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Macarelli V, Harding EC, Gershlick DC, Merkle FT. A Short Sequence Targets Transmembrane Proteins to Primary Cilia. Cells 2024; 13:1156. [PMID: 38995007 PMCID: PMC11240719 DOI: 10.3390/cells13131156] [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: 05/11/2024] [Revised: 06/26/2024] [Accepted: 07/02/2024] [Indexed: 07/13/2024] Open
Abstract
Primary cilia are finger-like sensory organelles that extend from the bodies of most cell types and have a distinct lipid and protein composition from the plasma membrane. This partitioning is maintained by a diffusion barrier that restricts the entry of non-ciliary proteins, and allows the selective entry of proteins harboring a ciliary targeting sequence (CTS). However, CTSs are not stereotyped and previously reported sequences are insufficient to drive efficient ciliary localisation across diverse cell types. Here, we describe a short peptide sequence that efficiently targets transmembrane proteins to primary cilia in all tested cell types, including human neurons. We generate human-induced pluripotent stem cell (hiPSC) lines stably expressing a transmembrane construct bearing an extracellular HaloTag and intracellular fluorescent protein, which enables the bright, specific labeling of primary cilia in neurons and other cell types to facilitate studies of cilia in health and disease. We demonstrate the utility of this resource by developing an image analysis pipeline for the automated measurement of primary cilia to detect changes in their length associated with altered signaling or disease state.
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Affiliation(s)
- Viviana Macarelli
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
- Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK
| | - Edward C Harding
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
| | - David C Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Florian T Merkle
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
- Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK
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2
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Reddy Palicharla V, Mukhopadhyay S. Molecular and structural perspectives on protein trafficking to the primary cilium membrane. Biochem Soc Trans 2024; 52:1473-1487. [PMID: 38864436 DOI: 10.1042/bst20231403] [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: 03/20/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/13/2024]
Abstract
The primary cilium is a dynamic subcellular compartment templated from the mother centriole or basal body. Cilia are solitary and tiny, but remarkably consequential in cellular pathways regulating proliferation, differentiation, and maintenance. Multiple transmembrane proteins such as G-protein-coupled receptors, channels, enzymes, and membrane-associated lipidated proteins are enriched in the ciliary membrane. The precise regulation of ciliary membrane content is essential for effective signal transduction and maintenance of tissue homeostasis. Surprisingly, a few conserved molecular factors, intraflagellar transport complex A and the tubby family adapter protein TULP3, mediate the transport of most membrane cargoes into cilia. Recent advances in cryogenic electron microscopy provide fundamental insights into these molecular players. Here, we review the molecular players mediating cargo delivery into the ciliary membrane through the lens of structural biology. These mechanistic insights into ciliary transport provide a framework for understanding of disease variants in ciliopathies, enable precise manipulation of cilia-mediated pathways, and provide a platform for the development of targeted therapeutics.
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Affiliation(s)
- Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, U.S.A
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, U.S.A
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3
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McWhite CD, Sae-Lee W, Yuan Y, Mallam AL, Gort-Freitas NA, Ramundo S, Onishi M, Marcotte EM. Alternative proteoforms and proteoform-dependent assemblies in humans and plants. Mol Syst Biol 2024:10.1038/s44320-024-00048-3. [PMID: 38918600 DOI: 10.1038/s44320-024-00048-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/27/2024] Open
Abstract
The variability of proteins at the sequence level creates an enormous potential for proteome complexity. Exploring the depths and limits of this complexity is an ongoing goal in biology. Here, we systematically survey human and plant high-throughput bottom-up native proteomics data for protein truncation variants, where substantial regions of the full-length protein are missing from an observed protein product. In humans, Arabidopsis, and the green alga Chlamydomonas, approximately one percent of observed proteins show a short form, which we can assign by comparison to RNA isoforms as either likely deriving from transcript-directed processes or limited proteolysis. While some detected protein fragments align with known splice forms and protein cleavage events, multiple examples are previously undescribed, such as our observation of fibrocystin proteolysis and nuclear translocation in a green alga. We find that truncations occur almost entirely between structured protein domains, even when short forms are derived from transcript variants. Intriguingly, multiple endogenous protein truncations of phase-separating translational proteins resemble cleaved proteoforms produced by enteroviruses during infection. Some truncated proteins are also observed in both humans and plants, suggesting that they date to the last eukaryotic common ancestor. Finally, we describe novel proteoform-specific protein complexes, where the loss of a domain may accompany complex formation.
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Affiliation(s)
- Claire D McWhite
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, 08544, USA.
| | - Wisath Sae-Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yaning Yuan
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Anna L Mallam
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA
| | | | - Silvia Ramundo
- Gregor Mendel Institute of Molecular Plant Biology, 1030, Wien, Austria
| | - Masayuki Onishi
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Edward M Marcotte
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA
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4
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Bannell TAK, Cockburn JJB. The molecular structure and function of fibrocystin, the key gene product implicated in autosomal recessive polycystic kidney disease (ARPKD). Ann Hum Genet 2024; 88:58-75. [PMID: 37905714 DOI: 10.1111/ahg.12535] [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: 07/11/2023] [Revised: 09/14/2023] [Accepted: 10/03/2023] [Indexed: 11/02/2023]
Abstract
Autosomal recessive polycystic kidney disease is an early onset inherited hepatorenal disorder affecting around 1 in 20,000 births with no approved specific therapies. The disease is almost always caused by variations in the polycystic kidney and hepatic disease 1 gene, which encodes fibrocystin (FC), a very large, single-pass transmembrane glycoprotein found in primary cilia, urine and urinary exosomes. By comparison to proteins involved in autosomal dominant PKD, our structural and molecular understanding of FC has lagged far behind such that there are no published experimentally determined structures of any part of the protein. Bioinformatics analyses predict that the ectodomain contains a long chain of immunoglobulin-like plexin-transcription factor domains, a protective antigen 14 domain, a tandem G8-TMEM2 homology region and a sperm protein, enterokinase and agrin domain. Here we review current knowledge on the molecular function of the protein from a structural perspective.
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Affiliation(s)
- Travis A K Bannell
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Joseph J B Cockburn
- Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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5
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Bear RM, Caspary T. Uncovering cilia function in glial development. Ann Hum Genet 2024; 88:27-44. [PMID: 37427745 PMCID: PMC10776815 DOI: 10.1111/ahg.12519] [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: 03/31/2023] [Revised: 06/14/2023] [Accepted: 06/19/2023] [Indexed: 07/11/2023]
Abstract
Primary cilia play critical roles in regulating signaling pathways that underlie several developmental processes. In the nervous system, cilia are known to regulate signals that guide neuron development. Cilia dysregulation is implicated in neurological diseases, and the underlying mechanisms remain poorly understood. Cilia research has predominantly focused on neurons and has overlooked the diverse population of glial cells in the brain. Glial cells play essential roles during neurodevelopment, and their dysfunction contributes to neurological disease; however, the relationship between cilia function and glial development is understudied. Here we review the state of the field and highlight the glial cell types where cilia are found and the ciliary functions that are linked to glial development. This work uncovers the importance of cilia in glial development and raises outstanding questions for the field. We are poised to make progress in understanding the function of glial cilia in human development and their contribution to neurological diseases.
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Affiliation(s)
- Rachel M. Bear
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Suite 301, Atlanta GA 30322
- Graduate Program in Neuroscience
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Suite 301, Atlanta GA 30322
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6
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Loukil A, Ebright E, Uezu A, Gao Y, Soderling SH, Goetz SC. Identification of new ciliary signaling pathways in the brain and insights into neurological disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572700. [PMID: 38187761 PMCID: PMC10769350 DOI: 10.1101/2023.12.20.572700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Primary cilia are conserved sensory hubs essential for signaling transduction and embryonic development. Ciliary dysfunction causes a variety of developmental syndromes with neurological features and cognitive impairment, whose basis mostly remains unknown. Despite connections to neural function, the primary cilium remains an overlooked organelle in the brain. Most neurons have a primary cilium; however, it is still unclear how this organelle modulates brain architecture and function, given the lack of any systemic dissection of neuronal ciliary signaling. Here, we present the first in vivo glance at the molecular composition of cilia in the mouse brain. We have adapted in vivo BioID (iBioID), targeting the biotin ligase BioID2 to primary cilia in neurons. We identified tissue-specific signaling networks enriched in neuronal cilia, including Eph/Ephrin and GABA receptor signaling pathways. Our iBioID ciliary network presents a wealth of neural ciliary hits that provides new insights into neurological disorders. Our findings are a promising first step in defining the fundamentals of ciliary signaling and their roles in shaping neural circuits and behavior. This work can be extended to pathological conditions of the brain, aiming to identify the molecular pathways disrupted in the brain cilium. Hence, finding novel therapeutic strategies will help uncover and leverage the therapeutic potential of the neuronal cilium.
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Affiliation(s)
- Abdelhalim Loukil
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD 57104, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Emma Ebright
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Akiyoshi Uezu
- Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA
| | - Yudong Gao
- Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA
| | - Scott H Soderling
- Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA
| | - Sarah C. Goetz
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
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7
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Tang D, Zheng K, Zhu J, Jin X, Bao H, Jiang L, Li H, Wang Y, Lu Y, Liu J, Liu H, Tang C, Feng S, Dong X, Xu L, Yin Y, Dang S, Wei X, Ren H, Dong B, Dai L, Cheng W, Wan M, Li Z, Chen J, Li H, Kong E, Wang K, Lu K, Qi S. ALS-linked C9orf72-SMCR8 complex is a negative regulator of primary ciliogenesis. Proc Natl Acad Sci U S A 2023; 120:e2220496120. [PMID: 38064514 PMCID: PMC10723147 DOI: 10.1073/pnas.2220496120] [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: 12/02/2022] [Accepted: 10/25/2023] [Indexed: 12/17/2023] Open
Abstract
Massive GGGGCC (G4C2) repeat expansion in C9orf72 and the resulting loss of C9orf72 function are the key features of ~50% of inherited amyotrophic lateral sclerosis and frontotemporal dementia cases. However, the biological function of C9orf72 remains unclear. We previously found that C9orf72 can form a stable GTPase activating protein (GAP) complex with SMCR8 (Smith-Magenis chromosome region 8). Herein, we report that the C9orf72-SMCR8 complex is a major negative regulator of primary ciliogenesis, abnormalities in which lead to ciliopathies. Mechanistically, the C9orf72-SMCR8 complex suppresses the primary cilium as a RAB8A GAP. Moreover, based on biochemical analysis, we found that C9orf72 is the RAB8A binding subunit and that SMCR8 is the GAP subunit in the complex. We further found that the C9orf72-SMCR8 complex suppressed the primary cilium in multiple tissues from mice, including but not limited to the brain, kidney, and spleen. Importantly, cells with C9orf72 or SMCR8 knocked out were more sensitive to hedgehog signaling. These results reveal the unexpected impact of C9orf72 on primary ciliogenesis and elucidate the pathogenesis of diseases caused by the loss of C9orf72 function.
