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Ahmed M, Fischer S, Robert KL, Lange KI, Stuck MW, Best S, Johnson CA, Pazour GJ, Blacque OE, Nandadasa S. Two functional forms of the Meckel-Gruber syndrome protein TMEM67 generated by proteolytic cleavage by ADAMTS9 mediate Wnt signaling and ciliogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.04.611229. [PMID: 39282264 PMCID: PMC11398388 DOI: 10.1101/2024.09.04.611229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/21/2024]
Abstract
TMEM67 mutations are the major cause of Meckel-Gruber syndrome. TMEM67 is involved in both ciliary transition zone assembly, and non-canonical Wnt signaling mediated by its extracellular domain. How TMEM67 performs these two separate functions is not known. We identify a novel cleavage motif in the extracellular domain of TMEM67 cleaved by the extracellular matrix metalloproteinase ADAMTS9. This cleavage regulates the abundance of two functional forms: A C-terminal portion which localizes to the ciliary transition zone regulating ciliogenesis, and a non-cleaved form which regulates Wnt signaling. By characterizing three TMEM67 ciliopathy patient variants within the cleavage motif utilizing mammalian cell culture and C. elegans, we show the cleavage motif is essential for cilia structure and function, highlighting its clinical significance. We generated a novel non-cleavable TMEM67 mouse model which develop severe ciliopathies phenocopying Tmem67 -/- mice, but in contrast, undergo normal Wnt signaling, substantiating the existence of two functional forms of TMEM67.
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Affiliation(s)
- Manu Ahmed
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA
| | - Sydney Fischer
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA
| | - Karyn L. Robert
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA
| | - Karen I. Lange
- School of Biomolecular & Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michael W. Stuck
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA
| | - Sunayna Best
- Division of Molecular Medicine, Leeds Institute of Medical Research, The University of Leeds, Leeds, UK
- Department of Clinical Genetics, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Colin A. Johnson
- Division of Molecular Medicine, Leeds Institute of Medical Research, The University of Leeds, Leeds, UK
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA
| | - Oliver E. Blacque
- School of Biomolecular & Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sumeda Nandadasa
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA
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2
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Fujii T, Liang L, Nakayama K, Katoh Y. Defects in diffusion barrier function of ciliary transition zone caused by ciliopathy variations of TMEM218. Hum Mol Genet 2024; 33:1442-1453. [PMID: 38751342 DOI: 10.1093/hmg/ddae083] [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: 03/15/2024] [Revised: 05/01/2024] [Accepted: 05/07/2024] [Indexed: 08/09/2024] Open
Abstract
Primary cilia are antenna-like structures protruding from the surface of various eukaryotic cells, and have distinct protein compositions in their membranes. This distinct protein composition is maintained by the presence of the transition zone (TZ) at the ciliary base, which acts as a diffusion barrier between the ciliary and plasma membranes. Defects in cilia and the TZ are known to cause a group of disorders collectively called the ciliopathies, which demonstrate a broad spectrum of clinical features, such as perinatally lethal Meckel syndrome (MKS), relatively mild Joubert syndrome (JBTS), and nonsyndromic nephronophthisis (NPHP). Proteins constituting the TZ can be grouped into the MKS and NPHP modules. The MKS module is composed of several transmembrane proteins and three soluble proteins. TMEM218 was recently reported to be mutated in individuals diagnosed as MKS and JBTS. However, little is known about how TMEM218 mutations found in MKS and JBTS affect the functions of cilia. In this study, we found that ciliary membrane proteins were not localized to cilia in TMEM218-knockout cells, indicating impaired barrier function of the TZ. Furthermore, the exogenous expression of JBTS-associated TMEM218 variants but not MKS-associated variants in TMEM218-knockout cells restored the localization of ciliary membrane proteins. In particular, when expressed in TMEM218-knockout cells, the TMEM218(R115H) variant found in JBTS was able to restore the barrier function of cells, whereas the MKS variant TMEM218(R115C) could not. Thus, the severity of symptoms of MKS and JBTS individuals appears to correlate with the degree of their ciliary defects at the cellular level.
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Affiliation(s)
- Taiju Fujii
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Luxiaoxue Liang
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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3
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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 PMCID: PMC11346432 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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4
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Houston BJ, Merriner DJ, Stathatos GG, Nguyen JH, O'Connor AE, Lopes AM, Conrad DF, Baker M, Dunleavy JE, O'Bryan MK. Genetic mutation of Cep76 results in male infertility due to abnormal sperm tail composition. Life Sci Alliance 2024; 7:e202302452. [PMID: 38570187 PMCID: PMC10992998 DOI: 10.26508/lsa.202302452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
The transition zone is a specialised gate at the base of cilia/flagella, which separates the ciliary compartment from the cytoplasm and strictly regulates protein entry. We identified a potential new regulator of the male germ cell transition zone, CEP76. We demonstrated that CEP76 was involved in the selective entry and incorporation of key proteins required for sperm function and fertility into the ciliary compartment and ultimately the sperm tail. In the mutant, sperm tails were shorter and immotile as a consequence of deficits in essential sperm motility proteins including DNAH2 and AKAP4, which accumulated at the sperm neck in the mutant. Severe annulus, fibrous sheath, and outer dense fibre abnormalities were also detected in sperm lacking CEP76. Finally, we identified that CEP76 dictates annulus positioning and structure. This study suggests CEP76 as a male germ cell transition zone protein and adds further evidence to the hypothesis that the spermatid transition zone and annulus are part of the same functional structure.
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Affiliation(s)
- Brendan J Houston
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - D Jo Merriner
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - G Gemma Stathatos
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Joseph H Nguyen
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Anne E O'Connor
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Alexandra M Lopes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Institute of Molecular Pathology & Immunology, University of Porto, Porto, Portugal
| | - Donald F Conrad
- Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Mark Baker
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, Australia
- School of Biomedical Sciences and Pharmacy, College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, Australia
| | - Jessica Em Dunleavy
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Moira K O'Bryan
- https://ror.org/01ej9dk98 School of BioSciences and Bio21 Molecular Sciences and Biotechnology Institute, The University of Melbourne, Parkville, Australia
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5
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Rao VG, Subramanianbalachandar V, Magaj MM, Redemann S, Kulkarni SS. Mechanisms of cilia regeneration in Xenopus multiciliated epithelium in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.14.544972. [PMID: 37398226 PMCID: PMC10312767 DOI: 10.1101/2023.06.14.544972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cilia regeneration is a physiological event, and while studied extensively in unicellular organisms, it remains poorly understood in vertebrates. In this study, using Xenopus multiciliated cells (MCCs) as a model, we demonstrate that, unlike unicellular organisms, deciliation removes the transition zone (TZ) and the ciliary axoneme. While MCCs immediately begin the regeneration of the ciliary axoneme, surprisingly, the assembly of TZ is delayed. However, ciliary tip proteins, Sentan and Clamp, localize to regenerating cilia without delay. Using cycloheximide (CHX) to block new protein synthesis, we show that the TZ protein B9d1 is not a component of the cilia precursor pool and requires new transcription/translation, providing insights into the delayed repair of TZ. Moreover, MCCs in CHX treatment assemble fewer (∼ 10 vs. ∼150 in controls) but near wild-type length (ranging between 60 to 90%) cilia by gradually concentrating ciliogenesis proteins like IFTs at a select few basal bodies. Using mathematical modeling, we show that cilia length compared to cilia number influences the force generated by MCCs more. In summary, our results question the requirement of TZ in motile cilia assembly and provide insights into how cells determine organelle size and number.
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6
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Xie S, Naslavsky N, Caplan S. Emerging insights into CP110 removal during early steps of ciliogenesis. J Cell Sci 2024; 137:jcs261579. [PMID: 38415788 PMCID: PMC10941660 DOI: 10.1242/jcs.261579] [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] [Indexed: 02/29/2024] Open
Abstract
The primary cilium is an antenna-like projection from the plasma membrane that serves as a sensor of the extracellular environment and a crucial signaling hub. Primary cilia are generated in most mammalian cells, and their physiological significance is highlighted by the large number of severe developmental disorders or ciliopathies that occur when primary ciliogenesis is impaired. Primary ciliogenesis is a tightly regulated process, and a central early regulatory step is the removal of a key mother centriole capping protein, CP110 (also known as CCP110). This uncapping allows vesicles docked on the distal appendages of the mother centriole to fuse to form a ciliary vesicle, which is bent into a ciliary sheath as the microtubule-based axoneme grows and extends from the mother centriole. When the mother centriole migrates toward the plasma membrane, the ciliary sheath fuses with the plasma membrane to form the primary cilium. In this Review, we outline key early steps of primary ciliogenesis, focusing on several novel mechanisms for removal of CP110. We also highlight examples of ciliopathies caused by genetic variants that encode key proteins involved in the early steps of ciliogenesis.
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Affiliation(s)
- Shuwei Xie
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Naava Naslavsky
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Steve Caplan
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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7
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Moran AL, Louzao-Martinez L, Norris DP, Peters DJM, Blacque OE. Transport and barrier mechanisms that regulate ciliary compartmentalization and ciliopathies. Nat Rev Nephrol 2024; 20:83-100. [PMID: 37872350 DOI: 10.1038/s41581-023-00773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2023] [Indexed: 10/25/2023]
Abstract
Primary cilia act as cell surface antennae, coordinating cellular responses to sensory inputs and signalling molecules that regulate developmental and homeostatic pathways. Cilia are therefore critical to physiological processes, and defects in ciliary components are associated with a large group of inherited pleiotropic disorders - known collectively as ciliopathies - that have a broad spectrum of phenotypes and affect many or most tissues, including the kidney. A central feature of the cilium is its compartmentalized structure, which imparts its unique molecular composition and signalling environment despite its membrane and cytosol being contiguous with those of the cell. Such compartmentalization is achieved via active transport pathways that bring protein cargoes to and from the cilium, as well as gating pathways at the ciliary base that establish diffusion barriers to protein exchange into and out of the organelle. Many ciliopathy-linked proteins, including those involved in kidney development and homeostasis, are components of the compartmentalizing machinery. New insights into the major compartmentalizing pathways at the cilium, namely, ciliary gating, intraflagellar transport, lipidated protein flagellar transport and ciliary extracellular vesicle release pathways, have improved our understanding of the mechanisms that underpin ciliary disease and associated renal disorders.
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Affiliation(s)
- Ailis L Moran
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Laura Louzao-Martinez
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland.
