13/2022] Open
Abstract
Cilia are highly specialized organelles that extend from the cell membrane and function as cellular signaling hubs. Thus, cilia formation and the trafficking of signaling molecules into cilia are essential cellular processes. TULP3 and Tubby (TUB) are members of the tubby-like protein (TULP) family that regulate the ciliary trafficking of G-protein coupled receptors, but the functions of the remaining TULPs (i.e., TULP1 and TULP2) remain unclear. Herein, we explore whether these four structurally similar TULPs share a molecular function in ciliary protein trafficking. We found that TULP3 and TUB, but not TULP1 or TULP2, can rescue the defective cilia formation observed in TULP3-knockout (KO) hTERT RPE-1 cells. TULP3 and TUB also fully rescue the defective ciliary localization of ARL13B, INPP5E, and GPR161 in TULP3 KO RPE-1 cells, while TULP1 and TULP2 only mediate partial rescues. Furthermore, loss of TULP3 results in abnormal IFT140 localization, which can be fully rescued by TUB and partially rescued by TULP1 and TULP2. TUB's capacity for binding IFT-A is essential for its role in cilia formation and ciliary protein trafficking in RPE-1 cells, whereas its capacity for PIP2 binding is required for proper cilia length and IFT140 localization. Finally, chimeric TULP1 containing the IFT-A binding domain of TULP3 fully rescues ciliary protein trafficking, but not cilia formation. Together, these two TULP domains play distinct roles in ciliary protein trafficking but are insufficient for cilia formation in RPE-1 cells. In addition, TULP1 and TULP2 play other unknown molecular roles that should be addressed in the future.
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Affiliation(s)
- Julie J. Hong
- Department of Oral Biology, BK 21 FOUR Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - Kyung Eun Kim
- Department of Oral Biology, BK 21 FOUR Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - So Young Park
- Department of Oral Biology, BK 21 FOUR Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - Jinwoong Bok
- Department of Anatomy, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Jeong Taeg Seo
- Department of Oral Biology, BK 21 FOUR Project, Yonsei University College of Dentistry, Seoul 03722, Korea
| | - Seok Jun Moon
- Department of Oral Biology, BK 21 FOUR Project, Yonsei University College of Dentistry, Seoul 03722, Korea
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21
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Ratnapriya R, Acar İE, Geerlings MJ, Branham K, Kwong A, Saksens NTM, Pauper M, Corominas J, Kwicklis M, Zipprer D, Starostik MR, Othman M, Yashar B, Abecasis GR, Chew EY, Ferrington DA, Hoyng CB, Swaroop A, den Hollander AI. Family-based exome sequencing identifies rare coding variants in age-related macular degeneration. Hum Mol Genet 2021; 29:2022-2034. [PMID: 32246154 PMCID: PMC7390936 DOI: 10.1093/hmg/ddaa057] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/18/2020] [Accepted: 03/26/2020] [Indexed: 12/24/2022] Open
Abstract
Genome-wide association studies (GWAS) have identified 52 independent variants at 34 genetic loci that are associated with age-related macular degeneration (AMD), the most common cause of incurable vision loss in the elderly worldwide. However, causal genes at the majority of these loci remain unknown. In this study, we performed whole exome sequencing of 264 individuals from 63 multiplex families with AMD and analyzed the data for rare protein-altering variants in candidate target genes at AMD-associated loci. Rare coding variants were identified in the CFH, PUS7, RXFP2, PHF12 and TACC2 genes in three or more families. In addition, we detected rare coding variants in the C9, SPEF2 and BCAR1 genes, which were previously suggested as likely causative genes at respective AMD susceptibility loci. Identification of rare variants in the CFH and C9 genes in our study validated previous reports of rare variants in complement pathway genes in AMD. We then extended our exome-wide analysis and identified rare protein-altering variants in 13 genes outside the AMD-GWAS loci in three or more families. Two of these genes, SCN10A and KIR2DL4, are of interest because variants in these genes also showed association with AMD in case-control cohorts, albeit not at the level of genome-wide significance. Our study presents the first large-scale, exome-wide analysis of rare variants in AMD. Further independent replications and molecular investigation of candidate target genes, reported here, would assist in gaining novel insights into mechanisms underlying AMD pathogenesis.
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Affiliation(s)
- Rinki Ratnapriya
- Neurobiology, Neurodegeneration and Repair Laboratory (NNRL), National Eye Institute, Bethesda, MD 20892, USA.,Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA
| | - İlhan E Acar
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
| | - Maartje J Geerlings
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
| | - Kari Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Alan Kwong
- Center for Statistical Genetics, Department of Biostatistics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicole T M Saksens
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
| | - Marc Pauper
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
| | - Jordi Corominas
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
| | - Madeline Kwicklis
- Neurobiology, Neurodegeneration and Repair Laboratory (NNRL), National Eye Institute, Bethesda, MD 20892, USA
| | - David Zipprer
- Neurobiology, Neurodegeneration and Repair Laboratory (NNRL), National Eye Institute, Bethesda, MD 20892, USA
| | - Margaret R Starostik
- Neurobiology, Neurodegeneration and Repair Laboratory (NNRL), National Eye Institute, Bethesda, MD 20892, USA
| | - Mohammad Othman
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Beverly Yashar
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Goncalo R Abecasis
- Center for Statistical Genetics, Department of Biostatistics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Emily Y Chew
- Neurobiology, Neurodegeneration and Repair Laboratory (NNRL), National Eye Institute, Bethesda, MD 20892, USA
| | - Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory (NNRL), National Eye Institute, Bethesda, MD 20892, USA
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen 6500, The Netherlands
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22
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Zhang S, Liu Y, Huang Q, Yuan S, Liu H, Shi L, Yap YT, Li W, Zhen J, Zhang L, Hess RA, Zhang Z. Murine germ cell-specific disruption of Ift172 causes defects in spermiogenesis and male fertility. Reproduction 2021; 159:409-421. [PMID: 31958312 DOI: 10.1530/rep-17-0789] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 01/20/2020] [Indexed: 01/21/2023]
Abstract
Intraflagellar transport (IFT) is a conserved mechanism essential for the assembly and maintenance of most eukaryotic cilia and flagella. IFT172 is a component of the IFT complex. Global disruption of mouse Ift172 gene caused typical phenotypes of ciliopathy. Mouse Ift172 gene appears to translate two major proteins; the full-length protein is highly expressed in the tissues enriched in cilia and the smaller 130 kDa one is only abundant in the testis. In male germ cells, IFT172 is highly expressed in the manchette of elongating spermatids. A germ cell-specific Ift172 mutant mice were generated, and the mutant mice did not show gross abnormalities. There was no difference in testis/body weight between the control and mutant mice, but more than half of the adult homozygous mutant males were infertile and associated with abnormally developed germ cells in the spermiogenesis phase. The cauda epididymides in mutant mice contained less developed sperm that showed significantly reduced motility, and these sperm had multiple defects in ultrastructure and bent tails. In the mutant mice, testicular expression levels of some IFT components, including IFT20, IFT27, IFT74, IFT81 and IFT140, and a central apparatus protein SPAG16L were not changed. However, expression levels of ODF2, a component of the outer dense fiber, and AKAP4, a component of fibrous sheath, and two IFT components IFT25 and IFT57 were dramatically reduced. Our findings demonstrate that IFT172 is essential for normal male fertility and spermiogenesis in mice, probably by modulating specific IFT proteins and transporting/assembling unique accessory structural proteins into spermatozoa.