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Affiliation(s)
- Dan Tang
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Kaixuan Zheng
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Jiangli Zhu
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang453000, People’s Republic of China
| | - Xi Jin
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Hui Bao
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Lan Jiang
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Huihui Li
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Yichang Wang
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
| | - Ying Lu
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Jiaming Liu
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Hang Liu
- Division of Life Science, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Kowloon, Hong Kong Special Administrative Region, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, People’s Republic of China
- HKUST-Shenzhen Research Institute, Nanshan, Shenzhen518057, People’s Republic of China
| | - Chengbing Tang
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Shijian Feng
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Xiuju Dong
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Liangting Xu
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Yike Yin
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Shangyu Dang
- Division of Life Science, Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Kowloon, Hong Kong Special Administrative Region, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou511458, People’s Republic of China
- HKUST-Shenzhen Research Institute, Nanshan, Shenzhen518057, People’s Republic of China
| | - Xiawei Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
| | - Haiyan Ren
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Biao Dong
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
- Sichuan Real & Best Biotech Co., Ltd., Chengdu610219, People’s Republic of China
| | - Lunzhi Dai
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Wei Cheng
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Meihua Wan
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Zhonghan Li
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Jing Chen
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Hong Li
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Eryan Kong
- Institute of Psychiatry and Neuroscience, Xinxiang Medical University, Xinxiang453000, People’s Republic of China
| | - Kunjie Wang
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Kefeng Lu
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
| | - Shiqian Qi
- Department of Urology, Institute of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, and National Collaborative Innovation Center, Chengdu610041, People’s Republic of China
- National Health Commission Key Lab of Transplant Engineering and Immunology, West China Hospital, Sichuan University, Chengdu610041, People’s Republic of China
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8
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Harafuji N, Yang C, Wu M, Thiruvengadam G, Gordish-Dressman H, Thompson RG, Bell PD, Rosenberg AZ, Dafinger C, Liebau MC, Bebok Z, Caldovic L, Guay-Woodford LM. Differential regulation of MYC expression by PKHD1/Pkhd1 in human and mouse kidneys: phenotypic implications for recessive polycystic kidney disease. Front Cell Dev Biol 2023; 11:1270980. [PMID: 38125876 PMCID: PMC10731465 DOI: 10.3389/fcell.2023.1270980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/30/2023] [Indexed: 12/23/2023] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD; MIM#263200) is a severe, hereditary, hepato-renal fibrocystic disorder that leads to early childhood morbidity and mortality. Typical forms of ARPKD are caused by pathogenic variants in the PKHD1 gene, which encodes the fibrocystin/polyductin (FPC) protein. MYC overexpression has been proposed as a driver of renal cystogenesis, but little is known about MYC expression in recessive PKD. In the current study, we provide the first evidence that MYC is overexpressed in kidneys from ARPKD patients and confirm that MYC is upregulated in cystic kidneys from cpk mutant mice. In contrast, renal MYC expression levels were not altered in several Pkhd1 mutant mice that lack a significant cystic kidney phenotype. We leveraged previous observations that the carboxy-terminus of mouse FPC (FPC-CTD) is proteolytically cleaved through Notch-like processing, translocates to the nucleus, and binds to double stranded DNA, to examine whether the FPC-CTD plays a role in regulating MYC/Myc transcription. Using immunofluorescence, reporter gene assays, and ChIP, we demonstrate that both human and mouse FPC-CTD can localize to the nucleus, bind to the MYC/Myc P1 promoter, and activate MYC/Myc expression. Interestingly, we observed species-specific differences in FPC-CTD intracellular trafficking. Furthermore, our informatic analyses revealed limited sequence identity of FPC-CTD across vertebrate phyla and database queries identified temporal differences in PKHD1/Pkhd1 and CYS1/Cys1 expression patterns in mouse and human kidneys. Given that cystin, the Cys1 gene product, is a negative regulator of Myc transcription, these temporal differences in gene expression could contribute to the relative renoprotection from cystogenesis in Pkhd1-deficient mice. Taken together, our findings provide new mechanistic insights into differential mFPC-CTD and hFPC-CTD regulation of MYC expression in renal epithelial cells, which may illuminate the basis for the phenotypic disparities between human patients with PKHD1 pathogenic variants and Pkhd1-mutant mice.
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Affiliation(s)
- Naoe Harafuji
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | - Chaozhe Yang
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | - Maoqing Wu
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | - Girija Thiruvengadam
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
| | | | - R. Griffin Thompson
- Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - P. Darwin Bell
- Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Avi Z. Rosenberg
- Department of Pathology, Johns Hopkins University, Baltimore, MD, United States
| | - Claudia Dafinger
- Department of Pediatrics and Center for Molecular Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Max C. Liebau
- Department of Pediatrics, Center for Family Health, Center for Rare Diseases and Center for Molecular Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Zsuzsanna Bebok
- Heersink School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC, United States
- Department of Genomics and Precision Medicine, School of Medical and Health Sciences, The George Washington University, Washington, DC, United States
| | - Lisa M. Guay-Woodford
- Center for Translational Research, Children’s National Hospital, Washington, DC, United States
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC, United States
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9
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Walker RV, Yao Q, Xu H, Maranto A, Swaney KF, Ramachandran S, Li R, Cassina L, Polster BM, Outeda P, Boletta A, Watnick T, Qian F. Fibrocystin/Polyductin releases a C-terminal fragment that translocates into mitochondria and suppresses cystogenesis. Nat Commun 2023; 14:6513. [PMID: 37845212 PMCID: PMC10579373 DOI: 10.1038/s41467-023-42196-4] [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: 08/31/2022] [Accepted: 10/03/2023] [Indexed: 10/18/2023] Open
Abstract
Fibrocystin/Polyductin (FPC), encoded by PKHD1, is associated with autosomal recessive polycystic kidney disease (ARPKD), yet its precise role in cystogenesis remains unclear. Here we show that FPC undergoes complex proteolytic processing in developing kidneys, generating three soluble C-terminal fragments (ICDs). Notably, ICD15, contains a novel mitochondrial targeting sequence at its N-terminus, facilitating its translocation into mitochondria. This enhances mitochondrial respiration in renal epithelial cells, partially restoring impaired mitochondrial function caused by FPC loss. FPC inactivation leads to abnormal ultrastructural morphology of mitochondria in kidney tubules without cyst formation. Moreover, FPC inactivation significantly exacerbates renal cystogenesis and triggers severe pancreatic cystogenesis in a Pkd1 mouse mutant Pkd1V/V in which cleavage of Pkd1-encoded Polycystin-1 at the GPCR Proteolysis Site is blocked. Deleting ICD15 enhances renal cystogenesis without inducing pancreatic cysts in Pkd1V/V mice. These findings reveal a direct link between FPC and a mitochondrial pathway through ICD15 cleavage, crucial for cystogenesis mechanisms.
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Affiliation(s)
- Rebecca V Walker
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Qin Yao
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Hangxue Xu
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Anthony Maranto
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristen F Swaney
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sreekumar Ramachandran
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Mechanobiology Institute and Department of Biological Sciences, National University of Singapore, Singapore, 117411, Singapore
| | - Laura Cassina
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patricia Outeda
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alessandra Boletta
- Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
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10
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Clearman KR, Haycraft CJ, Croyle MJ, Collawn JF, Yoder BK. Functions of the primary cilium in the kidney and its connection with renal diseases. Curr Top Dev Biol 2023; 155:39-94. [PMID: 38043952 DOI: 10.1016/bs.ctdb.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The nonmotile primary cilium is a sensory structure found on most mammalian cell types that integrates multiple signaling pathways involved in tissue development and postnatal function. As such, mutations disrupting cilia activities cause a group of disorders referred to as ciliopathies. These disorders exhibit a wide spectrum of phenotypes impacting nearly every tissue. In the kidney, primary cilia dysfunction caused by mutations in polycystin 1 (Pkd1), polycystin 2 (Pkd2), or polycystic kidney and hepatic disease 1 (Pkhd1), result in polycystic kidney disease (PKD), a progressive disorder causing renal functional decline and end-stage renal disease. PKD affects nearly 1 in 1000 individuals and as there is no cure for PKD, patients frequently require dialysis or renal transplantation. Pkd1, Pkd2, and Pkhd1 encode membrane proteins that all localize in the cilium. Pkd1 and Pkd2 function as a nonselective cation channel complex while Pkhd1 protein function remains uncertain. Data indicate that the cilium may act as a mechanosensor to detect fluid movement through renal tubules. Other functions proposed for the cilium and PKD proteins in cyst development involve regulation of cell cycle and oriented division, regulation of renal inflammation and repair processes, maintenance of epithelial cell differentiation, and regulation of mitochondrial structure and metabolism. However, how loss of cilia or cilia function leads to cyst development remains elusive. Studies directed at understanding the roles of Pkd1, Pkd2, and Pkhd1 in the cilium and other locations within the cell will be important for developing therapeutic strategies to slow cyst progression.
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Affiliation(s)
- Kelsey R Clearman
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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11
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Sushmita K, Sharma S, Singh Kaushik M, Kateriya S. Algal rhodopsins encoding diverse signal sequence holds potential for expansion of organelle optogenetics. Biophys Physicobiol 2023; 20:e201008. [PMID: 38362319 PMCID: PMC10865886 DOI: 10.2142/biophysico.bppb-v20.s008] [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: 12/22/2022] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Rhodopsins have been extensively employed for optogenetic regulation of bioelectrical activity of excitable cells and other cellular processes across biological systems. Various strategies have been adopted to attune the cellular processes at the desired subcellular compartment (plasma membrane, endoplasmic reticulum, Golgi, mitochondria, lysosome) within the cell. These strategies include-adding signal sequences, tethering peptides, specific interaction sites, or mRNA elements at different sites in the optogenetic proteins for plasma membrane integration and subcellular targeting. However, a single approach for organelle optogenetics was not suitable for the relevant optogenetic proteins and often led to the poor expression, mislocalization, or altered physical and functional properties. Therefore, the current study is focused on the native subcellular targeting machinery of algal rhodopsins. The N- and C-terminus signal prediction led to the identification of rhodopsins with diverse organelle targeting signal sequences for the nucleus, mitochondria, lysosome, endosome, vacuole, and cilia. Several identified channelrhodopsins and ion-pumping rhodopsins possess effector domains associated with DNA metabolism (repair, replication, and recombination) and gene regulation. The identified algal rhodopsins with diverse effector domains and encoded native subcellular targeting sequences hold immense potential to establish expanded organelle optogenetic regulation and associated cellular signaling.
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Affiliation(s)
- Kumari Sushmita
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Sunita Sharma
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Manish Singh Kaushik
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Suneel Kateriya
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
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12
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Mahajan D, Madugula V, Lu L. Rab8 and TNPO1 are ciliary transport adaptors for GTPase Arl13b by interacting with its RVEP motif-containing ciliary targeting sequence. J Biol Chem 2023; 299:104604. [PMID: 36907439 PMCID: PMC10124946 DOI: 10.1016/j.jbc.2023.104604] [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: 08/24/2022] [Revised: 03/04/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
Arl13b, an ARF/Arl-family GTPase, is highly enriched in the cilium. Recent studies have established Arl13b as one of the most crucial regulators for ciliary organization, trafficking, and signaling. The ciliary localization of Arl13b is known to require the RVEP motif. However, its cognitive ciliary transport adaptor has been elusive. Here, by imaging the ciliary localization of truncation and point mutations, we defined the ciliary targeting sequence (CTS) of Arl13b as a C-terminal stretch of 17 amino acids containing the RVEP motif. We found Rab8-GDP, but not Rab8-GTP, and TNPO1 simultaneously and directly bind to the CTS of Arl13b in pull-down assays using cell lysates or purified recombinant proteins. Furthermore, Rab8-GDP substantially enhances the interaction between TNPO1 and CTS. Additionally, we determined that the RVEP motif is an essential element as its mutation abolishes the interaction of the CTS with Rab8-GDP and TNPO1 in pull-down and TurboID-based proximity ligation assays. Finally, knockdown of endogenous Rab8 or TNPO1 decreases the ciliary localization of endogenous Arl13b. Therefore, our results suggest Rab8 and TNPO1 might function together as a ciliary transport adaptor for Arl13b by interacting with its RVEP-containing CTS.
