101
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Hu J, Harris PC. Regulation of polycystin expression, maturation and trafficking. Cell Signal 2020; 72:109630. [PMID: 32275942 PMCID: PMC7269868 DOI: 10.1016/j.cellsig.2020.109630] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The major autosomal dominant polycystic kidney disease (ADPKD) genes, PKD1 and PKD2, are wildly expressed at the organ and tissue level. PKD1 encodes polycystin 1 (PC1), a large membrane associated receptor-like protein that can complex with the PKD2 product, PC2. Various cellular locations have been described for both PC1, including the plasma membrane and extracellular vesicles, and PC2, especially the endoplasmic reticulum (ER), but compelling evidence indicates that the primary cilium, a sensory organelle, is the key site for the polycystin complex to prevent PKD. As with other membrane proteins, the ER biogenesis pathway is key to appropriately folding, performing quality control, and exporting fully folded PC1 to the Golgi apparatus. There is a requirement for binding with PC2 and cleavage of PC1 at the GPS for this folding and export to occur. Six different monogenic defects in this pathway lead to cystic disease development, with PC1 apparently particularly sensitive to defects in this general protein processing pathway. Trafficking of membrane proteins, and the polycystins in particular, through the Golgi to the primary cilium have been analyzed in detail, but at this time, there is no clear consensus on a ciliary targeting sequence required to export proteins to the cilium. After transitioning though the trans-Golgi network, polycystin-bearing vesicles are likely sorted to early or recycling endosomes and then transported to the ciliary base, possibly via docking to transition fibers (TF). The membrane-bound polycystin complex then undergoes facilitated trafficking through the transition zone, the diffusion barrier at the base of the cilium, before entering the cilium. Intraflagellar transport (IFT) may be involved in moving the polycystins along the cilia, but data also indicates other mechanisms. The ciliary polycystin complex can be ubiquitinated and removed from cilia by internalization at the ciliary base and may be sent back to the plasma membrane for recycling or to lysosomes for degradation. Monogenic defects in processes regulating the protein composition of cilia are associated with syndromic disorders involving many organ systems, reflecting the pleotropic role of cilia during development and for tissue maintenance. Many of these ciliopathies have renal involvement, likely because of faulty polycystin signaling from cilia. Understanding the expression, maturation and trafficking of the polycystins helps understand PKD pathogenesis and suggests opportunities for therapeutic intervention.
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Affiliation(s)
- Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
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Zatoński T, Pazdro-Zastawny K, Morawska-Kochman M, Biela M, Kołtowska A, Rydzanicz M, Rozensztrauch A, Kosińska J, Dorobisz K, Płoski R, Śmigiel R. Single median maxillary central incisor syndrome and variant in SMO gene associated with SHH pathway. Int J Pediatr Otorhinolaryngol 2020; 134:110038. [PMID: 32335464 DOI: 10.1016/j.ijporl.2020.110038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 01/08/2023]
Abstract
Solitary median maxillary central incisor syndrome (SMMCI) is a rare congenital oronasal-dental midline anomaly. The aim of this paper is a presentation of a patient with SMMCI without other visible dentofacial anomalies, with a potentially new molecular etiology consisting of a gene-gene reaction and conservative therapeutic approach to nasal obstruction. Potentially pathogenic variants in the SMO gene (p.Gly422Glu) and in P2RY13 gene (p.Trp205*) inherited from the probant's father, and in the PLD2 gene (p.Gln319fs), inherited from the mother were found. A multidisciplinary approach is necessary for the management of patients with SMMCI, including a genetic consultation with genetic tests.
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Affiliation(s)
- Tomasz Zatoński
- Department and Clinic of Otolaryngology, Head and Neck Surgery, Medical University Hospital Wroclaw, Borowska 213, 50-556, Wroclaw, Poland
| | - Katarzyna Pazdro-Zastawny
- Department and Clinic of Otolaryngology, Head and Neck Surgery, Medical University Hospital Wroclaw, Borowska 213, 50-556, Wroclaw, Poland.
| | - Monika Morawska-Kochman
- Department and Clinic of Otolaryngology, Head and Neck Surgery, Medical University Hospital Wroclaw, Borowska 213, 50-556, Wroclaw, Poland
| | - Mateusz Biela
- Department of Pediatrics, Division Propaedeutic of Pediatrics and Rare Disorders, Medical University, Wroclaw, Poland
| | - Anna Kołtowska
- Department of Radiology, Medical University Hospital Wroclaw, Borowska 213, 50-556, Wroclaw, Poland
| | | | - Anna Rozensztrauch
- Department of Pediatrics, Division Propaedeutic of Pediatrics and Rare Disorders, Medical University, Wroclaw, Poland
| | - Joanna Kosińska
- Department of Genetics, Warsaw Medical University, Warsaw, Poland
| | - Karolina Dorobisz
- Department and Clinic of Otolaryngology, Head and Neck Surgery, Medical University Hospital Wroclaw, Borowska 213, 50-556, Wroclaw, Poland
| | - Rafał Płoski
- Department of Genetics, Warsaw Medical University, Warsaw, Poland
| | - Robert Śmigiel
- Department of Pediatrics, Division Propaedeutic of Pediatrics and Rare Disorders, Medical University, Wroclaw, Poland
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103
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Scheidt T, Alka O, Gonczarowska-Jorge H, Gruber W, Rathje F, Dell’Aica M, Rurik M, Kohlbacher O, Zahedi RP, Aberger F, Huber CG. Phosphoproteomics of short-term hedgehog signaling in human medulloblastoma cells. Cell Commun Signal 2020; 18:99. [PMID: 32576205 PMCID: PMC7310537 DOI: 10.1186/s12964-020-00591-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 05/05/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Aberrant hedgehog (HH) signaling is implicated in the development of various cancer entities such as medulloblastoma. Activation of GLI transcription factors was revealed as the driving force upon pathway activation. Increased phosphorylation of essential effectors such as Smoothened (SMO) and GLI proteins by kinases including Protein Kinase A, Casein Kinase 1, and Glycogen Synthase Kinase 3 β controls effector activity, stability and processing. However, a deeper and more comprehensive understanding of phosphorylation in the signal transduction remains unclear, particularly during early response processes involved in SMO activation and preceding GLI target gene regulation. METHODS We applied temporal quantitative phosphoproteomics to reveal phosphorylation dynamics underlying the short-term chemical activation and inhibition of early hedgehog signaling in HH responsive human medulloblastoma cells. Medulloblastoma cells were treated for 5.0 and 15 min with Smoothened Agonist (SAG) to induce and with vismodegib to inhibit the HH pathway. RESULTS Our phosphoproteomic profiling resulted in the quantification of 7700 and 10,000 phosphosites after 5.0 and 15 min treatment, respectively. The data suggest a central role of phosphorylation in the regulation of ciliary assembly, trafficking, and signal transduction already after 5.0 min treatment. ERK/MAPK signaling, besides Protein Kinase A signaling and mTOR signaling, were differentially regulated after short-term treatment. Activation of Polo-like Kinase 1 and inhibition of Casein Kinase 2A1 were characteristic for vismodegib treatment, while SAG treatment induced Aurora Kinase A activity. Distinctive phosphorylation of central players of HH signaling such as SMO, SUFU, GLI2 and GLI3 was observed only after 15 min treatment. CONCLUSIONS This study provides evidence that phosphorylation triggered in response to SMO modulation dictates the localization of hedgehog pathway components within the primary cilium and affects the regulation of the SMO-SUFU-GLI axis. The data are relevant for the development of targeted therapies of HH-associated cancers including sonic HH-type medulloblastoma. A deeper understanding of the mechanisms of action of SMO inhibitors such as vismodegib may lead to the development of compounds causing fewer adverse effects and lower frequencies of drug resistance. Video Abstract.
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Affiliation(s)
- Tamara Scheidt
- Department of Biosciences, Bioanalytical Research Laboratories and Molecular Cancer Research and Tumor Immunology, Cancer Cluster Salzburg, University of Salzburg, Hellbrunner Straße 34, 5020 Salzburg, Austria
| | - Oliver Alka
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Sand 14, 72076 Tübingen, Germany
| | - Humberto Gonczarowska-Jorge
- Leibniz-Institute of Analytical Sciences- ISAS - e.V, Dortmund, Germany
- Present address: CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70040-020 Brazil
| | - Wolfgang Gruber
- Department of Biosciences, Bioanalytical Research Laboratories and Molecular Cancer Research and Tumor Immunology, Cancer Cluster Salzburg, University of Salzburg, Hellbrunner Straße 34, 5020 Salzburg, Austria
- Present address: EVER Valinject GmbH, 4866 Unterach am Attersee, Austria
| | - Florian Rathje
- Department of Biosciences, Bioanalytical Research Laboratories and Molecular Cancer Research and Tumor Immunology, Cancer Cluster Salzburg, University of Salzburg, Hellbrunner Straße 34, 5020 Salzburg, Austria
| | | | - Marc Rurik
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Sand 14, 72076 Tübingen, Germany
| | - Oliver Kohlbacher
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Sand 14, 72076 Tübingen, Germany
- Biomolecular Interactions, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
- Institute for Translational Bioinformatics, University Hospital Tübingen, Hoppe-Seyler-Str. 9, 72076 Tübingen, Germany
- Applied Bioinformatics, Center for Bioinformatics, University of Tübingen, Sand 14, 72076 Tübingen, Germany
| | - René P. Zahedi
- Leibniz-Institute of Analytical Sciences- ISAS - e.V, Dortmund, Germany
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Canada
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Canada
| | - Fritz Aberger
- Department of Biosciences, Bioanalytical Research Laboratories and Molecular Cancer Research and Tumor Immunology, Cancer Cluster Salzburg, University of Salzburg, Hellbrunner Straße 34, 5020 Salzburg, Austria
| | - Christian G. Huber
- Department of Biosciences, Bioanalytical Research Laboratories and Molecular Cancer Research and Tumor Immunology, Cancer Cluster Salzburg, University of Salzburg, Hellbrunner Straße 34, 5020 Salzburg, Austria
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104
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Rajala A, McCauley A, Brush RS, Nguyen K, Rajala RV. Phosphoinositide Lipids in Ocular Tissues. BIOLOGY 2020; 9:biology9060125. [PMID: 32545642 PMCID: PMC7345453 DOI: 10.3390/biology9060125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 01/04/2023]
Abstract
Inositol phospholipids play an important role in cell physiology. The inositol head groups are reversibly phosphorylated to produce seven distinct phosphorylated inositides, commonly referred to as phosphoinositides (PIs). These seven PIs are dynamically interconverted from one PI to another by the action of PI kinases and PI phosphatases. The PI signals regulate a wide variety of cellular functions, including organelle distinction, vesicular transport, cytoskeletal organization, nuclear events, regulation of ion channels, cell signaling, and host–pathogen interactions. Most of the studies of PIs in ocular tissues are based on the PI enzymes and PI phosphatases. In this study, we examined the PI levels in the cornea, retinal pigment epithelium (RPE), and retina using PI-binding protein as probes. We have examined the lipids PI(3)P, PI(4)P, PI(3,4)P2, PI(4,5)P2, and PI(3,4,5)P3, and each is present in the cornea, RPE, and retina. Alterations in the levels of these PIs in mouse models of retinal disease and corneal infections have been reported, and the results of our study will help in the management of anomalous phosphoinositide metabolism in ocular tissues.