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Affiliation(s)
- Shiyang Zhang
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Yunhao Liu
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Qian Huang
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Shuo Yuan
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Hong Liu
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Lin Shi
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Yi Tian Yap
- Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Wei Li
- Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - Jingkai Zhen
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Ling Zhang
- School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, Hubei, China
| | - Rex A Hess
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, USA
| | - Zhibing Zhang
- Department of Physiology, Wayne State University, Detroit, Michigan, USA.,Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, USA
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23
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Functional compartmentalization of photoreceptor neurons. Pflugers Arch 2021; 473:1493-1516. [PMID: 33880652 DOI: 10.1007/s00424-021-02558-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 12/16/2022]
Abstract
Retinal photoreceptors are neurons that convert dynamically changing patterns of light into electrical signals that are processed by retinal interneurons and ultimately transmitted to vision centers in the brain. They represent the essential first step in seeing without which the remainder of the visual system is rendered moot. To support this role, the major functions of photoreceptors are segregated into three main specialized compartments-the outer segment, the inner segment, and the pre-synaptic terminal. This compartmentalization is crucial for photoreceptor function-disruption leads to devastating blinding diseases for which therapies remain elusive. In this review, we examine the current understanding of the molecular and physical mechanisms underlying photoreceptor functional compartmentalization and highlight areas where significant knowledge gaps remain.
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24
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Fang X, Peden AA, van Eeden FJM, Malicki JJ. Identification of additional outer segment targeting signals in zebrafish rod opsin. J Cell Sci 2021; 134:jcs.254995. [PMID: 33589494 DOI: 10.1242/jcs.254995] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/01/2021] [Indexed: 11/20/2022] Open
Abstract
In vertebrate photoreceptors, opsins are highly concentrated in a morphologically distinct ciliary compartment known as the outer segment (OS). Opsin is synthesized in the cell body and transported to the OS at a remarkable rate of 100 to 1000 molecules per second. Opsin transport defects contribute to photoreceptor loss and blindness in human ciliopathies. Previous studies revealed that the rhodopsin C-terminal tail, of 44 amino acids, is sufficient to mediate OS targeting in Xenopus photoreceptors. Here, we show that, although the Xenopus C-terminus retains this function in zebrafish, the homologous zebrafish sequence is not sufficient to target opsin to the OS. This functional difference is largely caused by a change of a single amino acid present in Xenopus but not in other vertebrates examined. Furthermore, we find that sequences in the third intracellular cytoplasmic loop (IC3) and adjacent regions of transmembrane helices 6 and 7 are also necessary for opsin transport in zebrafish. Combined with the cytoplasmic tail, these sequences are sufficient to target opsin to the ciliary compartment.
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Affiliation(s)
- Xiaoming Fang
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Andrew A Peden
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Fredericus J M van Eeden
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Jarema J Malicki
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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25
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Finetti F, Cassioli C, Cianfanelli V, Zevolini F, Onnis A, Gesualdo M, Brunetti J, Cecconi F, Baldari CT. The Intraflagellar Transport Protein IFT20 Recruits ATG16L1 to Early Endosomes to Promote Autophagosome Formation in T Cells. Front Cell Dev Biol 2021; 9:634003. [PMID: 33829015 PMCID: PMC8019791 DOI: 10.3389/fcell.2021.634003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/23/2021] [Indexed: 12/30/2022] Open
Abstract
Lymphocyte homeostasis, activation and differentiation crucially rely on basal autophagy. The fine-tuning of this process depends on autophagy-related (ATG) proteins and their interaction with the trafficking machinery that orchestrates the membrane rearrangements leading to autophagosome biogenesis. The underlying mechanisms are as yet not fully understood. The intraflagellar transport (IFT) system, known for its role in cargo transport along the axonemal microtubules of the primary cilium, has emerged as a regulator of autophagy in ciliated cells. Growing evidence indicates that ciliogenesis proteins participate in cilia-independent processes, including autophagy, in the non-ciliated T cell. Here we investigate the mechanism by which IFT20, an integral component of the IFT system, regulates basal T cell autophagy. We show that IFT20 interacts with the core autophagy protein ATG16L1 and that its CC domain is essential for its pro-autophagic activity. We demonstrate that IFT20 is required for the association of ATG16L1 with the Golgi complex and early endosomes, both of which have been identified as membrane sources for phagophore elongation. This involves the ability of IFT20 to interact with proteins that are resident at these subcellular localizations, namely the golgin GMAP210 at the Golgi apparatus and Rab5 at early endosomes. GMAP210 depletion, while leading to a dispersion of ATG16L1 from the Golgi, did not affect basal autophagy. Conversely, IFT20 was found to recruit ATG16L1 to early endosomes tagged for autophagosome formation by the BECLIN 1/VPS34/Rab5 complex, which resulted in the local accumulation of LC3. Hence IFT20 participates in autophagosome biogenesis under basal conditions by regulating the localization of ATG16L1 at early endosomes to promote autophagosome biogenesis. These data identify IFT20 as a new regulator of an early step of basal autophagy in T cells.
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Affiliation(s)
| | - Chiara Cassioli
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Valentina Cianfanelli
- Cell Stress and Survival Unit, Center for Autophagy, Recycling and Disease (CARD), Danish Cancer Society Research Center, Copenhagen, Denmark.,Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Anna Onnis
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Monica Gesualdo
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Jlenia Brunetti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Francesco Cecconi
- Cell Stress and Survival Unit, Center for Autophagy, Recycling and Disease (CARD), Danish Cancer Society Research Center, Copenhagen, Denmark.,Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.,Department of Biology, University of Rome Tor Vergata, Rome, Italy
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26
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Yang H, Zhang F, Long H, Lin Y, Liao J, Xia H, Huang K. IFT20 Mediates the Transport of Cell Migration Regulators From the Trans-Golgi Network to the Plasma Membrane in Breast Cancer Cells. Front Cell Dev Biol 2021; 9:632198. [PMID: 33748116 PMCID: PMC7968458 DOI: 10.3389/fcell.2021.632198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 02/05/2021] [Indexed: 11/24/2022] Open
Abstract
IFT20 is a subunit of the intraflagellar transport (IFT) system essential for the formation and function of cilia. Besides predominant research in the cilia field, some IFT subunits perform extraciliary roles in non-ciliated cancer cells. However, the specific roles of IFT subunits in tumorigenesis remain unknown. Here, we found that knockout of IFT20 in mouse breast cancer cells lacking primary cilia promoted epithelial mesenchymal transitions (EMTs), active lamellipodia formation, and cell migration. IFT20 localized at the trans-Golgi and trans-Golgi network (TGN), and displayed vesicular co-distributions with Rab8a, the marker of TGN-to-plasma membrane vesicular trafficking. Proximity-dependent biotin identification (BioID) and colocalization analyzes showed that Numb and Ctnnal1, whose depletion promoted cell migration, co-localized with IFT20 at the trans-Golgi/TGN or intracellular transport vesicles. Furthermore, Strep-Tactin pulldown assays revealed an interaction between IFT20 and Ctnnal1 or Numb. Loss of IFT20 lowered the expression of actin-associated Tagln2, whose knockdown promoted cell migration. Thus, the extraciliary function of ITF20 in breast cancer cell was associated with the negative regulation of migration.