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Affiliation(s)
- Divyanshu Mahajan
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Viswanadh Madugula
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, Singapore.
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13
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Palicharla VR, Hwang SH, Somatilaka BN, Legué E, Shimada IS, Familiari NE, Tran VM, Woodruff JB, Liem KF, Mukhopadhyay S. Interactions between TULP3 tubby domain and ARL13B amphipathic helix promote lipidated protein transport to cilia. Mol Biol Cell 2023; 34:ar18. [PMID: 36652335 PMCID: PMC10011728 DOI: 10.1091/mbc.e22-10-0473] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The primary cilium is a nexus for cell signaling and relies on specific protein trafficking for function. The tubby family protein TULP3 transports integral membrane proteins into cilia through interactions with the intraflagellar transport complex-A (IFT-A) and phosphoinositides. It was previously shown that short motifs called ciliary localization sequences (CLSs) are necessary and sufficient for TULP3-dependent ciliary trafficking of transmembrane cargoes. However, the mechanisms by which TULP3 regulates ciliary compartmentalization of nonintegral, membrane-associated proteins and whether such trafficking requires TULP3-dependent CLSs is unknown. Here we show that TULP3 is required for ciliary transport of the Joubert syndrome-linked palmitoylated GTPase ARL13B through a CLS. An N-terminal amphipathic helix, preceding the GTPase domain of ARL13B, couples with the TULP3 tubby domain for ciliary trafficking, irrespective of palmitoylation. ARL13B transport requires TULP3 binding to IFT-A but not to phosphoinositides, indicating strong membrane-proximate interactions, unlike transmembrane cargo transport requiring both properties of TULP3. TULP3-mediated trafficking of ARL13B also regulates ciliary enrichment of farnesylated and myristoylated downstream effectors of ARL13B. The lipidated cargoes show distinctive depletion kinetics from kidney epithelial cilia with relation to Tulp3 deletion-induced renal cystogenesis. Overall, these findings indicate an expanded role of the tubby domain in capturing analogous helical secondary structural motifs from diverse cargoes.
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Affiliation(s)
- Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Sun-Hee Hwang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | | | - Emilie Legué
- Vertebrate Developmental Biology Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520
| | - Issei S Shimada
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Nicole E Familiari
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Vanna M Tran
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jeffrey B Woodruff
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Karel F Liem
- Vertebrate Developmental Biology Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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14
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Goggolidou P, Richards T. The genetics of Autosomal Recessive Polycystic Kidney Disease (ARPKD). Biochim Biophys Acta Mol Basis Dis 2022; 1868:166348. [PMID: 35032595 DOI: 10.1016/j.bbadis.2022.166348] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/27/2021] [Accepted: 01/06/2022] [Indexed: 12/21/2022]
Abstract
ARPKD is a genetically inherited kidney disease that manifests by bilateral enlargement of cystic kidneys and liver fibrosis. It shows a range of severity, with 30% of individuals dying early on and the majority having good prognosis if they survive the first year of life. The reasons for this variability remain unclear. Two genes have been shown to cause ARPKD when mutated, PKHD1, mutations in which lead to most of ARPKD cases and DZIP1L, which is associated with moderate ARPKD. This mini review will explore the genetics of ARPKD and discuss potential genetic modifiers and phenocopies that could affect diagnosis.
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Affiliation(s)
- Paraskevi Goggolidou
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK.
| | - Taylor Richards
- Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
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15
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Ishiko S, Morisada N, Kondo A, Nagai S, Aoto Y, Okada E, Rossanti R, Sakakibara N, Nagano C, Horinouchi T, Yamamura T, Ninchoji T, Kaito H, Hamada R, Shima Y, Nakanishi K, Matsuo M, Iijima K, Nozu K. Clinical features of autosomal recessive polycystic kidney disease in the Japanese population and analysis of splicing in PKHD1 gene for determination of phenotypes. Clin Exp Nephrol 2021; 26:140-153. [PMID: 34536170 PMCID: PMC8770369 DOI: 10.1007/s10157-021-02135-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/07/2021] [Indexed: 11/05/2022]
Abstract
Background Autosomal recessive polycystic kidney disease (ARPKD) is caused by mutations in the PKHD1 gene. The clinical spectrum is often more variable than previously considered. We aimed to analyze the clinical features of genetically diagnosed ARPKD in the Japanese population. Methods We conducted a genetic analysis of patients with clinically diagnosed or suspected ARPKD in Japan. Moreover, we performed a minigene assay to elucidate the mechanisms that could affect phenotypes. Results PKHD1 pathogenic variants were identified in 32 patients (0–46 years). Approximately one-third of the patients showed prenatal anomalies, and five patients died within one year after birth. Other manifestations were detected as follows: chronic kidney disease stages 1–2 in 15/26 (57.7%), Caroli disease in 9/32 (28.1%), hepatic fibrosis in 7/32 (21.9%), systemic hypertension in 13/27 (48.1%), and congenital hypothyroidism in 3 patients. There have been reported that truncating mutations in both alleles led to severe phenotypes with perinatal demise. However, one patient without a missense mutation survived the neonatal period. In the minigene assay, c.2713C > T (p.Gln905Ter) and c.6808 + 1G > A expressed a transcript that skipped exon 25 (123 bp) and exon 41 (126 bp), resulting in an in-frame mutation, which might have contributed to the milder phenotype. Missense mutations in cases of neonatal demise did not show splicing abnormalities. Conclusion Clinical manifestations ranged from cases of neonatal demise to those diagnosed in adulthood. The minigene assay results indicate the importance of functional analysis, and call into question the fundamental belief that at least one non-truncating mutation is necessary for perinatal survival. Supplementary Information The online version contains supplementary material available at 10.1007/s10157-021-02135-3.
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Affiliation(s)
- Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan. .,Department of Clinical Genetics, Hyogo Prefectural Kobe Children's Hospital, 1-6-7, Minatojimaminami-machi, Chou-ku, Kobe, Hyogo, 650-0047, Japan.
| | - Atsushi Kondo
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Sadayuki Nagai
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Eri Okada
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Takeshi Ninchoji
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Hiroshi Kaito
- Department of Nephrology, Hyogo Prefectural Kobe Children's Hospital, 1-6-7, Minatojimaminami-machi, Chou-ku, Kobe, Hyogo, 650-0047, Japan
| | - Riku Hamada
- Department of Nephrology, Tokyo Metropolitan Children's Medical Center, 2-8-29 Musashidai, Fichu-shi, Tokyo, 183-8561, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, 811-1, Kimiidera, Wakayama, Wakayama, 641-8509, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of Ryukyus, 207 Uehara, Nishihara-cho, Nakagami-gun, Okinawa, 903-2015, Japan
| | - Masafumi Matsuo
- KNC Department of Nucleic Acid Drug Discovery, Faculty of Rehabilitation, Kobe Gakuin University, 518 Arise Ikawadani-cho, Nishi-ku, Kobe Hyogo, 651-2113, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
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16
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Comparison of Ciliary Targeting of Two Rhodopsin-Like GPCRs: Role of C-Terminal Localization Sequences in Relation to Cilium Type. J Neurosci 2021; 41:7514-7531. [PMID: 34301828 PMCID: PMC8425976 DOI: 10.1523/jneurosci.0357-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/20/2021] [Accepted: 06/16/2021] [Indexed: 11/21/2022] Open
Abstract
Primary cilia exhibit a distinct complement of proteins, including G-protein-coupled receptors (GPCRs) that mediate sensory and developmental signals. The localization of GPCRs to the ciliary membrane involves ciliary localization sequences (CLSs), but it is not known how CLSs might relate to cilium type. Here, we studied the localization of two rhodopsin (RHO)-like GPCRs, somatostatin receptor (SSTR3) and RHO, in three types of cilia, from inner medullary collecting duct (IMCD3) cells, hTERT-RPE1 cells (possessing pocket cilia), and rod photoreceptors (whose cilia grow into elaborate phototransductive outer segments). SSTR3 was localized specifically to all three types of cilia, whereas RHO showed more selectivity for the photoreceptor cilium. Focusing on C-terminal CLSs, we characterized a novel CLS in the SSTR3 C terminus, which was required for the robust ciliary localization of SSTR3. Replacing the C terminus of RHO with this SSTR3 CLS-enhanced ciliary localization, compared with full-length RHO in IMCD3 and hTERT-RPE1 cells. Addition of the SSTR3 CLS to the single transmembrane protein CD8A enabled ciliary localization. In hTERT-RPE1 cells, a partial SSTR3 CLS added to CD8A effected specific localization to the periciliary (pocket) membrane, demonstrating C-terminal localization sequence targeting to this domain. Using retinas from mice, including both sexes, we show that deletion of the C terminus of RHO reduced the rod outer segment localization and that addition of the SSTR3 C-terminal CLS to the truncated RHO partly rescued this mislocalization. Overall, the study details elements of the different C termini of SSTR3 and RHO that are major effectors in determining specificity of cilium (or pericilium) localization among different types of cilia.SIGNIFICANCE STATEMENT The localization of G-protein-coupled receptors to primary cilia is key to many types of signal transduction. After characterizing a novel C-terminal CLS in SSTR3, we investigated how SSTR3 and RHO localization to the cilium relates to C-terminal CLSs and to cilium type. We found that the SSTR3 C-terminal CLS was effective in three different types of cilia, but the RHO C terminus showed a clear localization preference for the highly elaborate photoreceptor cilium. When added to CD8A, part of the SSTR3 CLS promoted specific periciliary membrane localization in hTERT-RPE1 cells, demonstrating an effective CLS for this domain. Thus, we demonstrate that elements of the C termini of SSTR3 and RHO determine different localization patterns among different types of cilia.
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17
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The cellular pathways and potential therapeutics of Polycystic Kidney Disease. Biochem Soc Trans 2021; 49:1171-1188. [PMID: 34156429 DOI: 10.1042/bst20200757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/28/2021] [Accepted: 06/03/2021] [Indexed: 02/07/2023]
Abstract
Polycystic Kidney Disease (PKD) refers to a group of disorders, driven by the formation of cysts in renal tubular cells and is currently one of the leading causes of end-stage renal disease. The range of symptoms observed in PKD is due to mutations in cilia-localising genes, resulting in changes in cellular signalling. As such, compounds that are currently in preclinical and clinical trials target some of these signalling pathways that are dysregulated in PKD. In this review, we highlight these pathways including cAMP, EGF and AMPK signalling and drugs that target them and may show promise in lessening the disease burden of PKD patients. At present, tolvaptan is the only approved therapy for ADPKD, however, it carries several adverse side effects whilst comparatively, no pharmacological drug is approved for ARPKD treatment. Aside from this, drugs that have been the subject of multiple clinical trials such as metformin, which targets AMPK signalling and somatostatins, which target cAMP signalling have shown great promise in reducing cyst formation and cellular proliferation. This review also discusses other potential and novel targets that can be used for future interventions, such as β-catenin and TAZ, where research has shown that a reduction in the overexpression of these signalling components results in amelioration of disease phenotype. Thus, it becomes apparent that well-designed preclinical investigations and future clinical trials into these pathways and other potential signalling targets are crucial in bettering disease prognosis for PKD patients and could lead to personalised therapy approaches.
