1
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Moran AL, Louzao-Martinez L, Norris DP, Peters DJM, Blacque OE. Transport and barrier mechanisms that regulate ciliary compartmentalization and ciliopathies. Nat Rev Nephrol 2024; 20:83-100. [PMID: 37872350 DOI: 10.1038/s41581-023-00773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2023] [Indexed: 10/25/2023]
Abstract
Primary cilia act as cell surface antennae, coordinating cellular responses to sensory inputs and signalling molecules that regulate developmental and homeostatic pathways. Cilia are therefore critical to physiological processes, and defects in ciliary components are associated with a large group of inherited pleiotropic disorders - known collectively as ciliopathies - that have a broad spectrum of phenotypes and affect many or most tissues, including the kidney. A central feature of the cilium is its compartmentalized structure, which imparts its unique molecular composition and signalling environment despite its membrane and cytosol being contiguous with those of the cell. Such compartmentalization is achieved via active transport pathways that bring protein cargoes to and from the cilium, as well as gating pathways at the ciliary base that establish diffusion barriers to protein exchange into and out of the organelle. Many ciliopathy-linked proteins, including those involved in kidney development and homeostasis, are components of the compartmentalizing machinery. New insights into the major compartmentalizing pathways at the cilium, namely, ciliary gating, intraflagellar transport, lipidated protein flagellar transport and ciliary extracellular vesicle release pathways, have improved our understanding of the mechanisms that underpin ciliary disease and associated renal disorders.
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Affiliation(s)
- Ailis L Moran
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Laura Louzao-Martinez
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.
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2
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Lin AT, Hammond-Kaarremaa L, Liu HL, Stantis C, McKechnie I, Pavel M, Pavel SSM, Wyss SSÁ, Sparrow DQ, Carr K, Aninta SG, Perri A, Hartt J, Bergström A, Carmagnini A, Charlton S, Dalén L, Feuerborn TR, France CAM, Gopalakrishnan S, Grimes V, Harris A, Kavich G, Sacks BN, Sinding MHS, Skoglund P, Stanton DWG, Ostrander EA, Larson G, Armstrong CG, Frantz LAF, Hawkins MTR, Kistler L. The history of Coast Salish "woolly dogs" revealed by ancient genomics and Indigenous Knowledge. Science 2023; 382:1303-1308. [PMID: 38096292 PMCID: PMC7615573 DOI: 10.1126/science.adi6549] [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: 10/25/2023] [Indexed: 12/18/2023]
Abstract
Ancestral Coast Salish societies in the Pacific Northwest kept long-haired "woolly dogs" that were bred and cared for over millennia. However, the dog wool-weaving tradition declined during the 19th century, and the population was lost. In this study, we analyzed genomic and isotopic data from a preserved woolly dog pelt from "Mutton," collected in 1859. Mutton is the only known example of an Indigenous North American dog with dominant precolonial ancestry postdating the onset of settler colonialism. We identified candidate genetic variants potentially linked with their distinct woolly phenotype. We integrated these data with interviews from Coast Salish Elders, Knowledge Keepers, and weavers about shared traditional knowledge and memories surrounding woolly dogs, their importance within Coast Salish societies, and how colonial policies led directly to their disappearance.
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Affiliation(s)
- Audrey T Lin
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Richard Gilder Graduate School, American Museum of Natural History, New York, NY, USA
| | - Liz Hammond-Kaarremaa
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Vancouver Island University, Nanaimo, BC, Canada
| | - Hsiao-Lei Liu
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Chris Stantis
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA
| | - Iain McKechnie
- Department of Anthropology, University of Victoria, Victoria, BC, Canada
| | - Michael Pavel
- Twana/Skokomish Indian Tribe, Skokomish Nation, WA, USA
| | - Susan sa'hLa mitSa Pavel
- Twana/Skokomish Indian Tribe, Skokomish Nation, WA, USA
- Coast Salish Wool Weaving Center, Skokomish Nation, WA, USA
- The Evergreen State College, Olympia, WA, USA
| | | | | | | | - Sabhrina Gita Aninta
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Angela Perri
- Department of Anthropology, Texas A&M University, College Station, TX, USA
- Chronicle Heritage, Phoenix, AZ, USA
| | - Jonathan Hartt
- Department of Indigenous Studies, Simon Fraser University, Burnaby, BC, Canada
| | - Anders Bergström
- Ancient Genomics Laboratory, The Francis Crick Institute, London, UK
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Alberto Carmagnini
- Palaeogenomics Group, Institute of Palaeoanatomy, Domestication Research and the History of Veterinary Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sophy Charlton
- PalaeoBARN, School of Archaeology, University of Oxford, Oxford, UK
- BioArCh, Department of Archaeology, University of York, York, UK
| | - Love Dalén
- Centre for Palaeogenetics, Stockholm, Sweden
- Department of Zoology, Stockholm University, Stockholm, Sweden
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Tatiana R Feuerborn