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Affiliation(s)
- Huihui Yang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Fan Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Huan Long
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yiwen Lin
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jiahui Liao
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education (Hubei-MOST & KLOBM), Wuhan University, Wuhan, China
| | - Haibin Xia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education (Hubei-MOST & KLOBM), Wuhan University, Wuhan, China
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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27
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Barnes CL, Malhotra H, Calvert PD. Compartmentalization of Photoreceptor Sensory Cilia. Front Cell Dev Biol 2021; 9:636737. [PMID: 33614665 PMCID: PMC7889997 DOI: 10.3389/fcell.2021.636737] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/07/2021] [Indexed: 12/12/2022] Open
Abstract
Functional compartmentalization of cells is a universal strategy for segregating processes that require specific components, undergo regulation by modulating concentrations of those components, or that would be detrimental to other processes. Primary cilia are hair-like organelles that project from the apical plasma membranes of epithelial cells where they serve as exclusive compartments for sensing physical and chemical signals in the environment. As such, molecules involved in signal transduction are enriched within cilia and regulating their ciliary concentrations allows adaptation to the environmental stimuli. The highly efficient organization of primary cilia has been co-opted by major sensory neurons, olfactory cells and the photoreceptor neurons that underlie vision. The mechanisms underlying compartmentalization of cilia are an area of intense current research. Recent findings have revealed similarities and differences in molecular mechanisms of ciliary protein enrichment and its regulation among primary cilia and sensory cilia. Here we discuss the physiological demands on photoreceptors that have driven their evolution into neurons that rely on a highly specialized cilium for signaling changes in light intensity. We explore what is known and what is not known about how that specialization appears to have driven unique mechanisms for photoreceptor protein and membrane compartmentalization.
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Affiliation(s)
| | | | - Peter D. Calvert
- Department of Ophthalmology and Visual Sciences, Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, United States
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28
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Review: Intraflagellar transport proteins in the retina. Mol Vis 2020; 26:652-660. [PMID: 33088169 PMCID: PMC7553723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 10/02/2020] [Indexed: 10/28/2022] Open
Abstract
Intraflagellar transport (IFT) is an essential process in all organisms that serves to move proteins along flagella or cilia in either direction. IFT is performed by IFT particles, which are multiprotein complexes organized into two subcomplexes, A and B. The IFT proteins form interactions with each other, with cargo proteins, and with membranes during the transport process. Several IFT proteins are expressed in many parts of the retina, such as the outer plexiform and outer nuclear layers, and function in the transport of photoreceptor proteins between the inner and outer segments. Mutants of IFT protein genes have been characterized in model organisms such as Chlamydomonas, C. elegans, zebrafish, and the mouse. These mutants have defective ciliogenesis or abnormalities in retinal photoreceptors. Mutations in IFT genes are associated with syndromic and non-syndromic forms of retinal disease in humans, frequently with early onset of disease.
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29
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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30
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Yang H, Huang K. Dissecting the Vesicular Trafficking Function of IFT Subunits. Front Cell Dev Biol 2020; 7:352. [PMID: 32010685 PMCID: PMC6974671 DOI: 10.3389/fcell.2019.00352] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 12/05/2019] [Indexed: 12/22/2022] Open
Abstract
Intraflagellar transport (IFT) was initially identified as a transport machine with multiple protein subunits, and it is essential for the assembly, disassembly, and maintenance of cilium/flagellum, which serves as the nexus of extracellular-to-intracellular signal integration. To date, in addition to its well-established and indispensable roles in ciliated cells, most IFT subunits have presented more general functions of vesicular trafficking in the non-ciliated cells. Thus, this review aims to summarize the recent progress on the vesicular trafficking functions of the IFT subunits and to highlight the issues that may arise in future research.
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Affiliation(s)
- Huihui Yang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,Institute of Hydrobiology, University of Chinese Academy of Sciences, Beijing, China
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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31
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Zhang L, Zhen J, Huang Q, Liu H, Li W, Zhang S, Min J, Li Y, Shi L, Woods J, Chen X, Shi Y, Liu Y, Hess RA, Song S, Zhang Z. Mouse spermatogenesis-associated protein 1 (SPATA1), an IFT20 binding partner, is an acrosomal protein. Dev Dyn 2020; 249:543-555. [PMID: 31816150 DOI: 10.1002/dvdy.141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 11/16/2019] [Accepted: 11/18/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Intraflagellar transport is a motor-driven trafficking system that is required for the formation of cilia. Intraflagellar transport protein 20 (IFT20) is a master regulator for the control of spermatogenesis and male fertility in mice. However, the mechanism of how IFT20 regulates spermatogenesis is unknown. RESULTS Spermatogenesis associated 1 (SPATA1) was identified to be a major potential binding partner of IFT20 by a yeast two-hybrid screening. The interaction between SPATA1 and IFT20 was examined by direct yeast two-hybrid, co-localization, and co-immunoprecipitation assays. SPATA1 is highly abundant in the mouse testis, and is also expressed in the heart and kidney. During the first wave of spermatogenesis, SPATA1 is detectable at postnatal day 24 and its expression is increased at day 30 and 35. Immunofluorescence staining of mouse testis sections and epididymal sperm demonstrated that SPATA1 is localized mainly in the acrosome of developing spermatids but not in epididymal sperm. IFT20 is also present in the acrosome area of round spermatids. In conditional Ift20 knockout mice, testicular expression level and acrosomal localization of SPATA1 are not changed. CONCLUSIONS SPATA1 is an IFT20 binding protein and may provide a docking site for IFT20 complex binding to the acrosome area.