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8
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Wang Y, Yao H, Zhang Y, Mu N, Lu T, Du Z, Wu Y, Li X, Su M, Shao M, Sun X, Su L, Liu X. TMEM216 promotes primary ciliogenesis and Hedgehog signaling through the SUFU-GLI2/GLI3 axis. Sci Signal 2024; 17:eabo0465. [PMID: 38261656 DOI: 10.1126/scisignal.abo0465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 01/04/2024] [Indexed: 01/25/2024]
Abstract
Primary cilia are enriched in signaling receptors, and defects in their formation or function can induce conditions such as polycystic kidney disease, postaxial hexadactyly, and microphthalmia. Mammalian Hedgehog (Hh) signaling is important in the development of primary cilia, and TMEM216, a transmembrane protein that localizes to the base of cilia, is also implicated in ciliogenesis in zebrafish. Here, we found that Tmem216-deficient mice had impaired Hh signaling and displayed typical ciliopathic phenotypes. These phenomena were also observed in cells deficient in TMEM216. Furthermore, TMEM216 interacted with core Hh signaling proteins, including SUFU, a negative regulator of Hh, and GLI2/GLI3, transcription factors downstream of Hh. The competition between TMEM216 and SUFU for binding to GLI2/GLI3 inhibited the cleavage of GLI2/GLI3 into their repressor forms, which resulted in the nuclear accumulation of full-length GLI2 and the decreased nuclear localization of cleaved GLI3, ultimately leading to the activation of Hh signaling. Together, these data suggest that the TMEM216-SUFU-GLI2/GLI3 axis plays a role in TMEM216 deficiency-induced ciliopathies and Hh signaling abnormalities.
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Affiliation(s)
- Yingying Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Huili Yao
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Yu Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Ning Mu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Tong Lu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Zhiyuan Du
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Yingdi Wu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xiaopeng Li
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Min Su
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Ming Shao
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xiaoyang Sun
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Ling Su
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Xiangguo Liu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
- Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
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9
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Kalot R, Sentell Z, Kitzler TM, Torban E. Primary cilia and actin regulatory pathways in renal ciliopathies. FRONTIERS IN NEPHROLOGY 2024; 3:1331847. [PMID: 38292052 PMCID: PMC10824913 DOI: 10.3389/fneph.2023.1331847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024]
Abstract
Ciliopathies are a group of rare genetic disorders caused by defects to the structure or function of the primary cilium. They often affect multiple organs, leading to brain malformations, congenital heart defects, and anomalies of the retina or skeletal system. Kidney abnormalities are among the most frequent ciliopathic phenotypes manifesting as smaller, dysplastic, and cystic kidneys that are often accompanied by renal fibrosis. Many renal ciliopathies cause chronic kidney disease and often progress to end-stage renal disease, necessitating replacing therapies. There are more than 35 known ciliopathies; each is a rare hereditary condition, yet collectively they account for a significant proportion of chronic kidney disease worldwide. The primary cilium is a tiny microtubule-based organelle at the apex of almost all vertebrate cells. It serves as a "cellular antenna" surveying environment outside the cell and transducing this information inside the cell to trigger multiple signaling responses crucial for tissue morphogenesis and homeostasis. Hundreds of proteins and unique cellular mechanisms are involved in cilia formation. Recent evidence suggests that actin remodeling and regulation at the base of the primary cilium strongly impacts ciliogenesis. In this review, we provide an overview of the structure and function of the primary cilium, focusing on the role of actin cytoskeleton and its regulators in ciliogenesis. We then describe the key clinical, genetic, and molecular aspects of renal ciliopathies. We highlight what is known about actin regulation in the pathogenesis of these diseases with the aim to consider these recent molecular findings as potential therapeutic targets for renal ciliopathies.
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Affiliation(s)
- Rita Kalot
- Department of Medicine and Department of Physiology, McGill University, Montreal, QC, Canada
- The Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Zachary Sentell
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Thomas M. Kitzler
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- McGill University Health Center, Montreal, QC, Canada
| | - Elena Torban
- Department of Medicine and Department of Physiology, McGill University, Montreal, QC, Canada
- The Research Institute of the McGill University Health Center, Montreal, QC, Canada
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10
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Chatzifrangkeskou M, Kouis P, Skourides PA. JNK regulates ciliogenesis through the interflagellar transport complex and actin networks. J Cell Biol 2023; 222:e202303052. [PMID: 37851005 PMCID: PMC10585068 DOI: 10.1083/jcb.202303052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/16/2023] [Accepted: 08/29/2023] [Indexed: 10/19/2023] Open
Abstract
The c-Jun N-terminal kinase (JNK) regulates various important physiological processes. Although the JNK pathway has been under intense investigation for over 20 yr, its complexity is still perplexing, with multiple protein partners underlying the diversity of its activity. We show that JNK is associated with the basal bodies in both primary and motile cilia. Loss of JNK disrupts basal body migration and docking and leads to severe ciliogenesis defects. JNK's involvement in ciliogenesis stems from a dual role in the regulation of the actin networks of multiciliated cells (MCCs) and the establishment of the intraflagellar transport-B core complex. JNK signaling is also critical for the maintenance of the actin networks and ciliary function in mature MCCs. JNK is implicated in the development of diabetes, neurodegeneration, and liver disease, all of which have been linked to ciliary dysfunction. Our work uncovers a novel role of JNK in ciliogenesis and ciliary function that could have important implications for JNK's role in the disease.
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Affiliation(s)
| | - Panayiotis Kouis
- Respiratory Physiology Laboratory, Medical School, University of Cyprus, Nicosia, Cyprus
| | - Paris A. Skourides
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
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11
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Truong HM, Cruz-Colón KO, Martínez-Márquez JY, Willer JR, Travis AM, Biswas SK, Lo WK, Bolz HJ, Pearring JN. The tectonic complex regulates membrane protein composition in the photoreceptor cilium. Nat Commun 2023; 14:5671. [PMID: 37704658 PMCID: PMC10500017 DOI: 10.1038/s41467-023-41450-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 08/30/2023] [Indexed: 09/15/2023] Open
Abstract
The primary cilium is a signaling organelle with a unique membrane composition maintained by a diffusional barrier residing at the transition zone. Many transition zone proteins, such as the tectonic complex, are linked to preserving ciliary composition but the mechanism remains unknown. To understand tectonic's role, we generate a photoreceptor-specific Tctn1 knockout mouse. Loss of Tctn1 results in the absence of the entire tectonic complex and associated MKS proteins yet has minimal effects on the transition zone structure of rod photoreceptors. We find that the protein composition of the photoreceptor cilium is disrupted as non-resident membrane proteins accumulate in the cilium over time, ultimately resulting in photoreceptor degeneration. We further show that fluorescent rhodopsin moves faster through the transition zone in photoreceptors lacking tectonic, which suggests that the tectonic complex acts as a physical barrier to slow down membrane protein diffusion in the photoreceptor transition zone to ensure proper removal of non-resident membrane proteins.
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Affiliation(s)
- Hanh M Truong
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | - Kevin O Cruz-Colón
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Jason R Willer
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Amanda M Travis
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Sondip K Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Hanno J Bolz
- Senckenberg Centre for Human Genetics, Frankfurt am Main, Germany
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Jillian N Pearring
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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12
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Zhang Q, Yang S, Chen X, Wang H, Li K, Zhang C, Liao S, Qin L, Hou Q. Identification of novel TMEM231 gene splice variants and pathological findings in a fetus with Meckel Syndrome. Front Genet 2023; 14:1252873. [PMID: 37736303 PMCID: PMC10509762 DOI: 10.3389/fgene.2023.1252873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 08/22/2023] [Indexed: 09/23/2023] Open
Abstract
Background: Meckel Syndrome (MKS, OMIM #249000) is a rare and fatal autosomal recessive ciliopathy with high clinical and genetic heterogeneity. MKS shows complex allelism with other related ciliopathies such as Joubert Syndrome (JBTS, OMIM #213300). In MKS, the formation and function of the primary cilium is defective, resulting in a multisystem disorder including occipital encephalocele, polycystic kidneys, postaxial polydactyly, liver fibrosis, central nervous system malformations and genital anomalies. This study aimed to analyze the genotype of MKS patients and investigate the correlation between genotype and phenotype. Methods: A nonconsanguineous couple who conceived four times with a fetus affected by multiorgan dysfunction and intrauterine fetal death was studied. Whole exome sequencing (WES) was performed in the proband to identify the potentially pathogenic variant. Sanger sequencing was performed in family members. In silico tools were used to analyse the pathogenicity of the identified variants. cDNA TA-cloning sequencing was performed to validate the effects of intronic variants on mRNA splicing. Quantitative real-time PCR was performed to investigate the effect of the variants on gene expression. Immunofluorescence was performed to observe pathological changes of the primary cilium in kidney tissue from the proband. Results: Two splice site variants of TMEM231 (NM_001077418.2, c.583-1G>C and c.583-2_588delinsTCCTCCC) were identified in the proband, and the two variants have not been previously reported. The parents were confirmed as carriers. The two variants were predicted to be pathogenic by in silico tools and were classified as pathogenic/likely pathogenic variants according to the American College of Medical Genetics and Genomics guideline. cDNA TA cloning analysis showed that both splice site variants caused a deletion of exon 5. RT-PCR revealed that the expression of TMEM231 was significantly decreased and immunofluorescence showed that the primary cilium was almost absent in the proband's kidney tissue. Conclusion: We reported the clinical, genetic, molecular and histochemical characterisation of a family affected by MKS. Our findings not only extended the mutation spectrum of the TMEM231 gene, but also revealed for the first time the pathological aetiology of primary cilia in humans and provide a basis for genetic counselling of the parents to their offspring.