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18
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Molecular Pathophysiology of Autosomal Recessive Polycystic Kidney Disease. Int J Mol Sci 2021; 22:ijms22126523. [PMID: 34204582 PMCID: PMC8235086 DOI: 10.3390/ijms22126523] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/19/2022] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is a rare disorder and one of the most severe forms of polycystic kidney disease, leading to end-stage renal disease (ESRD) in childhood. PKHD1 is the gene that is responsible for the vast majority of ARPKD. However, some cases have been related to a new gene that was recently identified (DZIP1L gene), as well as several ciliary genes that can mimic a ARPKD-like phenotypic spectrum. In addition, a number of molecular pathways involved in the ARPKD pathogenesis and progression were elucidated using cellular and animal models. However, the function of the ARPKD proteins and the molecular mechanism of the disease currently remain incompletely understood. Here, we review the clinics, treatment, genetics, and molecular basis of ARPKD, highlighting the most recent findings in the field.
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19
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Deretic D, Lorentzen E, Fresquez T. The ins and outs of the Arf4-based ciliary membrane-targeting complex. Small GTPases 2021; 12:1-12. [PMID: 31068062 PMCID: PMC7781591 DOI: 10.1080/21541248.2019.1616355] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/09/2019] [Accepted: 05/02/2019] [Indexed: 10/26/2022] Open
Abstract
The small GTPase Arf4-based ciliary membrane-targeting complex recognizes specific targeting signals within sensory receptors and regulates their directed movement to primary cilia. Activated Arf4 directly binds the VxPx ciliary-targeting signal (CTS) of the light-sensing receptor rhodopsin. Recent findings revealed that at the trans-Golgi, marked by the small GTPase Rab6, activated Arf4 forms a functional complex with rhodopsin and the Arf guanine nucleotide exchange factor (GEF) GBF1, providing positive feedback that drives further Arf4 activation in ciliary trafficking. Arf4 function is conserved across diverse cell types; however, it appears that not all its aspects are conserved across species, as mouse Arf4 is a natural mutant in the conserved α3 helix, which is essential for its interaction with rhodopsin. Generally, activated Arf4 regulates the assembly of the targeting nexus containing the Arf GAP ASAP1 and the Rab11a-FIP3-Rabin8 dual effector complex, which controls the assembly of the highly conserved Rab11a-Rabin8-Rab8 ciliary-targeting module. It was recently found that this module interacts with the R-SNARE VAMP7, likely in its activated, c-Src-phosphorylated form. Rab11 and Rab8 bind VAMP7 regulatory longin domain (LD), whereas Rabin8 interacts with the SNARE domain, capturing VAMP7 for delivery to the ciliary base and subsequent pairing with the cognate SNAREs syntaxin 3 and SNAP-25. This review will focus on the implications of these novel findings that further illuminate the role of well-ordered Arf and Rab interaction networks in targeting of sensory receptors to primary cilia. Abbreviations: CTS: Ciliary-Targeting Signal; GAP: GTPase Activating Protein; GEF: Guanine Nucleotide Exchange Factor; RTC(s), Rhodopsin Transport Carrier(s); SNARE: Soluble N-ethylmaleimide-sensitive Factor Attachment Protein Receptor; TGN: Trans-Golgi Network.
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Affiliation(s)
- Dusanka Deretic
- Departments of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM, USA
- Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, USA
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Theresa Fresquez
- Departments of Surgery, Division of Ophthalmology, University of New Mexico, Albuquerque, NM, USA
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20
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Liebau MC. Early clinical management of autosomal recessive polycystic kidney disease. Pediatr Nephrol 2021; 36:3561-3570. [PMID: 33594464 PMCID: PMC8497312 DOI: 10.1007/s00467-021-04970-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/06/2021] [Accepted: 01/26/2021] [Indexed: 12/16/2022]
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is a rare but highly relevant disorder in pediatric nephrology. This genetic disease is mainly caused by variants in the PKHD1 gene and is characterized by fibrocystic hepatorenal phenotypes with major clinical variability. ARPKD frequently presents perinatally, and the management of perinatal and early disease symptoms may be challenging. This review discusses aspects of early manifestations in ARPKD and its clincial management with a special focus on kidney disease.
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Affiliation(s)
- Max Christoph Liebau
- Department of Pediatrics and Center for Molecular Medicine, Medical Faculty and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
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21
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Haumann S, Müller RU, Liebau MC. Metabolic Changes in Polycystic Kidney Disease as a Potential Target for Systemic Treatment. Int J Mol Sci 2020; 21:ijms21176093. [PMID: 32847032 PMCID: PMC7503958 DOI: 10.3390/ijms21176093] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 12/16/2022] Open
Abstract
Autosomal recessive and autosomal dominant polycystic kidney disease (ARPKD, ADPKD) are systemic disorders with pronounced hepatorenal phenotypes. While the main underlying genetic causes of both ARPKD and ADPKD have been well-known for years, the exact molecular mechanisms resulting in the observed clinical phenotypes in the different organs, remain incompletely understood. Recent research has identified cellular metabolic changes in PKD. These findings are of major relevance as there may be an immediate translation into clinical trials and potentially clinical practice. Here, we review important results in the field regarding metabolic changes in PKD and their modulation as a potential target of systemic treatment.
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Affiliation(s)
- Sophie Haumann
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany;
| | - Roman-Ulrich Müller
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany;
- CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
- Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany
| | - Max C. Liebau
- Department of Pediatrics, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany;
- Center for Molecular Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
- Correspondence: ; Tel.: +49-221-478-4359
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22
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Hu J, Harris PC. Regulation of polycystin expression, maturation and trafficking. Cell Signal 2020; 72:109630. [PMID: 32275942 PMCID: PMC7269868 DOI: 10.1016/j.cellsig.2020.109630] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The major autosomal dominant polycystic kidney disease (ADPKD) genes, PKD1 and PKD2, are wildly expressed at the organ and tissue level. PKD1 encodes polycystin 1 (PC1), a large membrane associated receptor-like protein that can complex with the PKD2 product, PC2. Various cellular locations have been described for both PC1, including the plasma membrane and extracellular vesicles, and PC2, especially the endoplasmic reticulum (ER), but compelling evidence indicates that the primary cilium, a sensory organelle, is the key site for the polycystin complex to prevent PKD. As with other membrane proteins, the ER biogenesis pathway is key to appropriately folding, performing quality control, and exporting fully folded PC1 to the Golgi apparatus. There is a requirement for binding with PC2 and cleavage of PC1 at the GPS for this folding and export to occur. Six different monogenic defects in this pathway lead to cystic disease development, with PC1 apparently particularly sensitive to defects in this general protein processing pathway. Trafficking of membrane proteins, and the polycystins in particular, through the Golgi to the primary cilium have been analyzed in detail, but at this time, there is no clear consensus on a ciliary targeting sequence required to export proteins to the cilium. After transitioning though the trans-Golgi network, polycystin-bearing vesicles are likely sorted to early or recycling endosomes and then transported to the ciliary base, possibly via docking to transition fibers (TF). The membrane-bound polycystin complex then undergoes facilitated trafficking through the transition zone, the diffusion barrier at the base of the cilium, before entering the cilium. Intraflagellar transport (IFT) may be involved in moving the polycystins along the cilia, but data also indicates other mechanisms. The ciliary polycystin complex can be ubiquitinated and removed from cilia by internalization at the ciliary base and may be sent back to the plasma membrane for recycling or to lysosomes for degradation. Monogenic defects in processes regulating the protein composition of cilia are associated with syndromic disorders involving many organ systems, reflecting the pleotropic role of cilia during development and for tissue maintenance. Many of these ciliopathies have renal involvement, likely because of faulty polycystin signaling from cilia. Understanding the expression, maturation and trafficking of the polycystins helps understand PKD pathogenesis and suggests opportunities for therapeutic intervention.
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Affiliation(s)
- Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
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23
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Fisher S, Kuna D, Caspary T, Kahn RA, Sztul E. ARF family GTPases with links to cilia. Am J Physiol Cell Physiol 2020; 319:C404-C418. [PMID: 32520609 PMCID: PMC7500214 DOI: 10.1152/ajpcell.00188.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The ADP-ribosylation factor (ARF) superfamily of regulatory GTPases, including both the ARF and ARF-like (ARL) proteins, control a multitude of cellular functions, including aspects of vesicular traffic, lipid metabolism, mitochondrial architecture, the assembly and dynamics of the microtubule and actin cytoskeletons, and other pathways in cell biology. Considering their general utility, it is perhaps not surprising that increasingly ARF/ARLs have been found in connection to primary cilia. Here, we critically evaluate the current knowledge of the roles four ARF/ARLs (ARF4, ARL3, ARL6, ARL13B) play in cilia and highlight key missing information that would help move our understanding forward. Importantly, these GTPases are themselves regulated by guanine nucleotide exchange factors (GEFs) that activate them and by GTPase-activating proteins (GAPs) that act as both effectors and terminators of signaling. We believe that the identification of the GEFs and GAPs and better models of the actions of these GTPases and their regulators will provide a much deeper understanding and appreciation of the mechanisms that underly ciliary functions and the causes of a number of human ciliopathies.
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Affiliation(s)
- Skylar Fisher
- 1Department of Biochemistry, Emory University
School of Medicine, Atlanta,
Georgia
| | - Damian Kuna
- 2Department of Cell, Developmental and Integrative
Biology, University of Alabama at Birmingham,
Birmingham, Alabama
| | - Tamara Caspary
- 3Department of Human Genetics, Emory
University School of Medicine, Atlanta,
Georgia
| | - Richard A. Kahn
- 1Department of Biochemistry, Emory University
School of Medicine, Atlanta,
Georgia
| | - Elizabeth Sztul
- 2Department of Cell, Developmental and Integrative
Biology, University of Alabama at Birmingham,
Birmingham, Alabama
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Primary Cilia Signaling Promotes Axonal Tract Development and Is Disrupted in Joubert Syndrome-Related Disorders Models. Dev Cell 2020; 51:759-774.e5. [PMID: 31846650 DOI: 10.1016/j.devcel.2019.11.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/08/2019] [Accepted: 11/10/2019] [Indexed: 12/18/2022]
Abstract
Appropriate axonal growth and connectivity are essential for functional wiring of the brain. Joubert syndrome-related disorders (JSRD), a group of ciliopathies in which mutations disrupt primary cilia function, are characterized by axonal tract malformations. However, little is known about how cilia-driven signaling regulates axonal growth and connectivity. We demonstrate that the deletion of related JSRD genes, Arl13b and Inpp5e, in projection neurons leads to de-fasciculated and misoriented axonal tracts. Arl13b deletion disrupts the function of its downstream effector, Inpp5e, and deregulates ciliary-PI3K/AKT signaling. Chemogenetic activation of ciliary GPCR signaling and cilia-specific optogenetic modulation of downstream second messenger cascades (PI3K, AKT, and AC3) commonly regulated by ciliary signaling receptors induce rapid changes in axonal dynamics. Further, Arl13b deletion leads to changes in transcriptional landscape associated with dysregulated PI3K/AKT signaling. These data suggest that ciliary signaling acts to modulate axonal connectivity and that impaired primary cilia signaling underlies axonal tract defects in JSRD.
