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Du R, Zhou C, Chen S, Li T, Lin Y, Xu A, Huang Y, Mei H, Huang X, Tan D, Zheng R, Liang C, Cai Y, Shao Y, Zhang W, Liu L, Zeng C. Atypical phenotypes and novel OCRL variations in southern Chinese patients with Lowe syndrome. Pediatr Nephrol 2024; 39:2377-2391. [PMID: 38589698 DOI: 10.1007/s00467-024-06356-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 04/10/2024]
Abstract
BACKGROUND Lowe syndrome is characterized by the presence of congenital cataracts, psychomotor retardation, and dysfunctional proximal renal tubules. This study presents a case of an atypical phenotype, investigates the genetic characteristics of eight children diagnosed with Lowe syndrome in southern China, and performs functional analysis of the novel variants. METHODS Whole-exome sequencing was conducted on eight individuals diagnosed with Lowe syndrome from three medical institutions in southern China. Retrospective collection and analysis of clinical and genetic data were performed, and functional analysis was conducted on the five novel variants. RESULTS In our cohort, the clinical symptoms of the eight Lowe syndrome individuals varied. One patient was diagnosed with Lowe syndrome but did not present with congenital cataracts. Common features among all patients included cognitive impairment, short stature, and low molecular weight proteinuria. Eight variations in the OCRL gene were identified, encompassing three previously reported and five novel variations. Among the novel variations, three nonsense mutations were determined to be pathogenic, and two patients harboring novel missense variations of uncertain significance exhibited severe typical phenotypes. Furthermore, all novel variants were associated with altered protein expression levels and impacted primary cilia formation. CONCLUSION This study describes the first case of an atypical Lowe syndrome patient without congenital cataracts in China and performs a functional analysis of novel variants in the OCRL gene, thereby expanding the understanding of the clinical manifestations and genetic diversity associated with Lowe syndrome.
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Affiliation(s)
- Rong Du
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
- Department of Endocrinology, Genetic, and Rare Diseases, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China
| | - Chengcheng Zhou
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Shehong Chen
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
- Department of Pediatrics, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Tong Li
- Department of Pediatric Endocrinology, The First Affiliated Hospital of Shantou University Medical College, Shantou, 515041, China
| | - Yunting Lin
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Aijing Xu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Yonglan Huang
- Department of Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Huifen Mei
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
- Department of Endocrinology, Genetic, and Rare Diseases, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China
| | - Xiaoli Huang
- Department of Pediatric Neurology, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China
| | - Dongdong Tan
- Department of Endocrinology, Genetic, and Rare Diseases, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China
| | - Ruidan Zheng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Cuili Liang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Yanna Cai
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Yongxian Shao
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
| | - Wen Zhang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
- Department of Endocrinology, Genetic, and Rare Diseases, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China
| | - Li Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China
- Department of Endocrinology, Genetic, and Rare Diseases, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China
| | - Chunhua Zeng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangdong Provincial Clinical Research Center for Child Health, National Children's Medical Center for South Central Region, Guangzhou Medical University, Guangzhou, 510623, China.
- Department of Endocrinology, Genetic, and Rare Diseases, Guangzhou Women and Children's Medical Center Liuzhou Hospital, Liuzhou, 545000, China.
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2
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Mohd Rafiq N, Fujise K, Rosenfeld MS, Xu P, De Camilli P. Parkinsonism Sac domain mutation in Synaptojanin-1 affects ciliary properties in iPSC-derived dopaminergic neurons. Proc Natl Acad Sci U S A 2024; 121:e2318943121. [PMID: 38635628 PMCID: PMC11047088 DOI: 10.1073/pnas.2318943121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 03/04/2024] [Indexed: 04/20/2024] Open
Abstract
Synaptojanin-1 (SJ1) is a major neuronal-enriched PI(4, 5)P2 4- and 5-phosphatase implicated in the shedding of endocytic factors during endocytosis. A mutation (R258Q) that impairs selectively its 4-phosphatase activity causes Parkinsonism in humans and neurological defects in mice (SJ1RQKI mice). Studies of these mice showed, besides an abnormal assembly state of endocytic factors at synapses, the presence of dystrophic nerve terminals selectively in a subset of nigro-striatal dopamine (DA)-ergic axons, suggesting a special lability of DA neurons to the impairment of SJ1 function. Here we have further investigated the impact of SJ1 on DA neurons using iPSC-derived SJ1 KO and SJ1RQKI DA neurons and their isogenic controls. In addition to the expected enhanced clustering of endocytic factors in nerve terminals, we observed in both SJ1 mutant neuronal lines increased cilia length. Further analysis of cilia of SJ1RQDA neurons revealed abnormal accumulation of the Ca2+ channel Cav1.3 and of ubiquitin chains, suggesting a defect in the clearing of ubiquitinated proteins at the ciliary base, where a focal concentration of SJ1 was observed. We suggest that SJ1 may contribute to the control of ciliary protein dynamics in DA neurons, with implications on cilia-mediated signaling.
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Affiliation(s)
- Nisha Mohd Rafiq
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Kenshiro Fujise
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Martin Shaun Rosenfeld
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Peng Xu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
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3
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Hoffman HK, Prekeris R. HOPS-dependent lysosomal fusion controls Rab19 availability for ciliogenesis in polarized epithelial cells. J Cell Sci 2024; 137:jcs261047. [PMID: 37665101 PMCID: PMC10499034 DOI: 10.1242/jcs.261047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 07/20/2023] [Indexed: 09/05/2023] Open
Abstract
Primary cilia are sensory cellular organelles crucial for organ development and homeostasis. Ciliogenesis in polarized epithelial cells requires Rab19-mediated clearing of apical cortical actin to allow the cilium to grow from the apically docked basal body into the extracellular space. Loss of the lysosomal membrane-tethering homotypic fusion and protein sorting (HOPS) complex disrupts this actin clearing and ciliogenesis, but it remains unclear how the ciliary function of HOPS relates to its canonical function in regulating late endosome-lysosome fusion. Here, we show that disruption of HOPS-dependent lysosomal fusion indirectly impairs actin clearing and ciliogenesis by disrupting the targeting of Rab19 to the basal body, and that this effect is specific to polarized epithelial cells. We also find that Rab19 functions in endolysosomal cargo trafficking in addition to having its previously identified role in ciliogenesis. In summary, we show that inhibition of lysosomal fusion leads to the abnormal accumulation of Rab19 on late endosomes, thus depleting Rab19 from the basal body and thereby disrupting Rab19-mediated actin clearing and ciliogenesis in polarized epithelial cells.
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Affiliation(s)
- Huxley K. Hoffman
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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4
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Hernández-Cáceres MP, Pinto-Nuñez D, Rivera P, Burgos P, Díaz-Castro F, Criollo A, Yañez MJ, Morselli E. Role of lipids in the control of autophagy and primary cilium signaling in neurons. Neural Regen Res 2024; 19:264-271. [PMID: 37488876 PMCID: PMC10503597 DOI: 10.4103/1673-5374.377414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 03/09/2023] [Accepted: 04/27/2023] [Indexed: 07/26/2023] Open
Abstract
The brain is, after the adipose tissue, the organ with the greatest amount of lipids and diversity in their composition in the human body. In neurons, lipids are involved in signaling pathways controlling autophagy, a lysosome-dependent catabolic process essential for the maintenance of neuronal homeostasis and the function of the primary cilium, a cellular antenna that acts as a communication hub that transfers extracellular signals into intracellular responses required for neurogenesis and brain development. A crosstalk between primary cilia and autophagy has been established; however, its role in the control of neuronal activity and homeostasis is barely known. In this review, we briefly discuss the current knowledge regarding the role of autophagy and the primary cilium in neurons. Then we review the recent literature about specific lipid subclasses in the regulation of autophagy, in the control of primary cilium structure and its dependent cellular signaling in physiological and pathological conditions, specifically focusing on neurons, an area of research that could have major implications in neurodevelopment, energy homeostasis, and neurodegeneration.
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Affiliation(s)
- María Paz Hernández-Cáceres
- Instituto de Investigación en Ciencias Odontológicas (ICOD), Facultad de Odontología, Universidad de Chile, Santiago, Chile
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
| | - Daniela Pinto-Nuñez
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
| | - Patricia Rivera
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
- Physiology Department, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paulina Burgos
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
| | - Francisco Díaz-Castro
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
- Physiology Department, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alfredo Criollo
- Instituto de Investigación en Ciencias Odontológicas (ICOD), Facultad de Odontología, Universidad de Chile, Santiago, Chile
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas & Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Autophagy Research Center, Santiago, Chile
| | - Maria Jose Yañez
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
| | - Eugenia Morselli
- Department of Basic Sciences, Faculty of Medicine and Science, Universidad San Sebastián, Santiago, Chile
- Autophagy Research Center, Santiago, Chile
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5
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Kalot R, Sentell Z, Kitzler TM, Torban E. Primary cilia and actin regulatory pathways in renal ciliopathies. FRONTIERS IN NEPHROLOGY 2024; 3:1331847. [PMID: 38292052 PMCID: PMC10824913 DOI: 10.3389/fneph.2023.1331847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024]
Abstract
Ciliopathies are a group of rare genetic disorders caused by defects to the structure or function of the primary cilium. They often affect multiple organs, leading to brain malformations, congenital heart defects, and anomalies of the retina or skeletal system. Kidney abnormalities are among the most frequent ciliopathic phenotypes manifesting as smaller, dysplastic, and cystic kidneys that are often accompanied by renal fibrosis. Many renal ciliopathies cause chronic kidney disease and often progress to end-stage renal disease, necessitating replacing therapies. There are more than 35 known ciliopathies; each is a rare hereditary condition, yet collectively they account for a significant proportion of chronic kidney disease worldwide. The primary cilium is a tiny microtubule-based organelle at the apex of almost all vertebrate cells. It serves as a "cellular antenna" surveying environment outside the cell and transducing this information inside the cell to trigger multiple signaling responses crucial for tissue morphogenesis and homeostasis. Hundreds of proteins and unique cellular mechanisms are involved in cilia formation. Recent evidence suggests that actin remodeling and regulation at the base of the primary cilium strongly impacts ciliogenesis. In this review, we provide an overview of the structure and function of the primary cilium, focusing on the role of actin cytoskeleton and its regulators in ciliogenesis. We then describe the key clinical, genetic, and molecular aspects of renal ciliopathies. We highlight what is known about actin regulation in the pathogenesis of these diseases with the aim to consider these recent molecular findings as potential therapeutic targets for renal ciliopathies.