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Affiliation(s)
- Qian Zhang
- Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Shuya Yang
- People’s Hospital of Henan University, Henan University, Zhengzhou, China
| | - Xin Chen
- Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Hongdan Wang
- Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Keyan Li
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Chaonan Zhang
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Shixiu Liao
- Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Litao Qin
- Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Qiaofang Hou
- Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, People’s Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
- People’s Hospital of Henan University, Henan University, Zhengzhou, China
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13
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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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14
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Downie ML, Gupta S, Voinescu C, Levine AP, Sadeghi-Alavijeh O, Dufek-Kamperis S, Cao J, Christian M, Kari JA, Thalgahagoda S, Ranawaka R, Abeyagunawardena A, Gbadegesin R, Parekh R, Kleta R, Bockenhauer D, Stanescu HC, Gale DP. Common Risk Variants in AHI1 Are Associated With Childhood Steroid Sensitive Nephrotic Syndrome. Kidney Int Rep 2023; 8:1562-1574. [PMID: 37547536 PMCID: PMC10403666 DOI: 10.1016/j.ekir.2023.05.018] [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: 02/03/2023] [Revised: 04/21/2023] [Accepted: 05/22/2023] [Indexed: 08/08/2023] Open
Abstract
Introduction Steroid-sensitive nephrotic syndrome (SSNS) is the most common form of kidney disease in children worldwide. Genome-wide association studies (GWAS) have demonstrated the association of SSNS with genetic variation at HLA-DQ/DR and have identified several non-HLA loci that aid in further understanding of disease pathophysiology. We sought to identify additional genetic loci associated with SSNS in children of Sri Lankan and European ancestry. Methods We conducted a GWAS in a cohort of Sri Lankan individuals comprising 420 pediatric patients with SSNS and 2339 genetic ancestry matched controls obtained from the UK Biobank. We then performed a transethnic meta-analysis with a previously reported European cohort of 422 pediatric patients and 5642 controls. Results Our GWAS confirmed the previously reported association of SSNS with HLA-DR/DQ (rs9271602, P = 1.12 × 10-27, odds ratio [OR] = 2.75). Transethnic meta-analysis replicated these findings and identified a novel association at AHI1 (rs2746432, P = 2.79 × 10-8, OR = 1.37), which was also replicated in an independent South Asian cohort. AHI1 is implicated in ciliary protein transport and immune dysregulation, with rare variation in this gene contributing to Joubert syndrome type 3. Conclusions Common variation in AHI1 confers risk of the development of SSNS in both Sri Lankan and European populations. The association with common variation in AHI1 further supports the role of immune dysregulation in the pathogenesis of SSNS and demonstrates that variation across the allele frequency spectrum in a gene can contribute to disparate monogenic and polygenic diseases.
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Affiliation(s)
- Mallory L. Downie
- Department of Renal Medicine, University College London, London, UK
- Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Sanjana Gupta
- Department of Renal Medicine, University College London, London, UK
| | - Catalin Voinescu
- Department of Renal Medicine, University College London, London, UK
| | - Adam P. Levine
- Department of Pathology, University College London, London, UK
| | | | | | - Jingjing Cao
- Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada
| | | | - Jameela A. Kari
- Pediatric Nephrology Centre of Excellence, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | | | - Randula Ranawaka
- Department of Pediatrics, University of Peradeniya, Peradeniya, Sri Lanka
| | | | - Rasheed Gbadegesin
- Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina, USA
| | - Rulan Parekh
- Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada
- Department of Medicine, Women’s College Hospital, Toronto, Canada
| | - Robert Kleta
- Department of Renal Medicine, University College London, London, UK
- Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, UK
- Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | | | - Daniel P. Gale
- Department of Renal Medicine, University College London, London, UK
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15
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Mill P, Christensen ST, Pedersen LB. Primary cilia as dynamic and diverse signalling hubs in development and disease. Nat Rev Genet 2023; 24:421-441. [PMID: 37072495 PMCID: PMC7615029 DOI: 10.1038/s41576-023-00587-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 04/20/2023]
Abstract
Primary cilia, antenna-like sensory organelles protruding from the surface of most vertebrate cell types, are essential for regulating signalling pathways during development and adult homeostasis. Mutations in genes affecting cilia cause an overlapping spectrum of >30 human diseases and syndromes, the ciliopathies. Given the immense structural and functional diversity of the mammalian cilia repertoire, there is a growing disconnect between patient genotype and associated phenotypes, with variable severity and expressivity characteristic of the ciliopathies as a group. Recent technological developments are rapidly advancing our understanding of the complex mechanisms that control biogenesis and function of primary cilia across a range of cell types and are starting to tackle this diversity. Here, we examine the structural and functional diversity of primary cilia, their dynamic regulation in different cellular and developmental contexts and their disruption in disease.
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Affiliation(s)
- Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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16
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Safavian D, Kim MS, Xie H, El-Zeiry M, Palander O, Dai L, Collins RF, Froese C, Shannon R, Nagata KI, Trimble WS. Septin-mediated RhoA activation engages the exocyst complex to recruit the cilium transition zone. J Cell Biol 2023; 222:e201911062. [PMID: 36912772 PMCID: PMC10039714 DOI: 10.1083/jcb.201911062] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/25/2022] [Accepted: 01/05/2023] [Indexed: 03/14/2023] Open
Abstract
Septins are filamentous GTPases that play important but poorly characterized roles in ciliogenesis. Here, we show that SEPTIN9 regulates RhoA signaling at the base of cilia by binding and activating the RhoA guanine nucleotide exchange factor, ARHGEF18. GTP-RhoA is known to activate the membrane targeting exocyst complex, and suppression of SEPTIN9 causes disruption of ciliogenesis and mislocalization of an exocyst subunit, SEC8. Using basal body-targeted proteins, we show that upregulating RhoA signaling at the cilium can rescue ciliary defects and mislocalization of SEC8 caused by global SEPTIN9 depletion. Moreover, we demonstrate that the transition zone components, RPGRIP1L and TCTN2, fail to accumulate at the transition zone in cells lacking SEPTIN9 or depleted of the exocyst complex. Thus, SEPTIN9 regulates the recruitment of transition zone proteins on Golgi-derived vesicles by activating the exocyst via RhoA to allow the formation of primary cilia.
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Affiliation(s)
- Darya Safavian
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Moshe S. Kim
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Hong Xie
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Maha El-Zeiry
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Oliva Palander
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Lu Dai
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Richard F. Collins
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Carol Froese
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rachel Shannon
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Koh-ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan
| | - William S. Trimble
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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17
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Structure of the N-terminal coiled-coil domains of the ciliary protein Rpgrip1l. iScience 2023; 26:106249. [PMID: 36915689 PMCID: PMC10006689 DOI: 10.1016/j.isci.2023.106249] [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: 07/27/2022] [Revised: 12/30/2022] [Accepted: 02/16/2023] [Indexed: 02/25/2023] Open
Abstract
Rpgrip1l is one of the key ciliary proteins located at the transition zone of the primary cilium, an important organelle for cells to sense the outer environment. Mutations in the RPGRIP1L gene are associated with various ciliopathies. Here, we focused on the N-terminal coiled-coil of Rpgrip1l. By comprehensive biochemical and structural characterizations, we demonstrated that the two predicted coiled-coil regions (CC12) located at Rpgrip1l N-terminus each can form a stable parallel dimer. We further showed that overexpression of Rpgrip1l CC12 in NIH/3T3 cells significantly shortened the length of primary cilia, and this effect depended on the dimer formation. In addition, we found that CC12 of the homolog protein Rpgrip1 in mouse and human were significantly different from Rpgrip1l. Finally, we confirmed that some disease-related mutations can alter the dimeric states of CC12 of Rpgrip1l or Rpgrip1, which might explain the pathogenic mechanisms.
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18
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Amorini M, Iapadre G, Mancuso A, Ceravolo I, Farello G, Scardamaglia A, Gramaglia S, Ceravolo A, Salpietro A, Cuppari C. An Overview of Genes Involved in the Pure Joubert Syndrome and in Joubert Syndrome-Related Disorders (JSRD). JOURNAL OF PEDIATRIC NEUROLOGY 2023. [DOI: 10.1055/s-0042-1760242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AbstractJoubert syndrome (JS) is a rare autosomal recessive disease characterized by a peculiar brain malformation, hypotonia, ataxia, developmental delay, abnormal eye movements, and neonatal breathing abnormalities. This picture is often associated with variable multiorgan involvement, mainly of the retina, kidneys and liver, defining a group of conditions termed syndrome and Joubert syndrome-related disorders (JSRD). Currently, more than 30 causative genes have been identified, involved in the development and stability of the primary cilium. Correlations genotype–phenotype are emerging between clinical presentations and mutations in JSRD genes, with implications in terms of molecular diagnosis, prenatal diagnosis, follow-up, and management of mutated patients.
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Affiliation(s)
- Maria Amorini
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
| | - Giulia Iapadre
- Department of Pediatrics, University of L'Aquila, L'Aquila, Italy
| | - Alessio Mancuso
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
| | - Ida Ceravolo
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Giovanni Farello
- Department of Life, Health and Environmental Sciences, Pediatric Clinic, Coppito (AQ), Italy
| | - Annarita Scardamaglia
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Simone Gramaglia
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
| | | | | | - Caterina Cuppari
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
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19
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Park K, Leroux MR. Composition, organization and mechanisms of the transition zone, a gate for the cilium. EMBO Rep 2022; 23:e55420. [PMID: 36408840 PMCID: PMC9724682 DOI: 10.15252/embr.202255420] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/08/2022] [Accepted: 10/31/2022] [Indexed: 11/22/2022] Open
Abstract
The cilium evolved to provide the ancestral eukaryote with the ability to move and sense its environment. Acquiring these functions required the compartmentalization of a dynein-based motility apparatus and signaling proteins within a discrete subcellular organelle contiguous with the cytosol. Here, we explore the potential molecular mechanisms for how the proximal-most region of the cilium, termed transition zone (TZ), acts as a diffusion barrier for both membrane and soluble proteins and helps to ensure ciliary autonomy and homeostasis. These include a unique complement and spatial organization of proteins that span from the microtubule-based axoneme to the ciliary membrane; a protein picket fence; a specialized lipid microdomain; differential membrane curvature and thickness; and lastly, a size-selective molecular sieve. In addition, the TZ must be permissive for, and functionally integrates with, ciliary trafficking systems (including intraflagellar transport) that cross the barrier and make the ciliary compartment dynamic. The quest to understand the TZ continues and promises to not only illuminate essential aspects of human cell signaling, physiology, and development, but also to unravel how TZ dysfunction contributes to ciliopathies that affect multiple organ systems, including eyes, kidney, and brain.