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25
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Cilia and polycystic kidney disease. Semin Cell Dev Biol 2020; 110:139-148. [PMID: 32475690 DOI: 10.1016/j.semcdb.2020.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/03/2020] [Accepted: 05/03/2020] [Indexed: 11/20/2022]
Abstract
Polycystic kidney disease (PKD), comprising autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD), is characterized by incessant cyst formation in the kidney and liver. ADPKD and ARPKD represent the leading genetic causes of renal disease in adults and children, respectively. ADPKD is caused by mutations in PKD1 encoding polycystin1 (PC1) and PKD2 encoding polycystin 2 (PC2). PC1/2 are multi-pass transmembrane proteins that form a complex localized in the primary cilium. Predominant ARPKD cases are caused by mutations in polycystic kidney and hepatic disease 1 (PKHD1) gene that encodes the Fibrocystin/Polyductin (FPC) protein, whereas a small subset of cases are caused by mutations in DAZ interacting zinc finger protein 1 like (DZIP1L) gene. FPC is a type I transmembrane protein, localizing to the cilium and basal body, in addition to other compartments, and DZIP1L encodes a transition zone/basal body protein. Apparently, PC1/2 and FPC are signaling molecules, while the mechanism that cilia employ to govern renal tubule morphology and prevent cyst formation is unclear. Nonetheless, recent genetic and biochemical studies offer a glimpse of putative physiological malfunctions and the pathomechanisms underlying both disease entities. In this review, I summarize the results of genetic studies that deduced the function of PC1/2 on cilia and of cilia themselves in cyst formation in ADPKD, and I discuss studies regarding regulation of polycystin biogenesis and cilia trafficking. I also summarize the synergistic genetic interactions between Pkd1 and Pkhd1, and the unique tissue patterning event controlled by FPC, but not PC1. Interestingly, while DZIP1L mutations generate compromised PC1/2 cilia expression, FPC deficiency does not affect PC1/2 biogenesis and ciliary localization, indicating that divergent mechanisms could lead to cyst formation in ARPKD. I conclude by outlining promising areas for future PKD research and highlight rationales for potential therapeutic interventions for PKD treatment.
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Jung J, Seo GH, Kim YM, Han YM, Park JK, Kim GH, Lee JH, Park YS, Lee BS, Kim EAR, Lee PR, Lee BH. Fatal outcome of autosomal recessive polycystic kidney disease in neonates with recessive PKHD1 mutations. Medicine (Baltimore) 2020; 99:e20113. [PMID: 32384486 PMCID: PMC7440252 DOI: 10.1097/md.0000000000020113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Autosomal recessive polycystic kidney disease (ARPKD) is the most common inherited childhood-onset renal disease, with underlying ciliopathy, and varies widely in clinical severity. The aim of this study was to describe the most severe form of ARPKD, with a fatal clinical course, and its association with mutations in polycystic kidney and hepatic disease 1 (fibrocystin) (PKHD1). Clinical, imaging, pathological, and molecular genetic findings were reviewed in patients prenatally affected with ARPKD and their families.Five unrelated Korean families, including 9 patients, were analyzed. Among the 9 patients, 2 fetuses died in utero, 6 patients did not survive longer than a few days, and 1 patient survived for 5 months with ventilator support and renal replacement therapy. A total of 6 truncating mutations (all nonsense) and 4 missense mutations were detected in a compound heterozygous state, including 4 novel mutations. The most severe phenotypes were shared among all affected patients in each family, irrespective of mutation types.Our data suggest a strong genotype-phenotype relationship in ARPKD, with minimal intra-familial heterogeneity. These findings are important for informing future reproductive planning in affected families.
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Affiliation(s)
- Jiwon Jung
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul
| | | | - Yoo-Mi Kim
- Department of Pediatrics, Chungnam National University School of Medicine, Chungnam National University Hospital, Daejeon
| | - Young Mi Han
- Department of Pediatrics, Pusan National University Children's Hospital, Pusan
| | - Ji Kwon Park
- Department of Obsteterics, Gyeongsang National University Changwon Hospital, Gyeongsang National University School of Medicine, Changwon
| | - Gu-Hwan Kim
- Medical Genetics Center, Asan Medical Center Children's Hospital
| | - Joo Hoon Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul
| | - Young Seo Park
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul
| | - Byong Sop Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul
| | - Ellen Ai-Rhan Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul
| | - Pil-Ryang Lee
- Department of Obstetrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Beom Hee Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul
- Medical Genetics Center, Asan Medical Center Children's Hospital
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27
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Maharjan Y, Lee JN, Kwak SA, Dutta RK, Park C, Choe SK, Park R. TMEM135 regulates primary ciliogenesis through modulation of intracellular cholesterol distribution. EMBO Rep 2020; 21:e48901. [PMID: 32157776 PMCID: PMC7202201 DOI: 10.15252/embr.201948901] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 01/31/2020] [Accepted: 02/14/2020] [Indexed: 11/09/2022] Open
Abstract
Recent evidence has linked the lysosomal cholesterol accumulation in Niemann–Pick type C1 with anomalies associated with primary ciliogenesis. Here, we report that perturbed intracellular cholesterol distribution imposed by lysosomal cholesterol accumulation during TMEM135 depletion is closely associated with impaired ciliogenesis. TMEM135 depletion does not affect the formation of the basal body and the ciliary transition zone. TMEM135 depletion severely blunts Rab8 trafficking to the centrioles without affecting the centriolar localization of Rab11 and Rabin8, the upstream regulators of Rab8 activation. Although TMEM135 depletion prevents enhanced IFT20 localization at the centrioles, ciliary vesicle formation is not affected. Furthermore, enhanced IFT20 localization at the centrioles is dependent on Rab8 activation. Supplementation of cholesterol in complex with cyclodextrin rescues Rab8 trafficking to the centrioles and Rab8 activation, thereby recovering primary ciliogenesis in TMEM135‐depleted cells. Taken together, our data suggest that TMEM135 depletion prevents ciliary vesicle elongation, a characteristic of impaired Rab8 function. Our study thus reveals a previously uncharacterized effect of erroneous intracellular cholesterol distribution on impairing Rab8 function and primary ciliogenesis.
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Affiliation(s)
- Yunash Maharjan
- Department of Biomedical Science & Engineering, Gwangju Institute of Science & Technology, Gwangju, Korea
| | - Joon No Lee
- Department of Biomedical Science & Engineering, Gwangju Institute of Science & Technology, Gwangju, Korea
| | - Seong Ae Kwak
- Department of Microbiology and Center for Metabolic Function Regulation, Wonkwang University School of Medicine, Iksan, Korea
| | - Raghbendra Kumar Dutta
- Department of Biomedical Science & Engineering, Gwangju Institute of Science & Technology, Gwangju, Korea
| | - Channy Park
- Department of Biomedical Science & Engineering, Gwangju Institute of Science & Technology, Gwangju, Korea
| | - Seong-Kyu Choe
- Department of Microbiology and Center for Metabolic Function Regulation, Wonkwang University School of Medicine, Iksan, Korea
| | - Raekil Park
- Department of Biomedical Science & Engineering, Gwangju Institute of Science & Technology, Gwangju, Korea
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28
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Establishing and regulating the composition of cilia for signal transduction. Nat Rev Mol Cell Biol 2020; 20:389-405. [PMID: 30948801 DOI: 10.1038/s41580-019-0116-4] [Citation(s) in RCA: 226] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The primary cilium is a hair-like surface-exposed organelle of the eukaryotic cell that decodes a variety of signals - such as odorants, light and Hedgehog morphogens - by altering the local concentrations and activities of signalling proteins. Signalling within the cilium is conveyed through a diverse array of second messengers, including conventional signalling molecules (such as cAMP) and some unusual intermediates (such as sterols). Diffusion barriers at the ciliary base establish the unique composition of this signalling compartment, and cilia adapt their proteome to signalling demands through regulated protein trafficking. Much progress has been made on the molecular understanding of regulated ciliary trafficking, which encompasses not only exchanges between the cilium and the rest of the cell but also the shedding of signalling factors into extracellular vesicles.
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29
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Gigante ED, Caspary T. Signaling in the primary cilium through the lens of the Hedgehog pathway. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e377. [PMID: 32084300 DOI: 10.1002/wdev.377] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 12/14/2022]
Abstract
Cilia are microtubule-based, cell-surface projections whose machinery is evolutionarily conserved. In vertebrates, cilia are observed on almost every cell type and are either motile or immotile. Immotile sensory, or primary cilia, are responsive to extracellular ligands and signals. Cilia can be thought of as compartments, functionally distinct from the cell that provides an environment for signaling cascades. Hedgehog is a critical developmental signaling pathway which is functionally linked to primary cilia in vertebrates. The major components of the vertebrate Hedgehog signaling pathway dynamically localize to the ciliary compartment and ciliary membrane. Critically, G-protein coupled receptor (GPCR) Smoothened, the obligate transducer of the pathway, is enriched and activated in the cilium. While Smoothened is the most intensely studied ciliary receptor, many GPCRs localize within cilia. Understanding the link between Smoothened and cilia defines common features, and distinctions, of GPCR signaling within the primary cilium. This article is categorized under: Signaling Pathways > Global Signaling Mechanisms Signaling Pathways > Cell Fate Signaling.
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Affiliation(s)
- Eduardo D Gigante
- Graduate Program in Neuroscience, Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
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30
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Pazour GJ, Quarmby L, Smith AO, Desai PB, Schmidts M. Cilia in cystic kidney and other diseases. Cell Signal 2019; 69:109519. [PMID: 31881326 DOI: 10.1016/j.cellsig.2019.109519] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 12/21/2019] [Accepted: 12/21/2019] [Indexed: 12/23/2022]
Abstract
Epithelial cells lining the ducts and tubules of the kidney nephron and collecting duct have a single non-motile cilium projecting from their surface into the lumen of the tubule. These organelles were long considered vestigial remnants left as a result of evolution from a ciliated ancestor, but we now recognize them as critical sensory antennae. In the kidney, the polycystins and fibrocystin, products of the major human polycystic kidney disease genes, localize to this organelle. The polycystins and fibrocystin, through an unknown mechanism, monitor the diameter of the kidney tubules and regulate the proliferation and differentiation of the cells lining the tubule. When the polycystins, fibrocystin or cilia themselves are defective, the cell perceives this as a pro-proliferative signal, which leads to tubule dilation and cystic disease. In addition to critical roles in preventing cyst formation in the kidney, cilia are also important in cystic and fibrotic diseases of the liver and pancreas, and ciliary defects lead to a variety of developmental abnormalities that cause structural birth defects in most organs.
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Affiliation(s)
- Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, United States of America.
| | - Lynne Quarmby
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
| | - Abigail O Smith
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, United States of America
| | - Paurav B Desai
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, United States of America
| | - Miriam Schmidts
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Mathildenstrasse 1, 79112 Freiburg, Germany.
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31
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Roy K, Marin EP. Lipid Modifications in Cilia Biology. J Clin Med 2019; 8:jcm8070921. [PMID: 31252577 PMCID: PMC6678300 DOI: 10.3390/jcm8070921] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/22/2019] [Accepted: 06/24/2019] [Indexed: 12/17/2022] Open
Abstract
Cilia are specialized cellular structures with distinctive roles in various signaling cascades. Ciliary proteins need to be trafficked to the cilium to function properly; however, it is not completely understood how these proteins are delivered to their final localization. In this review, we will focus on how different lipid modifications are important in ciliary protein trafficking and, consequently, regulation of signaling pathways. Lipid modifications can play a variety of roles, including tethering proteins to the membrane, aiding trafficking through facilitating interactions with transporter proteins, and regulating protein stability and abundance. Future studies focusing on the role of lipid modifications of ciliary proteins will help our understanding of how cilia maintain specific protein pools strictly connected to their functions.