- Center for Evolutionary Hologenomics, The Globe Institute, University of Copenhagen, Copenhagen, Denmark
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Shyam Gopalakrishnan
- Center for Evolutionary Hologenomics, The Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Vaughan Grimes
- Department of Archaeology, Memorial University of Newfoundland, St. Johns, NL, Canada
| | - Alex Harris
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Gwénaëlle Kavich
- Museum Conservation Institute, Smithsonian Institution, Suitland, MD, USA
| | - Benjamin N Sacks
- Mammalian Ecology and Conservation Unit, Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, Davis, CA, USA
| | | | - Pontus Skoglund
- Ancient Genomics Laboratory, The Francis Crick Institute, London, UK
| | - David W G Stanton
- Palaeogenomics Group, Institute of Palaeoanatomy, Domestication Research and the History of Veterinary Medicine, Ludwig-Maximilians-Universität, Munich, Germany
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Elaine A Ostrander
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Greger Larson
- PalaeoBARN, School of Archaeology, University of Oxford, Oxford, UK
| | - Chelsey G Armstrong
- Department of Indigenous Studies, Simon Fraser University, Burnaby, BC, Canada
| | - Laurent A F Frantz
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
- Palaeogenomics Group, Institute of Palaeoanatomy, Domestication Research and the History of Veterinary Medicine, Ludwig-Maximilians-Universität, Munich, Germany
| | - Melissa T R Hawkins
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Logan Kistler
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
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3
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Zhang RK, Sun WY, Liu YX, Zhang EY, Fan ZC. RABL2 promotes the outward transition zone passage of signaling proteins in cilia via ARL3. Proc Natl Acad Sci U S A 2023; 120:e2302603120. [PMID: 37579161 PMCID: PMC10450674 DOI: 10.1073/pnas.2302603120] [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: 02/20/2023] [Accepted: 07/10/2023] [Indexed: 08/16/2023] Open
Abstract
Certain transmembrane and membrane-tethered signaling proteins export from cilia as BBSome cargoes via the outward BBSome transition zone (TZ) diffusion pathway, indispensable for maintaining their ciliary dynamics to enable cells to sense and transduce extracellular stimuli inside the cell. Murine Rab-like 2 (Rabl2) GTPase resembles Chlamydomonas Arf-like 3 (ARL3) GTPase in promoting outward TZ passage of the signaling protein cargo-laden BBSome. During this process, ARL3 binds to and recruits the retrograde IFT train-dissociated BBSome as its effector to diffuse through the TZ for ciliary retrieval, while how RABL2 and ARL3 cross talk in this event remains uncertain. Here, we report that Chlamydomonas RABL2 in a GTP-bound form (RABL2GTP) cycles through cilia via IFT as an IFT-B1 cargo, dissociates from retrograde IFT trains at a ciliary region right above the TZ, and converts to RABL2GDP for activating ARL3GDP as an ARL3 guanine nucleotide exchange factor. This confers ARL3GTP to detach from the ciliary membrane and become available for binding and recruiting the phospholipase D (PLD)-laden BBSome, autonomous of retrograde IFT association, to diffuse through the TZ for ciliary retrieval. Afterward, RABL2GDP exits cilia by being bound to the ARL3GTP/BBSome entity as a BBSome cargo. Our data identify ciliary signaling proteins exported from cilia via the RABL2-ARL3 cascade-mediated outward BBSome TZ diffusion pathway. According to this model, hedgehog signaling defect-induced Bardet-Biedl syndrome caused by RABL2 mutations in humans could be well explained in a mutation-specific manner, providing us with a mechanistic understanding behind the outward BBSome TZ passage required for proper ciliary signaling.
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Affiliation(s)
- Rui-Kai Zhang
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin300457, China
| | - Wei-Yue Sun
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin300457, China
| | - Yan-Xia Liu
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin300457, China
| | | | - Zhen-Chuan Fan
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin300457, China
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4
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Li FL, Guan KL. The Arf family GTPases: Regulation of vesicle biogenesis and beyond. Bioessays 2023; 45:e2200214. [PMID: 36998106 PMCID: PMC10282109 DOI: 10.1002/bies.202200214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 04/01/2023]
Abstract
The Arf family proteins are best known for their roles in the vesicle biogenesis. However, they also play fundamental roles in a wide range of cellular regulation besides vesicular trafficking, such as modulation of lipid metabolic enzymes, cytoskeleton remodeling, ciliogenesis, lysosomal, and mitochondrial morphology and functions. Growing studies continue to expand the downstream effector landscape of Arf proteins, especially for the less-studied members, revealing new biological functions, such as amino acid sensing. Experiments with cutting-edge technologies and in vivo functional studies in the last decade help to provide a more comprehensive view of Arf family functions. In this review, we summarize the cellular functions that are regulated by at least two different Arf members with an emphasis on those beyond vesicle biogenesis.