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Affiliation(s)
- Kwangjin Park
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
- Present address:
Terry Fox LaboratoryBC CancerVancouverBCCanada
- Present address:
Department of Medical GeneticsUniversity of British ColumbiaVancouverBCCanada
| | - Michel R Leroux
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
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20
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Wang J, Thomas HR, Thompson RG, Waldrep SC, Fogerty J, Song P, Li Z, Ma Y, Santra P, Hoover JD, Yeo NC, Drummond IA, Yoder BK, Amack JD, Perkins B, Parant JM. Variable phenotypes and penetrance between and within different zebrafish ciliary transition zone mutants. Dis Model Mech 2022; 15:dmm049568. [PMID: 36533556 PMCID: PMC9844136 DOI: 10.1242/dmm.049568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 11/04/2022] [Indexed: 12/23/2022] Open
Abstract
Meckel syndrome, nephronophthisis, Joubert syndrome and Bardet-Biedl syndrome are caused by mutations in proteins that localize to the ciliary transition zone (TZ). The phenotypically distinct syndromes suggest that these TZ proteins have differing functions. However, mutations in a single TZ gene can result in multiple syndromes, suggesting that the phenotype is influenced by modifier genes. We performed a comprehensive analysis of ten zebrafish TZ mutants, including mks1, tmem216, tmem67, rpgrip1l, cc2d2a, b9d2, cep290, tctn1, nphp1 and nphp4, as well as mutants in ift88 and ift172. Our data indicate that variations in phenotypes exist between different TZ mutants, supporting different tissue-specific functions of these TZ genes. Further, we observed phenotypic variations within progeny of a single TZ mutant, reminiscent of multiple disease syndromes being associated with mutations in one gene. In some mutants, the dynamics of the phenotype became complex with transitory phenotypes that are corrected over time. We also demonstrated that multiple-guide-derived CRISPR/Cas9 F0 'crispant' embryos recapitulate zygotic null phenotypes, and rapidly identified ciliary phenotypes in 11 cilia-associated gene candidates (ankfn1, ccdc65, cfap57, fhad1, nme7, pacrg, saxo2, c1orf194, ttc26, zmynd12 and cfap52).
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Affiliation(s)
- Jun Wang
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Holly R. Thomas
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Robert G. Thompson
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Stephanie C. Waldrep
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Joseph Fogerty
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - Ping Song
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - Zhang Li
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, AL 35294, USA
| | - Yongjie Ma
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Peu Santra
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Jonathan D. Hoover
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Nan Cher Yeo
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Iain A. Drummond
- Davis Center for Aging and Regeneration, Mount Desert Island Biological Laboratory, 159 Old Bar Harbor Road, Bar Harbor, ME 04609, USA
| | - Bradley K. Yoder
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, AL 35294, USA
| | - Jeffrey D. Amack
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Brian Perkins
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44106, USA
| | - John M. Parant
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
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21
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Wang L, Wen X, Wang Z, Lin Z, Li C, Zhou H, Yu H, Li Y, Cheng Y, Chen Y, Lou G, Pan J, Cao M. Ciliary transition zone proteins coordinate ciliary protein composition and ectosome shedding. Nat Commun 2022; 13:3997. [PMID: 35810181 PMCID: PMC9271036 DOI: 10.1038/s41467-022-31751-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 06/30/2022] [Indexed: 11/09/2022] Open
Abstract
The transition zone (TZ) of the cilium/flagellum serves as a diffusion barrier that controls the entry/exit of ciliary proteins. Mutations of the TZ proteins disrupt barrier function and lead to multiple human diseases. However, the systematic regulation of ciliary composition and signaling-related processes by different TZ proteins is not completely understood. Here, we reveal that loss of TCTN1 in Chlamydomonas reinhardtii disrupts the assembly of wedge-shaped structures in the TZ. Proteomic analysis of cilia from WT and three TZ mutants, tctn1, cep290, and nphp4, shows a unique role of each TZ subunit in the regulation of ciliary composition, explaining the phenotypic diversity of different TZ mutants. Interestingly, we find that defects in the TZ impair the formation and biological activity of ciliary ectosomes. Collectively, our findings provide systematic insights into the regulation of ciliary composition by TZ proteins and reveal a link between the TZ and ciliary ectosomes. Cilia project from cells to serve sensory functions, and ciliary disruption can result in multiple disorders known as ciliopathies. Here the authors show that the ciliopathy gene TCTN1 functions to regulate the ciliary transition zone and ectosome formation.
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Affiliation(s)
- Liang Wang
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China.
| | - Xin Wen
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Zhengmao Wang
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266071, Qingdao, China.,MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Zaisheng Lin
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Chunhong Li
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Huilin Zhou
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Huimin Yu
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Yuhan Li
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Yifei Cheng
- School of Life Sciences, Jiangsu Normal University, 221116, Xuzhou, China
| | - Yuling Chen
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Geer Lou
- Shanghai Biotree Biotech Co. Ltd, 201815, Shanghai, China
| | - Junmin Pan
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, 266071, Qingdao, China.,MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Muqing Cao
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China.
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22
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Xie C, Habif JC, Ukhanov K, Uytingco CR, Zhang L, Campbell RJ, Martens JR. Reversal of ciliary mechanisms of disassembly rescues olfactory dysfunction in ciliopathies. JCI Insight 2022; 7:158736. [PMID: 35771640 PMCID: PMC9462494 DOI: 10.1172/jci.insight.158736] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022] Open
Abstract
Ciliopathies are a class of genetic diseases resulting in cilia dysfunction in multiple organ systems, including the olfactory system. Currently, there are no available curative treatments for olfactory dysfunction and other symptoms in ciliopathies. The loss or shortening of olfactory cilia, as seen in multiple mouse models of the ciliopathy Bardet–Biedl syndrome (BBS), results in olfactory dysfunction. However, the underlying mechanism of the olfactory cilia reduction is unknown, thus limiting the development of therapeutic approaches for BBS and other ciliopathies. Here, we demonstrated that phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], a phosphoinositide typically excluded from olfactory cilia, aberrantly redistributed into the residual cilia of BBS mouse models, which caused F-actin ciliary infiltration. Importantly, PI(4,5)P2 and F-actin were necessary for olfactory cilia shortening. Using a gene therapeutic approach, the hydrolyzation of PI(4,5)P2 by overexpression of inositol polyphosphate-5-phosphatase E (INPP5E) restored cilia length and rescued odor detection and odor perception in BBS. Together, our data indicate that PI(4,5)P2/F-actin–dependent cilia disassembly is a common mechanism contributing to the loss of olfactory cilia in BBS and provide valuable pan-therapeutic intervention targets for the treatment of ciliopathies.
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Affiliation(s)
- Chao Xie
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Julien C Habif
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Kirill Ukhanov
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Cedric R Uytingco
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Lian Zhang
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Robert J Campbell
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, United States of America
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23
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Dutta P, Ray K. Ciliary membrane, localised lipid modification and cilia function. J Cell Physiol 2022; 237:2613-2631. [PMID: 35661356 DOI: 10.1002/jcp.30787] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 11/08/2022]
Abstract
Cilium, a tiny microtubule-based cellular appendage critical for cell signalling and physiology, displays a large variety of receptors. The composition and turnover of ciliary lipids and receptors determine cell behaviour. Due to the exclusion of ribosomal machinery and limited membrane area, a cilium needs adaptive logistics to actively reconstitute the lipid and receptor compositions during development and differentiation. How is this dynamicity generated? Here, we examine whether, along with the Intraflagellar-Transport, targeted changes in sector-wise lipid composition could control the receptor localisation and functions in the cilia. We discuss how an interplay between ciliary lipid composition, localised lipid modification, and receptor function could contribute to cilia growth and signalling. We argue that lipid modification at the cell-cilium interface could generate an added thrust for a selective exchange of membrane lipids and the transmembrane and membrane-associated proteins.
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Affiliation(s)
- Priya Dutta
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Krishanu Ray
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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24
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Chen X, Shi Z, Yang F, Zhou T, Xie S. Deciphering cilia and ciliopathies using proteomic approaches. FEBS J 2022; 290:2590-2603. [PMID: 35633520 DOI: 10.1111/febs.16538] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/21/2022] [Accepted: 05/19/2022] [Indexed: 12/01/2022]
Abstract
Cilia are microtubule-based organelles that protrude from the cell surface and play crucial roles in cellular signaling pathways and extracellular fluid movement. Defects in the ciliary structures and functions are implicated in a set of hereditary disorders, including polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome, which are collectively termed as ciliopathies. The application of mass spectrometry-based proteomic approaches to explore ciliary components provides important clues for understanding their physiological and pathological roles. In this review, we focus primarily on proteomic studies involving the identification of proteins in motile cilia and primary cilia, proteomes in ciliopathies, and interactomes of ciliopathy proteins. Collectively, the integration of these data sets will be beneficial for the comprehensive understanding of ciliary structures and exploring potential biomarkers and therapeutic targets for ciliopathies.
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Affiliation(s)
- Xiying Chen
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhouyuanjing Shi
- Department of Gastroenterology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Yang
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Tianhua Zhou
- Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Shanshan Xie
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
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25
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Lange KI, Best S, Tsiropoulou S, Berry I, Johnson CA, Blacque OE. Interpreting ciliopathy-associated missense variants of uncertain significance (VUS) in Caenorhabditis elegans. Hum Mol Genet 2022; 31:1574-1587. [PMID: 34964473 PMCID: PMC9122650 DOI: 10.1093/hmg/ddab344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 12/26/2022] Open
Abstract
Better methods are required to interpret the pathogenicity of disease-associated variants of uncertain significance (VUS), which cannot be actioned clinically. In this study, we explore the use of an animal model (Caenorhabditis elegans) for in vivo interpretation of missense VUS alleles of TMEM67, a cilia gene associated with ciliopathies. CRISPR/Cas9 gene editing was used to generate homozygous knock-in C. elegans worm strains carrying TMEM67 patient variants engineered into the orthologous gene (mks-3). Quantitative phenotypic assays of sensory cilia structure and function (neuronal dye filling, roaming and chemotaxis assays) measured how the variants impacted mks-3 gene function. Effects of the variants on mks-3 function were further investigated by looking at MKS-3::GFP localization and cilia ultrastructure. The quantitative assays in C. elegans accurately distinguished between known benign (Asp359Glu, Thr360Ala) and known pathogenic (Glu361Ter, Gln376Pro) variants. Analysis of eight missense VUS generated evidence that three are benign (Cys173Arg, Thr176Ile and Gly979Arg) and five are pathogenic (Cys170Tyr, His782Arg, Gly786Glu, His790Arg and Ser961Tyr). Results from worms were validated by a genetic complementation assay in a human TMEM67 knock-out hTERT-RPE1 cell line that tests a TMEM67 signalling function. We conclude that efficient genome editing and quantitative functional assays in C. elegans make it a tractable in vivo animal model for rapid, cost-effective interpretation of ciliopathy-associated missense VUS alleles.