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Affiliation(s)
- Kasturi Roy
- Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, PO Box 208029, New Haven, CT 06520-8029, USA.
| | - Ethan P Marin
- Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, PO Box 208029, New Haven, CT 06520-8029, USA
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32
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Sherpa RT, Pala R, Mohieldin AM, Nauli SM. Measurement of cytoplasmic and cilioplasmic calcium in a single living cell. Methods Cell Biol 2019; 153:25-42. [PMID: 31395382 DOI: 10.1016/bs.mcb.2019.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cellular signaling represents an evolution of biological systems to sense external stimuli and communicate extracellular microenvironment to the intracellular compartments. The processes underlying molecular signaling have been widely studied due to their important cellular functions. There are numerous techniques available to quantitate the different molecules involved in cellular processes. Among them, calcium is a ubiquitous signaling molecule involved in many biological pathways. Over time the methods to measure intracellular calcium have advanced to better understand its role as a second messenger. In this chapter, we introduce a method to study a single cilium, a mechanosensor that elicits a calcium signaling cascade. To successfully observe the calcium changes in this thin cylindrical-like projection from the cell surface, we utilize a genetically encoded sensor with a high spatial and temporal resolution. In addition, the probe must be localized to the ciliary compartment in order to observe the intraciliary calcium signaling dynamics. To this end, a cilium targeting genetically encoded indicator is used to observe calcium fluxes in both cytoplasm and cilioplasm.
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Affiliation(s)
- Rinzhin T Sherpa
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Chapman University, Irvine, CA, United States
| | - Rajasekharreddy Pala
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Chapman University, Irvine, CA, United States
| | - Ashraf M Mohieldin
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Chapman University, Irvine, CA, United States
| | - Surya M Nauli
- Department of Biomedical & Pharmaceutical Sciences, Chapman University School of Pharmacy (CUSP), Chapman University, Irvine, CA, United States; Department of Medicine, University of California Irvine, Irvine, CA, United States.
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33
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Hwang SH, Somatilaka BN, Badgandi H, Palicharla VR, Walker R, Shelton JM, Qian F, Mukhopadhyay S. Tulp3 Regulates Renal Cystogenesis by Trafficking of Cystoproteins to Cilia. Curr Biol 2019; 29:790-802.e5. [PMID: 30799239 DOI: 10.1016/j.cub.2019.01.047] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 11/09/2018] [Accepted: 01/17/2019] [Indexed: 12/25/2022]
Abstract
Polycystic kidney disease proteins, polycystin-1 and polycystin-2, localize to primary cilia. Polycystin knockouts have severe cystogenesis compared to ciliary disruption, whereas simultaneous ciliary loss suppresses excessive cyst growth. These data suggest the presence of a cystogenic activator that is inhibited by polycystins and an independent but relatively minor cystogenic inhibitor, either of which are cilia dependent. However, current genetic models targeting cilia completely ablate the compartment, making it difficult to uncouple cystoprotein function from ciliary localization. Thus, the role of cilium-generated signaling in cystogenesis is unclear. We recently demonstrated that the tubby family protein Tulp3 determines ciliary trafficking of polycystins in kidney collecting duct cells without affecting protein levels or cilia. Here, we demonstrate that embryonic-stage, nephron-specific Tulp3 knockout mice developed cystic kidneys, while retaining intact cilia. Cystic kidneys showed increased mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK), mTOR, and persistently high cyclic AMP (cAMP) signaling, suggesting contribution of multiple factors to cystogenesis. Based on kidney-to-body-weight ratio, cystic index, and epithelial proliferation in developing tubules or cysts, the severity of cystogenesis upon Tulp3 deletion was intermediate between that caused by loss of polycystin-1 or cilia. However, concomitant Tulp3 loss did not inhibit cystogenesis in polycystin-1 knockouts, unlike ciliary disruption. Interestingly, ciliary trafficking of the small guanosine triphosphatase (GTPase) Arl13b, loss of which causes cystogenic severity similar to ciliary loss, was reduced prior to cyst initiation. Thus, we propose that cystogenesis in Tulp3 mutants results from a reduction of ciliary levels of polycystins, Arl13b, and Arl13b-dependent lipidated cargoes. Arl13b might be the ciliary factor that represses cystogenesis distinct from polycystins.
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Affiliation(s)
- Sun-Hee Hwang
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Bandarigoda N Somatilaka
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Hemant Badgandi
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Rebecca Walker
- Division of Nephrology, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201, USA
| | - John M Shelton
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Feng Qian
- Division of Nephrology, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201, USA
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
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Picariello T, Brown JM, Hou Y, Swank G, Cochran DA, King OD, Lechtreck K, Pazour GJ, Witman GB. A global analysis of IFT-A function reveals specialization for transport of membrane-associated proteins into cilia. J Cell Sci 2019; 132:jcs220749. [PMID: 30659111 PMCID: PMC6382014 DOI: 10.1242/jcs.220749] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/02/2019] [Indexed: 12/28/2022] Open
Abstract
Intraflagellar transport (IFT), which is essential for the formation and function of cilia in most organisms, is the trafficking of IFT trains (i.e. assemblies of IFT particles) that carry cargo within the cilium. Defects in IFT cause several human diseases. IFT trains contain the complexes IFT-A and IFT-B. To dissect the functions of these complexes, we studied a Chlamydomonas mutant that is null for the IFT-A protein IFT140. The mutation had no effect on IFT-B but destabilized IFT-A, preventing flagella assembly. Therefore, IFT-A assembly requires IFT140. Truncated IFT140, which lacks the N-terminal WD repeats of the protein, partially rescued IFT and supported formation of half-length flagella that contained normal levels of IFT-B but greatly reduced amounts of IFT-A. The axonemes of these flagella had normal ultrastructure and, as investigated by SDS-PAGE, normal composition. However, composition of the flagellar 'membrane+matrix' was abnormal. Analysis of the latter fraction by mass spectrometry revealed decreases in small GTPases, lipid-anchored proteins and cell signaling proteins. Thus, IFT-A is specialized for the import of membrane-associated proteins. Abnormal levels of the latter are likely to account for the multiple phenotypes of patients with defects in IFT140.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Tyler Picariello
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jason M Brown
- Department of Biology, Salem State University, Salem, MA 01970, USA
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Gregory Swank
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Deborah A Cochran
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Oliver D King
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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35
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Richards T, Modarage K, Dean C, McCarthy-Boxer A, Hilton H, Esapa C, Norman J, Wilson P, Goggolidou P. Atmin modulates Pkhd1 expression and may mediate Autosomal Recessive Polycystic Kidney Disease (ARPKD) through altered non-canonical Wnt/Planar Cell Polarity (PCP) signalling. Biochim Biophys Acta Mol Basis Dis 2019; 1865:378-390. [PMID: 30414501 PMCID: PMC6335440 DOI: 10.1016/j.bbadis.2018.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/10/2018] [Accepted: 11/05/2018] [Indexed: 12/25/2022]
Abstract
Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a genetic disorder with an incidence of ~1:20,000 that manifests in a wide range of renal and liver disease severity in human patients and can lead to perinatal mortality. ARPKD is caused by mutations in PKHD1, which encodes the large membrane protein, Fibrocystin, required for normal branching morphogenesis of the ureteric bud during embryonic renal development. The variation in ARPKD phenotype suggests that in addition to PKHD1 mutations, other genes may play a role, acting as modifiers of disease severity. One such pathway involves non-canonical Wnt/Planar Cell Polarity (PCP) signalling that has been associated with other cystic kidney diseases, but has not been investigated in ARPKD. Analysis of the AtminGpg6 mouse showed kidney, liver and lung abnormalities, suggesting it as a novel mouse tool for the study of ARPKD. Further, modulation of Atmin affected Pkhd1 mRNA levels, altered non-canonical Wnt/PCP signalling and impacted cellular proliferation and adhesion, although Atmin does not bind directly to the C-terminus of Fibrocystin. Differences in ATMIN and VANGL2 expression were observed between normal human paediatric kidneys and age-matched ARPKD kidneys. Significant increases in ATMIN, WNT5A, VANGL2 and SCRIBBLE were seen in human ARPKD versus normal kidneys; no substantial differences were seen in DAAM2 or NPHP2. A striking increase in E-cadherin was also detected in ARPKD kidneys. This work indicates a novel role for non-canonical Wnt/PCP signalling in ARPKD and suggests ATMIN as a modulator of PKHD1.
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MESH Headings
- Adolescent
- Apoptosis
- Cadherins/metabolism
- Cell Adhesion
- Cell Line
- Cell Polarity
- Cell Proliferation
- Child
- Child, Preschool
- Cytoskeleton/metabolism
- Embryo, Mammalian/metabolism
- Humans
- Infant
- Infant, Newborn
- Kidney Tubules, Collecting
- Phenotype
- Polycystic Kidney, Autosomal Recessive/genetics
- Polycystic Kidney, Autosomal Recessive/pathology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Transcription Factors/metabolism
- Wnt Signaling Pathway
- beta Catenin/metabolism
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Affiliation(s)
- Taylor Richards
- School of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Kavindiya Modarage
- School of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK
| | - Charlotte Dean
- National Heart and Lung Institute, Imperial College, South Kensington Campus, London SW7 2AZ, UK; MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Aidan McCarthy-Boxer
- Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK
| | - Helen Hilton
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Chris Esapa
- MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Jill Norman
- Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK
| | - Patricia Wilson
- Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK
| | - Paraskevi Goggolidou
- School of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1LY, UK; MRC Harwell Institute, Mammalian Genetics Unit, Harwell Campus, Oxfordshire OX11 0RD, UK; Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill, London NW3 2PF, UK.
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36
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Patched1-ArhGAP36-PKA-Inversin axis determines the ciliary translocation of Smoothened for Sonic Hedgehog pathway activation. Proc Natl Acad Sci U S A 2018; 116:874-879. [PMID: 30598432 DOI: 10.1073/pnas.1804042116] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The Sonic Hedgehog (Shh) pathway conducts primarily in the primary cilium and plays important roles in cell proliferation, individual development, and tumorigenesis. Shh ligand binding with its ciliary membrane-localized transmembrane receptor Patched1 results in the removal of Patched1 from and the translocation of the transmembrane oncoprotein Smoothened into the cilium, leading to Shh signaling activation. However, how these processes are coupled remains unknown. Here, we show that the Patched1-ArhGAP36-PKA-Inversin axis determines the ciliary translocation of Smoothened. We find that Patched1 interacts with and stabilizes the PKA negative regulator ArhGAP36 to the centrosome. Activating the Shh pathway results in the removal of ArhGAP36 from the mother centriole and the centrosomal PKA accumulation. This PKA then phosphorylates Inversin and promotes its interaction with and the ciliary translocation of Smoothened. Knockdown of Inversin disrupts the ciliary translocation of Smoothened and Shh pathway activation. These findings reveal a regulatory molecular mechanism for the initial step of Shh pathway activation.
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37
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Abstract
Cystic kidneys are common causes of end-stage renal disease, both in children and in adults. Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are cilia-related disorders and the two main forms of monogenic cystic kidney diseases. ADPKD is a common disease that mostly presents in adults, whereas ARPKD is a rarer and often more severe form of polycystic kidney disease (PKD) that usually presents perinatally or in early childhood. Cell biological and clinical research approaches have expanded our knowledge of the pathogenesis of ADPKD and ARPKD and revealed some mechanistic overlap between them. A reduced 'dosage' of PKD proteins is thought to disturb cell homeostasis and converging signalling pathways, such as Ca2+, cAMP, mechanistic target of rapamycin, WNT, vascular endothelial growth factor and Hippo signalling, and could explain the more severe clinical course in some patients with PKD. Genetic diagnosis might benefit families and improve the clinical management of patients, which might be enhanced even further with emerging therapeutic options. However, many important questions about the pathogenesis of PKD remain. In this Primer, we provide an overview of the current knowledge of PKD and its treatment.