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Affiliation(s)
- Fu-Long Li
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kun-Liang Guan
- Department of Pharmacology and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
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5
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Li L, Li J, Ou Y, Wu J, Li H, Wang X, Tang L, Dai X, Yang C, Wei Z, Yin Z, Shu Y. Ccdc57 is required for straightening the body axis by regulating ciliary motility in the brain ventricle of zebrafish. J Genet Genomics 2023; 50:253-263. [PMID: 36669737 DOI: 10.1016/j.jgg.2022.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/22/2022] [Accepted: 12/31/2022] [Indexed: 01/19/2023]
Abstract
Recently, cilia defects have been proposed to contribute to scoliosis. Here, we demonstrate that coiled-coil domain-containing 57 (Ccdc57) plays an essential role in straightening the body axis of zebrafish by regulating ciliary beating in the brain ventricle (BV). Zygotic ccdc57 (Zccdc57) mutant zebrafish developes scoliosis without significant changes in their bone density and calcification, and the maternal-zygotic ccdc57 (MZccdc57) mutant embryos display curved bodies since the long-pec stage. The expression of ccdc57 is enriched in ciliated tissues and immunofluorescence analysis reveals colocalization of Ccdc57-HA with acetylated α-tubulin, implicating it in having a role in ciliary function. Further examination reveals that it is the coordinated cilia beating of multiple cilia bundles (MCB) in the MZccdc57 mutant embryos that is affected at 48 hours post fertilization, when the compromised cerebrospinal fluid flow and curved body axis have already occurred. Either ccdc57 mRNA injection or epinephrine treatment reverses the spinal curvature in MZccdc57 mutant larvae from ventrally curly to straight or even dorsally curly and significantly upregulates urotensin signaling. This study reveals the role of ccdc57 in maintaining coordinated cilia beating of MCB in the BV.
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Affiliation(s)
- Lu Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Juan Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Yuan Ou
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Jiaxin Wu
- School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Huilin Li
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Xin Wang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Liying Tang
- College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Xiangyan Dai
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University, Chongqing 400715, China
| | - Conghui Yang
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Zehong Wei
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China
| | - Zhan Yin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Yuqin Shu
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China; College of Life Sciences, Hunan Normal University, Changsha, Hunan 410081, China.
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6
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Liu YX, Sun WY, Xue B, Zhang RK, Li WJ, Xie X, Fan ZC. ARL3 mediates BBSome ciliary turnover by promoting its outward movement across the transition zone. J Cell Biol 2022; 221:213491. [PMID: 36129685 PMCID: PMC9499826 DOI: 10.1083/jcb.202111076] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 02/13/2022] [Accepted: 07/11/2022] [Indexed: 01/16/2023] Open
Abstract
Ciliary receptors and their certain downstream signaling components undergo intraflagellar transport (IFT) as BBSome cargoes to maintain their ciliary dynamics for sensing and transducing extracellular stimuli inside the cell. Cargo-laden BBSomes pass the transition zone (TZ) for ciliary retrieval, but how this passage is controlled remains elusive. Here, we show that phospholipase D (PLD)-laden BBSomes shed from retrograde IFT trains at the proximal ciliary region right above the TZ to act as Arf-like 3 (ARL3) GTPase-specific effectors in Chlamydomonas cilia. Under physiological condition, ARL3GDP binds to the membrane for diffusing into cilia. Following nucleotide exchange, ARL3GTP detaches from the ciliary membrane, binds to retrograde IFT train-shed and PLD-laden BBSomes at the proximal ciliary region right above the TZ, and recruits them to pass the TZ for ciliary retrieval likely via diffusion. ARL3 mediates the ciliary dynamics of certain signaling molecules through facilitating BBSome ciliary retrieval, providing a mechanistic understanding behind why ARL3-related Joubert syndrome shares overlapping phenotypes with Bardet-Biedl syndrome.
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Affiliation(s)
- Yan-Xia Liu
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Wei-Yue Sun
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Bin Xue
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Rui-Kai Zhang
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Wen-Juan Li
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Xixian Xie
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Zhen-Chuan Fan
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
- Correspondence to Zhen-Chuan Fan:
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7
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Primary cilia in satellite cells are the mechanical sensors for muscle hypertrophy. Proc Natl Acad Sci U S A 2022; 119:e2103615119. [PMID: 35671424 PMCID: PMC9214504 DOI: 10.1073/pnas.2103615119] [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: 11/18/2022] Open
Abstract
Skeletal muscle atrophy is commonly associated with aging, immobilization, muscle unloading, and congenital myopathies. Generation of mature muscle cells from skeletal muscle satellite cells (SCs) is pivotal in repairing muscle tissue. Exercise therapy promotes muscle hypertrophy and strength. Primary cilium is implicated as the mechanical sensor in some mammalian cells, but its role in skeletal muscle cells remains vague. To determine mechanical sensors for exercise-induced muscle hypertrophy, we established three SC-specific cilium dysfunctional mouse models-Myogenic factor 5 (Myf5)-Arf-like Protein 3 (Arl3)-/-, Paired box protein Pax-7 (Pax7)-Intraflagellar transport protein 88 homolog (Ift88)-/-, and Pax7-Arl3-/--by specifically deleting a ciliary protein ARL3 in MYF5-expressing SCs, or IFT88 in PAX7-expressing SCs, or ARL3 in PAX7-expressing SCs, respectively. We show that the Myf5-Arl3-/- mice develop grossly the same as WT mice. Intriguingly, mechanical stimulation-induced muscle hypertrophy or myoblast differentiation is abrogated in Myf5-Arl3-/- and Pax7-Arl3-/- mice or primary isolated Myf5-Arl3-/- and Pax7-Ift88-/- myoblasts, likely due to defective cilia-mediated Hedgehog (Hh) signaling. Collectively, we demonstrate SC cilia serve as mechanical sensors and promote exercise-induced muscle hypertrophy via Hh signaling pathway.