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Affiliation(s)
- Karen I Lange
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sunayna Best
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, West Yorkshire, UK
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ian Berry
- Bristol Genetics Laboratory, Pathology Sciences, Southmead Hospital, Bristol BS10 5NB, UK
| | - Colin A Johnson
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, West Yorkshire, UK
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
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26
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Tmem138 is localized to the connecting cilium essential for rhodopsin localization and outer segment biogenesis. Proc Natl Acad Sci U S A 2022; 119:e2109934119. [PMID: 35394880 PMCID: PMC9169668 DOI: 10.1073/pnas.2109934119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The connecting cilium (CC) of the photoreceptor provides the only route for the trafficking of the outer segment (OS) proteins. Failure of OS protein transport causes degenerative photoreceptor diseases, including retinitis pigmentosa. We demonstrate that Tmem138, a protein linked to ciliopathy, is localized to the photoreceptor CC. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 interacts with rhodopsin and two additional CC compartment proteins, Ahi1 and Tmem231, likely forming a membrane complex to facilitate trafficking of rhodopsin and other OS-bound proteins across the CC. The study thus implicates a new line of regulation on the delivery of OS proteins through interactions with CC membrane complex(es) and provides insights into photoreceptor ciliopathy diseases. Photoreceptor connecting cilium (CC) is structurally analogous to the transition zone (TZ) of primary cilia and gates the molecular trafficking between the inner and the outer segment (OS). Retinal dystrophies with underlying CC defects are manifested in a broad array of syndromic conditions known as ciliopathies as well as nonsyndromic retinal degenerations. Despite extensive studies, many questions remain in the mechanism of protein trafficking across the photoreceptor CC. Here, we genetically inactivated mouse Tmem138, a gene encoding a putative transmembrane protein localized to the ciliary TZ and linked to ciliopathies. Germline deletion of Tmem138 abolished OS morphogenesis, followed by rapid photoreceptor degeneration. Tmem138 was found localized to the photoreceptor CC and was required for localization of Ahi1 to the distal subdomain of the CC. Among the examined set of OS proteins, rhodopsin was mislocalized throughout the mutant cell body prior to OS morphogenesis. Ablation of Tmem138 in mature rods recapitulated the molecular changes in the germline mutants, causing failure of disc renewal and disintegration of the OS. Furthermore, Tmem138 interacts reciprocally with rhodopsin and a related protein Tmem231, and the ciliary localization of the latter was also altered in the mutant photoreceptors. Taken together, these results suggest a crucial role of Tmem138 in the functional organization of the CC, which is essential for rhodopsin localization and OS biogenesis.
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27
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Zhang R, Tang J, Li T, Zhou J, Pan W. INPP5E and Coordination of Signaling Networks in Cilia. Front Mol Biosci 2022; 9:885592. [PMID: 35463949 PMCID: PMC9019342 DOI: 10.3389/fmolb.2022.885592] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 03/22/2022] [Indexed: 11/13/2022] Open
Abstract
Primary cilia are ubiquitous mechanosensory organelles that specifically coordinate a series of cellular signal transduction pathways to control cellular physiological processes during development and in tissue homeostasis. Defects in the function or structure of primary cilia have been shown to be associated with a large range of diseases called ciliopathies. Inositol polyphosphate-5-phosphatase E (INPP5E) is an inositol polyphosphate 5-phosphatase that is localized on the ciliary membrane by anchorage via its C-terminal prenyl moiety and hydrolyzes both phosphatidylinositol-4, 5-bisphosphate (PtdIns(4,5)P2) and PtdIns(3,4,5)P3, leading to changes in the phosphoinositide metabolism, thereby resulting in a specific phosphoinositide distribution and ensuring proper localization and trafficking of proteins in primary cilia. In addition, INPP5E also works synergistically with cilia membrane-related proteins by playing key roles in the development and maintenance homeostasis of cilia. The mutation of INPP5E will cause deficiency of primary cilia signaling transduction, ciliary instability and ciliopathies. Here, we present an overview of the role of INPP5E and its coordination of signaling networks in primary cilia.
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Affiliation(s)
- Renshuai Zhang
- Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Sciences, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
| | - Jianming Tang
- Zhenjiang Hospital of Traditional Chinese Medicine, Zhenjiang, China
| | - Tianliang Li
- Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Sciences, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Sciences, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
| | - Wei Pan
- Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Sciences, Institute of Biomedical Sciences, Shandong Normal University, Jinan, China
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28
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Di Nardo A, Rühmkorf A, Award P, Brennecke A, Fagiolini M, Sahin M. Phenotypic characterization of Cdkl5-knockdown neurons establishes elongated cilia as a functional assay for CDKL5 Deficiency Disorder. Neurosci Res 2022; 176:73-78. [PMID: 34624412 PMCID: PMC8960319 DOI: 10.1016/j.neures.2021.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 11/28/2022]
Abstract
CDKL5 Deficiency Disorder (CDD) is a severe encephalopathy characterized by intractable epilepsy, infantile spasms, and cognitive disabilities. The detrimental CNS manifestations and lack of therapeutic interventions represent unmet needs, necessitating identification of CDD-dependent phenotypes for in vitro disease modeling and therapeutic testing. Here, we optimized a high-content assay to quantify cilia in CDKL5-deficient neurons. Our work shows that Cdkl5-knockdown neurons have elongated cilia and uncovers cilium lengthening in hippocampi of Cdkl5 knockout mice. Collectively, our findings identify cilia length alterations under CDKL5 activity loss in vitro and in vivo and reveal elongated cilia as a robust functional phenotype for CDD.
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Affiliation(s)
- Alessia Di Nardo
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA; Genetic and Developmental Disorders Research Unit, Biogen 115 Broadway, Cambridge, MA 02142, USA(1)
| | - Alina Rühmkorf
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Patricia Award
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ashton Brennecke
- Genetic and Developmental Disorders Research Unit, Biogen 115 Broadway, Cambridge, MA 02142, USA(1)
| | - Michela Fagiolini
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Hock E. Tan and K. Lisa Yang Center for Autism Research at Harvard University, Boston, MA 02115, USA
| | - Mustafa Sahin
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA.
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29
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Szymanska K, Boldt K, Logan CV, Adams M, Robinson PA, Ueffing M, Zeqiraj E, Wheway G, Johnson CA. Regulation of canonical Wnt signalling by the ciliopathy protein MKS1 and the E2 ubiquitin-conjugating enzyme UBE2E1. eLife 2022; 11:57593. [PMID: 35170427 PMCID: PMC8880992 DOI: 10.7554/elife.57593] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 02/10/2022] [Indexed: 11/24/2022] Open
Abstract
Primary ciliary defects cause a group of developmental conditions known as ciliopathies. Here, we provide mechanistic insight into ciliary ubiquitin processing in cells and for mouse model lacking the ciliary protein Mks1. In vivo loss of Mks1 sensitises cells to proteasomal disruption, leading to abnormal accumulation of ubiquitinated proteins. We identified UBE2E1, an E2 ubiquitin-conjugating enzyme that polyubiquitinates β-catenin, and RNF34, an E3 ligase, as novel interactants of MKS1. UBE2E1 and MKS1 colocalised, and loss of UBE2E1 recapitulates the ciliary and Wnt signalling phenotypes observed during loss of MKS1. Levels of UBE2E1 and MKS1 are co-dependent and UBE2E1 mediates both regulatory and degradative ubiquitination of MKS1. We demonstrate that processing of phosphorylated β-catenin occurs at the ciliary base through the functional interaction between UBE2E1 and MKS1. These observations suggest that correct β-catenin levels are tightly regulated at the primary cilium by a ciliary-specific E2 (UBE2E1) and a regulatory substrate-adaptor (MKS1).
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Affiliation(s)
- Katarzyna Szymanska
- Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom
| | - Karsten Boldt
- Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | | | - Matthew Adams
- Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom
| | | | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Elton Zeqiraj
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Gabrielle Wheway
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Colin A Johnson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
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30
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Bentley-Ford MR, LaBonty M, Thomas HR, Haycraft CJ, Scott M, LaFayette C, Croyle MJ, Andersen RS, Parant JM, Yoder BK. Evolutionarily conserved genetic interactions between nphp-4 and bbs-5 mutations exacerbate ciliopathy phenotypes. Genetics 2022; 220:iyab209. [PMID: 34850872 PMCID: PMC8733634 DOI: 10.1093/genetics/iyab209] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/08/2021] [Indexed: 12/13/2022] Open
Abstract
Primary cilia are sensory and signaling hubs with a protein composition that is distinct from the rest of the cell due to the barrier function of the transition zone (TZ) at the base of the cilium. Protein transport across the TZ is mediated in part by the BBSome, and mutations disrupting TZ and BBSome proteins cause human ciliopathy syndromes. Ciliopathies have phenotypic variability even among patients with identical genetic variants, suggesting a role for modifier loci. To identify potential ciliopathy modifiers, we performed a mutagenesis screen on nphp-4 mutant Caenorhabditis elegans and uncovered a novel allele of bbs-5. Nphp-4;bbs-5 double mutant worms have phenotypes not observed in either individual mutant strain. To test whether this genetic interaction is conserved, we also analyzed zebrafish and mouse mutants. While Nphp4 mutant zebrafish appeared overtly normal, Bbs5 mutants exhibited scoliosis. When combined, Nphp4;Bbs5 double mutant zebrafish did not exhibit synergistic effects, but the lack of a phenotype in Nphp4 mutants makes interpreting these data difficult. In contrast, Nphp4;Bbs5 double mutant mice were not viable and there were fewer mice than expected carrying three mutant alleles. In addition, postnatal loss of Bbs5 in mice using a conditional allele compromised survival when combined with an Nphp4 allele. As cilia are still formed in the double mutant mice, the exacerbated phenotype is likely a consequence of disrupted ciliary signaling. Collectively, these data support an evolutionarily conserved genetic interaction between Bbs5 and Nphp4 alleles that may contribute to the variability in ciliopathy phenotypes.
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Affiliation(s)
- Melissa R Bentley-Ford
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Melissa LaBonty
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Holly R Thomas
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL35294, USA
| | - Courtney J Haycraft
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mikyla Scott
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Cameron LaFayette
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mandy J Croyle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Reagan S Andersen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John M Parant
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL35294, USA
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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31
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Kanamaru T, Neuner A, Kurtulmus B, Pereira G. Balancing the length of the distal tip by septins is key for stability and signalling function of primary cilia. EMBO J 2022; 41:e108843. [PMID: 34981518 PMCID: PMC8724769 DOI: 10.15252/embj.2021108843] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 01/08/2023] Open
Abstract
Primary cilia are antenna-like organelles required for signalling transduction. How cilia structure is mechanistically maintained at steady-state to promote signalling is largely unknown. Here, we define that mammalian primary cilia axonemes are formed by proximal segment (PS) and distal segment (DS) delineated by tubulin polyglutamylation-rich and -poor regions, respectively. The analysis of proximal/distal segmentation indicated that perturbations leading to cilia over-elongation influenced PS or DS length with a different impact on cilia behaviour. We identified septins as novel repressors of DS growth. We show that septins control the localisation of MKS3 and CEP290 required for a functional transition zone (TZ), and the cilia tip accumulation of the microtubule-capping kinesin KIF7, a cilia-growth inhibitor. Live-cell imaging and analysis of sonic-hedgehog (SHH) signalling activation established that DS over-extension increased cilia ectocytosis events and decreased SHH activation. Our data underlines the importance of understanding cilia segmentation for length control and cilia-dependent signalling.