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Affiliation(s)
- Carsten Bergmann
- Department of Medicine, University Hospital Freiburg, Freiburg, Germany.
| | - Lisa M. Guay-Woodford
- Center for Translational Science, Children’s National Health System, Washington, DC, USA
| | - Peter C. Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Shigeo Horie
- Department of Urology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Dorien J. M. Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Vicente E. Torres
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Gjorgjieva M, Monteillet L, Calderaro J, Mithieux G, Rajas F. Polycystic kidney features of the renal pathology in glycogen storage disease type I: possible evolution to renal neoplasia. J Inherit Metab Dis 2018; 41:955-963. [PMID: 29869165 DOI: 10.1007/s10545-018-0207-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/07/2018] [Accepted: 05/22/2018] [Indexed: 12/12/2022]
Abstract
Glycogen storage disease type I (GSDI) is a rare genetic pathology characterized by glucose-6 phosphatase (G6Pase) deficiency, translating in hypoglycemia during short fasts. Besides metabolic perturbations, GSDI patients develop long-term complications, especially chronic kidney disease (CKD). In GSDI patients, CKD is characterized by an accumulation of glycogen and lipids in kidneys, leading to a gradual decline in renal function. At a molecular level, the activation of the renin-angiotensin system is responsible for the development of renal fibrosis, eventually leading to renal failure. The same CKD phenotype was observed in a mouse model with a kidney-specific G6Pase deficiency (K.G6pc-/- mice). Furthermore, GSDI patients and mice develop frequently renal cysts at late stages of the nephropathy, classifying GSDI as a potential polycystic kidney disease (PKD). PKDs are genetic disorders characterized by multiple renal cyst formation, frequently caused by the loss of expression of polycystic kidney genes, such as PKD1/2 and PKHD1. Interestingly, these genes are deregulated in K.G6pc-/- kidneys, suggesting their possible role in GSDI cystogenesis. Finally, renal cysts are known to predispose to renal malignancy development. In addition, HNF1B loss is a malignancy prediction factor. Interestingly, Hnf1b expression was decreased in K.G6pc-/- kidneys. While a single case of renal cancer has been reported in a GSDI patient, a clear cell renal carcinoma was recently observed in one K.G6pc-/- mouse (out of 36 studied mice) at a later stage of the disease. This finding highlights the need to further analyze renal cyst development in GSDI patients in order to evaluate the possible associated risk of carcinogenesis, even if the risk might be limited.
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Affiliation(s)
- Monika Gjorgjieva
- Institut National de la Santé et de la Recherche by Inserm, U1213, 69008, Lyon, France
- Université de Lyon, 69008, Lyon, France
- Université Lyon1, 69622, Villeurbanne, France
| | - Laure Monteillet
- Institut National de la Santé et de la Recherche by Inserm, U1213, 69008, Lyon, France
- Université de Lyon, 69008, Lyon, France
- Université Lyon1, 69622, Villeurbanne, France
| | - Julien Calderaro
- Inserm UMR-1162, Université Paris Descartes, Labex Immuno-Oncology, Université Paris Diderot, Université Paris 13, Paris, France
- APHP, Assistance-Publique Hôpitaux-de-Paris, Département de Pathologie, Hôpital Henri Mondor, 94010, Créteil, France
| | - Gilles Mithieux
- Institut National de la Santé et de la Recherche by Inserm, U1213, 69008, Lyon, France
- Université de Lyon, 69008, Lyon, France
- Université Lyon1, 69622, Villeurbanne, France
| | - Fabienne Rajas
- Institut National de la Santé et de la Recherche by Inserm, U1213, 69008, Lyon, France.
- Université de Lyon, 69008, Lyon, France.
- Université Lyon1, 69622, Villeurbanne, France.
- Inserm U1213, Université Lyon 1 Laennec, 7 rue Guillaume Paradin, 69372, Lyon Cedex 08, France.
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39
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Zhu S, Bhat S, Syan S, Kuchitsu Y, Fukuda M, Zurzolo C. Rab11a-Rab8a cascade regulates the formation of tunneling nanotubes through vesicle recycling. J Cell Sci 2018; 131:jcs.215889. [PMID: 30209134 DOI: 10.1242/jcs.215889] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 08/29/2018] [Indexed: 01/02/2023] Open
Abstract
Tunneling nanotubes (TNTs) are actin-enriched membranous channels enabling cells to communicate over long distances. TNT-like structures form between various cell types and mediate the exchange of different cargos, such as ions, vesicles, organelles and pathogens; thus, they may play a role in physiological conditions and diseases (e.g. cancer and infection). TNTs also allow the intercellular passage of protein aggregates related to neurodegenerative diseases, thus propagating protein misfolding. Understanding the mechanism of TNT formation is mandatory in order to reveal the mechanism of disease propagation and to uncover their physiological function. Vesicular transport controlled by the small GTPases Rab11a and Rab8a can promote the formation of different plasma membrane protrusions (filopodia, cilia and neurites). Here, we report that inhibiting membrane recycling reduces the number of TNT-connected cells and that overexpression of Rab11a and Rab8a increases the number of TNT-connected cells and the propagation of vesicles between cells in co-culture. We demonstrate that these two Rab GTPases act in a cascade in which Rab11a activation of Rab8a is independent of Rabin8. We also show that VAMP3 acts downstream of Rab8a to regulate TNT formation.
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Affiliation(s)
- Seng Zhu
- Unit of Membrane Trafficking and Pathogenesis, Department of Cell Biology and Infection, Pasteur Institute, Paris 75015, France
| | - Shaarvari Bhat
- Unit of Membrane Trafficking and Pathogenesis, Department of Cell Biology and Infection, Pasteur Institute, Paris 75015, France
| | - Sylvie Syan
- Unit of Membrane Trafficking and Pathogenesis, Department of Cell Biology and Infection, Pasteur Institute, Paris 75015, France
| | - Yoshihiko Kuchitsu
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Mitsunori Fukuda
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Chiara Zurzolo
- Unit of Membrane Trafficking and Pathogenesis, Department of Cell Biology and Infection, Pasteur Institute, Paris 75015, France
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40
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Szabó T, Orosz P, Balogh E, Jávorszky E, Máttyus I, Bereczki C, Maróti Z, Kalmár T, Szabó AJ, Reusz G, Várkonyi I, Marián E, Gombos É, Orosz O, Madar L, Balla G, Kappelmayer J, Tory K, Balogh I. Comprehensive genetic testing in children with a clinical diagnosis of ARPKD identifies phenocopies. Pediatr Nephrol 2018; 33:1713-1721. [PMID: 29956005 DOI: 10.1007/s00467-018-3992-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/12/2018] [Accepted: 05/29/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Autosomal recessive polycystic kidney disease (ARPKD) is genetically one of the least heterogeneous ciliopathies, resulting primarily from mutations of PKHD1. Nevertheless, 13-20% of patients diagnosed with ARPKD are found not to carry PKHD1 mutations by sequencing. Here, we assess whether PKHD1 copy number variations or second locus mutations explain these cases. METHODS Thirty-six unrelated patients with the clinical diagnosis of ARPKD were screened for PKHD1 point mutations and copy number variations. Patients without biallelic mutations were re-evaluated and screened for second locus mutations targeted by the phenotype, followed, if negative, by clinical exome sequencing. RESULTS Twenty-eight patients (78%) carried PKHD1 point mutations, three of whom on only one allele. Two of the three patients harbored in trans either a duplication of exons 33-35 or a large deletion involving exons 1-55. All eight patients without PKHD1 mutations (22%) harbored mutations in other genes (PKD1 (n = 2), HNF1B (n = 3), NPHP1, TMEM67, PKD1/TSC2). Perinatal respiratory failure, a kidney length > +4SD and early-onset hypertension increase the likelihood of PKHD1-associated ARPKD. A patient compound heterozygous for a second and a last exon truncating PKHD1 mutation (p.Gly4013Alafs*25) presented with a moderate phenotype, indicating that fibrocystin is partially functional in the absence of its C-terminal 62 amino acids. CONCLUSIONS We found all ARPKD cases without PKHD1 point mutations to be phenocopies, and none to be explained by biallelic PKHD1 copy number variations. Screening for copy number variations is recommended in patients with a heterozygous point mutation.
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Affiliation(s)
- Tamás Szabó
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Petronella Orosz
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Eszter Balogh
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary.,MTA-SE Lendulet Nephrogenetic Laboratory, Budapest, Hungary
| | - Eszter Jávorszky
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary.,MTA-SE Lendulet Nephrogenetic Laboratory, Budapest, Hungary
| | - István Máttyus
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Csaba Bereczki
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Zoltán Maróti
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Tibor Kalmár
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Attila J Szabó
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary.,MTA-SE Pediatrics and Nephrology Research Group, Budapest, Hungary
| | - George Reusz
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Ildikó Várkonyi
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary
| | - Erzsébet Marián
- Department of Pediatrics, Szabolcs-Szatmár-Bereg Jósa András County Hospital, Nyíregyháza, Hungary
| | - Éva Gombos
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - Orsolya Orosz
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - László Madar
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - György Balla
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Kappelmayer
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary
| | - Kálmán Tory
- Ist Department of Pediatrics, Semmelweis University Budapest, Bókay J. u. 53., Budapest, 1083, Hungary. .,MTA-SE Lendulet Nephrogenetic Laboratory, Budapest, Hungary.
| | - István Balogh
- Division of Clinical Genetics, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Nagyerdei krt. 98., Debrecen, Hungary.
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Gilder AL, Chapin HC, Padovano V, Hueschen CL, Rajendran V, Caplan MJ. Newly synthesized polycystin-1 takes different trafficking pathways to the apical and ciliary membranes. Traffic 2018; 19:933-945. [PMID: 30125442 PMCID: PMC6237641 DOI: 10.1111/tra.12612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 08/15/2018] [Accepted: 08/15/2018] [Indexed: 12/26/2022]
Abstract
Mutations in the genes encoding polycystin-1 (PC1) and polycystin 2 (PC2) cause autosomal dominant polycystic kidney disease. These transmembrane proteins colocalize in the primary cilia of renal epithelial cells, where they may participate in sensory processes. PC1 is also found in the apical membrane when expressed in cultured epithelial cells. PC1 undergoes autocatalytic cleavage, producing an extracellular N-terminal fragment that remains noncovalently attached to the transmembrane C-terminus. Exposing cells to alkaline solutions elutes the N-terminal fragment while the C-terminal fragment is retained in the cell membrane. Utilizing this observation, we developed a "strip-recovery" synchronization protocol to study PC1 trafficking in polarized LLC-PK1 renal epithelial cells. Following alkaline strip, a new cohort of PC1 repopulates the cilia within 30 minutes, while apical delivery of PC1 was not detectable until 3 hours. Brefeldin A (BFA) blocked apical PC1 delivery, while ciliary delivery of PC1 was BFA insensitive. Incubating cells at 20°C to block trafficking out of the trans-Golgi network also inhibits apical but not ciliary delivery. These results suggest that newly synthesized PC1 takes distinct pathways to the ciliary and apical membranes. Ciliary PC1 appears to by-pass BFA sensitive Golgi compartments, while apical delivery of PC1 traverses these compartments.