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8
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Lee H, Choi S, Ha S, Yoon S, Kim WY. ARL2 is required for homologous recombination repair and colon cancer stem cell survival. FEBS Open Bio 2022; 12:1523-1533. [PMID: 35567502 PMCID: PMC9340879 DOI: 10.1002/2211-5463.13438] [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: 02/05/2022] [Revised: 04/16/2022] [Accepted: 05/12/2022] [Indexed: 11/10/2022] Open
Abstract
ARL2 regulates the dynamics of cytological components and is highly expressed in colon cancer tissues. Here, we report novel roles of ARL2 in the cell nucleus and colon cancer stem cells (CSCs). ARL2 is expressed at relatively low levels in K‐RAS active colon cancer cells, but its expression is induced in CSCs. Depletion of ARL2 results in M phase arrest exclusively in non‐CSC cultured cells; in addition, DNA break stress accumulates in CSCs leading to apoptosis. ARL2 expression is positively associated with the expression of all six RAD51 family genes, which are essential for homologous recombination repair (HRR). Furthermore, ARL2 is required for HRR and detected within chromatin compartments. These results demonstrate the requirement of ARL2 in colon CSC maintenance, which possibly occurs through mediating double‐strand break DNA repair in the nucleus.
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Affiliation(s)
- Hani Lee
- College of Pharmacy, Sookmyung Women's University, Cheongparo 47 gil, Yongsangu, Seoul, 04312, Korea
| | - SeokGyeong Choi
- College of Pharmacy, Sookmyung Women's University, Cheongparo 47 gil, Yongsangu, Seoul, 04312, Korea
| | - Sojung Ha
- College of Pharmacy, Sookmyung Women's University, Cheongparo 47 gil, Yongsangu, Seoul, 04312, Korea
| | - Sukjoon Yoon
- Department of Biological Sciences, Sookmyung Women's University, Cheongparo 47 gil, Yongsangu, Seoul, 04312, Korea
| | - Woo-Young Kim
- College of Pharmacy, Sookmyung Women's University, Cheongparo 47 gil, Yongsangu, Seoul, 04312, Korea.,Research Institute of Pharmacal Research, Sookmyung Women's University, Cheongparo 47 gil, Yongsangu, Seoul, 04312, Korea
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9
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ElMaghloob Y, Sot B, McIlwraith MJ, Garcia E, Yelland T, Ismail S. ARL3 activation requires the co-GEF BART and effector-mediated turnover. eLife 2021; 10:e64624. [PMID: 33438581 PMCID: PMC7817177 DOI: 10.7554/elife.64624] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/12/2021] [Indexed: 12/28/2022] Open
Abstract
The ADP-ribosylation factor-like 3 (ARL3) is a ciliopathy G-protein which regulates the ciliary trafficking of several lipid-modified proteins. ARL3 is activated by its guanine exchange factor (GEF) ARL13B via an unresolved mechanism. BART is described as an ARL3 effector which has also been implicated in ciliopathies, although the role of its ARL3 interaction is unknown. Here, we show that, at physiological GTP:GDP levels, human ARL3GDP is weakly activated by ARL13B. However, BART interacts with nucleotide-free ARL3 and, in concert with ARL13B, efficiently activates ARL3. In addition, BART binds ARL3GTP and inhibits GTP dissociation, thereby stabilising the active G-protein; the binding of ARL3 effectors then releases BART. Finally, using live cell imaging, we show that BART accesses the primary cilium and colocalises with ARL13B. We propose a model wherein BART functions as a bona fide co-GEF for ARL3 and maintains the active ARL3GTP, until it is recycled by ARL3 effectors.
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Affiliation(s)
| | - Begoña Sot
- Fundación IMDEA-Nanociencia, Campus de CantoblancoMadridSpain
- Unidad Asociada de Nanobiotecnología (CNB-CSIC e IMDEA Nanociencia), Campus de CantoblancoMadridSpain
| | | | | | | | - Shehab Ismail
- CRUK- Beatson InstituteGlasgowUnited Kingdom
- Institute of Cancer Sciences, University of GlasgowGlasgowUnited Kingdom
- Department of Chemistry, KU Leuven, CelestijnenlaanHeverleeBelgium
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10
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Wang Y, Zhao W, Liu X, Guan G, Zhuang M. ARL3 is downregulated and acts as a prognostic biomarker in glioma. J Transl Med 2019; 17:210. [PMID: 31234870 PMCID: PMC6591946 DOI: 10.1186/s12967-019-1914-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Glioma is the most common primary malignant brain tumor in adults with a poor prognosis. ARL3 is a member of the ARF family, and plays a key role in ciliary function and lipid-modified protein trafficking. ARL3 has been reported to be involved in ciliary diseases, in which it affects kidney and photoreceptor development. However, the functional role of ARL3 in cancer remains unknown. In this study, we aimed to explore ARL3 expression and its roles in glioma prognosis. METHODS RT-PCR and immunohistochemistry were performed to examine the expression level of ARL3 in glioma samples. Data from The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA) and Repository for Molecular Brain Neoplasia Data (REMBRANDT) databases were employed to investigate ARL3 expression and its roles in glioma prognosis. A nomogram for predicting 3- or 5-year survival was established using Cox proportional hazards regression. Finally, gene ontology (GO) analysis, gene set enrichment analysis (GSEA), and gene set variation analysis (GSVA) were performed to explore the biological function. RESULTS ARL3 expression was downregulated in glioma, and associated with poor prognosis in glioma patients. The C-indexes, areas under the ROC curve and calibration plots of the nomogram indicated an effective predictive performance for glioma patients. In addition, GO and pathway analyses suggested the involvement of ARL3 in angiogenesis and immune cell infiltration in the microenvironment. CONCLUSIONS Low ARL3 expression predicted poor prognosis and contributed to antiangiogenesis and the proportion of infiltrating immune cells in the GBM microenvironment. Thus, ARL3 may be a prognostic marker and therapeutic target for glioma.