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Affiliation(s)
- Ammaji Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.R.); (A.M.); (R.S.B.); (K.N.)
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Austin McCauley
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.R.); (A.M.); (R.S.B.); (K.N.)
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Richard S. Brush
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.R.); (A.M.); (R.S.B.); (K.N.)
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Khuong Nguyen
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.R.); (A.M.); (R.S.B.); (K.N.)
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Raju V.S. Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.R.); (A.M.); (R.S.B.); (K.N.)
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, OK 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Correspondence: ; Tel.: +1-(405)-271-8255; Fax: +1-(405)-271-8128
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105
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Primary Cilia Signaling Promotes Axonal Tract Development and Is Disrupted in Joubert Syndrome-Related Disorders Models. Dev Cell 2020; 51:759-774.e5. [PMID: 31846650 DOI: 10.1016/j.devcel.2019.11.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/08/2019] [Accepted: 11/10/2019] [Indexed: 12/18/2022]
Abstract
Appropriate axonal growth and connectivity are essential for functional wiring of the brain. Joubert syndrome-related disorders (JSRD), a group of ciliopathies in which mutations disrupt primary cilia function, are characterized by axonal tract malformations. However, little is known about how cilia-driven signaling regulates axonal growth and connectivity. We demonstrate that the deletion of related JSRD genes, Arl13b and Inpp5e, in projection neurons leads to de-fasciculated and misoriented axonal tracts. Arl13b deletion disrupts the function of its downstream effector, Inpp5e, and deregulates ciliary-PI3K/AKT signaling. Chemogenetic activation of ciliary GPCR signaling and cilia-specific optogenetic modulation of downstream second messenger cascades (PI3K, AKT, and AC3) commonly regulated by ciliary signaling receptors induce rapid changes in axonal dynamics. Further, Arl13b deletion leads to changes in transcriptional landscape associated with dysregulated PI3K/AKT signaling. These data suggest that ciliary signaling acts to modulate axonal connectivity and that impaired primary cilia signaling underlies axonal tract defects in JSRD.
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106
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Martin-Hurtado A, Lastres-Becker I, Cuadrado A, Garcia-Gonzalo FR. NRF2 and Primary Cilia: An Emerging Partnership. Antioxidants (Basel) 2020; 9:antiox9060475. [PMID: 32498260 PMCID: PMC7346227 DOI: 10.3390/antiox9060475] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/30/2020] [Accepted: 05/31/2020] [Indexed: 02/07/2023] Open
Abstract
When not dividing, many cell types target their centrosome to the plasma membrane, where it nucleates assembly of a primary cilium, an antenna-like signaling structure consisting of nine concentric microtubule pairs surrounded by membrane. Primary cilia play important pathophysiological roles in many tissues, their dysfunction being associated with cancer and ciliopathies, a diverse group of congenital human diseases. Several recent studies have unveiled functional connections between primary cilia and NRF2 (nuclear factor erythroid 2-related factor 2), the master transcription factor orchestrating cytoprotective responses to oxidative and other cellular stresses. These NRF2-cilia relationships are reciprocal: primary cilia, by promoting autophagy, downregulate NRF2 activity. In turn, NRF2 transcriptionally regulates genes involved in ciliogenesis and Hedgehog (Hh) signaling, a cilia-dependent pathway with major roles in embryogenesis, stem cell function and tumorigenesis. Nevertheless, while we found that NRF2 stimulates ciliogenesis and Hh signaling, a more recent study reported that NRF2 negatively affects these processes. Herein, we review the available evidence linking NRF2 to primary cilia, suggest possible explanations to reconcile seemingly contradictory data, and discuss what the emerging interplay between primary cilia and NRF2 may mean for human health and disease.
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Affiliation(s)
- Ana Martin-Hurtado
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
| | - Isabel Lastres-Becker
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28013 Madrid, Spain
| | - Antonio Cuadrado
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28013 Madrid, Spain
| | - Francesc R. Garcia-Gonzalo
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), UAM-CSIC, 28029 Madrid, Spain; (A.M.-H.); (I.L.-B.); (A.C.)
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
- Instituto de Investigación del Hospital Universitario de La Paz (IdiPAZ), 28047 Madrid, Spain
- Correspondence:
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107
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Engle SE, Bansal R, Antonellis PJ, Berbari NF. Cilia signaling and obesity. Semin Cell Dev Biol 2020; 110:43-50. [PMID: 32466971 DOI: 10.1016/j.semcdb.2020.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/08/2020] [Accepted: 05/10/2020] [Indexed: 12/11/2022]
Abstract
An emerging number of rare genetic disorders termed ciliopathies are associated with pediatric obesity. It is becoming clear that the mechanisms associated with cilia dysfunction and obesity in these syndromes are complex. In addition to ciliopathic syndromic forms of obesity, several cilia-associated signaling gene mutations also lead to morbid obesity. While cilia have critical and diverse functions in energy homeostasis including their roles in centrally mediated food intake as well as in peripheral tissues, many questions remain. Here, we briefly discuss the syndromic ciliopathies and monoallelic cilia signaling gene mutations associated with obesity. We also describe potential ways cilia may be involved in common obesity. We discuss how neuronal cilia impact food intake potentially through leptin signaling and changes in ciliary G protein-coupled receptor (GPCR) signaling. We highlight several recent studies that have implicated the potential for cilia in peripheral tissues such as adipose and the pancreas to contribute to metabolic dysfunction. Then we discuss the potential for cilia to impact energy homeostasis through their roles in both development and adult tissue homeostasis. The studies discussed in this review highlight how a comprehensive understanding of the requirement of cilia for the regulation of diverse biological functions will contribute to our understanding of common forms of obesity.
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Affiliation(s)
- Staci E Engle
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Ruchi Bansal
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Patrick J Antonellis
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA; Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN, USA; Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN, USA.
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108
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Garcia E, Ismail S. Spatiotemporal Regulation of Signaling: Focus on T Cell Activation and the Immunological Synapse. Int J Mol Sci 2020; 21:E3283. [PMID: 32384769 PMCID: PMC7247333 DOI: 10.3390/ijms21093283] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/01/2020] [Accepted: 05/03/2020] [Indexed: 01/22/2023] Open
Abstract
In a signaling network, not only the functions of molecules are important but when (temporal) and where (spatial) those functions are exerted and orchestrated is what defines the signaling output. To temporally and spatially modulate signaling events, cells generate specialized functional domains with variable lifetime and size that concentrate signaling molecules, enhancing their transduction potential. The plasma membrane is a key in this regulation, as it constitutes a primary signaling hub that integrates signals within and across the membrane. Here, we examine some of the mechanisms that cells exhibit to spatiotemporally regulate signal transduction, focusing on the early events of T cell activation from triggering of T cell receptor to formation and maturation of the immunological synapse.
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Affiliation(s)
- Esther Garcia
- CR-UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Shehab Ismail
- CR-UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
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109
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Miyamoto T, Hosoba K, Itabashi T, Iwane AH, Akutsu SN, Ochiai H, Saito Y, Yamamoto T, Matsuura S. Insufficiency of ciliary cholesterol in hereditary Zellweger syndrome. EMBO J 2020; 39:e103499. [PMID: 32368833 PMCID: PMC7298307 DOI: 10.15252/embj.2019103499] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 03/13/2020] [Accepted: 03/20/2020] [Indexed: 11/22/2022] Open
Abstract
Primary cilia are antenna‐like organelles on the surface of most mammalian cells that receive sonic hedgehog (Shh) signaling in embryogenesis and carcinogenesis. Cellular cholesterol functions as a direct activator of a seven‐transmembrane oncoprotein called Smoothened (Smo) and thereby induces Smo accumulation on the ciliary membrane where it transduces the Shh signal. However, how cholesterol is supplied to the ciliary membrane remains unclear. Here, we report that peroxisomes are essential for the transport of cholesterol into the ciliary membrane. Zellweger syndrome (ZS) is a peroxisome‐deficient hereditary disorder with several ciliopathy‐related features and cells from these patients showed a reduced cholesterol level in the ciliary membrane. Reverse genetics approaches revealed that the GTP exchange factor Rabin8, the Rab GTPase Rab10, and the microtubule minus‐end‐directed kinesin KIFC3 form a peroxisome‐associated complex to control the movement of peroxisomes along microtubules, enabling communication between peroxisomes and ciliary pocket membranes. Our findings suggest that insufficient ciliary cholesterol levels may underlie ciliopathies.
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Affiliation(s)
- Tatsuo Miyamoto
- Department of Genetics and Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Kosuke Hosoba
- Department of Genetics and Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.,Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takeshi Itabashi
- Laboratory for Cell Field Structure, RIKEN Center for Biosystems Dynamics Research, Higashi-Hiroshima, Japan
| | - Atsuko H Iwane
- Laboratory for Cell Field Structure, RIKEN Center for Biosystems Dynamics Research, Higashi-Hiroshima, Japan
| | - Silvia Natsuko Akutsu
- Department of Genetics and Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Hiroshi Ochiai
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Yumiko Saito
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan.,Program of Life and Environmental Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takashi Yamamoto
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan.,Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Shinya Matsuura
- Department of Genetics and Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
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110
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Molecular dysregulation of ciliary polycystin-2 channels caused by variants in the TOP domain. Proc Natl Acad Sci U S A 2020; 117:10329-10338. [PMID: 32332171 PMCID: PMC7229662 DOI: 10.1073/pnas.1920777117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Genetic variants in PKD2 which encodes for the polycystin-2 ion channel are responsible for many clinical cases of autosomal dominant polycystic kidney disease (ADPKD). Despite our strong understanding of the genetic basis of ADPKD, we do not know how most variants impact channel function. Polycystin-2 is found in organelle membranes, including the primary cilium-an antennae-like structure on the luminal side of the collecting duct. In this study, we focus on the structural and mechanistic regulation of polycystin-2 by its TOP domain-a site with unknown function that is commonly altered by missense variants. We use direct cilia electrophysiology, cryogenic electron microscopy, and superresolution imaging to determine that variants of the TOP domain finger 1 motif destabilizes the channel structure and impairs channel opening without altering cilia localization and channel assembly. Our findings support the channelopathy classification of PKD2 variants associated with ADPKD, where polycystin-2 channel dysregulation in the primary cilia may contribute to cystogenesis.