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Affiliation(s)
- Rita Kalot
- Department of Medicine and Department of Physiology, McGill University, Montreal, QC, Canada
- The Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Zachary Sentell
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Thomas M. Kitzler
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- McGill University Health Center, Montreal, QC, Canada
| | - Elena Torban
- Department of Medicine and Department of Physiology, McGill University, Montreal, QC, Canada
- The Research Institute of the McGill University Health Center, Montreal, QC, Canada
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6
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Zheng W, Ziemssen F, Suesskind D, Voykov B, Schnichels S. TRPP2 is located in the primary cilia of human non-pigmented ciliary epithelial cells. Graefes Arch Clin Exp Ophthalmol 2024; 262:93-102. [PMID: 37378878 PMCID: PMC10806040 DOI: 10.1007/s00417-023-06150-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 05/30/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
PURPOSE Mechanosensitive channels (MSCs) and primary cilium possess a possible relevance for the sensation of intraocular pressure (IOP). However, there is only limited data on their expression and localization in the ciliary body epithelium (CBE). The purpose of this study was to characterize the expression and localization of TRPP2 in a human non-pigmented ciliary epithelial cell (HNPCE) line. METHODS The expression of the TRPP2 was studied by quantitative (q)RT-PCR and in situ hybridization in rat and human tissue. Protein expression and distribution were studied by western blot analysis, immunohistochemistry, and immunoelectron microscopy. Cellular location of TRPP2 was determined in rat and human CBE by immunofluorescence and immunoblot analysis. Electron microscopy studies were conducted to evaluate where and with substructure TRPP2 is localized in the HNPCE cell line. RESULTS The expression of TRPP2 in rat and human non-pigmented ciliary epithelium was detected. TRPP2 was mainly located in nuclei, but also showed a punctate distribution pattern in the cytoplasm of HNPCE of the tissue and the cell line. In HNPCE cell culture, primary cilia did exhibit different length following serum starvation and hydrostatic pressure. TRPP2 was found to be colocalized with these cilia in HNPCE cells. CONCLUSION The expression of TRPP2 and the primary cilium in the CB may indicate a possible role, such as the sensing of hydrostatic pressure, for the regulation of IOP. Functional studies via patch clamp or pharmacological intervention have yet to clarify the relevance for the physiological situation or aqueous humor regulation.
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Affiliation(s)
- Wenxu Zheng
- Centre for Ophthalmology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Focke Ziemssen
- Centre for Ophthalmology, Eberhard Karls University Tübingen, Tübingen, Germany.
- University Eye Hospital Leipzig, Leipzig, Germany.
- Klinik und Poliklinik für Augenheilkunde, Liebigstr. 10-14, 72072, Leipzig, Germany.
| | - Daniela Suesskind
- Centre for Ophthalmology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Bogomil Voykov
- Centre for Ophthalmology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Sven Schnichels
- Centre for Ophthalmology, Eberhard Karls University Tübingen, Tübingen, Germany
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7
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Rafiq NM, Fujise K, Rosenfeld MS, Xu P, Wu Y, De Camilli P. Parkinsonism Sac domain mutation in Synaptojanin-1 affects ciliary properties in iPSC-derived dopaminergic neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.562142. [PMID: 37873399 PMCID: PMC10592818 DOI: 10.1101/2023.10.12.562142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Synaptojanin-1 (SJ1) is a major neuronal-enriched PI(4,5)P2 4- and 5-phosphatase implicated in the shedding of endocytic factors during endocytosis. A mutation (R258Q) that impairs selectively its 4-phosphatase activity causes Parkinsonism in humans and neurological defects in mice (SJ1RQKI mice). Studies of these mice showed, besides an abnormal assembly state of endocytic factors at synapses, the presence of dystrophic nerve terminals selectively in a subset of nigro-striatal dopamine (DA)-ergic axons, suggesting a special lability of DA neurons to the impairment of SJ1 function. Here we have further investigated the impact of SJ1 on DA neurons using iPSC-derived SJ1 KO and SJ1RQKI DA neurons and their isogenic controls. In addition to the expected enhanced clustering of endocytic factors in nerve terminals, we observed in both SJ1 mutant neuronal lines increased cilia length. Further analysis of cilia of SJ1RQDA neurons revealed abnormal accumulation of the Ca2+ channel Cav1.3 and of ubiquitin chains, suggesting an impaired clearing of proteins from cilia which may result from an endocytic defect at the ciliary base, where a focal concentration of SJ1 was observed. We suggest that SJ1 may contribute to the control of ciliary protein dynamics in DA neurons, with implications on cilia-mediated signaling.
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Affiliation(s)
- Nisha Mohd Rafiq
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair. Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Kenshiro Fujise
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair. Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Martin Shaun Rosenfeld
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair. Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Peng Xu
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair. Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Yumei Wu
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair. Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair. Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
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8
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Abstract
Phosphoinositides (PIs) are phospholipids derived from phosphatidylinositol. PIs are regulated via reversible phosphorylation, which is directed by the opposing actions of PI kinases and phosphatases. PIs constitute a minor fraction of the total cellular lipid pool but play pleiotropic roles in multiple aspects of cell biology. Genetic mutations of PI regulatory enzymes have been identified in rare congenital developmental syndromes, including ciliopathies, and in numerous human diseases, such as cancer and metabolic and neurological disorders. Accordingly, PI regulatory enzymes have been targeted in the design of potential therapeutic interventions for human diseases. Recent advances place PIs as central regulators of membrane dynamics within functionally distinct subcellular compartments. This brief review focuses on the emerging role PIs play in regulating cell signaling within the primary cilium and in directing transfer of molecules at interorganelle membrane contact sites and identifies new roles for PIs in subcellular spaces.
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Affiliation(s)
- Elizabeth Michele Davies
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Christina Anne Mitchell
- Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Harald Alfred Stenmark
- Department of Molecular Cell Biology, Institute for Cancer Research. The Norwegian Radium Hospital, Montebello, N-0379 Oslo, Norway
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway
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9
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Morleo M, Vieira HL, Pennekamp P, Palma A, Bento-Lopes L, Omran H, Lopes SS, Barral DC, Franco B. Crosstalk between cilia and autophagy: implication for human diseases. Autophagy 2023; 19:24-43. [PMID: 35613303 PMCID: PMC9809938 DOI: 10.1080/15548627.2022.2067383] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Macroautophagy/autophagy is a self-degradative process necessary for cells to maintain their energy balance during development and in response to nutrient deprivation. Autophagic processes are tightly regulated and have been found to be dysfunctional in several pathologies. Increasing experimental evidence points to the existence of an interplay between autophagy and cilia. Cilia are microtubule-based organelles protruding from the cell surface of mammalian cells that perform a variety of motile and sensory functions and, when dysfunctional, result in disorders known as ciliopathies. Indeed, selective autophagic degradation of ciliary proteins has been shown to control ciliogenesis and, conversely, cilia have been reported to control autophagy. Moreover, a growing number of players such as lysosomal and mitochondrial proteins are emerging as actors of the cilia-autophagy interplay. However, some of the published data on the cilia-autophagy axis are contradictory and indicate that we are just starting to understand the underlying molecular mechanisms. In this review, the current knowledge about this axis and challenges are discussed, as well as the implication for ciliopathies and autophagy-associated disorders.
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Affiliation(s)
- Manuela Morleo
- Telethon Institute of Genetics and Medicine (TIGEM), 80078, Pozzuoli, Italy,Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Helena L.A. Vieira
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal,UCIBIO, Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal,Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Petra Pennekamp
- Department of General Pediatrics, University Hospital Münster, University of Münster, Münster48149, Germany,Member of the European Reference Networks ERN-LUNG, Lisbon, Portugal
| | - Alessandro Palma
- Department of Onco-hematology, Gene and Cell Therapy, Bambino Gesù Children’s Hospital - IRCCS, Rome, Italy
| | - Liliana Bento-Lopes
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal
| | - Heymut Omran
- Department of General Pediatrics, University Hospital Münster, University of Münster, Münster48149, Germany,Member of the European Reference Networks ERN-LUNG, Lisbon, Portugal
| | - Susana S. Lopes
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal,Member of the European Reference Networks ERN-LUNG, Lisbon, Portugal
| | - Duarte C. Barral
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), 80078, Pozzuoli, Italy,Medical Genetics, Department of Translational Medical Science, University of Naples “Federico II”, Naples, Italy,Scuola Superiore Meridionale, School for Advanced Studies, Naples, Italy,CONTACT Brunella Franco CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal
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10
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Park K, Leroux MR. Composition, organization and mechanisms of the transition zone, a gate for the cilium. EMBO Rep 2022; 23:e55420. [PMID: 36408840 PMCID: PMC9724682 DOI: 10.15252/embr.202255420] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/08/2022] [Accepted: 10/31/2022] [Indexed: 11/22/2022] Open
Abstract
The cilium evolved to provide the ancestral eukaryote with the ability to move and sense its environment. Acquiring these functions required the compartmentalization of a dynein-based motility apparatus and signaling proteins within a discrete subcellular organelle contiguous with the cytosol. Here, we explore the potential molecular mechanisms for how the proximal-most region of the cilium, termed transition zone (TZ), acts as a diffusion barrier for both membrane and soluble proteins and helps to ensure ciliary autonomy and homeostasis. These include a unique complement and spatial organization of proteins that span from the microtubule-based axoneme to the ciliary membrane; a protein picket fence; a specialized lipid microdomain; differential membrane curvature and thickness; and lastly, a size-selective molecular sieve. In addition, the TZ must be permissive for, and functionally integrates with, ciliary trafficking systems (including intraflagellar transport) that cross the barrier and make the ciliary compartment dynamic. The quest to understand the TZ continues and promises to not only illuminate essential aspects of human cell signaling, physiology, and development, but also to unravel how TZ dysfunction contributes to ciliopathies that affect multiple organ systems, including eyes, kidney, and brain.
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Affiliation(s)
- Kwangjin Park
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
- Present address:
Terry Fox LaboratoryBC CancerVancouverBCCanada
- Present address:
Department of Medical GeneticsUniversity of British ColumbiaVancouverBCCanada
| | - Michel R Leroux
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
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11
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The Role of Primary Cilia-Associated Phosphoinositide Signaling in Development. J Dev Biol 2022; 10:jdb10040051. [PMID: 36547473 PMCID: PMC9785882 DOI: 10.3390/jdb10040051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 12/07/2022] Open
Abstract
Primary cilia are microtube-based organelles that extend from the cell surface and function as biochemical and mechanical extracellular signal sensors. Primary cilia coordinate a series of signaling pathways during development. Cilia dysfunction leads to a pleiotropic group of developmental disorders, termed ciliopathy. Phosphoinositides (PIs), a group of signaling phospholipids, play a crucial role in development and tissue homeostasis by regulating membrane trafficking, cytoskeleton reorganization, and organelle identity. Accumulating evidence implicates the involvement of PI species in ciliary defects and ciliopathies. The abundance and localization of PIs in the cell are tightly regulated by the opposing actions of kinases and phosphatases, some of which are recently discovered in the context of primary cilia. Here, we review several cilium-associated PI kinases and phosphatases, including their localization along cilia, function in regulating the ciliary biology under normal conditions, as well as the connection of their disease-associated mutations with ciliopathies.