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Affiliation(s)
- Yulin Wang
- Department of Neurosurgery, The First Affiliated Hospital of Shantou University Medical College, 57 Changping Road, Shantou, 515041, Guangdong, China
| | - Weijiang Zhao
- Center for Neuroscience, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Xin Liu
- Department of Stomatology, The First Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Gefei Guan
- Department of Neurosurgery, The First Hospital of China Medical University, Shenyang, 110001, Liaoning, China
| | - Minghua Zhuang
- Department of Neurosurgery, The First Affiliated Hospital of Shantou University Medical College, 57 Changping Road, Shantou, 515041, Guangdong, China.
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11
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Bhattarai SR, Begum S, Popow R, Ezratty EJ. The ciliary GTPase Arl3 maintains tissue architecture by directing planar spindle orientation during epidermal morphogenesis. Development 2019; 146:dev.161885. [PMID: 30952667 DOI: 10.1242/dev.161885] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/08/2019] [Indexed: 12/17/2022]
Abstract
Arl/ARF GTPases regulate ciliary trafficking, but their tissue-specific functions are unclear. Here, we demonstrate that ciliary GTPase Arl3 is required for mitotic spindle orientation of mouse basal stem cells during skin development. Arl3 loss diminished cell divisions within the plane of the epithelium, leading to increased perpendicular divisions, expansion of progenitor cells and loss of epithelial integrity. These observations suggest that an Arl3-dependent mechanism maintains cell division polarity along the tissue axis, and disruption of planar spindle orientation has detrimental consequences for epidermal architecture. Defects in planar cell polarity (PCP) can disrupt spindle positioning during tissue morphogenesis. Upon Arl3 loss, the PCP signaling molecules Celsr1 and Vangl2 failed to maintain planar polarized distributions, resulting in defective hair follicle angling, a hallmark of disrupted PCP. In the absence of Celsr1 polarity, frizzled 6 lost its asymmetrical distribution and abnormally segregated to the apical cortex of basal cells. We propose that Arl3 regulates polarized endosomal trafficking of PCP components to compartmentalized membrane domains. Cell-cell communication via ciliary GTPase signaling directs mitotic spindle orientation and PCP signaling, processes that are crucial for the maintenance of epithelial architecture.
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Affiliation(s)
- Samip R Bhattarai
- Department of Pathology and Cell Biology, Columbia University Medical Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Salma Begum
- Department of Pathology and Cell Biology, Columbia University Medical Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Rachel Popow
- Department of Pathology and Cell Biology, Columbia University Medical Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Ellen J Ezratty
- Department of Pathology and Cell Biology, Columbia University Medical Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Kösling SK, Fansa EK, Maffini S, Wittinghofer A. Mechanism and dynamics of INPP5E transport into and inside the ciliary compartment. Biol Chem 2018; 399:277-292. [PMID: 29140789 DOI: 10.1515/hsz-2017-0226] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/03/2017] [Indexed: 11/15/2022]
Abstract
The inositol polyphosphate 5'-phosphatase E (INPP5E) localizes to cilia. We showed that the carrier protein phosphodiesterase 6 delta subunit (PDE6δ) mediates the sorting of farnesylated INPP5E into cilia due to high affinity binding and release by the ADP-ribosylation factor (Arf)-like protein Arl3·GTP. However, the dynamics of INPP5E transport into and inside the ciliary compartment are not fully understood. Here, we investigate the movement of INPP5E using live cell fluorescence microscopy and fluorescence recovery after photobleaching (FRAP) analysis. We show that PDE6δ and the dynein transport system are essential for ciliary sorting and entry of INPP5E. However, its innerciliary transport is regulated solely by the intraflagellar transport (IFT) system, independent from PDE6δ activity and INPP5E farnesylation. By contrast, movement of Arl3 into and within cilia occurs freely by diffusion and IFT-independently. The farnesylation defective INPP5E CaaX box mutant loses the exclusive ciliary localization. The accumulation of this mutant at centrioles after photobleaching suggests an affinity trap mechanism for ciliary entry, that in case of the wild type is overcome by the interaction with PDE6δ. Collectively, we postulate a three-step mechanism regulating ciliary localization of INPP5E, consisting of farnesylation- and PDE6δ-mediated targeting, INPP5E-PDE6δ complex diffusion into the cilium with transfer to the IFT system, and retention inside cilia.