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Affiliation(s)
- Ling Zhang
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China
| | - Jingkai Zhen
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China
| | - Qian Huang
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China.,Department of Physiology, Wayne State University, Detroit, Michigan
| | - Hong Liu
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China.,Department of Physiology, Wayne State University, Detroit, Michigan
| | - Wei Li
- Department of Physiology, Wayne State University, Detroit, Michigan
| | - Shiyang Zhang
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China.,Department of Physiology, Wayne State University, Detroit, Michigan
| | - Jie Min
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China
| | - Yuhong Li
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China.,Department of Physiology, Wayne State University, Detroit, Michigan
| | - Lin Shi
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China.,Department of Physiology, Wayne State University, Detroit, Michigan
| | - James Woods
- Department of Physiology, Wayne State University, Detroit, Michigan
| | - Xuequn Chen
- Department of Physiology, Wayne State University, Detroit, Michigan
| | - Yuqin Shi
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China
| | - Yunhao Liu
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China
| | - Rex A Hess
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, Illinois
| | - Shizhen Song
- Department of Occupational and Environmental Health, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan, China
| | - Zhibing Zhang
- Department of Physiology, Wayne State University, Detroit, Michigan.,Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan
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32
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Sorusch N, Yildirim A, Knapp B, Janson J, Fleck W, Scharf C, Wolfrum U. SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins. Front Cell Dev Biol 2019; 7:216. [PMID: 31637240 PMCID: PMC6787559 DOI: 10.3389/fcell.2019.00216] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 09/18/2019] [Indexed: 01/19/2023] Open
Abstract
The human Usher syndrome (USH) is a retinal ciliopathy, characterized by profound congenital deafness, variable vestibular dysfunction and pre-pubertal onset of retinitis pigmentosa. In the effected sensory cells, USH protein networks are assumed to function in ciliary transport processes. The USH1G protein SANS is a scaffold of the ciliary/periciliary USH protein network of photoreceptor cells. Moreover, SANS is associated with microtubules, the transport routes for protein delivery toward the cilium. To enlighten the role of SANS in ciliary transport processes, we aimed to identify transport related proteins associated with SANS. The intraflagellar transport (IFT) system is a conserved mechanism for bi-directional transport toward and through primary cilia. Thus, we tested the direct binding of SANS to IFT molecules, namely IFT20, IFT57, and IFT74 in 1:1 yeast-two-hybrid assay. The identified SANS-IFT interactions were validated in vitro via independent complementary interaction assays and in cells by applying membrane targeting assays. Quantitative immunofluorescence microscopy revealed the co-localization of SANS with IFT20, IFT52, and IFT57 particularly at ciliary base of wild type mouse photoreceptor cells. Analysis of photoreceptor cells of SANS knock out mice revealed the decrease of IFTs in the ciliary compartment indicating a role of SANS in the proper positioning of IFT-B molecules in primary cilia. Our study demonstrated direct binding of IFT complex B proteins IFT52 and IFT57 to the N-terminal ankyrin repeats and the central domain of SANS. Our data also indicate that pathologic mutations in the N-terminus of SANS lead to the loos of SANS binding to IFT-B molecules. Our findings provide direct evidence for a molecular link between the ciliary USH protein network and the IFT transport module in primary cilia.
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Affiliation(s)
| | | | | | | | | | | | - Uwe Wolfrum
- Molecular Cell Biology, Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
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33
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Satir P, Satir BH. The conserved ancestral signaling pathway from cilium to nucleus. J Cell Sci 2019; 132:132/15/jcs230441. [PMID: 31375541 DOI: 10.1242/jcs.230441] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022] Open
Abstract
Many signaling molecules are localized to both the primary cilium and nucleus. Localization of specific transmembrane receptors and their signaling scaffold molecules in the cilium is necessary for correct physiological function. After a specific signaling event, signaling molecules leave the cilium, usually in the form of an endocytic vesicle scaffold, and move to the nucleus, where they dissociate from the scaffold and enter the nucleus to affect gene expression. This ancient pathway probably arose very early in eukaryotic evolution as the nucleus and cilium co-evolved. Because there are similarities in molecular composition of the nuclear and ciliary pores the entry and exit of proteins in both organelles rely on similar mechanisms. In this Hypothesis, we propose that the pathway is a dynamic universal cilia-based signaling pathway with some variations from protists to man. Everywhere the cilium functions as an important organelle for molecular storage of certain key receptors and selection and concentration of their associated signaling molecules that move from cilium to nucleus. This could also have important implications for human diseases such as Huntington disease.
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Affiliation(s)
- Peter Satir
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY 10461 .,B&P Nanobiology Consultants, 7 Byfield Lane, Greenwich, CT 06830, USA
| | - Birgit H Satir
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY 10461.,B&P Nanobiology Consultants, 7 Byfield Lane, Greenwich, CT 06830, USA
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34
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Cassioli C, Baldari CT. A Ciliary View of the Immunological Synapse. Cells 2019; 8:E789. [PMID: 31362462 PMCID: PMC6721628 DOI: 10.3390/cells8080789] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/15/2019] [Accepted: 07/25/2019] [Indexed: 12/28/2022] Open
Abstract
The primary cilium has gone from being a vestigial organelle to a crucial signaling hub of growing interest given the association between a group of human disorders, collectively known as ciliopathies, and defects in its structure or function. In recent years many ciliogenesis proteins have been observed at extraciliary sites in cells and likely perform cilium-independent functions ranging from regulation of the cytoskeleton to vesicular trafficking. Perhaps the most striking example is the non-ciliated T lymphocyte, in which components of the ciliary machinery are repurposed for the assembly and function of the immunological synapse even in the absence of a primary cilium. Furthermore, the specialization traits described at the immunological synapse are similar to those seen in the primary cilium. Here, we review common regulators and features shared by the immunological synapse and the primary cilium that document the remarkable homology between these structures.
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Affiliation(s)
- Chiara Cassioli
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Cosima T Baldari
- Department of Life Sciences, University of Siena, 53100 Siena, Italy.
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35
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Finetti F, Cassioli C, Cianfanelli V, Onnis A, Paccagnini E, Kabanova A, Baldari CT. The intraflagellar transport protein IFT20 controls lysosome biogenesis by regulating the post-Golgi transport of acid hydrolases. Cell Death Differ 2019; 27:310-328. [PMID: 31142807 DOI: 10.1038/s41418-019-0357-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/16/2019] [Accepted: 05/14/2019] [Indexed: 01/08/2023] Open
Abstract
The assembly and function of the primary cilium depends on multimolecular intraflagellar transport (IFT) complexes that shuttle their cargo along the axonemal microtubules through their interaction with molecular motors. The IFT system has been moreover recently implicated in a reciprocal interplay between autophagy and ciliogenesis. We have previously reported that IFT20 and other components of the IFT complexes participate in the assembly of the immune synapse in the non-ciliated T cell, suggesting that other cellular processes regulated by the IFT system in ciliated cells, including autophagy, may be shared by cells lacking a cilium. Starting from the observation of a defect in autophagic clearance and an accumulation of lipid droplets in IFT20-deficient T cells, we show that IFT20 is required for lysosome biogenesis and function by controlling the lysosomal targeting of acid hydrolases. This function involves its ability to regulate the retrograde traffic of the cation-independent mannose-6-phosphate receptor (CI-MPR) to the trans-Golgi network, which is achieved by coupling recycling CI-MPRs to the microtubule motor dynein. Consistent with the lysosomal defect, an upregulation of the TFEB-dependent expression of the lysosomal gene network can be observed in IFT20-deficient cells, which is associated with defective tonic T-cell antigen receptor signaling and mTOR activity. We additionally show that the lysosome-related function of IFT20 extends to non-ciliated cells other than T cells, as well as to ciliated cells. Our findings provide the first evidence that a component of the IFT system that controls ciliogenesis is implicated in the biogenesis of lysosomes.