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12
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Galarreta CI, Kennedy C, Blair DR, Slavotinek A. Expanding the phenotype of PIK3C2A related syndrome: Report of two siblings with novel features and genotype. Am J Med Genet A 2022; 188:2724-2731. [PMID: 35770347 DOI: 10.1002/ajmg.a.62881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/05/2022] [Accepted: 04/15/2022] [Indexed: 01/25/2023]
Abstract
A pair of siblings was ascertained due to multiple congenital anomalies, including strikingly similar facial, skeletal, and ocular abnormalities. Exome sequencing of both the children and their mother revealed two novel PIK3C2A variants in the siblings, c.4381delC (p.Arg1461Glufs*31) and c.1555C > T (p.Arg519Ter). PIK3C2A belongs to the Class IIa family of Phosphatidylinositol-3-kinases, which create second messenger lipids that regulate a wide range of downstream signaling pathways involved in cell growth, survival and migration. Tiosano et al. (2019) identified the first monogenic disorder associated with biallelic PIK3C2A loss-of-function variants (oculoskeletodental syndrome). The novel syndrome was characterized by short stature, coarse facial features, ocular and skeletal abnormalities. This report describes two additional siblings affected by the PIK3C2A-related syndrome, confirms core clinical features, establishes intrafamilial variability and expands the phenotype to include proteinuria.
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Affiliation(s)
- Carolina I Galarreta
- Medical Genetics and Metabolism Department, Valley Children's Hospital, Madera, California, USA
| | - Colleen Kennedy
- Medical Genetics and Metabolism Department, Valley Children's Hospital, Madera, California, USA
| | - David R Blair
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, California, USA
| | - Anne Slavotinek
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, California, USA
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13
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Kowal TJ, Dhande OS, Wang B, Wang Q, Ning K, Liu W, Berbari NF, Hu Y, Sun Y. Distribution of prototypical primary cilia markers in subtypes of retinal ganglion cells. J Comp Neurol 2022; 530:2176-2187. [PMID: 35434813 PMCID: PMC9219574 DOI: 10.1002/cne.25326] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/27/2022] [Accepted: 03/21/2022] [Indexed: 11/07/2022]
Abstract
Loss of retinal ganglion cells (RGCs) underlies several forms of retinal disease including glaucomatous optic neuropathy, a leading cause of irreversible blindness. Several rare genetic disorders associated with cilia dysfunction have retinal degeneration as a clinical hallmark. Much of the focus of ciliopathy associated blindness is on the connecting cilium of photoreceptors; however, RGCs also possess primary cilia. It is unclear what roles RGC cilia play, what proteins and signaling machinery localize to RGC cilia, or how RGC cilia are differentiated across the subtypes of RGCs. To better understand these questions, we assessed the presence or absence of a prototypical cilia marker Arl13b and a widely distributed neuronal cilia marker AC3 in different subtypes of mouse RGCs. Interestingly, not all RGC subtype cilia are the same and there are significant differences even among these standard cilia markers. Alpha-RGCs positive for osteopontin, calretinin, and SMI32 primarily possess AC3-positive cilia. Directionally selective RGCs that are CART positive or Trhr positive localize either Arl13b or AC3, respectively, in cilia. Intrinsically photosensitive RGCs differentially localize Arl13b and AC3 based on melanopsin expression. Taken together, we characterized the localization of gold standard cilia markers in different subtypes of RGCs and conclude that cilia within RGC subtypes may be differentially organized. Future studies aimed at understanding RGC cilia function will require a fundamental ability to observe the cilia across subtypes as their signaling protein composition is elucidated. A comprehensive understanding of RGC cilia may reveal opportunities to understanding how their dysfunction leads to retinal degeneration.
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Affiliation(s)
- Tia J. Kowal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Onkar S. Dhande
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Biao Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Qing Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Wendy Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Nicolas F. Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis IN 46202 USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
- Palo Alto Veterans Administration, Palo Alto, CA 94304
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14
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Nguyen TD, Truong ME, Reiter JF. The Intimate Connection Between Lipids and Hedgehog Signaling. Front Cell Dev Biol 2022; 10:876815. [PMID: 35757007 PMCID: PMC9222137 DOI: 10.3389/fcell.2022.876815] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/13/2022] [Indexed: 01/19/2023] Open
Abstract
Hedgehog (HH) signaling is an intercellular communication pathway involved in directing the development and homeostasis of metazoans. HH signaling depends on lipids that covalently modify HH proteins and participate in signal transduction downstream. In many animals, the HH pathway requires the primary cilium, an organelle with a specialized protein and lipid composition. Here, we review the intimate connection between HH signaling and lipids. We highlight how lipids in the primary cilium can create a specialized microenvironment to facilitate signaling, and how HH and components of the HH signal transduction pathway use lipids to communicate between cells.
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Affiliation(s)
- Thi D. Nguyen
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States
| | - Melissa E. Truong
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Jeremy F. Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States,Chan Zuckerberg Biohub, San Francisco, CA, United States,*Correspondence: Jeremy F. Reiter,
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15
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Dutta P, Ray K. Ciliary membrane, localised lipid modification and cilia function. J Cell Physiol 2022; 237:2613-2631. [PMID: 35661356 DOI: 10.1002/jcp.30787] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 11/08/2022]
Abstract
Cilium, a tiny microtubule-based cellular appendage critical for cell signalling and physiology, displays a large variety of receptors. The composition and turnover of ciliary lipids and receptors determine cell behaviour. Due to the exclusion of ribosomal machinery and limited membrane area, a cilium needs adaptive logistics to actively reconstitute the lipid and receptor compositions during development and differentiation. How is this dynamicity generated? Here, we examine whether, along with the Intraflagellar-Transport, targeted changes in sector-wise lipid composition could control the receptor localisation and functions in the cilia. We discuss how an interplay between ciliary lipid composition, localised lipid modification, and receptor function could contribute to cilia growth and signalling. We argue that lipid modification at the cell-cilium interface could generate an added thrust for a selective exchange of membrane lipids and the transmembrane and membrane-associated proteins.
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Affiliation(s)
- Priya Dutta
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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16
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Tran KT, Le VS, Dao LTM, Nguyen HK, Mai AK, Nguyen HT, Ngo MD, Tran QA, Nguyen LT. Novel findings from family-based exome sequencing for children with biliary atresia. Sci Rep 2021; 11:21815. [PMID: 34750413 PMCID: PMC8575792 DOI: 10.1038/s41598-021-01148-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/21/2021] [Indexed: 12/13/2022] Open
Abstract
Biliary atresia (BA) is a progressive inflammation and fibrosis of the biliary tree characterized by the obstruction of bile flow, which results in liver failure, scarring and cirrhosis. This study aimed to explore the elusive aetiology of BA by conducting whole exome sequencing for 41 children with BA and their parents (35 trios, including 1 family with 2 BA-diagnosed children and 5 child-mother cases). We exclusively identified and validated a total of 28 variants (17 X-linked, 6 de novo and 5 homozygous) in 25 candidate genes from our BA cohort. These variants were among the 10% most deleterious and had a low minor allele frequency against the employed databases: Kinh Vietnamese (KHV), GnomAD and 1000 Genome Project. Interestingly, AMER1, INVS and OCRL variants were found in unrelated probands and were first reported in a BA cohort. Liver specimens and blood samples showed identical variants, suggesting that somatic variants were unlikely to occur during morphogenesis. Consistent with earlier attempts, this study implicated genetic heterogeneity and non-Mendelian inheritance of BA.
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Affiliation(s)
- Kien Trung Tran
- Vinmec Research Institute of Stem Cell and Gene Technology, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam.
| | - Vinh Sy Le
- Vinmec Research Institute of Stem Cell and Gene Technology, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
- University of Engineering and Technology, Vietnam National University Hanoi, 144 Xuan Thuy, Cau Giay District, Hanoi, Vietnam
| | - Lan Thi Mai Dao
- Vinmec Research Institute of Stem Cell and Gene Technology, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
| | - Huyen Khanh Nguyen
- Bioequivalence Center, National Institute of Drug Quality Control, 11/157 Bang B, Hoang Mai District, Hanoi, Vietnam
| | - Anh Kieu Mai
- Vinmec International Hospital, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
| | - Ha Thi Nguyen
- Vinmec International Hospital, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
| | - Minh Duy Ngo
- Vinmec International Hospital, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
| | - Quynh Anh Tran
- Vietnam National Children's Hospital, 18/879 La Thanh, Dong Da District, Hanoi, Vietnam
| | - Liem Thanh Nguyen
- Vinmec Research Institute of Stem Cell and Gene Technology, 458 Minh Khai, Hai Ba Trung District, Hanoi, Vietnam
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17
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Oltrabella F, Jackson-Crawford A, Yan G, Rixham S, Starborg T, Lowe M. IPIP27A cooperates with OCRL to support endocytic traffic in the zebrafish pronephric tubule. Hum Mol Genet 2021; 31:1183-1196. [PMID: 34673953 DOI: 10.1093/hmg/ddab307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/12/2021] [Accepted: 10/14/2021] [Indexed: 01/08/2023] Open
Abstract
Endocytosis is a fundamentally important process through which material is internalized into cells from the extracellular environment. In the renal proximal tubule, endocytosis of the abundant scavenger receptor megalin and its co-receptor cubilin play a vital role in retrieving low molecular weight proteins from the renal filtrate. Although we know much about megalin and its ligands, the machinery and mechanisms by which the receptor is trafficked through the endosomal system remain poorly defined. In this study, we show that Ipip27A, an interacting partner of the Lowe syndrome protein OCRL, is required for endocytic traffic of megalin within the proximal renal tubule of zebrafish larvae. Knockout of Ipip27A phenocopies the endocytic phenotype seen upon loss of OCRL, with a deficit in uptake of both fluid-phase and protein cargo, which is accompanied by a reduction in megalin abundance and altered endosome morphology. Rescue and co-depletion experiments indicate that Ipip27A functions together with OCRL to support proximal tubule endocytosis. The results therefore identify Ipip27A as a new player in endocytic traffic in the proximal tubule in vivo and support the view that defective endocytosis underlies the renal tubulopathy in Lowe syndrome and Dent-2 disease.