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Affiliation(s)
- Taishi Kanamaru
- Centre for Organismal Studies (COS)University of HeidelbergHeidelbergGermany
- German Cancer Research Centre (DKFZ)DKFZ‐ZMBH AllianceHeidelbergGermany
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
| | - Annett Neuner
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
| | - Bahtiyar Kurtulmus
- Centre for Organismal Studies (COS)University of HeidelbergHeidelbergGermany
- German Cancer Research Centre (DKFZ)DKFZ‐ZMBH AllianceHeidelbergGermany
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
| | - Gislene Pereira
- Centre for Organismal Studies (COS)University of HeidelbergHeidelbergGermany
- German Cancer Research Centre (DKFZ)DKFZ‐ZMBH AllianceHeidelbergGermany
- Centre for Molecular Biology (ZMBH)University of HeidelbergHeidelbergGermany
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32
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Three Novel Variants of CEP290 and CC2D2DA and a Link Between ZNF77 and SHH Signaling Pathway Are Found in Two Meckel-Gruber Syndrome Fetuses. Reprod Sci 2022; 29:2322-2332. [PMID: 34981460 PMCID: PMC9352615 DOI: 10.1007/s43032-021-00835-5] [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: 11/05/2021] [Accepted: 12/15/2021] [Indexed: 11/06/2022]
Abstract
Meckel-Gruber syndrome (MKS) is a rare lethal autosomal recessive inherited disorder. Missed diagnosis might happen in clinical works due to an unclear genotype–phenotype correlation. We analyzed two families visiting our center; the parents are normal; each of the family aborted a fetus at 12WG. Following ultrasonography and pathological examination, both were diagnosed as MKS. Whole exome sequencing identified a compound heterozygous of two novel variants of CEP290 and a heterozygous of a novel variant of CC2D2A. Frameshift mutations in ZNF77 were also detected. Western blot analyzing whole-brain tissue showed that the expression of ZNF77, CC2D2A, and CEP290 was enhanced. HEK293T transfected with over-expression wildtype/mutated ZNF77 plasmid showed that SHH was increased in wildtype ZNF77 cells, while SHH and CC2D2A were increased in mutated ZNF77 cells. Our research provided two novel pathogenic variants of CEP290 and CC2D2A and suggested that ZNF77 might promote the expression of CC2D2A and regulate the amount of SHH.
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33
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Chandra B, Tung ML, Hsu Y, Scheetz T, Sheffield VC. Retinal ciliopathies through the lens of Bardet-Biedl Syndrome: Past, present and future. Prog Retin Eye Res 2021; 89:101035. [PMID: 34929400 DOI: 10.1016/j.preteyeres.2021.101035] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
The primary cilium is a highly specialized and evolutionary conserved organelle in eukaryotes that plays a significant role in cell signaling and trafficking. Over the past few decades tremendous progress has been made in understanding the physiology of cilia and the underlying pathomechanisms of various ciliopathies. Syndromic ciliopathies consist of a group of disorders caused by ciliary dysfunction or abnormal ciliogenesis. These disorders have multiorgan involvement in addition to retinal degeneration underscoring the ubiquitous distribution of primary cilia in different cell types. Genotype-phenotype correlation is often challenging due to the allelic heterogeneity and pleiotropy of these disorders. In this review, we discuss the clinical and genetic features of syndromic ciliopathies with a focus on Bardet-Biedl syndrome (BBS) as a representative disorder. We discuss the structure and function of primary cilia and their role in retinal photoreceptors. We describe the progress made thus far in understanding the functional and genetic characterization including expression quantitative trait locus (eQTL) analysis of BBS genes. In the future directions section, we discuss the emerging technologies, such as gene therapy, as well as anticipated challenges and their implications in therapeutic development for ciliopathies.
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Affiliation(s)
- Bharatendu Chandra
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Moon Ley Tung
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Todd Scheetz
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Val C Sheffield
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA.
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34
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Abrams SR, Reiter JF. Ciliary Hedgehog signaling regulates cell survival to build the facial midline. eLife 2021; 10:e68558. [PMID: 34672258 PMCID: PMC8592574 DOI: 10.7554/elife.68558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 10/20/2021] [Indexed: 01/03/2023] Open
Abstract
Craniofacial defects are among the most common phenotypes caused by ciliopathies, yet the developmental and molecular etiology of these defects is poorly understood. We investigated multiple mouse models of human ciliopathies (including Tctn2, Cc2d2a, and Tmem231 mutants) and discovered that each displays hypotelorism, a narrowing of the midface. As early in development as the end of gastrulation, Tctn2 mutants displayed reduced activation of the Hedgehog (HH) pathway in the prechordal plate, the head organizer. This prechordal plate defect preceded a reduction of HH pathway activation and Shh expression in the adjacent neurectoderm. Concomitant with the reduction of HH pathway activity, Tctn2 mutants exhibited increased cell death in the neurectoderm and facial ectoderm, culminating in a collapse of the facial midline. Enhancing HH signaling by decreasing the gene dosage of a negative regulator of the pathway, Ptch1, decreased cell death and rescued the midface defect in both Tctn2 and Cc2d2a mutants. These results reveal that ciliary HH signaling mediates communication between the prechordal plate and the neurectoderm to provide cellular survival cues essential for development of the facial midline.
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Affiliation(s)
- Shaun R Abrams
- Department of Biochemistry and Biophysics, Cardiovascular Research InstituteSan FranciscoUnited States
- Oral and Craniofacial Sciences Program, School of DentistrySan FranciscoUnited States
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research InstituteSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
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35
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Mecklenburg N, Kowalczyk I, Witte F, Görne J, Laier A, Mamo TM, Gonschior H, Lehmann M, Richter M, Sporbert A, Purfürst B, Hübner N, Hammes A. Identification of disease-relevant modulators of the SHH pathway in the developing brain. Development 2021; 148:272000. [PMID: 34463328 DOI: 10.1242/dev.199307] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 07/19/2021] [Indexed: 12/13/2022]
Abstract
Pathogenic gene variants in humans that affect the sonic hedgehog (SHH) pathway lead to severe brain malformations with variable penetrance due to unknown modifier genes. To identify such modifiers, we established novel congenic mouse models. LRP2-deficient C57BL/6N mice suffer from heart outflow tract defects and holoprosencephaly caused by impaired SHH activity. These defects are fully rescued on a FVB/N background, indicating a strong influence of modifier genes. Applying comparative transcriptomics, we identified Pttg1 and Ulk4 as candidate modifiers upregulated in the rescue strain. Functional analyses showed that ULK4 and PTTG1, both microtubule-associated proteins, are positive regulators of SHH signaling, rendering the pathway more resilient to disturbances. In addition, we characterized ULK4 and PTTG1 as previously unidentified components of primary cilia in the neuroepithelium. The identification of genes that powerfully modulate the penetrance of genetic disturbances affecting the brain and heart is likely relevant to understanding the variability in human congenital disorders.
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Affiliation(s)
- Nora Mecklenburg
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Izabela Kowalczyk
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Franziska Witte
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Jessica Görne
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Alena Laier
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Tamrat M Mamo
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Hannes Gonschior
- Cellular Imaging, Light Microscopy, Leibniz-Research Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Martin Lehmann
- Cellular Imaging, Light Microscopy, Leibniz-Research Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Matthias Richter
- Advanced Light Microscopy Technology Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Anje Sporbert
- Advanced Light Microscopy Technology Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Bettina Purfürst
- Electron microscopy technology platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Norbert Hübner
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, 10785 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany.,Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Annette Hammes
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
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36
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Roopasree OJ, Adivitiya, Chakraborty S, Kateriya S, Veleri S. Centriole is the pivot coordinating dynamic signaling for cell proliferation and organization during early development in the vertebrates. Cell Biol Int 2021; 45:2178-2197. [PMID: 34288241 DOI: 10.1002/cbin.11667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/12/2021] [Indexed: 11/07/2022]
Abstract
Vertebrates have an elaborate and functionally segmented body. It evolves from a single cell by systematic cell proliferation but attains a complex body structure with exquisite precision. This development requires two cellular events: cell cycle and ciliogenesis. For these events, the dynamic molecular signaling is converged at the centriole. The cell cycle helps in cell proliferation and growth of the body and is a highly regulated and integrated process. Its errors cause malignancies and developmental disorders. The cells newly proliferated are organized during organogenesis. For a cellular organization, dedicated signaling hubs are developed in the cells, and most often cilia are utilized. The cilium is generated from one of the centrioles involved in cell proliferation. The developmental signaling pathways hosted in cilia are essential for the elaboration of the body plan. The cilium's compartmental seclusion is ideal for noise-free molecular signaling and is essential for the precision of the body layout. The dysfunctional centrioles and primary cilia distort the development of body layout that manifest as serious developmental disorders. Thus, centriole has a dual role in the growth and cellular organization. It organizes dynamically expressed molecules of cell cycle and ciliogenesis and plays a balancing act to generate new cells and organize them during development. A putative master molecule may regulate and coordinate the dynamic gene expression at the centrioles. The convergence of many critical signaling components at the centriole reiterates the idea that centriole is a major molecular workstation involved in elaborating the structural design and complexity in vertebrates. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- O J Roopasree
- Agroprocessing Technology Division, CSIR-National Institute of Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala 695019 and Academy of CSIR, Uttar Pradesh - 201002, India
| | - Adivitiya
- Laboratory of Optobiology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Soura Chakraborty
- Laboratory of Optobiology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Suneel Kateriya
- Laboratory of Optobiology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Shobi Veleri
- Drug Safety Division, ICMR-National Institute of Nutrition, Hyderabad, 500007, India
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37
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Suciu SK, Long AB, Caspary T. Smoothened and ARL13B are critical in mouse for superior cerebellar peduncle targeting. Genetics 2021; 218:6300527. [PMID: 34132778 PMCID: PMC8864748 DOI: 10.1093/genetics/iyab084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/15/2021] [Indexed: 01/07/2023] Open
Abstract
Patients with the ciliopathy Joubert syndrome present with physical anomalies, intellectual disability, and a hindbrain malformation described as the "molar tooth sign" due to its appearance on an MRI. This radiological abnormality results from a combination of hypoplasia of the cerebellar vermis and inappropriate targeting of the white matter tracts of the superior cerebellar peduncles. ARL13B is a cilia-enriched regulatory GTPase established to regulate cell fate, cell proliferation, and axon guidance through vertebrate Hedgehog signaling. In patients, mutations in ARL13B cause Joubert syndrome. To understand the etiology of the molar tooth sign, we used mouse models to investigate the role of ARL13B during cerebellar development. We found that ARL13B regulates superior cerebellar peduncle targeting and these fiber tracts require Hedgehog signaling for proper guidance. However, in mouse, the Joubert-causing R79Q mutation in ARL13B does not disrupt Hedgehog signaling nor does it impact tract targeting. We found a small cerebellar vermis in mice lacking ARL13B function but no cerebellar vermis hypoplasia in mice expressing the Joubert-causing R79Q mutation. In addition, mice expressing a cilia-excluded variant of ARL13B that transduces Hedgehog normally showed normal tract targeting and vermis width. Taken together, our data indicate that ARL13B is critical for the control of cerebellar vermis width as well as superior cerebellar peduncle axon guidance, likely via Hedgehog signaling. Thus, our work highlights the complexity of ARL13B in molar tooth sign etiology.