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Affiliation(s)
- Stefanie Kristine Kösling
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
| | - Eyad Kalawy Fansa
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, D-44227 Dortmund, Germany
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13
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Alkanderi S, Molinari E, Shaheen R, Elmaghloob Y, Stephen LA, Sammut V, Ramsbottom SA, Srivastava S, Cairns G, Edwards N, Rice SJ, Ewida N, Alhashem A, White K, Miles CG, Steel DH, Alkuraya FS, Ismail S, Sayer JA. ARL3 Mutations Cause Joubert Syndrome by Disrupting Ciliary Protein Composition. Am J Hum Genet 2018; 103:612-620. [PMID: 30269812 PMCID: PMC6174286 DOI: 10.1016/j.ajhg.2018.08.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/24/2018] [Indexed: 01/19/2023] Open
Abstract
Joubert syndrome (JBTS) is a genetically heterogeneous autosomal-recessive neurodevelopmental ciliopathy. We investigated further the underlying genetic etiology of Joubert syndrome by studying two unrelated families in whom JBTS was not associated with pathogenic variants in known JBTS-associated genes. Combined autozygosity mapping of both families highlighted a candidate locus on chromosome 10 (chr10: 101569997-109106128, UCSC Genome Browser hg 19), and exome sequencing revealed two missense variants in ARL3 within the candidate locus. The encoded protein, ADP ribosylation factor-like GTPase 3 (ARL3), is a small GTP-binding protein that is involved in directing lipid-modified proteins into the cilium in a GTP-dependent manner. Both missense variants replace the highly conserved Arg149 residue, which we show to be necessary for the interaction with its guanine nucleotide exchange factor ARL13B, such that the mutant protein is associated with reduced INPP5E and NPHP3 localization in cilia. We propose that ARL3 provides a potential hub in the network of proteins implicated in ciliopathies, whereby perturbation of ARL3 leads to the mislocalization of multiple ciliary proteins as a result of abnormal displacement of lipidated protein cargo.
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Affiliation(s)
- Sumaya Alkanderi
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Elisa Molinari
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Ranad Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Yasmin Elmaghloob
- Structural Biology of the Cilia Lab, Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Louise A Stephen
- Structural Biology of the Cilia Lab, Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Veronica Sammut
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Simon A Ramsbottom
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Shalabh Srivastava
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK; Renal Services, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne NE7 7DN, UK
| | - George Cairns
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Noel Edwards
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Sarah J Rice
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Nour Ewida
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Amal Alhashem
- Department of Pediatrics, Prince Sultan Medical Military City, Riyadh 12233, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Kathryn White
- Electron Microscopy Research Services, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Colin G Miles
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - David H Steel
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK; Sunderland Eye Infirmary, Queen Alexandra Road, Sunderland SR2 9HP, UK
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Shehab Ismail
- Structural Biology of the Cilia Lab, Beatson Institute for Cancer Research, Switchback Road, Bearsden, Glasgow G61 1BD, UK; Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, UK.
| | - John A Sayer
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK; Renal Services, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne NE7 7DN, UK.
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14
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Zhang Y, Huang Y, Srivathsan A, Lim TK, Lin Q, He CY. The unusual flagellar-targeting mechanism and functions of the trypanosome ortholog of the ciliary GTPase Arl13b. J Cell Sci 2018; 131:jcs.219071. [PMID: 30097558 PMCID: PMC6140319 DOI: 10.1242/jcs.219071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 07/28/2018] [Indexed: 12/11/2022] Open
Abstract
The small GTPase Arl13b is one of the most conserved and ancient ciliary proteins. In human and animals, Arl13b is primarily associated with the ciliary membrane, where it acts as a guanine-nucleotide-exchange factor (GEF) for Arl3 and is implicated in a variety of ciliary and cellular functions. We have identified and characterized Trypanosoma brucei (Tb)Arl13, the sole Arl13b homolog in this evolutionarily divergent, protozoan parasite. TbArl13 has conserved flagellar functions and exhibits catalytic activity towards two different TbArl3 homologs. However, TbArl13 is distinctly associated with the axoneme through a dimerization/docking (D/D) domain. Replacing the D/D domain with a sequence encoding a flagellar membrane protein created a viable alternative to the wild-type TbArl13 in our RNA interference (RNAi)-based rescue assay. Therefore, flagellar enrichment is crucial for TbArl13, but mechanisms to achieve this could be flexible. Our findings thus extend the understanding of the roles of Arl13b and Arl13b–Arl3 pathway in a divergent flagellate of medical importance. This article has an associated First Person interview with the first author of the paper. Highlighted Article: All roads lead to cilia – how the essential flagellar enrichment of Arl13 is achieved in trypanosome cells using a fundamentally different strategy compared with that of animal cells.