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Affiliation(s)
- Francesca Oltrabella
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Medical Scientific Liaison - Nephrology, Astellas Pharma, Via Dante, 20123 Milano, Italy
| | - Anthony Jackson-Crawford
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Department of Blood Sciences, Grange University Hospital, Llanyravon, Gwent, NP44 8YN
| | - Guanhua Yan
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Sarah Rixham
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Tobias Starborg
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Rosalind Franklin Institute, Harwell Campus, Didcot, OX11 0FA, UK
| | - Martin Lowe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, The Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
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18
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Madhivanan K, Ramadesikan S, Hsieh WC, Aguilar MC, Hanna CB, Bacallao RL, Aguilar RC. Lowe syndrome patient cells display mTOR- and RhoGTPase-dependent phenotypes alleviated by rapamycin and statins. Hum Mol Genet 2021; 29:1700-1715. [PMID: 32391547 DOI: 10.1093/hmg/ddaa086] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/20/2020] [Accepted: 05/04/2020] [Indexed: 12/25/2022] Open
Abstract
Lowe syndrome (LS) is an X-linked developmental disease characterized by cognitive deficiencies, bilateral congenital cataracts and renal dysfunction. Unfortunately, this disease leads to the early death of affected children often due to kidney failure. Although this condition was first described in the early 1950s and the affected gene (OCRL1) was identified in the early 1990s, its pathophysiological mechanism is not fully understood and there is no LS-specific cure available to patients. Here we report two important signaling pathways affected in LS patient cells. While RhoGTPase signaling abnormalities led to adhesion and spreading defects as compared to normal controls, PI3K/mTOR hyperactivation interfered with primary cilia assembly (scenario also observed in other ciliopathies with compromised kidney function). Importantly, we identified two FDA-approved drugs able to ameliorate these phenotypes. Specifically, statins mitigated adhesion and spreading abnormalities while rapamycin facilitated ciliogenesis in LS patient cells. However, no single drug was able to alleviate both phenotypes. Based on these and other observations, we speculate that Ocrl1 has dual, independent functions supporting proper RhoGTPase and PI3K/mTOR signaling. Therefore, this study suggest that Ocrl1-deficiency leads to signaling defects likely to require combinatorial drug treatment to suppress patient phenotypes and symptoms.
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Affiliation(s)
- Kayalvizhi Madhivanan
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Building, Room 321, 201 S. University street, West Lafayette, IN 47907, USA
| | - Swetha Ramadesikan
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Building, Room 321, 201 S. University street, West Lafayette, IN 47907, USA
| | - Wen-Chieh Hsieh
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Building, Room 321, 201 S. University street, West Lafayette, IN 47907, USA
| | - Mariana C Aguilar
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Building, Room 321, 201 S. University street, West Lafayette, IN 47907, USA
| | - Claudia B Hanna
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Building, Room 321, 201 S. University street, West Lafayette, IN 47907, USA
| | - Robert L Bacallao
- Division of Nephrology, Indiana University School of Medicine, 340 W 10th St #6200, Indianapolis, IN 46202, USA
| | - R Claudio Aguilar
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Building, Room 321, 201 S. University street, West Lafayette, IN 47907, USA
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19
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Hong Y, Luo Y. Zebrafish Model in Ophthalmology to Study Disease Mechanism and Drug Discovery. Pharmaceuticals (Basel) 2021; 14:ph14080716. [PMID: 34451814 PMCID: PMC8400593 DOI: 10.3390/ph14080716] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/16/2021] [Accepted: 07/21/2021] [Indexed: 12/14/2022] Open
Abstract
Visual impairment and blindness are common and seriously affect people’s work and quality of life in the world. Therefore, the effective therapies for eye diseases are of high priority. Zebrafish (Danio rerio) is an alternative vertebrate model as a useful tool for the mechanism elucidation and drug discovery of various eye disorders, such as cataracts, glaucoma, diabetic retinopathy, age-related macular degeneration, photoreceptor degeneration, etc. The genetic and embryonic accessibility of zebrafish in combination with a behavioral assessment of visual function has made it a very popular model in ophthalmology. Zebrafish has also been widely used in ocular drug discovery, such as the screening of new anti-angiogenic compounds or neuroprotective drugs, and the oculotoxicity test. In this review, we summarized the applications of zebrafish as the models of eye disorders to study disease mechanism and investigate novel drug treatments.
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Affiliation(s)
| | - Yan Luo
- Correspondence: ; Tel.: +86-020-87335931
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20
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Ng B, De Silva S, Bindra M. Papillorenal syndrome: a systemic diagnosis not to be missed on funduscopy. BMJ Case Rep 2021; 14:14/7/e241708. [PMID: 34285019 DOI: 10.1136/bcr-2021-241708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A 45-year-old man presented to the ophthalmology department with visual symptoms in his left eye. Almost two decades ago, he required a renal transplant for focal segmental glomerular sclerosis and a detailed enquiry revealed a strong family history of renal and ocular disease. Fundus examination demonstrated significant optic disc dysplasia in his left eye and optical coherence tomography showed intraretinal fluid bilaterally. The diagnosis of papillorenal syndrome was suspected and genetic testing identified a heterozygous pathogenic variant in the PAX2 gene c.76dupG, p.Val26Glyfs*28, confirming the diagnosis. The patient was treated conservatively, and his vision eventually improved and stabilised. His renal disease and transplant were concurrently monitored by nephrologists. In this case, history-taking and ophthalmic examination raised suspicion of this rare systemic condition, which led to genetic testing and molecular confirmation of the diagnosis. We therefore highlight this case to raise awareness of papillorenal syndrome, which has significant systemic implications and also impacts familial screening and genetic counselling.
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Affiliation(s)
- Benjamin Ng
- Department of Ophthalmology, Stoke Mandeville Hospital, Aylesbury, UK
| | - Samantha De Silva
- Department of Ophthalmology, Stoke Mandeville Hospital, Aylesbury, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Mandeep Bindra
- Department of Ophthalmology, Stoke Mandeville Hospital, Aylesbury, UK
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21
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Abstract
Autophagy is a major intracellular degradation system and plays important roles in various physiological processes such as metabolic adaptation and intracellular homeostasis. It degrades intracellular components both randomly and selectively. Autophagic activity is tightly regulated primarily by nutrient availability, but also by other extracellular and intracellular signals. Growing evidence suggests that there are multiple links between autophagy and the primary cilium. The primary cilium is an organelle present on the cell surface and is important for keeping cellular integrity by transducing extracellular stimuli inside the cell. Recent studies have revealed that autophagy selectively degrades the ciliogenesis inhibitory proteins OFD1 and MYH9, promoting ciliogenesis. Conversely, autophagy also inhibits ciliogenesis under growth conditions. The primary cilium can also regulate autophagic activity. These findings suggest that the relationship between autophagy and the primary cilia is bidirectional, and that both are important for maintaining the normal function of various organs.
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Affiliation(s)
- Yasuhiro Yamamoto
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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22
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A 3D Renal Proximal Tubule on Chip Model Phenocopies Lowe Syndrome and Dent II Disease Tubulopathy. Int J Mol Sci 2021; 22:ijms22105361. [PMID: 34069732 PMCID: PMC8161077 DOI: 10.3390/ijms22105361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/28/2022] Open
Abstract
Lowe syndrome and Dent II disease are X-linked monogenetic diseases characterised by a renal reabsorption defect in the proximal tubules and caused by mutations in the OCRL gene, which codes for an inositol-5-phosphatase. The life expectancy of patients suffering from Lowe syndrome is largely reduced because of the development of chronic kidney disease and related complications. There is a need for physiological human in vitro models for Lowe syndrome/Dent II disease to study the underpinning disease mechanisms and to identify and characterise potential drugs and drug targets. Here, we describe a proximal tubule organ on chip model combining a 3D tubule architecture with fluid flow shear stress that phenocopies hallmarks of Lowe syndrome/Dent II disease. We demonstrate the high suitability of our in vitro model for drug target validation. Furthermore, using this model, we demonstrate that proximal tubule cells lacking OCRL expression upregulate markers typical for epithelial–mesenchymal transition (EMT), including the transcription factor SNAI2/Slug, and show increased collagen expression and deposition, which potentially contributes to interstitial fibrosis and disease progression as observed in Lowe syndrome and Dent II disease.
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23
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Wang B, He W, Prosseda PP, Li L, Kowal TJ, Alvarado JA, Wang Q, Hu Y, Sun Y. OCRL regulates lysosome positioning and mTORC1 activity through SSX2IP-mediated microtubule anchoring. EMBO Rep 2021; 22:e52173. [PMID: 33987909 DOI: 10.15252/embr.202052173] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/18/2021] [Accepted: 04/08/2021] [Indexed: 11/09/2022] Open
Abstract
Lysosomal positioning and mTOR (mammalian target of rapamycin) signaling coordinate cellular responses to nutrient levels. Inadequate nutrient sensing can result in growth delays, a hallmark of Lowe syndrome. OCRL mutations cause Lowe syndrome, but the role of OCRL in nutrient sensing is unknown. Here, we show that OCRL is localized to the centrosome by its ASH domain and that it recruits microtubule-anchoring factor SSX2IP to the centrosome, which is important in the formation of the microtubule-organizing center. Deficiency of OCRL in human and mouse cells results in loss of microtubule-organizing centers and impaired microtubule-based lysosome movement, which in turn leads to mTORC1 inactivation and abnormal nutrient sensing. Centrosome-targeted PACT-SSX2IP can restore microtubule anchoring and mTOR activity. Importantly, boosting the activity of mTORC1 restores the nutrient sensing ability of Lowe patients' cells. Our findings highlight mTORC1 as a novel therapeutic target for Lowe syndrome.
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Affiliation(s)
- Biao Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Wei He
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Philipp P Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Tia J Kowal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Jorge A Alvarado
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Qing Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, USA.,Palo Alto Veterans Administration, Palo Alto, CA, USA
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24
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Functional compartmentalization of photoreceptor neurons. Pflugers Arch 2021; 473:1493-1516. [PMID: 33880652 DOI: 10.1007/s00424-021-02558-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 12/16/2022]
Abstract
Retinal photoreceptors are neurons that convert dynamically changing patterns of light into electrical signals that are processed by retinal interneurons and ultimately transmitted to vision centers in the brain. They represent the essential first step in seeing without which the remainder of the visual system is rendered moot. To support this role, the major functions of photoreceptors are segregated into three main specialized compartments-the outer segment, the inner segment, and the pre-synaptic terminal. This compartmentalization is crucial for photoreceptor function-disruption leads to devastating blinding diseases for which therapies remain elusive. In this review, we examine the current understanding of the molecular and physical mechanisms underlying photoreceptor functional compartmentalization and highlight areas where significant knowledge gaps remain.