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Affiliation(s)
- Sarah K Suciu
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA 30322, USA,Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Alyssa B Long
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA,Corresponding author: Department of Human Genetics, 615 Michael Street, Suite 301, Atlanta, GA 30322.
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38
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Chen C, Xu Q, Zhang Y, Davies BA, Huang Y, Katzmann DJ, Harris PC, Hu J, Ling K. Ciliopathy protein HYLS1 coordinates the biogenesis and signaling of primary cilia by activating the ciliary lipid kinase PIPKIγ. SCIENCE ADVANCES 2021; 7:7/26/eabe3401. [PMID: 34162535 PMCID: PMC8221637 DOI: 10.1126/sciadv.abe3401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/10/2021] [Indexed: 05/04/2023]
Abstract
Mutation of ciliopathy protein HYLS1 causes the perinatal lethal hydrolethalus syndrome (HLS), yet the underlying molecular etiology and pathogenesis remain elusive. Here, we reveal unexpected mechanistic insights into the role of mammalian HYLS1 in regulating primary cilia. HYLS1 is recruited to the ciliary base via a direct interaction with the type Iγ phosphatidylinositol 4-phosphate [PI(4)P] 5-kinase (PIPKIγ). HYLS1 activates PIPKIγ by interrupting the autoinhibitory dimerization of PIPKIγ, which thereby expedites depletion of centrosomal PI(4)P to allow axoneme nucleation. HYLS1 deficiency interrupts the assembly of ciliary NPHP module and agonist-induced ciliary exit of β-arrestin, which, in turn, disturbs the removal of ciliary Gpr161 and activation of hedgehog (Hh) signaling. Consistent with this model of pathogenesis, the HLS mutant HYLS1D211G supports ciliogenesis but not activation of Hh signaling. These results implicate mammalian HYLS1 as a multitasking protein that facilitates ciliogenesis and ciliary signaling by coordinating with the ciliary lipid kinase PIPKIγ.
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Affiliation(s)
- Chuan Chen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Qingwen Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuxia Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Brian A Davies
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yan Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - David J Katzmann
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Peter C Harris
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Kun Ling
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
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39
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Conduit SE, Davies EM, Fulcher AJ, Oorschot V, Mitchell CA. Superresolution Microscopy Reveals Distinct Phosphoinositide Subdomains Within the Cilia Transition Zone. Front Cell Dev Biol 2021; 9:634649. [PMID: 33996795 PMCID: PMC8120242 DOI: 10.3389/fcell.2021.634649] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 04/06/2021] [Indexed: 11/30/2022] Open
Abstract
Primary cilia are evolutionary conserved microtubule-based organelles that protrude from the surface of most mammalian cells. Phosphoinositides (PI) are membrane-associated signaling lipids that regulate numerous cellular events via the recruitment of lipid-binding effectors. The temporal and spatial membrane distribution of phosphoinositides is regulated by phosphoinositide kinases and phosphatases. Recently phosphoinositide signaling and turnover has been observed at primary cilia. However, the precise localization of the phosphoinositides to specific ciliary subdomains remains undefined. Here we use superresolution microscopy (2D stimulated emission depletion microscopy) to map phosphoinositide distribution at the cilia transition zone. PI(3,4,5)P3 and PI(4,5)P2 localized to distinct subregions of the transition zone in a ring-shape at the inner transition zone membrane. Interestingly, the PI(3,4,5)P3 subdomain was more distal within the transition zone relative to PtdIns(4,5)P2. The phosphoinositide effector kinase pAKT(S473) localized in close proximity to these phosphoinositides. The inositol polyphosphate 5-phosphatase, INPP5E, degrades transition zone phosphoinositides, however, studies of fixed cells have reported recombinant INPP5E localizes to the ciliary axoneme, distant from its substrates. Notably, here using live cell imaging and optimized fixation/permeabilization protocols INPP5E was found concentrated at the cilia base, in a distribution characteristic of the transition zone in a ring-shaped domain of similar dimensions to the phosphoinositides. Collectively, this superresolution map places the phosphoinositides in situ with the transition zone proteins and reveals that INPP5E also likely localizes to a subdomain of the transition zone membrane, where it is optimally situated to control local phosphoinositide metabolism.
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Affiliation(s)
- Sarah E Conduit
- Cancer Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Elizabeth M Davies
- Cancer Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Alex J Fulcher
- Monash Micro Imaging, Monash University, Clayton, VIC, Australia
| | - Viola Oorschot
- Monash Ramaciotti Centre for Structural Cryo-Electron Microscopy, Monash University, Clayton, VIC, Australia
| | - Christina A Mitchell
- Cancer Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
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40
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Hedström U, Öberg L, Vaarala O, Dellgren G, Silverborn M, Bjermer L, Westergren-Thorsson G, Hallgren O, Zhou X. Impaired Differentiation of Chronic Obstructive Pulmonary Disease Bronchial Epithelial Cells Grown on Bronchial Scaffolds. Am J Respir Cell Mol Biol 2021; 65:201-213. [PMID: 33882260 PMCID: PMC8399573 DOI: 10.1165/rcmb.2019-0395oc] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is characterized by airway inflammation, small airway remodeling, and emphysema. Airway remodeling in patients with COPD involves both the airway epithelium and the subepithelial extracellular matrix (ECM). However, it is currently unknown how epithelial remodeling in COPD airways depends on the relative influence from inherent defects in the epithelial cells and alterations in the ECM. To address this, we analyzed global gene expression in COPD human bronchial epithelial cells (HBEC) and normal HBEC after repopulation on decellularized bronchial scaffolds derived from patients with COPD or donors without COPD. COPD HBEC grown on bronchial scaffolds showed an impaired ability to initiate ciliated-cell differentiation, which was evident on all scaffolds regardless of their origin. In addition, although normal HBEC were less affected by the disease state of the bronchial scaffolds, COPD HBEC showed a gene expression pattern indicating increased proliferation and a retained basal-cell phenotype when grown on COPD bronchial scaffolds compared with normal bronchial scaffolds. By using mass spectrometry, we identified 13 matrisome proteins as being differentially abundant between COPD bronchial scaffolds and normal bronchial scaffolds. These observations are consistent with COPD pathology and suggest that both epithelial cells and the ECM contribute to epithelial-cell remodeling in COPD airways.
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Affiliation(s)
- Ulf Hedström
- Department of Bioscience COPD/IPF, and.,Division of Lung Biology, Department of Experimental Medical Science, and
| | - Lisa Öberg
- Department of Translational Science and Experimental Medicine, Research and Early Development, Respiratory and Immunology, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Sweden
| | | | - Göran Dellgren
- Transplant Institute and.,Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Martin Silverborn
- Transplant Institute and.,Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Leif Bjermer
- Division of Respiratory Medicine and Allergology, Department of Clinical Sciences, Lund University, Lund, Sweden; and
| | | | - Oskar Hallgren
- Division of Lung Biology, Department of Experimental Medical Science, and.,Division of Respiratory Medicine and Allergology, Department of Clinical Sciences, Lund University, Lund, Sweden; and
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41
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Nonredundant roles of DIAPHs in primary ciliogenesis. J Biol Chem 2021; 296:100680. [PMID: 33872598 PMCID: PMC8122175 DOI: 10.1016/j.jbc.2021.100680] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 11/21/2022] Open
Abstract
Primary cilia are hubs for several signaling pathways, and disruption in cilia function and formation leads to a range of diseases collectively known as ciliopathies. Both ciliogenesis and cilia maintenance depend on vesicle trafficking along a network of microtubules and actin filaments toward the basal body. The DIAPH (Diaphanous-related) family of formins promote both actin polymerization and microtubule (MT) stability. Recently, we showed that the formin DIAPH1 is involved in ciliogenesis. However, the role of other DIAPH family members in ciliogenesis had not been investigated. Here we show that depletion of either DIAPH2 or DIAPH3 also disrupted ciliogenesis and cilia length. DIAPH3 depletion also reduced trafficking within cilia. To specifically examine the role of DIAPH3 at the base, we used fused full-length DIAPH3 to centrin, which targeted DIAPH3 to the basal body, causing increased trafficking to the ciliary base, an increase in cilia length, and formation of bulbs at the tips of cilia. Additionally, we confirmed that the microtubule-stabilizing properties of DIAPH3 are important for its cilia length functions and trafficking. These results indicate the importance of DIAPH proteins in regulating cilia maintenance. Moreover, defects in ciliogenesis caused by DIAPH depletion could only be rescued by expression of the specific family member depleted, indicating nonredundant roles for these proteins.