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111
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Phosphoinositides in Retinal Function and Disease. Cells 2020; 9:cells9040866. [PMID: 32252387 PMCID: PMC7226789 DOI: 10.3390/cells9040866] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023] Open
Abstract
Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play many important roles in all eukaryotic cells. These include modulation of physical properties of membranes, activation or inhibition of membrane-associated proteins, recruitment of peripheral membrane proteins that act as effectors, and control of membrane trafficking. They also serve as precursors for important second messengers, inositol (1,4,5) trisphosphate and diacylglycerol. Animal models and human diseases involving defects in phosphoinositide regulatory pathways have revealed their importance for function in the mammalian retina and retinal pigmented epithelium. New technologies for localizing, measuring and genetically manipulating them are revealing new information about their importance for the function and health of the vertebrate retina.
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Jászai J, Thamm K, Karbanová J, Janich P, Fargeas CA, Huttner WB, Corbeil D. Prominins control ciliary length throughout the animal kingdom: New lessons from human prominin-1 and zebrafish prominin-3. J Biol Chem 2020; 295:6007-6022. [PMID: 32201384 DOI: 10.1074/jbc.ra119.011253] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 03/18/2020] [Indexed: 01/18/2023] Open
Abstract
Prominins (proms) are transmembrane glycoproteins conserved throughout the animal kingdom. They are associated with plasma membrane protrusions, such as primary cilia, as well as extracellular vesicles derived thereof. Primary cilia host numerous signaling pathways affected in diseases known as ciliopathies. Human PROM1 (CD133) is detected in both somatic and cancer stem cells and is also expressed in terminally differentiated epithelial and photoreceptor cells. Genetic mutations in the PROM1 gene result in retinal degeneration by impairing the proper formation of the outer segment of photoreceptors, a modified cilium. Here, we investigated the impact of proms on two distinct examples of ciliogenesis. First, we demonstrate that the overexpression of a dominant-negative mutant variant of human PROM1 (i.e. mutation Y819F/Y828F) significantly decreases ciliary length in Madin-Darby canine kidney cells. These results contrast strongly to the previously observed enhancing effect of WT PROM1 on ciliary length. Mechanistically, the mutation impeded the interaction of PROM1 with ADP-ribosylation factor-like protein 13B, a key regulator of ciliary length. Second, we observed that in vivo knockdown of prom3 in zebrafish alters the number and length of monocilia in the Kupffer's vesicle, resulting in molecular and anatomical defects in the left-right asymmetry. These distinct loss-of-function approaches in two biological systems reveal that prom proteins are critical for the integrity and function of cilia. Our data provide new insights into ciliogenesis and might be of particular interest for investigations of the etiologies of ciliopathies.
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Affiliation(s)
- József Jászai
- Tissue Engineering Laboratories, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany; Institute of Anatomy, Medizinische Fakultät der Technischen Universität Dresden, Fiedlerstrasse 42, 01307 Dresden, Germany.
| | - Kristina Thamm
- Tissue Engineering Laboratories, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany
| | - Jana Karbanová
- Tissue Engineering Laboratories, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany
| | - Peggy Janich
- Tissue Engineering Laboratories, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany
| | - Christine A Fargeas
- Tissue Engineering Laboratories, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany
| | - Wieland B Huttner
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Denis Corbeil
- Tissue Engineering Laboratories, Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany.
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113
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Omnus DJ, Cadou A, Thomas FB, Bader JM, Soh N, Chung GHC, Vaughan AN, Stefan CJ. A heat-sensitive Osh protein controls PI4P polarity. BMC Biol 2020; 18:28. [PMID: 32169085 PMCID: PMC7071650 DOI: 10.1186/s12915-020-0758-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 02/26/2020] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Phosphoinositide lipids provide spatial landmarks during polarized cell growth and migration. Yet how phosphoinositide gradients are oriented in response to extracellular cues and environmental conditions is not well understood. Here, we elucidate an unexpected mode of phosphatidylinositol 4-phosphate (PI4P) regulation in the control of polarized secretion. RESULTS We show that PI4P is highly enriched at the plasma membrane of growing daughter cells in budding yeast where polarized secretion occurs. However, upon heat stress conditions that redirect secretory traffic, PI4P rapidly increases at the plasma membrane in mother cells resulting in a more uniform PI4P distribution. Precise control of PI4P distribution is mediated through the Osh (oxysterol-binding protein homology) proteins that bind and present PI4P to a phosphoinositide phosphatase. Interestingly, Osh3 undergoes a phase transition upon heat stress conditions, resulting in intracellular aggregates and reduced cortical localization. Both the Osh3 GOLD and ORD domains are sufficient to form heat stress-induced aggregates, indicating that Osh3 is highly tuned to heat stress conditions. Upon loss of Osh3 function, the polarized distribution of both PI4P and the exocyst component Exo70 are impaired. Thus, an intrinsically heat stress-sensitive PI4P regulatory protein controls the spatial distribution of phosphoinositide lipid metabolism to direct secretory trafficking as needed. CONCLUSIONS Our results suggest that control of PI4P metabolism by Osh proteins is a key determinant in the control of polarized growth and secretion.
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Affiliation(s)
- Deike J Omnus
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
- Present address: Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Angela Cadou
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Ffion B Thomas
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Jakob M Bader
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
- Present address: Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Nathaniel Soh
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Gary H C Chung
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Andrew N Vaughan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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114
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Gogendeau D, Lemullois M, Le Borgne P, Castelli M, Aubusson-Fleury A, Arnaiz O, Cohen J, Vesque C, Schneider-Maunoury S, Bouhouche K, Koll F, Tassin AM. MKS-NPHP module proteins control ciliary shedding at the transition zone. PLoS Biol 2020; 18:e3000640. [PMID: 32163404 PMCID: PMC7093003 DOI: 10.1371/journal.pbio.3000640] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/24/2020] [Accepted: 02/24/2020] [Indexed: 12/21/2022] Open
Abstract
Ciliary shedding occurs from unicellular organisms to metazoans. Although required during the cell cycle and during neurogenesis, the process remains poorly understood. In all cellular models, this phenomenon occurs distal to the transition zone (TZ), suggesting conserved molecular mechanisms. The TZ module proteins (Meckel Gruber syndrome [MKS]/Nephronophtysis [NPHP]/Centrosomal protein of 290 kDa [CEP290]/Retinitis pigmentosa GTPase regulator-Interacting Protein 1-Like Protein [RPGRIP1L]) are known to cooperate to establish TZ formation and function. To determine whether they control deciliation, we studied the function of 5 of them (Transmembrane protein 107 [TMEM107], Transmembrane protein 216 [TMEM216], CEP290, RPGRIP1L, and NPHP4) in Paramecium. All proteins are recruited to the TZ of growing cilia and localize with 9-fold symmetry at the level of the most distal part of the TZ. We demonstrate that depletion of the MKS2/TMEM216 and TMEM107 proteins induces constant deciliation of some cilia, while depletion of either NPHP4, CEP290, or RPGRIP1L prevents Ca2+/EtOH deciliation. Our results constitute the first evidence for a role of conserved TZ proteins in deciliation and open new directions for understanding motile cilia physiology. Functional analysis and subcellular localisation of the conserved transition zone proteins in the ciliate Paramecium tetraurelia demonstrates their involvement in the ciliary shedding process, opening new avenues fir understanding the molecular mechanism of deciliation.
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Affiliation(s)
- Delphine Gogendeau
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Michel Lemullois
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Pierrick Le Borgne
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Manon Castelli
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anne Aubusson-Fleury
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Olivier Arnaiz
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Jean Cohen
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Christine Vesque
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Developmental Biology Laboratory-Institut de Biologie Paris-Seine (IBPS), Paris, France
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Developmental Biology Laboratory-Institut de Biologie Paris-Seine (IBPS), Paris, France
| | - Khaled Bouhouche
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - France Koll
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anne-Marie Tassin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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115
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Establishing and regulating the composition of cilia for signal transduction. Nat Rev Mol Cell Biol 2020; 20:389-405. [PMID: 30948801 DOI: 10.1038/s41580-019-0116-4] [Citation(s) in RCA: 226] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The primary cilium is a hair-like surface-exposed organelle of the eukaryotic cell that decodes a variety of signals - such as odorants, light and Hedgehog morphogens - by altering the local concentrations and activities of signalling proteins. Signalling within the cilium is conveyed through a diverse array of second messengers, including conventional signalling molecules (such as cAMP) and some unusual intermediates (such as sterols). Diffusion barriers at the ciliary base establish the unique composition of this signalling compartment, and cilia adapt their proteome to signalling demands through regulated protein trafficking. Much progress has been made on the molecular understanding of regulated ciliary trafficking, which encompasses not only exchanges between the cilium and the rest of the cell but also the shedding of signalling factors into extracellular vesicles.
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116
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Gigante ED, Caspary T. Signaling in the primary cilium through the lens of the Hedgehog pathway. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e377. [PMID: 32084300 DOI: 10.1002/wdev.377] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 12/14/2022]
Abstract
Cilia are microtubule-based, cell-surface projections whose machinery is evolutionarily conserved. In vertebrates, cilia are observed on almost every cell type and are either motile or immotile. Immotile sensory, or primary cilia, are responsive to extracellular ligands and signals. Cilia can be thought of as compartments, functionally distinct from the cell that provides an environment for signaling cascades. Hedgehog is a critical developmental signaling pathway which is functionally linked to primary cilia in vertebrates. The major components of the vertebrate Hedgehog signaling pathway dynamically localize to the ciliary compartment and ciliary membrane. Critically, G-protein coupled receptor (GPCR) Smoothened, the obligate transducer of the pathway, is enriched and activated in the cilium. While Smoothened is the most intensely studied ciliary receptor, many GPCRs localize within cilia. Understanding the link between Smoothened and cilia defines common features, and distinctions, of GPCR signaling within the primary cilium. This article is categorized under: Signaling Pathways > Global Signaling Mechanisms Signaling Pathways > Cell Fate Signaling.