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Affiliation(s)
- Francesca Finetti
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100, Siena, Italy.
| | - Chiara Cassioli
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Valentina Cianfanelli
- Cell Stress and Survival Unit, Danish Cancer Society Research Center, 2100, Copenhagen, Denmark
| | - Anna Onnis
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Eugenio Paccagnini
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Anna Kabanova
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100, Siena, Italy
| | - Cosima T Baldari
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100, Siena, Italy.
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36
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Chadha A, Volland S, Baliaouri NV, Tran EM, Williams DS. The route of the visual receptor rhodopsin along the cilium. J Cell Sci 2019; 132:jcs.229526. [PMID: 30975916 DOI: 10.1242/jcs.229526] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 04/02/2019] [Indexed: 11/20/2022] Open
Abstract
The photoreceptor outer segment is the most elaborate primary cilium, containing large amounts of rhodopsin (RHO) in disk membranes that grow from a connecting cilium. The movement of RHO along the connecting cilium precedes formation of the disk membranes. However, the route that RHO takes has not been clearly determined; some reports suggest that it follows an intracellular, vesicular route along the axoneme, possibly as an adaptation for the high load of delivery or the morphogenesis of the disk endomembranes. We addressed this question by studying RHO in cilia of IMCD3 cells and mouse rod photoreceptors. In IMCD3 cilia, fluorescence recovery after photobleaching (FRAP) experiments with fluorescently tagged RHO supported the idea of RHO motility in the ciliary plasma membrane and was inconsistent with the hypothesis of RHO motility within the lumen of the cilium. In rod photoreceptors, FRAP of RHO-EGFP was altered by externally applied lectin, supporting the idea of plasmalemmal RHO dynamics. Quantitative immunoelectron microscopy corroborated our live-cell conclusions, as RHO was found to be distributed along the plasma membrane of the connecting cilium, with negligible labeling within the axoneme. Taken together, the present findings demonstrate RHO trafficking entirely via the ciliary plasma membrane.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Abhishek Chadha
- Departments of Ophthalmology and Neurobiology, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA
| | - Stefanie Volland
- Departments of Ophthalmology and Neurobiology, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA
| | - Natella V Baliaouri
- Departments of Ophthalmology and Neurobiology, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA
| | - Elaine M Tran
- Departments of Ophthalmology and Neurobiology, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA
| | - David S Williams
- Departments of Ophthalmology and Neurobiology, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA .,Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.,Brain Research Institute, University of California, Los Angeles, CA 90095, USA
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37
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Wang R, Deng X, Yuan C, Xin H, Liu G, Zhu Y, Jiang X, Wang C. IFT80 Improves Invasion Ability in Gastric Cancer Cell Line via ift80/p75NGFR/MMP9 Signaling. Int J Mol Sci 2018; 19:ijms19113616. [PMID: 30453504 PMCID: PMC6274718 DOI: 10.3390/ijms19113616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/13/2018] [Accepted: 11/13/2018] [Indexed: 01/13/2023] Open
Abstract
The assembly and maintenance of cilia depend on intraflagellar transport (IFT) proteins, which play an important role in development and homeostasis. IFT80 is a newly defined IFT protein and partial mutation of IFT80 in humans causes diseases such as Jeune asphyxiating thoracic dystrophy (JATD) and short rib polydactyly (SRP) type III, both characterized by abnormal skeletal development. However, the role and mechanism of IFT80 in the invasion of gastric cancer is unknown. We established SGC-7901 and MKN-45 gastric cancer cell lines that stably overexpressed IFT80, as verified by quantitative reverse transcription-PCR, Western blot, and immunofluorescence. Matrix metalloproteinase-9 (MMP9) plays an important role in tumor invasion, and its expression was assessed by quantitative reverse transcription-PCR, Western blotting, and immunofluorescence. The invasion ability of IFT80 on SGC-7901 and MKN-45 cells was examined by the Matrigel invasion assay. The relationship between p75NGFR, and the p75NGFR antagonists, PD90780 and IFT80, were detected by quantitative reverse transcription-PCR and Western blotting. We first detected an IFT80 expression pattern, and found that IFT80 was highly expressed in gastric cancer clinical samples. Overexpression of IFT80 in the gastric cancer cell lines, SGC-7901 and MKN-45, led to lengthening cilia. Additionally, overexpression of IFT80 significantly improved proliferation and invasion, but inhibited apoptosis, in gastric cancer cells. We further found that overexpression of IFT80 increased p75NGFR and MMP9 mRNA and protein expression. Treatment with the p75NGFR antagonist PD90780 inhibited the increased invasion ability resulting from overexpression of IFT80 in SGC-7901 and MKN-45 gastric cancer cells. Thus, these results suggest that IFT80 plays an important role in invasion of gastric cancer through regulating the ift80/p75NGFR/MMP9 signal pathways.
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Affiliation(s)
- Rui Wang
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
| | - Xiaoyan Deng
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
| | - Chengfu Yuan
- College of Medical Science, China Three Gorges University, Yichang 443002, China.
| | - Hongmei Xin
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
| | - Geli Liu
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
| | - Yong Zhu
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Xue Jiang
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
| | - Changdong Wang
- Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016, China.
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38
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Campbell LJ, West MC, Jensen AM. A high content, small molecule screen identifies candidate molecular pathways that regulate rod photoreceptor outer segment renewal. Sci Rep 2018; 8:14017. [PMID: 30228302 PMCID: PMC6143611 DOI: 10.1038/s41598-018-32336-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 09/05/2018] [Indexed: 01/04/2023] Open
Abstract
The outer segment of the vertebrate rod photoreceptor is a highly modified cilium composed of many discrete membranous discs that are filled with the protein machinery necessary for phototransduction. The unique outer segment structure is renewed daily with growth at the base of the outer segment where new discs are formed and shedding at the distal end where old discs are phagocytized by the retinal pigment epithelium. In order to understand how outer segment renewal is regulated to maintain outer segment length and function, we used a small molecule screening approach with the transgenic (hsp70:HA-mCherryTM) zebrafish, which expresses a genetically-encoded marker of outer segment renewal. We identified compounds with known bioactivity that affect five content areas: outer segment growth, outer segment shedding, clearance of shed outer segment tips, Rhodopsin mislocalization, and differentiation at the ciliary marginal zone. Signaling pathways that are targeted by the identified compounds include cyclooxygenase in outer segment growth, γ-Secretase in outer segment shedding, and mTor in RPE phagocytosis. The data generated by this screen provides a foundation for further investigation of the signaling pathways that regulate photoreceptor outer segment renewal.