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25
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Barnes CL, Malhotra H, Calvert PD. Compartmentalization of Photoreceptor Sensory Cilia. Front Cell Dev Biol 2021; 9:636737. [PMID: 33614665 PMCID: PMC7889997 DOI: 10.3389/fcell.2021.636737] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/07/2021] [Indexed: 12/12/2022] Open
Abstract
Functional compartmentalization of cells is a universal strategy for segregating processes that require specific components, undergo regulation by modulating concentrations of those components, or that would be detrimental to other processes. Primary cilia are hair-like organelles that project from the apical plasma membranes of epithelial cells where they serve as exclusive compartments for sensing physical and chemical signals in the environment. As such, molecules involved in signal transduction are enriched within cilia and regulating their ciliary concentrations allows adaptation to the environmental stimuli. The highly efficient organization of primary cilia has been co-opted by major sensory neurons, olfactory cells and the photoreceptor neurons that underlie vision. The mechanisms underlying compartmentalization of cilia are an area of intense current research. Recent findings have revealed similarities and differences in molecular mechanisms of ciliary protein enrichment and its regulation among primary cilia and sensory cilia. Here we discuss the physiological demands on photoreceptors that have driven their evolution into neurons that rely on a highly specialized cilium for signaling changes in light intensity. We explore what is known and what is not known about how that specialization appears to have driven unique mechanisms for photoreceptor protein and membrane compartmentalization.
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Affiliation(s)
| | | | - Peter D. Calvert
- Department of Ophthalmology and Visual Sciences, Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, United States
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26
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Ramadesikan S, Skiba L, Lee J, Madhivanan K, Sarkar D, De La Fuente A, Hanna CB, Terashi G, Hazbun T, Kihara D, Aguilar RC. Genotype & phenotype in Lowe Syndrome: specific OCRL1 patient mutations differentially impact cellular phenotypes. Hum Mol Genet 2021; 30:198-212. [PMID: 33517444 DOI: 10.1093/hmg/ddab025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/15/2020] [Accepted: 01/08/2021] [Indexed: 12/26/2022] Open
Abstract
Lowe Syndrome (LS) is a lethal genetic disorder caused by mutations in the OCRL1 gene which encodes the lipid 5' phosphatase Ocrl1. Patients exhibit a characteristic triad of symptoms including eye, brain and kidney abnormalities with renal failure as the most common cause of premature death. Over 200 OCRL1 mutations have been identified in LS, but their specific impact on cellular processes is unknown. Despite observations of heterogeneity in patient symptom severity, there is little understanding of the correlation between genotype and its impact on phenotype. Here, we show that different mutations had diverse effects on protein localization and on triggering LS cellular phenotypes. In addition, some mutations affecting specific domains imparted unique characteristics to the resulting mutated protein. We also propose that certain mutations conformationally affect the 5'-phosphatase domain of the protein, resulting in loss of enzymatic activity and causing common and specific phenotypes (a conformational disease scenario). This study is the first to show the differential effect of patient 5'-phosphatase mutations on cellular phenotypes and introduces a conformational disease component in LS. This work provides a framework that explains symptom heterogeneity and can help stratify patients as well as to produce a more accurate prognosis depending on the nature and location of the mutation within the OCRL1 gene.
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Affiliation(s)
- Swetha Ramadesikan
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Lisette Skiba
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jennifer Lee
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | | - Daipayan Sarkar
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | | - Claudia B Hanna
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Genki Terashi
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Tony Hazbun
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Daisuke Kihara
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.,Department of Computer Science, Purdue University, West Lafayette, IN 47907, USA
| | - R Claudio Aguilar
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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27
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Yarishkin O, Phuong TTT, Baumann JM, De Ieso ML, Vazquez-Chona F, Rudzitis CN, Sundberg C, Lakk M, Stamer WD, Križaj D. Piezo1 channels mediate trabecular meshwork mechanotransduction and promote aqueous fluid outflow. J Physiol 2021; 599:571-592. [PMID: 33226641 PMCID: PMC7849624 DOI: 10.1113/jp281011] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 01/13/2023] Open
Abstract
KEY POINTS Trabecular meshwork (TM) is a highly mechanosensitive tissue in the eye that regulates intraocular pressure through the control of aqueous humour drainage. Its dysfunction underlies the progression of glaucoma but neither the mechanisms through which TM cells sense pressure nor their role in aqueous humour outflow are understood at the molecular level. We identified the Piezo1 channel as a key TM transducer of tensile stretch, shear flow and pressure. Its activation resulted in intracellular signals that altered organization of the cytoskeleton and cell-extracellular matrix contacts and modulated the trabecular component of aqueous outflow whereas another channel, TRPV4, mediated a delayed mechanoresponse. This study helps elucidate basic mechanotransduction properties that may contribute to intraocular pressure regulation in the vertebrate eye. ABSTRACT Chronic elevations in intraocular pressure (IOP) can cause blindness by compromising the function of trabecular meshwork (TM) cells in the anterior eye, but how these cells sense and transduce pressure stimuli is poorly understood. Here, we demonstrate functional expression of two mechanically activated channels in human TM cells. Pressure-induced cell stretch evoked a rapid increase in transmembrane current that was inhibited by antagonists of the mechanogated channel Piezo1, Ruthenium Red and GsMTx4, and attenuated in Piezo1-deficient cells. The majority of TM cells exhibited a delayed stretch-activated current that was mediated independently of Piezo1 by TRPV4 (transient receptor potential cation channel, subfamily V, member 4) channels. Piezo1 functions as the principal TM transducer of physiological levels of shear stress, with both shear and the Piezo1 agonist Yoda1 increasing the number of focal cell-matrix contacts. Analysis of TM-dependent fluid drainage from the anterior eye showed significant inhibition by GsMTx4. Collectively, these results suggest that TM mechanosensitivity utilizes kinetically, regulatory and functionally distinct pressure transducers to inform the cells about force-sensing contexts. Piezo1-dependent control of shear flow sensing, calcium homeostasis, cytoskeletal dynamics and pressure-dependent outflow suggests potential for a novel therapeutic target in treating glaucoma.
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Affiliation(s)
- Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Jackson M Baumann
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - Michael L De Ieso
- Duke Eye Center, Duke University School of Medicine, Durham, NC, USA
| | - Felix Vazquez-Chona
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Christopher N Rudzitis
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Chad Sundberg
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - W Daniel Stamer
- Duke Eye Center, Duke University School of Medicine, Durham, NC, USA
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
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28
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Tong SJ, Wall AA, Hung Y, Luo L, Stow JL. Guanine nucleotide exchange factors activate Rab8a for Toll-like receptor signalling. Small GTPases 2021; 12:27-43. [PMID: 30843452 PMCID: PMC7781844 DOI: 10.1080/21541248.2019.1587278] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 02/08/2019] [Accepted: 02/20/2019] [Indexed: 02/03/2023] Open
Abstract
Macrophages are important immune sentinels that detect and clear pathogens and initiate inflammatory responses through the activation of surface receptors, including Toll-like receptors (TLRs). Activated TLRs employ complex cellular trafficking and signalling pathways to initiate transcription for inflammatory cytokine programs. We have previously shown that Rab8a is activated by multiple TLRs and regulates downstream Akt/mTOR signalling by recruiting the effector PI3Kγ, but the guanine nucleotide exchange factors (GEF) canonically required for Rab8a activation in TLR pathways is not known. Using GST affinity pull-downs and mass spectrometry analysis, we identified a Rab8 specific GEF, GRAB, as a Rab8a binding partner in LPS-activated macrophages. Co-immunoprecipitation and fluorescence microscopy showed that both GRAB and a structurally similar GEF, Rabin8, undergo LPS-inducible binding to Rab8a and are localised on cell surface ruffles and macropinosomes where they coincide with sites of Rab8a mediated signalling. Rab nucleotide activation assays with CRISPR-Cas9 mediated knock-out (KO) cell lines of GRAB, Rabin8 and double KOs showed that both GEFs contribute to TLR4 induced Rab8a GTP loading, but not membrane recruitment. In addition, measurement of signalling profiles and live cell imaging with the double KOs revealed that either GEF is individually sufficient to mediate PI3Kγ-dependent Akt/mTOR signalling at macropinosomes during TLR4-driven inflammation, suggesting a redundant relationship between these proteins. Thus, both GRAB and Rabin8 are revealed as key positive regulators of Rab8a nucleotide exchange for TLR signalling and inflammatory programs. These GEFs may be useful as potential targets for manipulating inflammation. Abbreviations: TLR: Toll-like Receptor; OCRL: oculocerebrorenal syndrome of Lowe protein; PI3Kγ: phosphoinositol-3-kinase gamma; LPS: lipopolysaccharide; GEF: guanine nucleotide exchange factor; GST: glutathione S-transferases; BMMs: bone marrow derived macrophages; PH: pleckstrin homology; GAP: GTPase activating protein; ABCA1: ATP binding cassette subfamily A member 1; GDI: GDP dissociation inhibitor; LRP1: low density lipoprotein receptor-related protein 1.
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Affiliation(s)
- Samuel J. Tong
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland, Brisbane, QLD, Australia
| | - Adam A. Wall
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland, Brisbane, QLD, Australia
| | - Yu Hung
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland, Brisbane, QLD, Australia
| | - Lin Luo
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland, Brisbane, QLD, Australia
| | - Jennifer L. Stow
- Institute for Molecular Bioscience (IMB) and IMB Centre for Inflammation and Disease Research (CIDR), The University of Queensland, Brisbane, QLD, Australia
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29
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Brücker L, Kretschmer V, May-Simera HL. The entangled relationship between cilia and actin. Int J Biochem Cell Biol 2020; 129:105877. [PMID: 33166678 DOI: 10.1016/j.biocel.2020.105877] [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: 08/25/2020] [Revised: 10/23/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022]
Abstract
Primary cilia are microtubule-based sensory cell organelles that are vital for tissue and organ development. They act as an antenna, receiving and transducing signals, enabling communication between cells. Defects in ciliogenesis result in severe genetic disorders collectively termed ciliopathies. In recent years, the importance of the direct and indirect involvement of actin regulators in ciliogenesis came into focus as it was shown that F-actin polymerisation impacts ciliation. The ciliary basal body was further identified as both a microtubule and actin organising centre. In the current review, we summarize recent studies on F-actin in and around primary cilia, focusing on different actin regulators and their effect on ciliogenesis, from the initial steps of basal body positioning and regulation of ciliary assembly and disassembly. Since primary cilia are also involved in several intracellular signalling pathways such as planar cell polarity (PCP), subsequently affecting actin rearrangements, the multiple effectors of this pathway are highlighted in more detail with a focus on the feedback loops connecting actin networks and cilia proteins. Finally, we elucidate the role of actin regulators in the development of ciliopathy symptoms and cancer.
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Affiliation(s)
- Lena Brücker
- Cilia Cell Biology, Institute of Molecular Physiology, Johannes-Gutenberg University, Mainz, Germany
| | - Viola Kretschmer
- Cilia Cell Biology, Institute of Molecular Physiology, Johannes-Gutenberg University, Mainz, Germany
| | - Helen Louise May-Simera
- Cilia Cell Biology, Institute of Molecular Physiology, Johannes-Gutenberg University, Mainz, Germany.