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Affiliation(s)
- Eduardo D Gigante
- Graduate Program in Neuroscience, Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
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117
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Constable S, Long AB, Floyd KA, Schurmans S, Caspary T. The ciliary phosphatidylinositol phosphatase Inpp5e plays positive and negative regulatory roles in Shh signaling. Development 2020; 147:dev.183301. [PMID: 31964774 DOI: 10.1242/dev.183301] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/02/2020] [Indexed: 01/04/2023]
Abstract
Sonic hedgehog (Shh) signal transduction specifies ventral cell fates in the neural tube and is mediated by the Gli transcription factors that play both activator (GliA) and repressor (GliR) roles. Cilia are essential for Shh signal transduction and the ciliary phosphatidylinositol phosphatase Inpp5e is linked to Shh regulation. In the course of a forward genetic screen for recessive mouse mutants, we identified a functional null allele of inositol polyphosphate-5-phosphatase E (Inpp5e), ridge top (rdg), with expanded ventral neural cell fates at E10.5. By E12.5, Inpp5erdg/rdg embryos displayed normal neural patterning and this correction over time required Gli3, the predominant repressor in neural patterning. Inpp5erdg function largely depended on the presence of cilia and on smoothened, the obligate transducer of Shh signaling, indicating that Inpp5e functions within the cilium to regulate the pathway. These data indicate that Inpp5e plays a more complicated role in Shh signaling than previously appreciated. We propose that Inpp5e attenuates Shh signaling in the neural tube through regulation of the relative timing of GliA and GliR production, which is important in understanding how the duration of Shh signaling regulates neural tube patterning.
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Affiliation(s)
- Sandii Constable
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Alyssa B Long
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Katharine A Floyd
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Stéphane Schurmans
- Laboratory of Functional Genetics, GIGA-R Centre, Université de Liège, Liège 4000, Belgium
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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118
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Regulation of the Extracellular Matrix by Ciliary Machinery. Cells 2020; 9:cells9020278. [PMID: 31979260 PMCID: PMC7072529 DOI: 10.3390/cells9020278] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/13/2020] [Accepted: 01/19/2020] [Indexed: 12/14/2022] Open
Abstract
The primary cilium is an organelle involved in cellular signalling. Mutations affecting proteins involved in cilia assembly or function result in diseases known as ciliopathies, which cause a wide variety of phenotypes across multiple tissues. These mutations disrupt various cellular processes, including regulation of the extracellular matrix. The matrix is important for maintaining tissue homeostasis through influencing cell behaviour and providing structural support; therefore, the matrix changes observed in ciliopathies have been implicated in the pathogenesis of these diseases. Whilst many studies have associated the cilium with processes that regulate the matrix, exactly how these matrix changes arise is not well characterised. This review aims to bring together the direct and indirect evidence for ciliary regulation of matrix, in order to summarise the possible mechanisms by which the ciliary machinery could regulate the composition, secretion, remodelling and organisation of the matrix.
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119
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Klink BU, Gatsogiannis C, Hofnagel O, Wittinghofer A, Raunser S. Structure of the human BBSome core complex. eLife 2020; 9:53910. [PMID: 31951201 PMCID: PMC7018512 DOI: 10.7554/elife.53910] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/15/2020] [Indexed: 01/09/2023] Open
Abstract
The BBSome is a heterooctameric protein complex that plays a central role in primary cilia homeostasis. Its malfunction causes the severe ciliopathy Bardet-Biedl syndrome (BBS). The complex acts as a cargo adapter that recognizes signaling proteins such as GPCRs and links them to the intraflagellar transport machinery. The underlying mechanism is poorly understood. Here we present a high-resolution cryo-EM structure of a human heterohexameric core subcomplex of the BBSome. The structure reveals the architecture of the complex in atomic detail. It explains how the subunits interact with each other and how disease-causing mutations hamper this interaction. The complex adopts a conformation that is open for binding to membrane-associated GTPase Arl6 and a large positively charged patch likely strengthens the interaction with the membrane. A prominent negatively charged cleft at the center of the complex is likely involved in binding of positively charged signaling sequences of cargo proteins.
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Affiliation(s)
- Björn Udo Klink
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Christos Gatsogiannis
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Oliver Hofnagel
- 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
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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120
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Natoli TA, Modur V, Ibraghimov-Beskrovnaya O. Glycosphingolipid metabolism and polycystic kidney disease. Cell Signal 2020; 69:109526. [PMID: 31911181 DOI: 10.1016/j.cellsig.2020.109526] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 12/21/2022]
Abstract
Sphingolipids and glycosphingolipids are classes of structurally and functionally important lipids that regulate multiple cellular processes, including membrane organization, proliferation, cell cycle regulation, apoptosis, transport, migration, and inflammatory signalling pathways. Imbalances in sphingolipid levels or subcellular localization result in dysregulated cellular processes and lead to the development and progression of multiple disorders, including polycystic kidney disease. This review will describe metabolic pathways of glycosphingolipids with a focus on the evidence linking glycosphingolipid mediated regulation of cell signalling, lipid microdomains, cilia, and polycystic kidney disease. We will discuss molecular mechanisms of glycosphingolipid dysregulation and their impact on cystogenesis. We will further highlight how modulation of sphingolipid metabolism can be translated into new approaches for the treatment of polycystic kidney disease and describe current clinical studies with glucosylceramide synthase inhibitors in Autosomal Dominant Polycystic Kidney Disease.
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Affiliation(s)
- Thomas A Natoli
- Rare and Neurological Disease Research, Sanofi-Genzyme, 49 New York Ave., Framingham, MA 01701, USA
| | - Vijay Modur
- Rare Disease Development, Sanofi-Genzyme, 50 Binney St., Cambridge, MA 02142, USA
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121
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Abstract
Recent evidence has indicated that caveolins are localized at the base of primary cilia, which are microtubule-based sensory organelles present on the cell surface, and that Caveolin-1 (CAV1) plays important roles in regulating ciliary membrane composition and function. Here we describe methods to analyze the localization and function of CAV1 in primary cilia of cultured mammalian cells. These include methods for culturing and transfecting mammalian cells with a CAV1-encoding plasmid or small interfering RNA (siRNA), analysis of mammalian cells by immunofluorescence microscopy (IFM) with antibodies against ciliary markers and CAV1, as well as methods for analyzing ciliary CAV1 function in siRNA-treated cells by IFM and cell-based signaling assays.
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122
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Gigante ED, Taylor MR, Ivanova AA, Kahn RA, Caspary T. ARL13B regulates Sonic hedgehog signaling from outside primary cilia. eLife 2020; 9:50434. [PMID: 32129762 PMCID: PMC7075693 DOI: 10.7554/elife.50434] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 02/25/2020] [Indexed: 01/13/2023] Open
Abstract
ARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B's role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.
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Affiliation(s)
- Eduardo D Gigante
- Neuroscience Graduate Program, Emory University School of MedicineAtlantaUnited States,Department of Human Genetics, Emory University School of MedicineAtlantaUnited States
| | - Megan R Taylor
- Emory College of Arts and Sciences, Emory University School of MedicineAtlantaUnited States
| | - Anna A Ivanova
- Department of Biochemistry, Emory University School of MedicineAtlantaUnited States
| | - Richard A Kahn
- Department of Biochemistry, Emory University School of MedicineAtlantaUnited States
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of MedicineAtlantaUnited States
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123
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Actin-based regulation of ciliogenesis - The long and the short of it. Semin Cell Dev Biol 2019; 102:132-138. [PMID: 31862221 DOI: 10.1016/j.semcdb.2019.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/23/2019] [Accepted: 12/07/2019] [Indexed: 12/11/2022]
Abstract
The primary cilia is found on the mammalian cell surface where it serves as an antenna for the reception and transmission of a variety of cellular signaling pathways. At its core the cilium is a microtubule-based organelle, but it is clear that its assembly and function are dependent upon the coordinated regulation of both actin and microtubule dynamics. In particular, the discovery that the centrosome is able to act as both a microtubule and actin organizing centre implies that both cytoskeletal networks are acting directly on the process of cilia assembly. In this review, we set our recent results with the formin FHDC1 in the context of current reports that show each stage of ciliogenesis is impacted by changes in actin dynamics. These include direct effects of actin filament assembly on basal body positioning, vesicle trafficking to and entry into the cilium, cilia length, cilia membrane organization and cilia-dependent signaling.
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124
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Frederick JM, Hanke-Gogokhia C, Ying G, Baehr W. Diffuse or hitch a ride: how photoreceptor lipidated proteins get from here to there. Biol Chem 2019; 401:573-584. [DOI: 10.1515/hsz-2019-0375] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/02/2019] [Indexed: 12/23/2022]
Abstract
Abstract
Photoreceptors are polarized neurons, with specific subcellular compartmentalization and unique requirements for protein expression and trafficking. Each photoreceptor contains an outer segment (OS) where vision begins, an inner segment (IS) where protein synthesis occurs and a synaptic terminal for signal transmission to second-order neurons. The OS is a large, modified primary cilium attached to the IS by a slender connecting cilium (CC), the equivalent of the transition zone (TZ). Daily renewal of ~10% of the OS requires massive protein biosynthesis in the IS with reliable transport and targeting pathways. Transport of lipidated (‘sticky’) proteins depends on solubilization factors, phosphodiesterase δ (PDEδ) and uncoordinated protein-119 (UNC119), and the cargo dispensation factor (CDF), Arf-like protein 3-guanosine triphosphate (ARL3-GTP). As PDE6 and transducin still reside prominently in the OS of PDEδ and UNC119 germline knockout mice, respectively, we propose the existence of an alternate trafficking pathway, whereby lipidated proteins migrate in rhodopsin-containing vesicles of the secretory pathway.