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Affiliation(s)
- Leah J Campbell
- Biology Department, University of Massachusetts, Amherst, MA, 01003, USA.,Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Megan C West
- Biology Department, University of Massachusetts, Amherst, MA, 01003, USA
| | - Abbie M Jensen
- Biology Department, University of Massachusetts, Amherst, MA, 01003, USA. .,Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA, 01003, USA.
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39
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Morthorst SK, Christensen ST, Pedersen LB. Regulation of ciliary membrane protein trafficking and signalling by kinesin motor proteins. FEBS J 2018; 285:4535-4564. [PMID: 29894023 DOI: 10.1111/febs.14583] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/09/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022]
Abstract
Primary cilia are antenna-like sensory organelles that regulate a substantial number of cellular signalling pathways in vertebrates, both during embryonic development as well as in adulthood, and mutations in genes coding for ciliary proteins are causative of an expanding group of pleiotropic diseases known as ciliopathies. Cilia consist of a microtubule-based axoneme core, which is subtended by a basal body and covered by a bilayer lipid membrane of unique protein and lipid composition. Cilia are dynamic organelles, and the ability of cells to regulate ciliary protein and lipid content in response to specific cellular and environmental cues is crucial for balancing ciliary signalling output. Here we discuss mechanisms involved in regulation of ciliary membrane protein trafficking and signalling, with main focus on kinesin-2 and kinesin-3 family members.
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40
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Zhang Y, Liu H, Li W, Zhang Z, Zhang S, Teves ME, Stevens C, Foster JA, Campbell GE, Windle JJ, Hess RA, Pazour GJ, Zhang Z. Intraflagellar transporter protein 140 (IFT140), a component of IFT-A complex, is essential for male fertility and spermiogenesis in mice. Cytoskeleton (Hoboken) 2018; 75:70-84. [PMID: 29236364 DOI: 10.1002/cm.21427] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 11/11/2022]
Abstract
Intraflagellar transport (IFT) is a conserved mechanism essential for the assembly and maintenance of most eukaryotic cilia and flagella. However, little is known about its role in sperm flagella formation and male fertility. IFT140 is a component of IFT-A complex. In mouse, it is highly expressed in the testis. Ift140 gene was inactivated specifically in mouse spermatocytes/spermatids. The mutant mice did not show any gross abnormalities, but all were infertile and associated with significantly reduced sperm number and motility. Multiple sperm morphological abnormalities were discovered, including amorphous heads, short/bent flagella and swollen tail tips, as well as vesicles along the flagella due to spermiogenesis defects. The epididymides contained round bodies of cytoplasm derived from the sloughing of the cytoplasmic lobes and residual bodies. Knockout of Ift140 did not significantly affect testicular expression levels of selective IFT components but localization of IFT27 and IFT88, two components of IFT-B complex, was changed. Our findings demonstrate that IFT140 is a key regulator for male fertility and normal spermiogenesis in mice. It not only plays a role in sperm flagella assembling, but is also involved in critical assembly of proteins that interface between the germ cell plasma and the Sertoli cell.
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Affiliation(s)
- Yong Zhang
- Department of Dermatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Hong Liu
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan 430060, Hubei
| | - Wei Li
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Zhengang Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,Department of Gastroenterology, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei
| | - Shiyang Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan 430060, Hubei
| | - Maria E Teves
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Courtney Stevens
- Department of Biology, Randolph-Macon College, Ashland, Virginia 23005
| | - James A Foster
- Department of Biology, Randolph-Macon College, Ashland, Virginia 23005
| | - Gregory E Campbell
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Jolene J Windle
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Rex A Hess
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, 2001 S. Lincoln, Urbana, Illinois 61802-6199
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Zhibing Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan 430060, Hubei
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41
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Athanasiou D, Aguila M, Bellingham J, Li W, McCulley C, Reeves PJ, Cheetham ME. The molecular and cellular basis of rhodopsin retinitis pigmentosa reveals potential strategies for therapy. Prog Retin Eye Res 2018; 62:1-23. [PMID: 29042326 PMCID: PMC5779616 DOI: 10.1016/j.preteyeres.2017.10.002] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/03/2017] [Accepted: 10/13/2017] [Indexed: 12/12/2022]
Abstract
Inherited mutations in the rod visual pigment, rhodopsin, cause the degenerative blinding condition, retinitis pigmentosa (RP). Over 150 different mutations in rhodopsin have been identified and, collectively, they are the most common cause of autosomal dominant RP (adRP). Mutations in rhodopsin are also associated with dominant congenital stationary night blindness (adCSNB) and, less frequently, recessive RP (arRP). Recessive RP is usually associated with loss of rhodopsin function, whereas the dominant conditions are a consequence of gain of function and/or dominant negative activity. The in-depth characterisation of many rhodopsin mutations has revealed that there are distinct consequences on the protein structure and function associated with different mutations. Here we categorise rhodopsin mutations into seven discrete classes; with defects ranging from misfolding and disruption of proteostasis, through mislocalisation and disrupted intracellular traffic to instability and altered function. Rhodopsin adRP offers a unique paradigm to understand how disturbances in photoreceptor homeostasis can lead to neuronal cell death. Furthermore, a wide range of therapies have been tested in rhodopsin RP, from gene therapy and gene editing to pharmacological interventions. The understanding of the disease mechanisms associated with rhodopsin RP and the development of targeted therapies offer the potential of treatment for this currently untreatable neurodegeneration.
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Affiliation(s)
| | - Monica Aguila
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Wenwen Li
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Caroline McCulley
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Philip J Reeves
- School of Biological Sciences, University of Essex, Wivenhoe Park, Essex CO4 3SQ, UK.