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30
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Conduit SE, Vanhaesebroeck B. Phosphoinositide lipids in primary cilia biology. Biochem J 2020; 477:3541-3565. [PMID: 32970140 PMCID: PMC7518857 DOI: 10.1042/bcj20200277] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/30/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022]
Abstract
Primary cilia are solitary signalling organelles projecting from the surface of most cell types. Although the ciliary membrane is continuous with the plasma membrane it exhibits a unique phospholipid composition, a feature essential for normal cilia formation and function. Recent studies have illustrated that distinct phosphoinositide lipid species localise to specific cilia subdomains, and have begun to build a 'phosphoinositide map' of the cilium. The abundance and localisation of phosphoinositides are tightly regulated by the opposing actions of lipid kinases and lipid phosphatases that have also been recently discovered at cilia. The critical role of phosphoinositides in cilia biology is highlighted by the devastating consequences of genetic defects in cilia-associated phosphoinositide regulatory enzymes leading to ciliopathy phenotypes in humans and experimental mouse and zebrafish models. Here we provide a general introduction to primary cilia and the roles phosphoinositides play in cilia biology. In addition to increasing our understanding of fundamental cilia biology, this rapidly expanding field may inform novel approaches to treat ciliopathy syndromes caused by deregulated phosphoinositide metabolism.
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Affiliation(s)
- Sarah E. Conduit
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
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31
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Alvarado JA, Dhande OS, Prosseda PP, Kowal TJ, Ning K, Jabbehdari S, Hu Y, Sun Y. Developmental distribution of primary cilia in the retinofugal visual pathway. J Comp Neurol 2020; 529:1442-1455. [PMID: 32939774 DOI: 10.1002/cne.25029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/21/2020] [Accepted: 08/17/2020] [Indexed: 12/21/2022]
Abstract
The mammalian visual system is composed of circuitry connecting sensory input from the retina to the processing core of the visual cortex. The two main retinorecipient brain targets, the superior colliculus (SC) and dorsal lateral geniculate nucleus (dLGN), bridge retinal input and visual output. The primary cilium is a conserved organelle increasingly viewed as a critical sensor for the regulation of developmental and homeostatic pathways in most mammalian cell types. Moreover, cilia have been described as crucial for neurogenesis, neuronal maturation, and survival in the cortex and retina. However, cilia in the visual relay center remain to be fully described. In this study, we characterized the ciliation profile of the SC and dLGN and found that the overall number of ciliated cells declined during development. Interestingly, shorter ciliated cells in both regions were identified as neurons, whose numbers remained stable over time, suggesting that cilia retention is a critical feature for optimal neuronal function in SC and dLGN. Our study suggests that primary cilia are important for neuronal maturation and function in cells of the SC and dLGN.
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Affiliation(s)
- Jorge A Alvarado
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Onkar S Dhande
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Philipp P Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Tia J Kowal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Sayena Jabbehdari
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA.,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA.,Wu Tsai Neurosciences Institute, Stanford University School of Medicine, Stanford, California, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California, USA.,Wu Tsai Neurosciences Institute, Stanford University School of Medicine, Stanford, California, USA.,Palo Alto Veterans Administration, Palo Alto, California, USA
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32
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Nechipurenko IV. The Enigmatic Role of Lipids in Cilia Signaling. Front Cell Dev Biol 2020; 8:777. [PMID: 32850869 PMCID: PMC7431879 DOI: 10.3389/fcell.2020.00777] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/24/2020] [Indexed: 12/21/2022] Open
Abstract
Primary cilia are specialized cellular structures that project from the surface of most cell types in metazoans and mediate transduction of major signaling pathways. The ciliary membrane is contiguous with the plasma membrane, yet it exhibits distinct protein and lipid composition, which is essential for ciliary function. Diffusion barriers at the base of a cilium are responsible for establishing unique molecular composition of this organelle. Although considerable progress has been made in identifying mechanisms of ciliary protein trafficking in and out of cilia, it remains largely unknown how the distinct lipid identity of the ciliary membrane is achieved. In this mini review, I summarize recent developments in characterizing lipid composition and organization of the ciliary membrane and discuss the emerging roles of lipids in modulating activity of ciliary signaling components including ion channels and G protein-coupled receptors.
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Affiliation(s)
- Inna V. Nechipurenko
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
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33
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Ates KM, Wang T, Moreland T, Veeranan-Karmegam R, Ma M, Jeter C, Anand P, Wenzel W, Kim HG, Wolfe LA, Stephen J, Adams DR, Markello T, Tifft CJ, Settlage R, Gahl WA, Gonsalvez GB, Malicdan MC, Flanagan-Steet H, Pan YA. Deficiency in the endocytic adaptor proteins PHETA1/2 impairs renal and craniofacial development. Dis Model Mech 2020; 13:dmm041913. [PMID: 32152089 PMCID: PMC7272357 DOI: 10.1242/dmm.041913] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/27/2020] [Indexed: 12/20/2022] Open
Abstract
A critical barrier in the treatment of endosomal and lysosomal diseases is the lack of understanding of the in vivo functions of the putative causative genes. We addressed this by investigating a key pair of endocytic adaptor proteins, PH domain-containing endocytic trafficking adaptor 1 and 2 (PHETA1/2; also known as FAM109A/B, Ses1/2, IPIP27A/B), which interact with the protein product of OCRL, the causative gene for Lowe syndrome. Here, we conducted the first study of PHETA1/2 in vivo, utilizing the zebrafish system. We found that impairment of both zebrafish orthologs, pheta1 and pheta2, disrupted endocytosis and ciliogenesis in renal tissues. In addition, pheta1/2 mutant animals exhibited reduced jaw size and delayed chondrocyte differentiation, indicating a role in craniofacial development. Deficiency of pheta1/2 resulted in dysregulation of cathepsin K, which led to an increased abundance of type II collagen in craniofacial cartilages, a marker of immature cartilage extracellular matrix. Cathepsin K inhibition rescued the craniofacial phenotypes in the pheta1/2 double mutants. The abnormal renal and craniofacial phenotypes in the pheta1/2 mutant animals were consistent with the clinical presentation of a patient with a de novo arginine (R) to cysteine (C) variant (R6C) of PHETA1. Expressing the patient-specific variant in zebrafish exacerbated craniofacial deficits, suggesting that the R6C allele acts in a dominant-negative manner. Together, these results provide insights into the in vivo roles of PHETA1/2 and suggest that the R6C variant is contributory to the pathogenesis of disease in the patient.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Kristin M Ates
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA 24016, USA
| | - Tong Wang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Trevor Moreland
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | | | - Manxiu Ma
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA 24016, USA
| | - Chelsi Jeter
- JC Self Research Institute, Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Priya Anand
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Wolfgang Wenzel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Hyung-Goo Kim
- Neurological Disorder Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Lynne A Wolfe
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joshi Stephen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - David R Adams
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas Markello
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cynthia J Tifft
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert Settlage
- Advanced Research Computing Unit, Division of Information Technology, Virginia Tech, Blacksburg, VA 24060, USA
| | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
- National Institutes of Health Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Graydon B Gonsalvez
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - May Christine Malicdan
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
- National Institutes of Health Undiagnosed Diseases Program, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Y Albert Pan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24060, USA
- Department of Psychiatry and Behavioral Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
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34
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Liu H, Barnes J, Pedrosa E, Herman NS, Salas F, Wang P, Zheng D, Lachman HM. Transcriptome analysis of neural progenitor cells derived from Lowe syndrome induced pluripotent stem cells: identification of candidate genes for the neurodevelopmental and eye manifestations. J Neurodev Disord 2020; 12:14. [PMID: 32393163 PMCID: PMC7212686 DOI: 10.1186/s11689-020-09317-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 04/28/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Lowe syndrome (LS) is caused by loss-of-function mutations in the X-linked gene OCRL, which codes for an inositol polyphosphate 5-phosphatase that plays a key role in endosome recycling, clathrin-coated pit formation, and actin polymerization. It is characterized by congenital cataracts, intellectual and developmental disability, and renal proximal tubular dysfunction. Patients are also at high risk for developing glaucoma and seizures. We recently developed induced pluripotent stem cell (iPSC) lines from three patients with LS who have hypomorphic variants affecting the 3' end of the gene, and their neurotypical brothers to serve as controls. METHODS In this study, we used RNA sequencing (RNA-seq) to obtain transcriptome profiles in LS and control neural progenitor cells (NPCs). RESULTS In a comparison of the patient and control NPCs (n = 3), we found 16 differentially expressed genes (DEGs) at the multiple test adjusted p value (padj) < 0.1, with nine at padj < 0.05. Using nominal p value < 0.05, 319 DEGs were detected. The relatively small number of DEGs could be due to the fact that OCRL is not a transcription factor per se, although it could have secondary effects on gene expression through several different mechanisms. Although the number of DEGs passing multiple test correction was small, those that were found are quite consistent with some of the known molecular effects of OCRL protein, and the clinical manifestations of LS. Furthermore, using gene set enrichment analysis (GSEA), we found that genes increased expression in the patient NPCs showed enrichments of several gene ontology (GO) terms (false discovery rate < 0.25): telencephalon development, pallium development, NPC proliferation, and cortex development, which are consistent with a condition characterized by intellectual disabilities and psychiatric manifestations. In addition, a significant enrichment among the nominal DEGs for genes implicated in autism spectrum disorder (ASD) was found (e.g., AFF2, DNER, DPP6, DPP10, RELN, CACNA1C), as well as several that are strong candidate genes for the development of eye problems found in LS, including glaucoma. The most notable example is EFEMP1, a well-known candidate gene for glaucoma and other eye pathologies. CONCLUSION Overall, the RNA-seq findings present several candidate genes that could help explain the underlying basis for the neurodevelopmental and eye problems seen in boys with LS.
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Affiliation(s)
- Hequn Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jesse Barnes
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Erika Pedrosa
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Nathaniel S. Herman
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Franklin Salas
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Ping Wang
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Deyou Zheng
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Neurology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Herbert M. Lachman
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
- Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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Prosseda PP, Alvarado JA, Wang B, Kowal TJ, Ning K, Stamer WD, Hu Y, Sun Y. Optogenetic stimulation of phosphoinositides reveals a critical role of primary cilia in eye pressure regulation. SCIENCE ADVANCES 2020; 6:eaay8699. [PMID: 32494665 PMCID: PMC7190330 DOI: 10.1126/sciadv.aay8699] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/11/2020] [Indexed: 05/10/2023]
Abstract
Glaucoma is a group of progressive optic neuropathies that cause irreversible vision loss. Although elevated intraocular pressure (IOP) is associated with the development and progression of glaucoma, the mechanisms for its regulation are not well understood. Here, we have designed CIBN/CRY2-based optogenetic constructs to study phosphoinositide regulation within distinct subcellular compartments. We show that stimulation of CRY2-OCRL, an inositol 5-phosphatase, increases aqueous humor outflow and lowers IOP in vivo, which is caused by a calcium-dependent actin rearrangement of the trabecular meshwork cells. Phosphoinositide stimulation also rescues defective aqueous outflow and IOP in a Lowe syndrome mouse model but not in IFT88fl/fl mice that lack functional cilia. Thus, our study is the first to use optogenetics to regulate eye pressure and demonstrate that tight regulation of phosphoinositides is critical for aqueous humor homeostasis in both normal and diseased eyes.