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Affiliation(s)
- Jeanne M. Frederick
- Department of Ophthalmology and Visual Sciences , University of Utah Health Science Center , 65 Mario Capecchi Drive , Salt Lake City , UT 84132 , USA
| | - Christin Hanke-Gogokhia
- Department of Ophthalmology and Visual Sciences , University of Utah Health Science Center , 65 Mario Capecchi Drive , Salt Lake City , UT 84132 , USA
| | - Guoxin Ying
- Department of Ophthalmology and Visual Sciences , University of Utah Health Science Center , 65 Mario Capecchi Drive , Salt Lake City , UT 84132 , USA
| | - Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences , University of Utah Health Science Center , 65 Mario Capecchi Drive , Salt Lake City , UT 84132 , USA
- Department of Neurobiology and Anatomy , University of Utah , Salt Lake City , UT 84112 , USA
- Department of Biology , University of Utah , Salt Lake City , UT 84132 , USA
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125
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Abstract
Primary cilia project in a single copy from the surface of most vertebrate cell types; they detect and transmit extracellular cues to regulate diverse cellular processes during development and to maintain tissue homeostasis. The sensory capacity of primary cilia relies on the coordinated trafficking and temporal localization of specific receptors and associated signal transduction modules in the cilium. The canonical Hedgehog (HH) pathway, for example, is a bona fide ciliary signalling system that regulates cell fate and self-renewal in development and tissue homeostasis. Specific receptors and associated signal transduction proteins can also localize to primary cilia in a cell type-dependent manner; available evidence suggests that the ciliary constellation of these proteins can temporally change to allow the cell to adapt to specific developmental and homeostatic cues. Consistent with important roles for primary cilia in signalling, mutations that lead to their dysfunction underlie a pleiotropic group of diseases and syndromic disorders termed ciliopathies, which affect many different tissues and organs of the body. In this Review, we highlight central mechanisms by which primary cilia coordinate HH, G protein-coupled receptor, WNT, receptor tyrosine kinase and transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP) signalling and illustrate how defects in the balanced output of ciliary signalling events are coupled to developmental disorders and disease progression.
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126
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ERICH3 in Primary Cilia Regulates Cilium Formation and the Localisations of Ciliary Transport and Sonic Hedgehog Signaling Proteins. Sci Rep 2019; 9:16519. [PMID: 31712586 PMCID: PMC6848114 DOI: 10.1038/s41598-019-52830-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/23/2019] [Indexed: 01/05/2023] Open
Abstract
Intraflagellar transport (IFT) is essential for the formation and function of the microtubule-based primary cilium, which acts as a sensory and signalling device at the cell surface. Consisting of IFT-A/B and BBSome cargo adaptors that associate with molecular motors, IFT transports protein into (anterograde IFT) and out of (retrograde IFT) the cilium. In this study, we identify the mostly uncharacterised ERICH3 protein as a component of the mammalian primary cilium. Loss of ERICH3 causes abnormally short cilia and results in the accumulation of IFT-A/B proteins at the ciliary tip, together with reduced ciliary levels of retrograde transport regulators, ARL13B, INPP5E and BBS5. We also show that ERICH3 ciliary localisations require ARL13B and BBSome components. Finally, ERICH3 loss causes positive (Smoothened) and negative (GPR161) regulators of sonic hedgehog signaling (Shh) to accumulate at abnormally high levels in the cilia of pathway-stimulated cells. Together, these findings identify ERICH3 as a novel component of the primary cilium that regulates cilium length and the ciliary levels of Shh signaling molecules. We propose that ERICH3 functions within retrograde IFT-associated pathways to remove signaling proteins from cilia.
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Kremer L, Hennes E, Brause A, Ursu A, Robke L, Matsubayashi HT, Nihongaki Y, Flegel J, Mejdrová I, Eickhoff J, Baumann M, Nencka R, Janning P, Kordes S, Schöler HR, Sterneckert J, Inoue T, Ziegler S, Waldmann H. Discovery of the Hedgehog Pathway Inhibitor Pipinib that Targets PI4KIIIß. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Lea Kremer
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
| | - Elisabeth Hennes
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
| | - Alexandra Brause
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
| | - Andrei Ursu
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
- Faculty of Chemistry and Chemical Biology Technical University Dortmund Otto-Hahn-Straße 6 44221 Dortmund Germany
- Current address: Department of Chemistry The Scripps Research Institute 110 Scripps Way Jupiter FL 33458 USA
| | - Lucas Robke
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
- Faculty of Chemistry and Chemical Biology Technical University Dortmund Otto-Hahn-Straße 6 44221 Dortmund Germany
| | - Hideaki T. Matsubayashi
- Department of Cell Biology Johns Hopkins University School of Medicine 855 N. Wolfe Street, 453 Rangos Baltimore MD 21205 USA
| | - Yuta Nihongaki
- Department of Cell Biology Johns Hopkins University School of Medicine 855 N. Wolfe Street, 453 Rangos Baltimore MD 21205 USA
| | - Jana Flegel
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
| | - Ivana Mejdrová
- Institute of Organic Chemistry and Biochemistry Flemingovo nam. 2 16610 Prague 6 Czech Republic
| | - Jan Eickhoff
- Lead Discovery Center GmbH Otto-Hahn-Straße 15 44227 Dortmund Germany
| | - Matthias Baumann
- Lead Discovery Center GmbH Otto-Hahn-Straße 15 44227 Dortmund Germany
| | - Radim Nencka
- Institute of Organic Chemistry and Biochemistry Flemingovo nam. 2 16610 Prague 6 Czech Republic
| | - Petra Janning
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
| | - Susanne Kordes
- Lead Discovery Center GmbH Otto-Hahn-Straße 15 44227 Dortmund Germany
- Department of Cell and Developmental Biology Max Planck Institute for Molecular Biomedicine Röntgenstr. 20 48149 Münster Germany
| | - Hans R. Schöler
- Department of Cell and Developmental Biology Max Planck Institute for Molecular Biomedicine Röntgenstr. 20 48149 Münster Germany
- Medical Faculty University of Münster Domagkstr. 3 48149 Münster Germany
| | - Jared Sterneckert
- Department of Cell and Developmental Biology Max Planck Institute for Molecular Biomedicine Röntgenstr. 20 48149 Münster Germany
- Technische Universität Dresden DFG-Research Center for Regenerative Therapies Dresden 01307 Dresden Germany
| | - Takanari Inoue
- Department of Cell Biology Johns Hopkins University School of Medicine 855 N. Wolfe Street, 453 Rangos Baltimore MD 21205 USA
| | - Slava Ziegler
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
| | - Herbert Waldmann
- Department of Chemical Biology Max-Planck-Institute of Molecular Physiology Otto-Hahn-Straße 11 44227 Dortmund Germany
- Faculty of Chemistry and Chemical Biology Technical University Dortmund Otto-Hahn-Straße 6 44221 Dortmund Germany
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128
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Margaria JP, Campa CC, De Santis MC, Hirsch E, Franco I. The PI3K/Akt/mTOR pathway in polycystic kidney disease: A complex interaction with polycystins and primary cilium. Cell Signal 2019; 66:109468. [PMID: 31715259 DOI: 10.1016/j.cellsig.2019.109468] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/08/2019] [Accepted: 11/08/2019] [Indexed: 12/19/2022]
Abstract
Over-activation of the PI3K/Akt/mTOR network is a well-known pathogenic event that leads to hyper-proliferation. Pharmacological targeting of this pathway has been developed for the treatment of multiple diseases, including cancer. In polycystic kidney disease (PKD), the mTOR cascade promotes cyst growth by boosting proliferation, size and metabolism of kidney tubule epithelial cells. Therefore, mTOR inhibition has been tested in pre-clinical and clinical studies, but only the former showed positive results. This review reports recent discoveries describing the activity and molecular mechanisms of mTOR activation in tubule epithelial cells and cyst formation and discusses the evidence of an upstream regulation of mTOR by the PI3K/Akt axis. In particular, the complex interconnections of the PI3K/Akt/mTOR network with the principal signaling routes involved in the suppression of cyst formation are dissected. These interactions include the antagonism and the reciprocal negative regulation between mTOR complex 1 and the proteins whose deletion causes Autosomal Dominant PKD, the polycystins. In addition, the emerging role of phopshoinositides, membrane components modulated by PI3K, will be presented in the context of primary cilium signaling, cell polarization and protection from cyst formation. Overall, studies demonstrate that the activity of various members of the PI3K/Akt/mTOR network goes beyond the classical transduction of mitogenic signals and can impact several aspects of kidney tubule homeostasis and morphogenesis. These properties might be useful to guide the establishment of more effective treatment protocols to be tested in clinical trials.
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Affiliation(s)
- Jean Piero Margaria
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | - Carlo Cosimo Campa
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
| | - Maria Chiara De Santis
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | - Emilio Hirsch
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino 10126, Italy
| | - Irene Franco
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, 14157 Huddinge, Sweden.
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129
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Kinnebrew M, Iverson EJ, Patel BB, Pusapati GV, Kong JH, Johnson KA, Luchetti G, Eckert KM, McDonald JG, Covey DF, Siebold C, Radhakrishnan A, Rohatgi R. Cholesterol accessibility at the ciliary membrane controls hedgehog signaling. eLife 2019; 8:e50051. [PMID: 31657721 PMCID: PMC6850779 DOI: 10.7554/elife.50051] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/25/2019] [Indexed: 12/21/2022] Open
Abstract
Previously we proposed that transmission of the hedgehog signal across the plasma membrane by Smoothened is triggered by its interaction with cholesterol (Luchetti et al., 2016). But how is cholesterol, an abundant lipid, regulated tightly enough to control a signaling system that can cause birth defects and cancer? Using toxin-based sensors that distinguish between distinct pools of cholesterol, we find that Smoothened activation and Hedgehog signaling are driven by a biochemically-defined, small fraction of membrane cholesterol, termed accessible cholesterol. Increasing cholesterol accessibility by depletion of sphingomyelin, which sequesters cholesterol in complexes, amplifies Hedgehog signaling. Hedgehog ligands increase cholesterol accessibility in the membrane of the primary cilium by inactivating the transporter-like protein Patched 1. Trapping this accessible cholesterol blocks Hedgehog signal transmission across the membrane. Our work shows that the organization of cholesterol in the ciliary membrane can be modified by extracellular ligands to control the activity of cilia-localized signaling proteins.