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Affiliation(s)
- Yiliu Zhang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Yameng Huang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Amrita Srivathsan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Teck Kwang Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Qingsong Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Cynthia Y He
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Drive 4, Singapore 117543
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15
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Eichler TW, Totland C, Haugen M, Vedeler CA. CCDC104 Antibodies and Mitosis of Cancer Cells. Scand J Immunol 2017; 87:109-110. [PMID: 29193323 DOI: 10.1111/sji.12634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 11/17/2017] [Indexed: 11/27/2022]
Affiliation(s)
- T W Eichler
- Bergen Stem Cell Consortium/Department of Immunology and Transfusion Medicine, Haukeland University Hospital, Bergen, Norway
| | - C Totland
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - M Haugen
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - C A Vedeler
- Department of Neurology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
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16
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Klink BU, Zent E, Juneja P, Kuhlee A, Raunser S, Wittinghofer A. A recombinant BBSome core complex and how it interacts with ciliary cargo. eLife 2017; 6. [PMID: 29168691 PMCID: PMC5700813 DOI: 10.7554/elife.27434] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 11/03/2017] [Indexed: 01/07/2023] Open
Abstract
Cilia are small, antenna-like structures on the surface of eukaryotic cells that harbor a unique set of sensory proteins, including GPCRs and other membrane proteins. The transport of these proteins involves the BBSome, an eight-membered protein complex that is recruited to ciliary membranes by the G-protein Arl6. BBSome malfunction leads to Bardet-Biedl syndrome, a ciliopathy with severe consequences. Short ciliary targeting sequences (CTS) have been identified that trigger the transport of ciliary proteins. However, mechanistic studies that relate ciliary targeting to BBSome binding are missing. Here we used heterologously expressed BBSome subcomplexes to analyze the complex architecture and to investigate the binding of GPCRs and other receptors to the BBSome. A stable heterohexameric complex was identified that binds to GPCRs with interactions that only partially overlap with previously described CTS, indicating a more complex recognition than anticipated. Arl6•GTP does not affect these interactions, suggesting no direct involvement in cargo loading/unloading.
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Affiliation(s)
- Björn Udo Klink
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.,Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Eldar Zent
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Puneet Juneja
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Anne Kuhlee
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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17
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Whole-Organism Developmental Expression Profiling Identifies RAB-28 as a Novel Ciliary GTPase Associated with the BBSome and Intraflagellar Transport. PLoS Genet 2016; 12:e1006469. [PMID: 27930654 PMCID: PMC5145144 DOI: 10.1371/journal.pgen.1006469] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/08/2016] [Indexed: 01/18/2023] Open
Abstract
Primary cilia are specialised sensory and developmental signalling devices extending from the surface of most eukaryotic cells. Defects in these organelles cause inherited human disorders (ciliopathies) such as retinitis pigmentosa and Bardet-Biedl syndrome (BBS), frequently affecting many physiological and developmental processes across multiple organs. Cilium formation, maintenance and function depend on intracellular transport systems such as intraflagellar transport (IFT), which is driven by kinesin-2 and IFT-dynein motors and regulated by the Bardet-Biedl syndrome (BBS) cargo-adaptor protein complex, or BBSome. To identify new cilium-associated genes, we employed the nematode C. elegans, where ciliogenesis occurs within a short timespan during late embryogenesis when most sensory neurons differentiate. Using whole-organism RNA-Seq libraries, we discovered a signature expression profile highly enriched for transcripts of known ciliary proteins, including FAM-161 (FAM161A orthologue), CCDC-104 (CCDC104), and RPI-1 (RP1/RP1L1), which we confirm are cilium-localised in worms. From a list of 185 candidate ciliary genes, we uncover orthologues of human MAP9, YAP, CCDC149, and RAB28 as conserved cilium-associated components. Further analyses of C. elegans RAB-28, recently associated with autosomal-recessive cone-rod dystrophy, reveal that this small GTPase is exclusively expressed in ciliated neurons where it dynamically associates with IFT trains. Whereas inactive GDP-bound RAB-28 displays no IFT movement and diffuse localisation, GTP-bound (activated) RAB-28 concentrates at the periciliary membrane in a BBSome-dependent manner and undergoes bidirectional IFT. Functional analyses reveal that whilst cilium structure, sensory function and IFT are seemingly normal in a rab-28 null allele, overexpression of predicted GDP or GTP locked variants of RAB-28 perturbs cilium and sensory pore morphogenesis and function. Collectively, our findings present a new approach for identifying ciliary proteins, and unveil RAB28, a GTPase most closely related to the BBS protein RABL4/IFT27, as an IFT-associated cargo with BBSome-dependent cell autonomous and non-autonomous functions at the ciliary base. Ciliopathies are genetic disorders that arise from loss or mutation of genes that encode proteins which play roles in the biology of cilia, organelles found on most of the cells in the human body. Ciliopathy-associated ailments include–but are not limited to–kidney dysfunction, blindness, skeletal abnormalities, as well as brain disorders. Although a great number of cilium-targeted proteins are known, it is thought that a large proportion remain unidentified. Here, we use a developmental gene expression series to discover novel cilia genes in the nematode Caenorhabditis elegans. We present several cilium-localised proteins resulting from our analysis, including RAB-28, a GTPase previously implicated in the degenerative eye disease known as cone-rod dystrophy. Through live videomicroscopy, we show that RAB-28 undergoes bidirectional transport within the cilium. A RAB-28 inactivating mutation results in loss of transport, while an activating mutation results in stronger localisation at the ciliary base and robust transport, although overexpression results in a variety of cilia-related defects. Both the wild type and activating mutant proteins require the Bardet-Biedl Syndrome-related complex of proteins for their transport, linking RAB-28 to an established ciliary transport machinery.