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42
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Schmid FM, Schou KB, Vilhelm MJ, Holm MS, Breslin L, Farinelli P, Larsen LA, Andersen JS, Pedersen LB, Christensen ST. IFT20 modulates ciliary PDGFRα signaling by regulating the stability of Cbl E3 ubiquitin ligases. J Cell Biol 2017; 217:151-161. [PMID: 29237719 PMCID: PMC5748969 DOI: 10.1083/jcb.201611050] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/20/2017] [Accepted: 08/24/2017] [Indexed: 12/28/2022] Open
Abstract
PDGFRα signals from cilia to control development and tumorigenesis. Schmid et al. now show that intraflagellar transport protein 20 (IFT20) interacts with and stabilizes the E3 ubiquitin ligases c-Cbl and Cbl-b to promote feedback inhibition of PDGFRα signaling at the primary cilium. Primary cilia have pivotal roles as organizers of many different signaling pathways, including platelet-derived growth factor receptor α (PDGFRα) signaling, which, when aberrantly regulated, is associated with developmental disorders, tumorigenesis, and cancer. PDGFRα is up-regulated during ciliogenesis, and ciliary localization of the receptor is required for its appropriate ligand-mediated activation by PDGF-AA. However, the mechanisms regulating sorting of PDGFRα and feedback inhibition of PDGFRα signaling at the cilium are unknown. Here, we provide evidence that intraflagellar transport protein 20 (IFT20) interacts with E3 ubiquitin ligases c-Cbl and Cbl-b and is required for Cbl-mediated ubiquitination and internalization of PDGFRα for feedback inhibition of receptor signaling. In wild-type cells treated with PDGF-AA, c-Cbl becomes enriched in the cilium, and the receptor is subsequently ubiquitinated and internalized. In contrast, in IFT20-depleted cells, PDGFRα localizes aberrantly to the plasma membrane and is overactivated after ligand stimulation because of destabilization and degradation of c-Cbl and Cbl-b.
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Affiliation(s)
- Fabian Marc Schmid
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Kenneth Bødtker Schou
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Martin Juel Vilhelm
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Maria Schrøder Holm
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Loretta Breslin
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark.,Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Pietro Farinelli
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Lars Allan Larsen
- Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Lotte Bang Pedersen
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Tvorup Christensen
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
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43
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Seo S, Datta P. Photoreceptor outer segment as a sink for membrane proteins: hypothesis and implications in retinal ciliopathies. Hum Mol Genet 2017; 26:R75-R82. [PMID: 28453661 DOI: 10.1093/hmg/ddx163] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/24/2017] [Indexed: 12/28/2022] Open
Abstract
The photoreceptor outer segment (OS) is a unique modification of the primary cilium, specialized for light perception. Being homologous organelles, the primary cilium and the OS share common building blocks and molecular machinery to construct and maintain them. The OS, however, has several unique structural features that are not seen in primary cilia. Although these unique features of the OS have been well documented, their implications in protein localization have been under-appreciated. In this review, we compare the structural properties of the primary cilium and the OS, and propose a hypothesis that the OS can act as a sink for membrane proteins. We further discuss the implications of this hypothesis in polarized protein localization in photoreceptors and mechanisms of photoreceptor degeneration in retinal ciliopathies.
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Affiliation(s)
- Seongjin Seo
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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44
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Wang J, Fresquez T, Kandachar V, Deretic D. The Arf GEF GBF1 and Arf4 synergize with the sensory receptor cargo, rhodopsin, to regulate ciliary membrane trafficking. J Cell Sci 2017; 130:3975-3987. [PMID: 29025970 DOI: 10.1242/jcs.205492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 10/10/2017] [Indexed: 01/05/2023] Open
Abstract
The small GTPase Arf4 and the Arf GTPase-activating protein (GAP) ASAP1 cooperatively sequester sensory receptor cargo into transport carriers targeted to primary cilia, but the input that drives Arf4 activation in this process remains unknown. Here, we show, by using frog retinas and recombinant human proteins, that during the carrier biogenesis from the photoreceptor Golgi/trans-Golgi network (TGN) a functional complex is formed between Arf4, the Arf guanine nucleotide exchange factor (GEF) GBF1 and the light-sensing receptor, rhodopsin. Rhodopsin and Arf4 bind the regulatory N-terminal dimerization and cyclophillin-binding (DCB)-homology upstream of Sec7 (HUS) domain of GBF1. The complex is sensitive to Golgicide A (GCA), a selective inhibitor of GBF1 that accordingly blocks rhodopsin delivery to the cilia, without disrupting the photoreceptor Golgi. The emergence of newly synthesized rhodopsin in the endomembrane system is essential for GBF1-Arf4 complex formation in vivo Notably, GBF1 interacts with the Arf GAP ASAP1 in a GCA-resistant manner. Our findings indicate that converging signals on GBF1 from the influx of cargo into the Golgi/TGN and the feedback from Arf4, combined with input from ASAP1, control Arf4 activation during sensory membrane trafficking to primary cilia.
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Affiliation(s)
- Jing Wang
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Theresa Fresquez
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Vasundhara Kandachar
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Dusanka Deretic
- Department of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, New Mexico 87131, USA .,Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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45
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Monis WJ, Faundez V, Pazour GJ. BLOC-1 is required for selective membrane protein trafficking from endosomes to primary cilia. J Cell Biol 2017; 216:2131-2150. [PMID: 28576874 PMCID: PMC5496619 DOI: 10.1083/jcb.201611138] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/24/2017] [Accepted: 05/03/2017] [Indexed: 11/30/2022] Open
Abstract
Primary cilia perceive the extracellular environment through receptors localized in the ciliary membrane, but mechanisms directing specific proteins to this domain are poorly understood. To address this question, we knocked down proteins potentially important for ciliary membrane targeting and determined how this affects the ciliary trafficking of fibrocystin, polycystin-2, and smoothened. Our analysis showed that fibrocystin and polycystin-2 are dependent on IFT20, GMAP210, and the exocyst complex, while smoothened delivery is largely independent of these components. In addition, we found that polycystin-2, but not smoothened or fibrocystin, requires the biogenesis of lysosome-related organelles complex-1 (BLOC-1) for ciliary delivery. Consistent with the role of BLOC-1 in sorting from the endosome, we find that disrupting the recycling endosome reduces ciliary polycystin-2 and causes its accumulation in the recycling endosome. This is the first demonstration of a role for BLOC-1 in ciliary assembly and highlights the complexity of pathways taken to the cilium.
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Affiliation(s)
- William J Monis
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, GA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
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46
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Drew K, Lee C, Huizar RL, Tu F, Borgeson B, McWhite CD, Ma Y, Wallingford JB, Marcotte EM. Integration of over 9,000 mass spectrometry experiments builds a global map of human protein complexes. Mol Syst Biol 2017; 13:932. [PMID: 28596423 PMCID: PMC5488662 DOI: 10.15252/msb.20167490] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macromolecular protein complexes carry out many of the essential functions of cells, and many genetic diseases arise from disrupting the functions of such complexes. Currently, there is great interest in defining the complete set of human protein complexes, but recent published maps lack comprehensive coverage. Here, through the synthesis of over 9,000 published mass spectrometry experiments, we present hu.MAP, the most comprehensive and accurate human protein complex map to date, containing > 4,600 total complexes, > 7,700 proteins, and > 56,000 unique interactions, including thousands of confident protein interactions not identified by the original publications. hu.MAP accurately recapitulates known complexes withheld from the learning procedure, which was optimized with the aid of a new quantitative metric (k‐cliques) for comparing sets of sets. The vast majority of complexes in our map are significantly enriched with literature annotations, and the map overall shows improved coverage of many disease‐associated proteins, as we describe in detail for ciliopathies. Using hu.MAP, we predicted and experimentally validated candidate ciliopathy disease genes in vivo in a model vertebrate, discovering CCDC138, WDR90, and KIAA1328 to be new cilia basal body/centriolar satellite proteins, and identifying ANKRD55 as a novel member of the intraflagellar transport machinery. By offering significant improvements to the accuracy and coverage of human protein complexes, hu.MAP (http://proteincomplexes.org) serves as a valuable resource for better understanding the core cellular functions of human proteins and helping to determine mechanistic foundations of human disease.