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Affiliation(s)
- Maia Kinnebrew
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
| | - Ellen J Iverson
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
| | - Bhaven B Patel
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
| | - Ganesh V Pusapati
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
| | - Jennifer H Kong
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
| | - Kristen A Johnson
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Giovanni Luchetti
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
| | - Kaitlyn M Eckert
- Center for Human NutritionUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Jeffrey G McDonald
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
- Center for Human NutritionUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Douglas F Covey
- Taylor Family Institute for Innovative Psychiatric ResearchWashington University School of MedicineSt. LouisUnited States
- Department of Developmental BiologyWashington University School of MedicineSt. LouisUnited States
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUnited Kingdom
| | - Arun Radhakrishnan
- Department of Molecular GeneticsUniversity of Texas Southwestern Medical CenterDallasUnited States
| | - Rajat Rohatgi
- Department of BiochemistryStanford University School of MedicineStanfordUnited States
- Department of MedicineStanford University School of MedicineStanfordUnited States
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130
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Garcia G, Raleigh DR, Reiter JF. How the Ciliary Membrane Is Organized Inside-Out to Communicate Outside-In. Curr Biol 2019; 28:R421-R434. [PMID: 29689227 DOI: 10.1016/j.cub.2018.03.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cilia, organelles that move to execute functions like fertilization and signal to execute functions like photoreception and embryonic patterning, are composed of a core of nine-fold doublet microtubules overlain by a membrane. Distinct types of cilia display distinct membrane morphologies, ranging from simple domed cylinders to the highly ornate invaginations and membrane disks of photoreceptor outer segments. Critical for the ability of cilia to signal, both the protein and the lipid compositions of ciliary membranes are different from those of other cellular membranes. This specialization presents a unique challenge for the cell as, unlike membrane-bounded organelles, the ciliary membrane is contiguous with the surrounding plasma membrane. This distinct ciliary membrane is generated in concert with multiple membrane remodeling events that comprise the process of ciliogenesis. Once the cilium is formed, control of ciliary membrane composition relies on discrete molecular machines, including a barrier to membrane proteins entering the cilium at a specialized region of the base of the cilium called the transition zone and a trafficking adaptor that controls G protein-coupled receptor (GPCR) localization to the cilium called the BBSome. The ciliary membrane can be further remodeled by the removal of membrane proteins by the release of ciliary extracellular vesicles that may function in intercellular communication, removal of unneeded proteins or ciliary disassembly. Here, we review the structures and transport mechanisms that control ciliary membrane composition, and discuss how membrane specialization enables the cilium to function as the antenna of the cell.
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Affiliation(s)
- Galo Garcia
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - David R Raleigh
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Department of Radiation Oncology, University of California, San Francisco, CA 94143, USA; Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.
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131
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Kremer L, Hennes E, Brause A, Ursu A, Robke L, Matsubayashi HT, Nihongaki Y, Flegel J, Mejdrová I, Eickhoff J, Baumann M, Nencka R, Janning P, Kordes S, Schöler HR, Sterneckert J, Inoue T, Ziegler S, Waldmann H. Discovery of the Hedgehog Pathway Inhibitor Pipinib that Targets PI4KIIIß. Angew Chem Int Ed Engl 2019; 58:16617-16628. [PMID: 31454140 PMCID: PMC6900058 DOI: 10.1002/anie.201907632] [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: 06/19/2019] [Indexed: 01/20/2023]
Abstract
The Hedgehog (Hh) signaling pathway is crucial for vertebrate embryonic development, tissue homeostasis and regeneration. Hh signaling is upregulated in basal cell carcinoma and medulloblastoma and Hh pathway inhibitors targeting the Smoothened (SMO) protein are in clinical use. However, the signaling cascade is incompletely understood and novel druggable proteins in the pathway are in high demand. We describe the discovery of the Hh‐pathway modulator Pipinib by means of cell‐based screening. Target identification and validation revealed that Pipinib selectively inhibits phosphatidylinositol 4‐kinase IIIβ (PI4KB) and suppresses GLI‐mediated transcription and Hh target gene expression by impairing SMO translocation to the cilium. Therefore, inhibition of PI4KB and, consequently, reduction in phosphatidyl‐4‐phosphate levels may be considered an alternative approach to inhibit SMO function and thus, Hedgehog signaling.
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Affiliation(s)
- Lea Kremer
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Elisabeth Hennes
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Alexandra Brause
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Andrei Ursu
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Straße 6, 44221, Dortmund, Germany.,Current address: Department of Chemistry, The Scripps Research Institute, 110 Scripps Way, Jupiter, FL, 33458, USA
| | - Lucas Robke
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Straße 6, 44221, Dortmund, Germany
| | - Hideaki T Matsubayashi
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 N. Wolfe Street, 453 Rangos, Baltimore, MD, 21205, USA
| | - Yuta Nihongaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 N. Wolfe Street, 453 Rangos, Baltimore, MD, 21205, USA
| | - Jana Flegel
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Ivana Mejdrová
- Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 16610, Prague 6, Czech Republic
| | - Jan Eickhoff
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227, Dortmund, Germany
| | - Matthias Baumann
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227, Dortmund, Germany
| | - Radim Nencka
- Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 16610, Prague 6, Czech Republic
| | - Petra Janning
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Susanne Kordes
- Lead Discovery Center GmbH, Otto-Hahn-Straße 15, 44227, Dortmund, Germany.,Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | - Hans R Schöler
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany.,Medical Faculty, University of Münster, Domagkstr. 3, 48149, Münster, Germany
| | - Jared Sterneckert
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany.,Technische Universität Dresden, DFG-Research Center for Regenerative Therapies Dresden, 01307, Dresden, Germany
| | - Takanari Inoue
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 N. Wolfe Street, 453 Rangos, Baltimore, MD, 21205, USA
| | - Slava Ziegler
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Herbert Waldmann
- Department of Chemical Biology, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Straße 6, 44221, Dortmund, Germany
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132
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Martin-Hurtado A, Martin-Morales R, Robledinos-Antón N, Blanco R, Palacios-Blanco I, Lastres-Becker I, Cuadrado A, Garcia-Gonzalo FR. NRF2-dependent gene expression promotes ciliogenesis and Hedgehog signaling. Sci Rep 2019; 9:13896. [PMID: 31554934 PMCID: PMC6761261 DOI: 10.1038/s41598-019-50356-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/11/2019] [Indexed: 12/18/2022] Open
Abstract
The transcription factor NRF2 is a master regulator of cellular antioxidant and detoxification responses, but it also regulates other processes such as autophagy and pluripotency. In human embryonic stem cells (hESCs), NRF2 antagonizes neuroectoderm differentiation, which only occurs after NRF2 is repressed via a Primary Cilia-Autophagy-NRF2 (PAN) axis. However, the functional connections between NRF2 and primary cilia, microtubule-based plasma membrane protrusions that function as cellular antennae, remain poorly understood. For instance, nothing is known about whether NRF2 affects cilia, or whether cilia regulation of NRF2 extends beyond hESCs. Here, we show that NRF2 and primary cilia reciprocally regulate each other. First, we demonstrate that fibroblasts lacking primary cilia have higher NRF2 activity, which is rescued by autophagy-activating mTOR inhibitors, indicating that the PAN axis also operates in differentiated cells. Furthermore, NRF2 controls cilia formation and function. NRF2-null cells grow fewer and shorter cilia and display impaired Hedgehog signaling, a cilia-dependent pathway. These defects are not due to increased oxidative stress or ciliophagy, but rather to NRF2 promoting expression of multiple ciliogenic and Hedgehog pathway genes. Among these, we focused on GLI2 and GLI3, the transcription factors controlling Hh pathway output. Both their mRNA and protein levels are reduced in NRF2-null cells, consistent with their gene promoters containing consensus ARE sequences predicted to bind NRF2. Moreover, GLI2 and GLI3 fail to accumulate at the ciliary tip of NRF2-null cells upon Hh pathway activation. Given the importance of NRF2 and ciliary signaling in human disease, our data may have important biomedical implications.
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Affiliation(s)
- Ana Martin-Hurtado
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain
| | - Raquel Martin-Morales
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain
| | - Natalia Robledinos-Antón
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Ruth Blanco
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Ines Palacios-Blanco
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain
| | - Isabel Lastres-Becker
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Antonio Cuadrado
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain.,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Francesc R Garcia-Gonzalo
- Alberto Sols Biomedical Research Institute UAM-CSIC and Department of Biochemistry, School of Medicine, Autonomous University of Madrid (UAM), Madrid, Spain. .,La Paz University Hospital Research Institute (IdiPAZ), Madrid, Spain.
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133
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Kuhns S, Seixas C, Pestana S, Tavares B, Nogueira R, Jacinto R, Ramalho JS, Simpson JC, Andersen JS, Echard A, Lopes SS, Barral DC, Blacque OE. Rab35 controls cilium length, function and membrane composition. EMBO Rep 2019; 20:e47625. [PMID: 31432619 DOI: 10.15252/embr.201847625] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 12/12/2022] Open
Abstract
Rab and Arl guanine nucleotide-binding (G) proteins regulate trafficking pathways essential for the formation, function and composition of primary cilia, which are sensory devices associated with Sonic hedgehog (Shh) signalling and ciliopathies. Here, using mammalian cells and zebrafish, we uncover ciliary functions for Rab35, a multitasking G protein with endocytic recycling, actin remodelling and cytokinesis roles. Rab35 loss via siRNAs, morpholinos or knockout reduces cilium length in mammalian cells and the zebrafish left-right organiser (Kupffer's vesicle) and causes motile cilia-associated left-right asymmetry defects. Consistent with these observations, GFP-Rab35 localises to cilia, as do GEF (DENND1B) and GAP (TBC1D10A) Rab35 regulators, which also regulate ciliary length and Rab35 ciliary localisation. Mammalian Rab35 also controls the ciliary membrane levels of Shh signalling regulators, promoting ciliary targeting of Smoothened, limiting ciliary accumulation of Arl13b and the inositol polyphosphate 5-phosphatase (INPP5E). Rab35 additionally regulates ciliary PI(4,5)P2 levels and interacts with Arl13b. Together, our findings demonstrate roles for Rab35 in regulating cilium length, function and membrane composition and implicate Rab35 in pathways controlling the ciliary levels of Shh signal regulators.