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18
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Abstract
Arl2 and Arl3 are Arf-like small GTP-binding proteins of the Arf subfamily of the Ras superfamily. Despite their structural similarity and sharing of many interacting partners, Arl2 and Arl3 have different biochemical properties and biological functions. Growing evidence suggest that Arl2 and Arl3 play a fundamental role as regulators of trafficking of lipid modified proteins between different compartments. Here we highlight the similarities and differences between these 2 homologous proteins and discuss the sorting mechanism of lipidated cargo into the ciliary compartment through the carriers PDE6δ and Unc119 and the release factors Arl2 and Arl3.
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Affiliation(s)
- Eyad K Fansa
- a Max Planck Institute of Molecular Physiology , Dortmund , Germany
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19
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Jaiswal M, Fansa EK, Kösling SK, Mejuch T, Waldmann H, Wittinghofer A. Novel Biochemical and Structural Insights into the Interaction of Myristoylated Cargo with Unc119 Protein and Their Release by Arl2/3. J Biol Chem 2016; 291:20766-78. [PMID: 27481943 PMCID: PMC5034065 DOI: 10.1074/jbc.m116.741827] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/29/2016] [Indexed: 11/06/2022] Open
Abstract
Primary cilia are highly specialized small antenna-like cellular protrusions that extend from the cell surface of many eukaryotic cell types. The protein content inside cilia and cytoplasm is very different, but details of the sorting process are not understood for most ciliary proteins. Recently, we have shown that prenylated proteins are sorted according to their affinity to the carrier protein PDE6δ and the ability of Arl3 but not Arl2 to release high affinity cargo inside the cilia (Fansa, E. K., Kösling, S. K., Zent, E., Wittinghofer, A., and Ismail, S. (2016) Nat. Commun. 7, 11366). Here we address the question whether a similar principle governs the transport of myristoylated cargo by the carrier proteins Unc119a and Unc119b. We thus analyzed the binding strength of N-terminal myristoylated cargo peptides (GNAT1, NPHP3, Cystin1, RP2, and Src) to Unc119a and Unc119b proteins. The affinity between myristoylated cargo and carrier protein, Unc119, varies between subnanomolar and micromolar. Peptides derived from ciliary localizing proteins (GNAT1, NPHP3, and Cystin1) bind with high affinity to Unc119 proteins, whereas a peptide derived from a non-ciliary localizing protein (Src) has low affinity. The peptide with intermediate affinity (RP2) is localized at the ciliary transition zone as a gate keeper. We show that the low affinity peptides are released by both Arl2·GppNHp and Arl3·GppNHp, whereas the high affinity peptides are exclusively released by only Arl3·GppNHp. Determination of the x-ray structure of myristoylated NPHP3 peptide in complex with Unc119a reveals the molecular details of high affinity binding and suggests the importance of the residues at the +2 and +3 positions relative to the myristoylated glycine for high and low affinities. The mutational analysis of swapping the residues at the +2 and +3 positions between high and low affinity peptides results in reversing their affinities for Unc119a and leads to a partial mislocalization of a low affinity mutant of NPHP3.
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Affiliation(s)
| | | | | | - Tom Mejuch
- the Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Herbert Waldmann
- the Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
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20
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Nawrotek A, Zeghouf M, Cherfils J. Allosteric regulation of Arf GTPases and their GEFs at the membrane interface. Small GTPases 2016; 7:283-296. [PMID: 27449855 DOI: 10.1080/21541248.2016.1215778] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Arf GTPases assemble protein complexes on membranes to carry out major functions in cellular traffic. An essential step is their activation by guanine nucleotide exchange factors (GEFs), whose Sec7 domain stimulates GDP/GTP exchange. ArfGEFs form 2 major families: ArfGEFs with DCB, HUS and HDS domains (GBF1 and BIG1/BIG2 in humans), which act at the Golgi; and ArfGEFs with a C-terminal PH domain (cytohesin, EFA6 and BRAG), which function at the plasma membrane and endosomes. In addition, pathogenic bacteria encode an ArfGEF with a unique membrane-binding domain. Here we review the allosteric regulation of Arf GTPases and their GEFs at the membrane interface. Membranes contribute several regulatory layers: at the GTPase level, where activation by GTP is coupled to membrane recruitment by a built-in structural device; at the Sec7 domain, which manipulates this device to ensure that Arf-GTP is attached to membranes; and at the level of non-catalytic ArfGEF domains, which form direct or GTPase-mediated interactions with membranes that enable a spectacular diversity of regulatory regimes. Notably, we show here that membranes increase the efficiency of a large ArfGEF (human BIG1) by 32-fold by interacting directly with its N-terminal DCB and HUS domains. The diversity of allosteric regulatory regimes suggests that ArfGEFs can function in cascades and circuits to modulate the shape, amplitude and duration of Arf signals in cells. Because Arf-like GTPases feature autoinhibitory elements similar to those of Arf GTPases, we propose that their activation also requires allosteric interactions of these elements with membranes or other proteins.
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Affiliation(s)
- Agata Nawrotek
- a Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure de Cachan and Université Paris-Saclay , Cachan , France
| | - Mahel Zeghouf
- a Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure de Cachan and Université Paris-Saclay , Cachan , France
| | - Jacqueline Cherfils
- a Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure de Cachan and Université Paris-Saclay , Cachan , France
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21
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Abstract
A new bioinformatics tool predicts natively disordered protein control elements that function in cis, opening the door to more systematic studies of this biomedically important class of protein modules.
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Affiliation(s)
- Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
| | - Manjeet Kumar
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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