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Affiliation(s)
- Philipp P. Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
| | - Jorge A. Alvarado
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
| | - Biao Wang
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
| | - Tia J. Kowal
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
| | - Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
| | - W. Daniel Stamer
- Duke Eye Center, Department of Ophthalmology, Duke University, Durham, NC 27710, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, 1651 Page Mill Road, Rm 2220, Palo Alto, CA 94305, USA
- Palo Alto Veterans Administration, Palo Alto, CA 94304, USA
- Corresponding author.
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36
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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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Acosta-Tapia N, Galindo JF, Baldiris R. Insights into the Effect of Lowe Syndrome-Causing Mutation p.Asn591Lys of OCRL-1 through Protein-Protein Interaction Networks and Molecular Dynamics Simulations. J Chem Inf Model 2020; 60:1019-1027. [PMID: 31967472 DOI: 10.1021/acs.jcim.9b01077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inositol polyphosphate 5-phosphatase (OCRL-1) participates in the regulation of multiple cellular processes, through the conversion of phosphatidylinositol 4,5-phosphate to phosphatidylinositol 4-phosphate. Mutations in this protein are related to Lowe syndrome (LS) and Dent-2 disease. In this study, the impact of Lowe syndrome mutations on the interactions of OCRL-1 with other proteins was evaluated through bioinformatic and computational approaches. In the functional analysis of the interaction network of the proteins, we found that the terms of gene ontology (GO) of greater significance were related to the intracellular transport of proteins, the signal transduction mediated by small G proteins and vesicles associated with the Golgi apparatus. From the proteins present in the GO terms of greater significance Rab8a was selected because its interaction facilitates the intracellular distribution of OCRL-1. The mutation p.Asn591Lys, present in the interaction domain of OCRL-1 and Rab8a, was studied using molecular dynamics. The molecular dynamics analysis showed that the presence of this mutation causes changes in the positional fluctuations of the amino acids and affects the flexibility of the protein making the interaction with Rab8a weaker. Rab proteins establish some specific interactions, which are important for the intracellular localization of OCRL-1; therefore, our findings suggest that the phenotype observed in patients with LS, in this case, is due to the destabilizing effect of p.Asn591Lys affecting the localization of OCRL-1 and indirectly its 5-phosphatase activity in the Golgi apparatus, endosomes, and cilia.
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Affiliation(s)
- Natali Acosta-Tapia
- Programa de Biologı́a, Facultad de Ciencias Exactas y Naturales , Universidad de Cartagena , Cartagena de Indias , Colombia.,Grupo de Investigación CIPTEC, Facultad de Ingenierı́a , Fundación Universitaria Tecnológico Comfenalco , Cartagena de Indias 130015 , Colombia
| | - Johan Fabian Galindo
- Departamento de Quı́mica , Universidad Nacional de Colombia , Bogotá 111321 , Colombia
| | - Rosa Baldiris
- Programa de Biologı́a, Facultad de Ciencias Exactas y Naturales , Universidad de Cartagena , Cartagena de Indias , Colombia.,Grupo de Investigación CIPTEC, Facultad de Ingenierı́a , Fundación Universitaria Tecnológico Comfenalco , Cartagena de Indias 130015 , Colombia
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38
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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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Shivanna M, Anand M, Chakrabarti S, Khanna H. Ocular Ciliopathies: Genetic and Mechanistic Insights into Developing Therapies. Curr Med Chem 2019; 26:3120-3131. [PMID: 30221600 DOI: 10.2174/0929867325666180917102557] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/21/2018] [Accepted: 09/05/2018] [Indexed: 12/12/2022]
Abstract
Developing suitable medicines for genetic diseases requires a detailed understanding of not only the pathways that cause the disease, but also the identification of the genetic components involved in disease manifestation. This article focuses on the complexities associated with ocular ciliopathies - a class of debilitating disorders of the eye caused by ciliary dysfunction. Ciliated cell types have been identified in both the anterior and posterior segments of the eye. Photoreceptors (rods and cones) are the most studied ciliated neurons in the retina, which is located in the posterior eye. The photoreceptors contain a specialized lightsensing outer segment, or cilium. Any defects in the development or maintenance of the outer segment can result in severe retinal ciliopathies, such as retinitis pigmentosa and Leber congenital amaurosis. A role of cilia in the cell types involved in regulating aqueous fluid outflow in the anterior segment of the eye has also been recognized. Defects in these cell types are frequently associated with some forms of glaucoma. Here, we will discuss the significance of understanding the genetic heterogeneity and the pathogenesis of ocular ciliopathies to develop suitable treatment strategies for these blinding disorders.
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Affiliation(s)
- Mahesh Shivanna
- School of Optometry, Massachusetts College of Pharmacy and Health Sciences University, Worcester, MA, United States
| | - Manisha Anand
- UMASS Medical School, Worcester, MA 01605, United States
| | | | - Hemant Khanna
- UMASS Medical School, Worcester, MA 01605, United States
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40
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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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41
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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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Luscher A, Fröhlich F, Barisch C, Littlewood C, Metcalfe J, Leuba F, Palma A, Pirruccello M, Cesareni G, Stagi M, Walther TC, Soldati T, De Camilli P, Swan LE. Lowe syndrome-linked endocytic adaptors direct membrane cycling kinetics with OCRL in Dictyostelium discoideum. Mol Biol Cell 2019; 30:2268-2282. [PMID: 31216233 PMCID: PMC6743453 DOI: 10.1091/mbc.e18-08-0510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mutations of the inositol 5-phosphatase OCRL cause Lowe syndrome (LS), characterized by congenital cataract, low IQ, and defective kidney proximal tubule resorption. A key subset of LS mutants abolishes OCRL’s interactions with endocytic adaptors containing F&H peptide motifs. Converging unbiased methods examining human peptides and the unicellular phagocytic organism Dictyostelium discoideum reveal that, like OCRL, the Dictyostelium OCRL orthologue Dd5P4 binds two proteins closely related to the F&H proteins APPL1 and Ses1/2 (also referred to as IPIP27A/B). In addition, a novel conserved F&H interactor was identified, GxcU (in Dictyostelium) and the Cdc42-GEF FGD1-related F-actin binding protein (Frabin) (in human cells). Examining these proteins in D. discoideum, we find that, like OCRL, Dd5P4 acts at well-conserved and physically distinct endocytic stations. Dd5P4 functions in coordination with F&H proteins to control membrane deformation at multiple stages of endocytosis and suppresses GxcU-mediated activity during fluid-phase micropinocytosis. We also reveal that OCRL/Dd5P4 acts at the contractile vacuole, an exocytic osmoregulatory organelle. We propose F&H peptide-containing proteins may be key modifiers of LS phenotypes.
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Affiliation(s)
- Alexandre Luscher
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Florian Fröhlich
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Department of Genetics and Complex Diseases, Harvard School of Public Health, and Department of Cell Biology, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115
| | - Caroline Barisch
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Clare Littlewood
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Joe Metcalfe
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Florence Leuba
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Anita Palma
- Department of Biology, University of Rome, 00133 Rome, Italy
| | - Michelle Pirruccello
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510
| | - Gianni Cesareni
- Department of Biology, University of Rome, 00133 Rome, Italy
| | - Massimiliano Stagi
- Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
| | - Tobias C Walther
- Department of Genetics and Complex Diseases, Harvard School of Public Health, and Department of Cell Biology, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, 1211 Geneva-4, Switzerland
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510.,Department of Neuroscience and Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510
| | - Laura E Swan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.,Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510.,Department of Cellular and Molecular Physiology, University of Liverpool, L69 3BX Liverpool, United Kingdom
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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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Tiosano D, Baris HN, Chen A, Hitzert MM, Schueler M, Gulluni F, Wiesener A, Bergua A, Mory A, Copeland B, Gleeson JG, Rump P, van Meer H, Sival DA, Haucke V, Kriwinsky J, Knaup KX, Reis A, Hauer NN, Hirsch E, Roepman R, Pfundt R, Thiel CT, Wiesener MS, Aslanyan MG, Buchner DA. Mutations in PIK3C2A cause syndromic short stature, skeletal abnormalities, and cataracts associated with ciliary dysfunction. PLoS Genet 2019; 15:e1008088. [PMID: 31034465 PMCID: PMC6508738 DOI: 10.1371/journal.pgen.1008088] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 05/09/2019] [Accepted: 03/12/2019] [Indexed: 02/07/2023] Open
Abstract
PIK3C2A is a class II member of the phosphoinositide 3-kinase (PI3K) family that catalyzes the phosphorylation of phosphatidylinositol (PI) into PI(3)P and the phosphorylation of PI(4)P into PI(3,4)P2. At the cellular level, PIK3C2A is critical for the formation of cilia and for receptor mediated endocytosis, among other biological functions. We identified homozygous loss-of-function mutations in PIK3C2A in children from three independent consanguineous families with short stature, coarse facial features, cataracts with secondary glaucoma, multiple skeletal abnormalities, neurological manifestations, among other findings. Cellular studies of patient-derived fibroblasts found that they lacked PIK3C2A protein, had impaired cilia formation and function, and demonstrated reduced proliferative capacity. Collectively, the genetic and molecular data implicate mutations in PIK3C2A in a new Mendelian disorder of PI metabolism, thereby shedding light on the critical role of a class II PI3K in growth, vision, skeletal formation and neurological development. In particular, the considerable phenotypic overlap, yet distinct features, between this syndrome and Lowe’s syndrome, which is caused by mutations in the PI-5-phosphatase OCRL, highlight the key role of PI metabolizing enzymes in specific developmental processes and demonstrate the unique non-redundant functions of each enzyme. This discovery expands what is known about disorders of PI metabolism and helps unravel the role of PIK3C2A and class II PI3Ks in health and disease. Identifying the genetic basis of rare disorders can provide insight into gene function, susceptibility to disease, guide the development of new therapeutics, improve opportunities for genetic counseling, and help clinicians evaluate and potentially treat complicated clinical presentations. However, it is estimated that the genetic basis of approximately one-half of all rare genetic disorders remains unknown. We describe one such rare disorder based on genetic and clinical evaluations of individuals from 3 unrelated consanguineous families with a similar constellation of features including short stature, coarse facial features, cataracts with secondary glaucoma, multiple skeletal abnormalities, neurological manifestations including stroke, among other findings. We discovered that these features were due to deficiency of the PIK3C2A enzyme. PIK3C2A is a class II member of the phosphoinositide 3-kinase (PI3K) family that catalyzes the phosphorylation of the lipids phosphatidylinositol (PI) into PI(3)P and the phosphorylation of PI(4)P into PI(3,4)P2 that are essential for a variety of cellular processes including cilia formation and vesicle trafficking. This syndrome is the first monogenic disorder caused by mutations in a class II PI3K family member and thus sheds new light on their role in human development.