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Affiliation(s)
- Allison L Gilder
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Hannah C Chapin
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Valeria Padovano
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Christina L Hueschen
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Vanathy Rajendran
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Michael J Caplan
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.,Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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42
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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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43
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Lu L, Madugula V. Mechanisms of ciliary targeting: entering importins and Rabs. Cell Mol Life Sci 2018; 75:597-606. [PMID: 28852774 PMCID: PMC11105572 DOI: 10.1007/s00018-017-2629-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 08/11/2017] [Accepted: 08/16/2017] [Indexed: 12/29/2022]
Abstract
Primary cilium is a rod-like plasma membrane protrusion that plays important roles in sensing the cellular environment and initiating corresponding signaling pathways. The sensory functions of the cilium critically depend on the unique enrichment of ciliary residents, which is maintained by the ciliary diffusion barrier. It is still unclear how ciliary cargoes specifically enter the diffusion barrier and accumulate within the cilium. In this review, the organization and trafficking mechanism of the cilium are compared to those of the nucleus, which are much better understood at the moment. Though the cilium differs significantly from the nucleus in terms of molecular and cellular functions, analogous themes and principles in the membrane organization and cargo trafficking are notable between them. Therefore, knowledge in the nuclear trafficking can likely shed light on our understanding of the ciliary trafficking. Here, with a focus on membrane cargoes in mammalian cells, we briefly review various ciliary trafficking pathways from the Golgi to the periciliary membrane. Models for the subsequent import translocation across the diffusion barrier and the enrichment of cargoes within the ciliary membrane are discussed in detail. Based on recent discoveries, we propose a Rab-importin-based model in an attempt to accommodate various observations on ciliary targeting.
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Affiliation(s)
- Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore.
| | - Viswanadh Madugula
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
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44
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Vetter M, Boegholm N, Christensen A, Bhogaraju S, Andersen MB, Lorentzen A, Lorentzen E. Crystal structure of tetrameric human Rabin8 GEF domain. Proteins 2018; 86:405-413. [DOI: 10.1002/prot.25455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/24/2017] [Accepted: 01/05/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Melanie Vetter
- Department of Structural Cell Biology; Max-Planck-Institute of Biochemistry; Martinsried D-82152 Germany
| | - Niels Boegholm
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C DK-8000 Denmark
| | - Anni Christensen
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C DK-8000 Denmark
| | - Sagar Bhogaraju
- Department of Structural Cell Biology; Max-Planck-Institute of Biochemistry; Martinsried D-82152 Germany
| | - Marie B. Andersen
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C DK-8000 Denmark
| | - Anna Lorentzen
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C DK-8000 Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus C DK-8000 Denmark
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Abstract
INTRODUCTION Polycystic kidney disease (PKD) is clinically and genetically heterogeneous and constitutes the most common heritable kidney disease. Most patients are affected by the autosomal dominant form (ADPKD) which generally is an adult-onset multisystem disorder. By contrast, the rarer recessive form ARPKD usually already manifests perinatally or in childhood. In some patients, however, ADPKD and ARPKD can phenotypically overlap with early manifestation in ADPKD and only late onset in ARPKD. Progressive fibrocystic renal changes are often accompanied by severe hepatobiliary changes or other extrarenal abnormalities. Areas covered: A reduced dosage of disease proteins disturbs cell homeostasis and explains a more severe clinical course in some PKD patients. Cystic kidney disease is also a common feature of other ciliopathies and genetic syndromes. Genetic diagnosis may guide clinical management and helps to avoid invasive measures and to detect renal and extrarenal comorbidities early in the clinical course. Expert Commentary: The broad phenotypic and genetic heterogeneity of cystic and polycystic kidney diseases make NGS a particularly powerful approach. Interpretation of data becomes the challenge and bench and bedside benefit from digitized multidisciplinary interrelationships.
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Affiliation(s)
- Carsten Bergmann
- a Center for Human Genetics , Bioscientia , Ingelheim , Germany.,b Department of Medicine , University Hospital Freiburg , Freiburg , Germany
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46
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Klink BU, Zent E, Juneja P, Kuhlee A, Raunser S, Wittinghofer A. A recombinant BBSome core complex and how it interacts with ciliary cargo. eLife 2017; 6. [PMID: 29168691 PMCID: PMC5700813 DOI: 10.7554/elife.27434] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 11/03/2017] [Indexed: 01/07/2023] Open
Abstract
Cilia are small, antenna-like structures on the surface of eukaryotic cells that harbor a unique set of sensory proteins, including GPCRs and other membrane proteins. The transport of these proteins involves the BBSome, an eight-membered protein complex that is recruited to ciliary membranes by the G-protein Arl6. BBSome malfunction leads to Bardet-Biedl syndrome, a ciliopathy with severe consequences. Short ciliary targeting sequences (CTS) have been identified that trigger the transport of ciliary proteins. However, mechanistic studies that relate ciliary targeting to BBSome binding are missing. Here we used heterologously expressed BBSome subcomplexes to analyze the complex architecture and to investigate the binding of GPCRs and other receptors to the BBSome. A stable heterohexameric complex was identified that binds to GPCRs with interactions that only partially overlap with previously described CTS, indicating a more complex recognition than anticipated. Arl6•GTP does not affect these interactions, suggesting no direct involvement in cargo loading/unloading.
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Affiliation(s)
- Björn Udo Klink
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.,Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Eldar Zent
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Puneet Juneja
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Anne Kuhlee
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Alfred Wittinghofer
- Structural Biology Group, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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47
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Outeda P, Menezes L, Hartung EA, Bridges S, Zhou F, Zhu X, Xu H, Huang Q, Yao Q, Qian F, Germino GG, Watnick T. A novel model of autosomal recessive polycystic kidney questions the role of the fibrocystin C-terminus in disease mechanism. Kidney Int 2017; 92:1130-1144. [PMID: 28729032 PMCID: PMC6005173 DOI: 10.1016/j.kint.2017.04.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/09/2017] [Accepted: 04/27/2017] [Indexed: 12/11/2022]
Abstract
Autosomal recessive polycystic kidney disease (OMIM 263200) is a serious condition of the kidney and liver caused by mutations in a single gene, PKHD1. This gene encodes fibrocystin/polyductin (FPC, PD1), a large protein shown by in vitro studies to undergo Notch-like processing. Its cytoplasmic tail, reported to include a ciliary targeting sequence, a nuclear localization signal, and a polycystin-2 binding domain, is thought to traffic to the nucleus after cleavage. We now report a novel mouse line with a triple HA-epitope "knocked-in" to the C-terminus along with lox P sites flanking exon 67, which encodes most of the C-terminus (Pkhd1Flox67HA). The triple HA-epitope has no functional effect as assayed by phenotype and allows in vivo tracking of Fibrocystin. We used the HA tag to identify previously predicted Fibrocystin cleavage products in tissue. In addition, we found that Polycystin-2 fails to co-precipitate with Fibrocystin in kidney samples. Immunofluorescence studies with anti-HA antibodies demonstrate that Fibrocystin is primarily present in a sub-apical location the in kidney, biliary duct, and pancreatic ducts, partially overlapping with the Golgi. In contrast to previous studies, the endogenous protein in the primary cilia was not detectable in mouse tissues. After Cre-mediated deletion, homozygous Pkhd1Δ67 mice are completely normal. Thus, Pkhd1Flox67HA is a valid model to track Pkhd1-derived products containing the C-terminus. Significantly, exon 67 containing the nuclear localization signal and the polycystin-2 binding domain is not essential for Fibrocystin function in our model.
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Affiliation(s)
- Patricia Outeda
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Luis Menezes
- Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Erum A Hartung
- Division of Nephrology, Children's Hospital of Philadelphia, Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stacey Bridges
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Fang Zhou
- Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Study, Sichuan Academy of Sciences and Sichuan Provincial People's Hospital Chengdue, Sichuan, China
| | - Hangxue Xu
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Qiong Huang
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Qin Yao
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Gregory G Germino
- Kidney Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
| | - Terry Watnick
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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48
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Roy K, Jerman S, Jozsef L, McNamara T, Onyekaba G, Sun Z, Marin EP. Palmitoylation of the ciliary GTPase ARL13b is necessary for its stability and its role in cilia formation. J Biol Chem 2017; 292:17703-17717. [PMID: 28848045 PMCID: PMC5663873 DOI: 10.1074/jbc.m117.792937] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 08/18/2017] [Indexed: 01/01/2023] Open
Abstract
Primary cilia are hairlike extensions of the plasma membrane of most mammalian cells that serve specialized signaling functions. To traffic properly to cilia, multiple cilia proteins rely on palmitoylation, the post-translational attachment of a saturated 16-carbon lipid. However, details regarding the mechanism of how palmitoylation affects cilia protein localization and function are unknown. Herein, we investigated the protein ADP-ribosylation factor-like GTPase 13b (ARL13b) as a model palmitoylated ciliary protein. Using biochemical, cellular, and in vivo studies, we found that ARL13b palmitoylation occurs in vivo in mouse kidneys and that it is required for trafficking to and function within cilia. Myristoylation, a 14-carbon lipid, is shown to largely substitute for palmitoylation with regard to cilia localization of ARL13b, but not with regard to its function within cilia. The functional importance of palmitoylation results in part from a dramatic increase in ARL13b stability, which is not observed with myristoylation. Additional results show that blockade of depalmitoylation slows the degradation of ARL13b that occurs during cilia resorption, raising the possibility that the sensitivity of ARL13b stability to palmitoylation may be exploited by the cell to accelerate degradation of ARL13b by depalmitoylating it. Together, the results show that palmitoylation plays a unique and critical role in controlling the localization, stability, abundance, and thus function of ARL13b. Pharmacological manipulation of protein palmitoylation may be a strategy to alter cilia function.
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Affiliation(s)
- Kasturi Roy
- From the Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520-8029 and
| | - Stephanie Jerman
- the Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8029
| | - Levente Jozsef
- From the Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520-8029 and
| | - Thomas McNamara
- From the Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520-8029 and
| | - Ginikanwa Onyekaba
- From the Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520-8029 and
| | - Zhaoxia Sun
- the Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8029
| | - Ethan P Marin
- From the Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520-8029 and
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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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Guo J, Otis JM, Higginbotham H, Monckton C, Cheng J, Asokan A, Mykytyn K, Caspary T, Stuber GD, Anton ES. Primary Cilia Signaling Shapes the Development of Interneuronal Connectivity. Dev Cell 2017; 42:286-300.e4. [PMID: 28787594 DOI: 10.1016/j.devcel.2017.07.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 05/18/2017] [Accepted: 07/12/2017] [Indexed: 01/06/2023]
Abstract
Appropriate growth and synaptic integration of GABAergic inhibitory interneurons are essential for functional neural circuits in the brain. Here, we demonstrate that disruption of primary cilia function following the selective loss of ciliary GTPase Arl13b in interneurons impairs interneuronal morphology and synaptic connectivity, leading to altered excitatory/inhibitory activity balance. The altered morphology and connectivity of cilia mutant interneurons and the functional deficits are rescued by either chemogenetic activation of ciliary G-protein-coupled receptor (GPCR) signaling or the selective induction of Sstr3, a ciliary GPCR, in Arl13b-deficient cilia. Our results thus define a specific requirement for primary cilia-mediated GPCR signaling in interneuronal connectivity and inhibitory circuit formation.
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Affiliation(s)
- Jiami Guo
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - James M Otis
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Holden Higginbotham
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Chase Monckton
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - JrGang Cheng
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Aravind Asokan
- Department of Genetics and Gene Therapy Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Kirk Mykytyn
- Department of Biological Chemistry and Pharmacology, Neuroscience Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Garret D Stuber
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - E S Anton
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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