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Affiliation(s)
- Stefanie Kuhns
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland.,Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Cecília Seixas
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Sara Pestana
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Bárbara Tavares
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Renata Nogueira
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Raquel Jacinto
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - José S Ramalho
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Jeremy C Simpson
- School of Biology and Environmental Science, University College Dublin, Dublin 4, Ireland
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | | | - Susana S Lopes
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Duarte C Barral
- CEDOC, NOVA Medical School
- Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
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134
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The Autophagy-Cilia Axis: An Intricate Relationship. Cells 2019; 8:cells8080905. [PMID: 31443299 PMCID: PMC6721705 DOI: 10.3390/cells8080905] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 01/19/2023] Open
Abstract
Primary cilia are microtubule-based organelles protruding from the surface of almost all vertebrate cells. This organelle represents the cell’s antenna which acts as a communication hub to transfer extracellular signals into intracellular responses during development and in tissue homeostasis. Recently, it has been shown that loss of cilia negatively regulates autophagy, the main catabolic route of the cell, probably utilizing the autophagic machinery localized at the peri-ciliary compartment. On the other side, autophagy influences ciliogenesis in a context-dependent manner, possibly to ensure that the sensing organelle is properly formed in a feedback loop model. In this review we discuss the recent literature and propose that the autophagic machinery and the ciliary proteins are functionally strictly related to control both autophagy and ciliogenesis. Moreover, we report examples of diseases associated with autophagic defects which cause cilia abnormalities, and propose and discuss the hypothesis that, at least some of the clinical manifestations observed in human diseases associated to ciliary disfunction may be the result of a perturbed autophagy.
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135
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Volpatti JR, Al-Maawali A, Smith L, Al-Hashim A, Brill JA, Dowling JJ. The expanding spectrum of neurological disorders of phosphoinositide metabolism. Dis Model Mech 2019; 12:12/8/dmm038174. [PMID: 31413155 PMCID: PMC6737944 DOI: 10.1242/dmm.038174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositides (PIPs) are a ubiquitous group of seven low-abundance phospholipids that play a crucial role in defining localized membrane properties and that regulate myriad cellular processes, including cytoskeletal remodeling, cell signaling cascades, ion channel activity and membrane traffic. PIP homeostasis is tightly regulated by numerous inositol kinases and phosphatases, which phosphorylate and dephosphorylate distinct PIP species. The importance of these phospholipids, and of the enzymes that regulate them, is increasingly being recognized, with the identification of human neurological disorders that are caused by mutations in PIP-modulating enzymes. Genetic disorders of PIP metabolism include forms of epilepsy, neurodegenerative disease, brain malformation syndromes, peripheral neuropathy and congenital myopathy. In this Review, we provide an overview of PIP function and regulation, delineate the disorders associated with mutations in genes that modulate or utilize PIPs, and discuss what is understood about gene function and disease pathogenesis as established through animal models of these diseases. Summary: This Review highlights the intersection between phosphoinositides and the enzymes that regulate their metabolism, which together are crucial regulators of myriad cellular processes and neurological disorders.
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Affiliation(s)
- Jonathan R Volpatti
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Almundher Al-Maawali
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Lindsay Smith
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aqeela Al-Hashim
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Neuroscience, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Julie A Brill
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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136
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Lauring MC, Zhu T, Luo W, Wu W, Yu F, Toomre D. New software for automated cilia detection in cells (ACDC). Cilia 2019; 8:1. [PMID: 31388414 PMCID: PMC6670212 DOI: 10.1186/s13630-019-0061-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 06/26/2019] [Indexed: 12/12/2022] Open
Abstract
Background Primary cilia frequency and length are key metrics in studies of ciliogenesis and ciliopathies. Typically, quantitative cilia analysis is done manually, which is very time-consuming. While some open-source and commercial image analysis software applications can segment input data, they still require the user to optimize many parameters, suffer from user bias, and often lack rigorous performance quality assessment (e.g., false positives and false negatives). Further, optimal parameter combinations vary in detection accuracy depending on cilia reporter, cell type, and imaging modality. A good automated solution would analyze images quickly, robustly, and adaptably—across different experimental data sets—without significantly compromising the accuracy of manual analysis. Methods To solve this problem, we developed a new software for automated cilia detection in cells (ACDC). The software operates through four main steps: image importation, pre-processing, detection auto-optimization, and analysis. From a data set, a representative image with manually selected cilia (i.e., Ground Truth) is used for detection auto-optimization based on four parameters: signal-to-noise ratio, length, directional score, and intensity standard deviation. Millions of parameter combinations are automatically evaluated and optimized according to an accuracy ‘F1’ score, based on the amount of false positives and false negatives. Afterwards, the optimized parameter combination is used for automated detection and analysis of the entire data set. Results The ACDC software accurately and adaptably detected nuclei and primary cilia across different cell types (NIH3T3, RPE1), cilia reporters (AcTub, Smo-GFP, Arl13b), and image magnifications (60×, 40×). We found that false-positive and false-negative rates for Arl13b-stained cilia were 1–6%, yielding high F1 scores of 0.96–0.97 (max. = 1.00). The software detected significant differences in mean cilia length between control and cytochalasin D-treated cell populations and could monitor dynamic changes in cilia length from movie recordings. Automated analysis offered up to a 96-fold speed enhancement compared to manual analysis, requiring around 5 s/image, or nearly 18,000 cilia analyzed/hour. Conclusion The ACDC software is a solution for robust automated analysis of microscopic images of ciliated cells. The software is extremely adaptable, accurate, and offers immense time-savings compared to traditional manual analysis. Electronic supplementary material The online version of this article (10.1186/s13630-019-0061-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Max C Lauring
- 1Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510 USA
| | - Tianqi Zhu
- 2College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027 Zhejiang China
| | - Wei Luo
- 2College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027 Zhejiang China
| | - Wenqi Wu
- 2College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027 Zhejiang China
| | - Feng Yu
- 2College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, 310027 Zhejiang China
| | - Derek Toomre
- 1Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510 USA
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137
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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: 29] [Impact Index Per Article: 5.8] [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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138
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Characterization of Primary Cilia in Normal Fallopian Tube Epithelium and Serous Tubal Intraepithelial Carcinoma. Int J Gynecol Cancer 2019; 28:1535-1544. [PMID: 30095490 PMCID: PMC6166701 DOI: 10.1097/igc.0000000000001321] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Supplemental digital content is available in the text. Objectives The aim of this study was to investigate the distribution of primary cilia on secretory cells in normal fallopian tube (FT) and serous tubal intraepithelial carcinoma (STIC). Methods Fallopian tube tissue samples were obtained from 4 females undergoing prophylactic hysterectomies and 6 patients diagnosed with STIC. A mogp-TAg transgenic mouse STIC sample was also compared with a wild-type mouse FT sample. Serous tubal intraepithelial carcinoma was identified by hematoxylin and eosin staining and confirmed by positive Ki-67 and p53 immunohistochemical staining of tissue sections. We assessed the relative distribution of primary cilia on secretory cells and motile cilia on multiple ciliated cells by immunofluorescence and immunohistochemical staining. Ciliary function was assessed by immunofluorescence staining of specific ciliary marker proteins and responsiveness to Sonic Hedgehog signaling. Results Primary cilia are widespread on secretory cells in the ampulla, isthmus, and in particular, the fimbriae of human FT where they may appear to mediate ciliary-mediated Sonic Hedgehog signaling. A statistically significant reduction in the number of primary cilia on secretory cells was observed in human STIC samples compared with normal controls (P < 0.0002, Student t test), supported by similar findings in a mouse STIC sample. Immunohistochemical staining for dynein axonemal heavy chain 5 discriminated multiple motile cilia from primary cilia in human FT. Conclusions Primary cilia are widespread on secretory cells in the ampulla, isthmus, and in particular, the fimbriae of the human FT but are significantly reduced in both human and mouse STIC samples. Immunohistochemical staining for ciliary proteins may have clinical utility for early detection of STIC.
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139
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DiTirro D, Philbrook A, Rubino K, Sengupta P. The Caenorhabditis elegans Tubby homolog dynamically modulates olfactory cilia membrane morphogenesis and phospholipid composition. eLife 2019; 8:48789. [PMID: 31259686 PMCID: PMC6624019 DOI: 10.7554/elife.48789] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022] Open
Abstract
Plasticity in sensory signaling is partly mediated via regulated trafficking of signaling molecules to and from primary cilia. Tubby-related proteins regulate ciliary protein transport; however, their roles in remodeling cilia properties are not fully understood. We find that the C. elegans TUB-1 Tubby homolog regulates membrane morphogenesis and signaling protein transport in specialized sensory cilia. In particular, TUB-1 is essential for sensory signaling-dependent reshaping of olfactory cilia morphology. We show that compromised sensory signaling alters cilia membrane phosphoinositide composition via TUB-1-dependent trafficking of a PIP5 kinase. TUB-1 regulates localization of this lipid kinase at the cilia base in part via localization of the AP-2 adaptor complex subunit DPY-23. Our results describe new functions for Tubby proteins in the dynamic regulation of cilia membrane lipid composition, morphology, and signaling protein content, and suggest that this conserved family of proteins plays a critical role in mediating cilia structural and functional plasticity.
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Affiliation(s)
- Danielle DiTirro
- Department of Biology, Brandeis University, Waltham, United States
| | - Alison Philbrook
- Department of Biology, Brandeis University, Waltham, United States
| | - Kendrick Rubino
- Department of Biology, Brandeis University, Waltham, United States
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, United States
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140
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Tajhya R, Delling M. New insights into ion channel-dependent signalling during left-right patterning. J Physiol 2019; 598:1741-1752. [PMID: 31106399 DOI: 10.1113/jp277835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/23/2019] [Indexed: 01/20/2023] Open
Abstract
The left-right organizer (LRO) in the mouse consists of pit cells within the depression, located at the end of the developing notochord, also known as the embryonic node and crown cells lining the outer periphery of the node. Cilia on pit cells are posteriorly tilted, rotate clockwise and generate leftward fluid flow. Primary cilia on crown cells are required to interpret the directionality of fluid movement and initiate flow-dependent gene transcription. Crown cells express PC1-L1 and PC2, which may form a heteromeric polycystin channel complex on primary cilia. It is still only poorly understood how fluid flow activates the ciliary polycystin complex. Besides polycystin channels voltage gated channels like HCN4 and KCNQ1 have been implicated in establishing asymmetry. How this electrical network of ion channels initiates left-sided signalling cascades and differential gene expression is currently only poorly defined.