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Affiliation(s)
- Dov Tiosano
- Division of Pediatric Endocrinology, Ruth Children's Hospital, Rambam Medical Center, Haifa, Israel
- Rappaport Family Faculty of Medicine, Technion—Israel Institute of Technology, Haifa, Israel
| | - Hagit N. Baris
- Rappaport Family Faculty of Medicine, Technion—Israel Institute of Technology, Haifa, Israel
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | - Anlu Chen
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Marrit M. Hitzert
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Markus Schueler
- Department of Nephrology and Hypertension, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Federico Gulluni
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, Torino, Italy
| | - Antje Wiesener
- Institute of Human Genetics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Antonio Bergua
- Department of Ophthalmology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Adi Mory
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | - Brett Copeland
- Laboratory of Pediatric Brain Diseases, Rockefeller University, New York, New York, United States of America
| | - Joseph G. Gleeson
- Laboratory of Pediatric Brain Diseases, Rockefeller University, New York, New York, United States of America
- Department of Neurosciences, University of California, San Diego, La Jolla, California, United States of America
| | - Patrick Rump
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Hester van Meer
- Department of Pediatrics, Beatrix Children’s Hospital, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Deborah A. Sival
- Department of Pediatrics, Beatrix Children’s Hospital, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Volker Haucke
- Leibniz-Institut für Molekulare Pharmakologie, Berlin Faculty of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Josh Kriwinsky
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karl X. Knaup
- Department of Nephrology and Hypertension, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Nadine N. Hauer
- Institute of Human Genetics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Emilio Hirsch
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Turin, Torino, Italy
| | - Ronald Roepman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christian T. Thiel
- Institute of Human Genetics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Michael S. Wiesener
- Department of Nephrology and Hypertension, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Mariam G. Aslanyan
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - David A. Buchner
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
- Research Institute for Children’s Health, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Primary Cilium-Mediated Retinal Pigment Epithelium Maturation Is Disrupted in Ciliopathy Patient Cells. Cell Rep 2019; 22:189-205. [PMID: 29298421 PMCID: PMC6166245 DOI: 10.1016/j.celrep.2017.12.038] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/08/2017] [Accepted: 12/11/2017] [Indexed: 12/15/2022] Open
Abstract
Primary cilia are sensory organelles that protrude from the cell membrane. Defects in the primary cilium cause ciliopathy disorders, with retinal degeneration as a prominent phenotype. Here, we demonstrate that the retinal pigment epithelium (RPE), essential for photoreceptor development and function, requires a functional primary cilium for complete maturation and that RPE maturation defects in ciliopathies precede photoreceptor degeneration. Pharmacologically enhanced ciliogenesis in wild-type induced pluripotent stem cells (iPSC)-RPE leads to fully mature and functional cells. In contrast, ciliopathy patient-derived iPSC-RPE and iPSC-RPE with a knockdown of ciliary-trafficking protein remain immature, with defective apical processes, reduced functionality, and reduced adult-specific gene expression. Proteins of the primary cilium regulate RPE maturation by simultaneously suppressing canonical WNT and activating PKCδ pathways. A similar cilium-dependent maturation pathway exists in lung epithelium. Our results provide insights into ciliopathy-induced retinal degeneration, demonstrate a developmental role for primary cilia in epithelial maturation, and provide a method to mature iPSC epithelial cells for clinical applications. May-Simera et al. show that primary cilia regulate the maturation and polarization of human iPSC-RPE, mouse RPE, and human iPSC-lung epithelium through canonical WNT suppression and PKCδ activation. RPE cells derived from ciliopathy patients exhibit defective structure and function. These results provide insights into ciliopathy-induced retinal degeneration.
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Saito M, Sato T. [Current situation of researches on a sensor organelle, primary cilium, to understand the pathogenesis of ciliopathy]. Nihon Yakurigaku Zasshi 2019; 153:117-123. [PMID: 30867380 DOI: 10.1254/fpj.153.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Primary cilium is a membrane-protruding immotile sensory organelle. It had been supposed that the cilium was a static organelle for long periods. However, recent studies have uncovered that the cilium is dynamically organized organelle in a cell cycle-dependent manner; it is formed during G0/G1 phase and resorbed when the cells enter cell division cycle. Despite the primary cilium is very short and its surface area is extremely small, the cilium possesses a few kinds of G protein-coupled receptors, growth factor receptors and ion channels. Therefore, it can function as a signaling receptor for selective bioactive ligands and mechanical stresses. Dysregulation of the ciliary dynamics is linked with hereditary disorders, so called "ciliopathy", with clinical manifestations of microcephaly, polycystic kidney, situs inversus, polydactyly, and so on. No effective medical treatment for the ciliopathies has been available. Increasing evidences about the molecular mechanisms of ciliary dynamics and ciliary functions have revealed that enormous number of molecules regulate a cycle of ciliogenesis, cilium-derived signaling, ciliary resorption and elimination. However, it is a fact that research progress is far inferior to the full disclosure of the molecular mechanisms. Further studies are required to clarify the pathogenesis of the cilipathies. Moreover, efficient medical treatments are expected to be developed by pharmacological approaches.
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Affiliation(s)
- Masaki Saito
- Department of Molecular Pharmacology, Tohoku University School of Medicine
| | - Takeya Sato
- Department of Molecular Pharmacology, Tohoku University School of Medicine
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Abstract
Phosphoinositides (PIs) play pivotal roles in the regulation of many biological processes. The quality and quantity of PIs is regulated in time and space by the activity of PI kinases and PI phosphatases. The number of PI-metabolizing enzymes exceeds the number of PIs with, in many cases, more than one enzyme controlling the same biochemical step. This would suggest that the PI system has an intrinsic ability to buffer and compensate for the absence of a specific enzymatic activity. However, there are several examples of severe inherited human diseases caused by mutations in one of the PI enzymes, although other enzymes with the same activity are fully functional. The kidney depends strictly on PIs for physiological processes, such as cell polarization, filtration, solute reabsorption, and signal transduction. Indeed, alteration of the PI system in the kidney very often results in pathological conditions, both inherited and acquired. Most of the knowledge of the roles that PIs play in the kidney comes from the study of KO animal models for genes encoding PI enzymes and from the study of human genetic diseases, such as Lowe syndrome/Dent disease 2 and Joubert syndrome, caused by mutations in the genes encoding the PI phosphatases, OCRL and INPP5E, respectively.
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Affiliation(s)
- Leopoldo Staiano
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Maria Antonietta De Matteis
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy .,University of Naples Federico II, 80131 Naples, Italy
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48
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Hua K, Ferland RJ. Primary cilia proteins: ciliary and extraciliary sites and functions. Cell Mol Life Sci 2018; 75:1521-1540. [PMID: 29305615 PMCID: PMC5899021 DOI: 10.1007/s00018-017-2740-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 02/07/2023]
Abstract
Primary cilia are immotile organelles known for their roles in development and cell signaling. Defects in primary cilia result in a range of disorders named ciliopathies. Because this organelle can be found singularly on almost all cell types, its importance extends to most organ systems. As such, elucidating the importance of the primary cilium has attracted researchers from all biological disciplines. As the primary cilia field expands, caution is warranted in attributing biological defects solely to the function of this organelle, since many of these "ciliary" proteins are found at other sites in cells and likely have non-ciliary functions. Indeed, many, if not all, cilia proteins have locations and functions outside the primary cilium. Extraciliary functions are known to include cell cycle regulation, cytoskeletal regulation, and trafficking. Cilia proteins have been observed in the nucleus, at the Golgi apparatus, and even in immune synapses of T cells (interestingly, a non-ciliated cell). Given the abundance of extraciliary sites and functions, it can be difficult to definitively attribute an observed phenotype solely to defective cilia rather than to some defective extraciliary function or a combination of both. Thus, extraciliary sites and functions of cilia proteins need to be considered, as well as experimentally determined. Through such consideration, we will understand the true role of the primary cilium in disease as compared to other cellular processes' influences in mediating disease (or through a combination of both). Here, we review a compilation of known extraciliary sites and functions of "cilia" proteins as a means to demonstrate the potential non-ciliary roles for these proteins.
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Affiliation(s)
- Kiet Hua
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, 47 New Scotland Avenue, MC-136, Albany, NY, 12208, USA.
| | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, 47 New Scotland Avenue, MC-136, Albany, NY, 12208, USA.
- Department of Neurology, Albany Medical College, Albany, NY, 12208, USA.
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49
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Abstract
Cilia are microtubule-based organelles extending from a basal body at the surface of eukaryotic cells. Cilia regulate cell and fluid motility, sensation and developmental signaling, and ciliary defects cause human diseases (ciliopathies) affecting the formation and function of many tissues and organs. Over the past decade, various Rab and Rab-like membrane trafficking proteins have been shown to regulate cilia-related processes such as basal body maturation, ciliary axoneme extension, intraflagellar transport and ciliary signaling. In this review, we provide a comprehensive overview of Rab protein ciliary associations, drawing on findings from multiple model systems, including mammalian cell culture, mice, zebrafish, C. elegans, trypanosomes, and green algae. We also discuss several emerging mechanistic themes related to ciliary Rab cascades and functional redundancy.
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Affiliation(s)
- Oliver E Blacque
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
| | - Noemie Scheidel
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
| | - Stefanie Kuhns
- a School of Biomolecular and Biomedical Science , University College Dublin , Belfield, Dublin , Ireland
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50
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Phua SC, Nihongaki Y, Inoue T. Autonomy declared by primary cilia through compartmentalization of membrane phosphoinositides. Curr Opin Cell Biol 2018; 50:72-78. [PMID: 29477020 DOI: 10.1016/j.ceb.2018.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/22/2018] [Indexed: 12/16/2022]
Abstract
The primary cilium is a cell surface projection from plasma membrane which transduces external stimuli to diverse signaling pathways. To function as an independent signaling organelle, the molecular composition of the ciliary membrane has to be distinct from that of the plasma membrane. Here, we review recent findings which have deepened our understanding of the unique yet dynamic phosphoinositide profile found in the primary cilia.
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Affiliation(s)
- Siew Cheng Phua
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore 138667, Singapore
| | - Yuta Nihongaki
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Takanari Inoue
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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