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Affiliation(s)
- Kevin Drew
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA
| | - Chanjae Lee
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Ryan L Huizar
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Fan Tu
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Blake Borgeson
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Claire D McWhite
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Yun Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA.,The Otolaryngology Hospital, The First Affiliated Hospital of Sun Yat-sen University Sun Yat-sen University, Guangzhou, China
| | - John B Wallingford
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Edward M Marcotte
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA .,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
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47
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May-Simera H, Nagel-Wolfrum K, Wolfrum U. Cilia - The sensory antennae in the eye. Prog Retin Eye Res 2017; 60:144-180. [PMID: 28504201 DOI: 10.1016/j.preteyeres.2017.05.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Cilia are hair-like projections found on almost all cells in the human body. Originally believed to function merely in motility, the function of solitary non-motile (primary) cilia was long overlooked. Recent research has demonstrated that primary cilia function as signalling hubs that sense environmental cues and are pivotal for organ development and function, tissue hoemoestasis, and maintenance of human health. Cilia share a common anatomy and their diverse functional features are achieved by evolutionarily conserved functional modules, organized into sub-compartments. Defects in these functional modules are responsible for a rapidly growing list of human diseases collectively termed ciliopathies. Ocular pathogenesis is common in virtually all classes of syndromic ciliopathies, and disruptions in cilia genes have been found to be causative in a growing number of non-syndromic retinal dystrophies. This review will address what is currently known about cilia contribution to visual function. We will focus on the molecular and cellular functions of ciliary proteins and their role in the photoreceptor sensory cilia and their visual phenotypes. We also highlight other ciliated cell types in tissues of the eye (e.g. lens, RPE and Müller glia cells) discussing their possible contribution to disease progression. Progress in basic research on the cilia function in the eye is paving the way for therapeutic options for retinal ciliopathies. In the final section we describe the latest advancements in gene therapy, read-through of non-sense mutations and stem cell therapy, all being adopted to treat cilia dysfunction in the retina.
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Affiliation(s)
- Helen May-Simera
- Institute of Molecular Physiology, Cilia Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
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48
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Pearring JN, San Agustin JT, Lobanova ES, Gabriel CJ, Lieu EC, Monis WJ, Stuck MW, Strittmatter L, Jaber SM, Arshavsky VY, Pazour GJ. Loss of Arf4 causes severe degeneration of the exocrine pancreas but not cystic kidney disease or retinal degeneration. PLoS Genet 2017; 13:e1006740. [PMID: 28410364 PMCID: PMC5409180 DOI: 10.1371/journal.pgen.1006740] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/28/2017] [Accepted: 04/05/2017] [Indexed: 12/16/2022] Open
Abstract
Arf4 is proposed to be a critical regulator of membrane protein trafficking in early secretory pathway. More recently, Arf4 was also implicated in regulating ciliary trafficking, however, this has not been comprehensively tested in vivo. To directly address Arf4’s role in ciliary transport, we deleted Arf4 specifically in either rod photoreceptor cells, kidney, or globally during the early postnatal period. Arf4 deletion in photoreceptors did not cause protein mislocalization or retinal degeneration, as expected if Arf4 played a role in protein transport to the ciliary outer segment. Likewise, Arf4 deletion in kidney did not cause cystic disease, as expected if Arf4 were involved in general ciliary trafficking. In contrast, global Arf4 deletion in the early postnatal period resulted in growth restriction, severe pancreatic degeneration and early death. These findings are consistent with Arf4 playing a critical role in endomembrane trafficking, particularly in the pancreas, but not in ciliary function. Primary cilia are sensory organelles found on most cells and contain specific receptors that detect extracellular stimuli. Defects in trafficking receptors to cilia cause a diverse set of diseases called ciliopathies, which include polycystic kidney disease, obesity, cerebral anomalies and retinal degeneration. Based mostly on in vitro studies, the small GTPase Arf4 was thought to be critically important for localizing rhodopsin to the outer segment of photoreceptor cells and cystoproteins to kidney cilia. Here we genetically remove Arf4 from mice in either a tissue specific or time dependent manner. To our surprise, the loss of Arf4 does not cause retinal degeneration or cystic kidney disease. Since ciliary dysfunction causes retinal degeneration and cystic disease, our findings indicate that Arf4 does not play a role in ciliary function. Instead, mice have zymogen granule defects and degeneration of the exocrine pancreas supporting roles for Arf4 in regulating endomembrane trafficking in specific cells.
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Affiliation(s)
- Jillian N. Pearring
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Jovenal T. San Agustin
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Ekaterina S. Lobanova
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Christopher J. Gabriel
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Eric C. Lieu
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - William J. Monis
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Michael W. Stuck
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Lara Strittmatter
- Electron Microscopy Core, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Samer M. Jaber
- Department of Animal Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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49
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Lechtreck KF, Van De Weghe JC, Harris JA, Liu P. Protein transport in growing and steady-state cilia. Traffic 2017; 18:277-286. [PMID: 28248449 DOI: 10.1111/tra.12474] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 12/18/2022]
Abstract
Cilia and eukaryotic flagella are threadlike cell extensions with motile and sensory functions. Their assembly requires intraflagellar transport (IFT), a bidirectional motor-driven transport of protein carriers along the axonemal microtubules. IFT moves ample amounts of structural proteins including tubulin into growing cilia likely explaining its critical role for assembly. IFT continues in non-growing cilia contributing to a variety of processes ranging from axonemal maintenance and the export of non-ciliary proteins to cell locomotion and ciliary signaling. Here, we discuss recent data on cues regulating the type, amount and timing of cargo transported by IFT. A regulation of IFT-cargo interactions is critical to establish, maintain and adjust ciliary length, protein composition and function.
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Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | | | | | - Peiwei Liu
- Department of Cellular Biology, University of Georgia, Athens, Georgia
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50
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Nishita M, Satake T, Minami Y, Suzuki A. Regulatory mechanisms and cellular functions of non-centrosomal microtubules. J Biochem 2017; 162:1-10. [DOI: 10.1093/jb/mvx018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/02/2017] [Indexed: 02/07/2023] Open
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