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Affiliation(s)
- Rajeev Tajhya
- Department of Physiology, University of California, 1550 4th Street, San Francisco, CA, 94518, USA
| | - Markus Delling
- Department of Physiology, University of California, 1550 4th Street, San Francisco, CA, 94518, USA
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141
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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142
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Cilia and development. Curr Opin Genet Dev 2019; 56:15-21. [DOI: 10.1016/j.gde.2019.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/07/2019] [Accepted: 05/11/2019] [Indexed: 01/01/2023]
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143
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Hor CH, Goh EL. Small GTPases in hedgehog signalling: emerging insights into the disease mechanisms of Rab23-mediated and Arl13b-mediated ciliopathies. Curr Opin Genet Dev 2019; 56:61-68. [PMID: 31465935 DOI: 10.1016/j.gde.2019.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 01/31/2023]
Abstract
Small GTPases are known to have pivotal roles in intracellular trafficking, and several members of the small GTPases superfamily such as Rab10 [1,2•], Rab11 [3-5], Rab34 [6•,7], Rab8 [3,8], Rab23 [9-12], RSG1 [13-15], Arl13b [16-22], and Arl6 [22,23] were recently reported to mediate primary cilia function and/or Hh signalling. Although these functions are implicated in diseases such as ciliopathies, the molecular basis underlying how these small GTPases mediate primary cilia-dependent Hh signalling and pathogenesis of ciliopathies warrants further investigations. Notably, Rab23 and Arl13b have been implicated in ciliopathy-associated human diseases and could regulate Hh signalling cascade in multifaceted manners. This review thus specifically discuss the roles of Rab23 and Arl13b in primary cilia of mammalian systems, their cilia-dependent and cilia-independent modulation of hedgehog signalling pathways and their implications in Carpenter Syndrome and Joubert Syndrome respectively.
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Affiliation(s)
- Catherine Hh Hor
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Chemistry, Research Cluster on Health and Drug Discovery, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong
| | - Eyleen Lk Goh
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Research, National Neuroscience Institute, Singapore 308433, Singapore; Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore; KK Research Center, KK Women's and Children's Hospital, Singapore 229899, Singapore.
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144
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The photoreceptor cilium and its diseases. Curr Opin Genet Dev 2019; 56:22-33. [DOI: 10.1016/j.gde.2019.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/21/2019] [Accepted: 05/11/2019] [Indexed: 12/26/2022]
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145
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Khanna H. More Than Meets the Eye: Current Understanding of RPGR Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:521-538. [PMID: 29721984 DOI: 10.1007/978-3-319-75402-4_64] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
This article summarizes the recent advances in our understanding of a major retinal disease gene RPGR (retinitis pigmentosa GTPase regulator), mutations in which are associated with majority of X-linked forms of retinal degenerations. A great deal of work has been done to uncover the ciliary localization of RPGR and its interacting proteins in the retina. However, the molecular mechanisms of action of RPGR in the photoreceptors are still unclear. Recent studies have begun to shed light on the intracellular pathways in which RPGR is likely involved. The deregulation of such pathways may underlie the pathogenesis of severe retinal degeneration associated with RPGR. With the recent advances in the gene augmentation therapy for RPGR-associated disease, there is a lot of excitement in the field. Patients with RPGR mutations, however, present with clinically heterogeneous manifestations. It is therefore imperative to examine the function of RPGR in detail, so that we can design patient-oriented therapeutic strategies for this disease.
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Affiliation(s)
- Hemant Khanna
- Department of Ophthalmology and Neurobiology, UMASS Medical School, Worcester, MA, USA.
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146
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Gawden-Bone CM, Griffiths GM. Phospholipids: Pulling Back the Actin Curtain for Granule Delivery to the Immune Synapse. Front Immunol 2019; 10:700. [PMID: 31031745 PMCID: PMC6470250 DOI: 10.3389/fimmu.2019.00700] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/14/2019] [Indexed: 12/29/2022] Open
Abstract
Phosphoinositides, together with the phospholipids phosphatidylserine and phosphatidic acid, are important components of the plasma membrane acting as second messengers that, with diacylglycerol, regulate a diverse range of signaling events converting extracellular changes into cellular responses. Local changes in their distribution and membrane charge on the inner leaflet of the plasma membrane play important roles in immune cell function. Here we discuss their distribution and regulators highlighting the importance of membrane changes across the immune synapse on the cytoskeleton and the impact on the function of cytotoxic T lymphocytes.
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Affiliation(s)
| | - Gillian M Griffiths
- Cambridge Institute of Medical Research, University of Cambridge, Cambridge, United Kingdom
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147
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Ratzan W, Rayaprolu V, Killian SE, Bradley R, Kohout SC. The voltage sensing phosphatase (VSP) localizes to the apical membrane of kidney tubule epithelial cells. PLoS One 2019; 14:e0209056. [PMID: 30964862 PMCID: PMC6456211 DOI: 10.1371/journal.pone.0209056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 03/21/2019] [Indexed: 12/29/2022] Open
Abstract
Voltage-sensing phosphatases (VSPs) are transmembrane proteins that couple changes in membrane potential to hydrolysis of inositol signaling lipids. VSPs catalyze the dephosphorylation of phosphatidylinositol phosphates (PIPs) that regulate diverse aspects of cell membrane physiology including cell division, growth and migration. VSPs are highly conserved among chordates, and their RNA transcripts have been detected in the adult and embryonic stages of frogs, fish, chickens, mice and humans. However, the subcellular localization and biological function of VSP remains unknown. Using reverse transcriptase-PCR (RT-PCR), we show that both Xenopus laevis VSPs (Xl-VSP1 and Xl-VSP2) mRNAs are expressed in early embryos, suggesting that both Xl-VSPs are involved in early tadpole development. To understand which embryonic tissues express Xl-VSP mRNA, we used in situ hybridization (ISH) and found Xl-VSP mRNA in both the brain and kidney of NF stage 32-36 embryos. By Western blot analysis with a VSP antibody, we show increasing levels of Xl-VSP protein in the developing embryo, and by immunohistochemistry (IHC), we demonstrate that Xl-VSP protein is specifically localized to the apical membrane of both embryonic and adult kidney tubules. We further characterized the catalytic activity of both Xl-VSP homologs and found that while Xl-VSP1 catalyzes 3- and 5-phosphate removal, Xl-VSP2 is a less efficient 3-phosphatase with different substrate specificity. Our results suggest that Xl-VSP1 and Xl-VSP2 serve different functional roles and that VSPs are an integral component of voltage-dependent PIP signaling pathways during vertebrate kidney tubule development and function.
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Affiliation(s)
- Wil Ratzan
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States of America
| | - Vamseedhar Rayaprolu
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States of America
| | - Scott E. Killian
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States of America
| | - Roger Bradley
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States of America
| | - Susy C. Kohout
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States of America
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148
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Definition of phosphoinositide distribution in the nanoscale. Curr Opin Cell Biol 2019; 57:33-39. [DOI: 10.1016/j.ceb.2018.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 10/18/2018] [Accepted: 10/30/2018] [Indexed: 11/20/2022]
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149
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Hedger G, Koldsø H, Chavent M, Siebold C, Rohatgi R, Sansom MSP. Cholesterol Interaction Sites on the Transmembrane Domain of the Hedgehog Signal Transducer and Class F G Protein-Coupled Receptor Smoothened. Structure 2019; 27:549-559.e2. [PMID: 30595453 PMCID: PMC6408332 DOI: 10.1016/j.str.2018.11.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/28/2018] [Accepted: 11/02/2018] [Indexed: 12/12/2022]
Abstract
Transduction of Hedgehog signals across the plasma membrane is facilitated by the class F G-protein-coupled-receptor (GPCR) Smoothened (SMO). Recent studies suggest that SMO is modulated via interactions of its transmembrane (TM) domain with cholesterol. We apply molecular dynamics simulations of SMO embedded in cholesterol containing lipid bilayers, revealing a direct interaction of cholesterol with the TM domain at regions distinct from those observed in class A GPCRs. In particular the extracellular tips of helices TM2 and TM3 form a well-defined cholesterol interaction site. Potential of mean force calculations yield a free energy landscape for cholesterol binding. Alongside analysis of equilibrium cholesterol occupancy, this reveals the existence of a dynamic "greasy patch" interaction with the TM domain of SMO, which may be compared with previously identified lipid interaction sites on other membrane proteins. These predictions provide molecular-level insights into cholesterol interactions with a class F GPCR, suggesting potential druggable sites.
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Affiliation(s)
- George Hedger
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Matthieu Chavent
- Institut de Pharmacologie et de Biologie Structurale IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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150
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Picariello T, Brown JM, Hou Y, Swank G, Cochran DA, King OD, Lechtreck K, Pazour GJ, Witman GB. A global analysis of IFT-A function reveals specialization for transport of membrane-associated proteins into cilia. J Cell Sci 2019; 132:jcs220749. [PMID: 30659111 PMCID: PMC6382014 DOI: 10.1242/jcs.220749] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/02/2019] [Indexed: 12/28/2022] Open
Abstract
Intraflagellar transport (IFT), which is essential for the formation and function of cilia in most organisms, is the trafficking of IFT trains (i.e. assemblies of IFT particles) that carry cargo within the cilium. Defects in IFT cause several human diseases. IFT trains contain the complexes IFT-A and IFT-B. To dissect the functions of these complexes, we studied a Chlamydomonas mutant that is null for the IFT-A protein IFT140. The mutation had no effect on IFT-B but destabilized IFT-A, preventing flagella assembly. Therefore, IFT-A assembly requires IFT140. Truncated IFT140, which lacks the N-terminal WD repeats of the protein, partially rescued IFT and supported formation of half-length flagella that contained normal levels of IFT-B but greatly reduced amounts of IFT-A. The axonemes of these flagella had normal ultrastructure and, as investigated by SDS-PAGE, normal composition. However, composition of the flagellar 'membrane+matrix' was abnormal. Analysis of the latter fraction by mass spectrometry revealed decreases in small GTPases, lipid-anchored proteins and cell signaling proteins. Thus, IFT-A is specialized for the import of membrane-associated proteins. Abnormal levels of the latter are likely to account for the multiple phenotypes of patients with defects in IFT140.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Tyler Picariello
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jason M Brown
- Department of Biology, Salem State University, Salem, MA 01970, USA
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Gregory Swank
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Deborah A Cochran
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Oliver D King
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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