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42
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Hazime KS, Zhou Z, Joachimiak E, Bulgakova NA, Wloga D, Malicki JJ. STORM imaging reveals the spatial arrangement of transition zone components and IFT particles at the ciliary base in Tetrahymena. Sci Rep 2021; 11:7899. [PMID: 33846423 PMCID: PMC8041816 DOI: 10.1038/s41598-021-86909-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 03/22/2021] [Indexed: 11/17/2022] Open
Abstract
The base of the cilium comprising the transition zone (TZ) and transition fibers (TF) acts as a selecting gate to regulate the intraflagellar transport (IFT)-dependent trafficking of proteins to and from cilia. Before entering the ciliary compartment, IFT complexes and transported cargoes accumulate at or near the base of the cilium. The spatial organization of IFT proteins at the cilia base is key for understanding cilia formation and function. Using stochastic optical reconstruction microscopy (STORM) and computational averaging, we show that seven TZ, nine IFT, three Bardet–Biedl syndrome (BBS), and one centrosomal protein, form 9-clustered rings at the cilium base of a ciliate Tetrahymena thermophila. In the axial dimension, analyzed TZ proteins localize to a narrow region of about 30 nm while IFT proteins dock approximately 80 nm proximal to TZ. Moreover, the IFT-A subcomplex is positioned peripheral to the IFT-B subcomplex and the investigated BBS proteins localize near the ciliary membrane. The positioning of the HA-tagged N- and C-termini of the selected proteins enabled the prediction of the spatial orientation of protein particles and likely cargo interaction sites. Based on the obtained data, we built a comprehensive 3D-model showing the arrangement of the investigated ciliary proteins.
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Affiliation(s)
- Khodor S Hazime
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
| | - Zhu Zhou
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Natalia A Bulgakova
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, 3 Pasteur Street, 02-093, Warsaw, Poland.
| | - Jarema J Malicki
- Bateson Centre and the Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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43
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Wiegering A, Dildrop R, Vesque C, Khanna H, Schneider-Maunoury S, Gerhardt C. Rpgrip1l controls ciliary gating by ensuring the proper amount of Cep290 at the vertebrate transition zone. Mol Biol Cell 2021; 32:675-689. [PMID: 33625872 PMCID: PMC8108517 DOI: 10.1091/mbc.e20-03-0190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A range of severe human diseases called ciliopathies is caused by the dysfunction of primary cilia. Primary cilia are cytoplasmic protrusions consisting of the basal body (BB), the axoneme, and the transition zone (TZ). The BB is a modified mother centriole from which the axoneme, the microtubule-based ciliary scaffold, is formed. At the proximal end of the axoneme, the TZ functions as the ciliary gate governing ciliary protein entry and exit. Since ciliopathies often develop due to mutations in genes encoding proteins that localize to the TZ, the understanding of the mechanisms underlying TZ function is of eminent importance. Here, we show that the ciliopathy protein Rpgrip1l governs ciliary gating by ensuring the proper amount of Cep290 at the vertebrate TZ. Further, we identified the flavonoid eupatilin as a potential agent to tackle ciliopathies caused by mutations in RPGRIP1L as it rescues ciliary gating in the absence of Rpgrip1l.
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Affiliation(s)
- Antonia Wiegering
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany.,Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Renate Dildrop
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Christine Vesque
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Hemant Khanna
- Department of Ophthalmology and Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, CNRS UMR7622, INSERM U1156, Institut de Biologie Paris Seine (IBPS) - Developmental Biology Unit, 75005 Paris, France
| | - Christoph Gerhardt
- Institute for Animal Developmental and Molecular Biology, Heinrich Heine University, 40225 Düsseldorf, Germany
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44
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Protein Kinase A-Mediated Septin7 Phosphorylation Disrupts Septin Filaments and Ciliogenesis. Cells 2021; 10:cells10020361. [PMID: 33572403 PMCID: PMC7916176 DOI: 10.3390/cells10020361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 01/22/2023] Open
Abstract
Septins are GTP-binding proteins that form heteromeric filaments for proper cell growth and migration. Among the septins, septin7 (SEPT7) is an important component of all septin filaments. Here we show that protein kinase A (PKA) phosphorylates SEPT7 at Thr197, thus disrupting septin filament dynamics and ciliogenesis. The Thr197 residue of SEPT7, a PKA phosphorylating site, was conserved among different species. Treatment with cAMP or overexpression of PKA catalytic subunit (PKACA2) induced SEPT7 phosphorylation, followed by disruption of septin filament formation. Constitutive phosphorylation of SEPT7 at Thr197 reduced SEPT7‒SEPT7 interaction, but did not affect SEPT7‒SEPT6‒SEPT2 or SEPT4 interaction. Moreover, we noted that SEPT7 interacted with PKACA2 via its GTP-binding domain. Furthermore, PKA-mediated SEPT7 phosphorylation disrupted primary cilia formation. Thus, our data uncover the novel biological function of SEPT7 phosphorylation in septin filament polymerization and primary cilia formation.
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45
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Hsu Y, Seo S, Sheffield VC. Photoreceptor cilia, in contrast to primary cilia, grant entry to a partially assembled BBSome. Hum Mol Genet 2021; 30:87-102. [PMID: 33517424 DOI: 10.1093/hmg/ddaa284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 11/16/2020] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
The BBSome is a protein complex consisting of BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9 and BBS18 that associates with intraflagellar transport complexes and specializes in ciliary trafficking. In primary cilia, ciliary entry requires the fully assembled BBSome as well as the small GTPase, ARL6 (BBS3). Retinal photoreceptors possess specialized cilia. In light of key structural and functional differences between primary and specialized cilia, we examined the principles of BBSome recruitment to photoreceptor cilia. We performed sucrose gradient fractionation using retinal lysates of Bbs2-/-, Bbs7-/-, Bbs8-/- and Bbs3-/- mice to determine the status of BBSome assembly, then determined localization of BBSome components using immunohistochemistry. Surprisingly, we found that a subcomplex of the BBSome containing at least BBS1, BBS5, BBS8 and BBS9 is recruited to cilia in the absence of BBS2 or BBS7. In contrast, a BBSome subcomplex consisting of BBS1, BBS2, BBS5, BBS7 and BBS9 is found in Bbs8-/- retinas and is denied ciliary entry in photoreceptor cells. In addition, the BBSome remains fully assembled in Bbs3-/- retinas and can be recruited to photoreceptor cilia in the absence of BBS3. We compared phenotypic severity of their retinal degeneration phenotypes. These findings demonstrate that unlike primary cilia, photoreceptor cilia admit a partially assembled BBSome meeting specific requirements. In addition, the recruitment of the BBSome to photoreceptor cilia does not require BBS3. These findings indicate that the ciliary entry of the BBSome is subjected to cell-specific regulation, particularly in cells with highly adapted forms of cilia such as photoreceptors.
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Affiliation(s)
- Ying Hsu
- Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Val C Sheffield
- Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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Lange KI, Tsiropoulou S, Kucharska K, Blacque OE. Interpreting the pathogenicity of Joubert syndrome missense variants in Caenorhabditis elegans. Dis Model Mech 2021; 14:dmm.046631. [PMID: 33234550 PMCID: PMC7859701 DOI: 10.1242/dmm.046631] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/13/2020] [Indexed: 12/26/2022] Open
Abstract
Ciliopathies are inherited disorders caused by defects in motile and non-motile (primary) cilia. Ciliopathy syndromes and associated gene variants are often highly pleiotropic and represent exemplars for interrogating genotype-phenotype correlations. Towards understanding disease mechanisms in the context of ciliopathy mutations, we have used a leading model organism for cilia and ciliopathy research, Caenorhabditis elegans, together with gene editing, to characterise two missense variants (P74S and G155S) in mksr-2/B9D2 associated with Joubert syndrome (JBTS). B9D2 functions within the Meckel syndrome (MKS) module at the ciliary base transition zone (TZ) compartment and regulates the molecular composition and sensory/signalling functions of the cilium. Quantitative assays of cilium/TZ structure and function, together with knock-in reporters, confirm that both variant alleles are pathogenic in worms. G155S causes a more severe overall phenotype and disrupts endogenous MKSR-2 organisation at the TZ. Recapitulation of the patient biallelic genotype shows that compound heterozygous worms phenocopy worms homozygous for P74S. The P74S and G155S alleles also reveal evidence of a very close functional association between the B9D2-associated B9 complex and MKS-2/TMEM216. Together, these data establish C. elegans as a model for interpreting JBTS mutations and provide further insight into MKS module organisation. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Karen I Lange
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Katarzyna Kucharska
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
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Wang T, Liu YX, Luo FM, Dong Y, Li YL, Fan LL. A Novel Homozygous Variant of TMEM231 in a Case With Hypoplasia of the Cerebellar Vermis and Polydactyly. Front Pediatr 2021; 9:774575. [PMID: 34912761 PMCID: PMC8666876 DOI: 10.3389/fped.2021.774575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 10/22/2021] [Indexed: 12/25/2022] Open
Abstract
Background: Transmembrane protein 231 (TMEM231) is a component of the B9 complex that participates in the formation of the diffusion barrier between the cilia and plasma membrane. Mutations in TMEM231 gene may contribute to the Joubert syndrome (JBTS) or Meckel-Gruber syndrome (MKS). However, reports on JBTS or MKS caused by TMEM231 mutations are comparatively rare. Method: We describe a Chinese fetus with unexplained hypoplasia of the cerebellar vermis and polydactyly, detected by ultrasound imaging. The fetus was primarily diagnosed with JBTS/MKS. The parents of this fetus were non-consanguineous and healthy. Whole-exome sequencing (WES) and bioinformatics strategies were employed to explore the genetic lesion of this family. Results: An unknown missense variant (c.19C>T;p.R7W) of TMEM231 gene was detected. The variant was predicted as pathogenic and was absent in our 200 healthy controls. Conclusion: WES was employed to explore the genetic lesion of a fetus with unexplained hypoplasia of the cerebellar vermis and polydactyly. A novel variant in TMEM231 gene was identified. Our study not only provided data for genetic counseling and prenatal diagnosis to this family but also broadened the spectrum of TMEM231 mutations.
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Affiliation(s)
- Tao Wang
- Departments of Reproductive Genetics, HeBei General Hospital, ShiJiaZhuang, China
| | - Yu-Xing Liu
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Fang-Mei Luo
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Yi Dong
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China
| | - Ya-Li Li
- Departments of Reproductive Genetics, HeBei General Hospital, ShiJiaZhuang, China
| | - Liang-Liang Fan
- Departments of Reproductive Genetics, HeBei General Hospital, ShiJiaZhuang, China.,Department of Cell Biology, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Disease, School of Life Sciences, Central South University, Changsha, China
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Abstract
Olfactory sensory neurons (OSNs) are bipolar neurons, unusual because they turn over continuously and have a multiciliated dendrite. The extensive changes in gene expression accompanying OSN differentiation in mice are largely known, especially the transcriptional regulators responsible for altering gene expression, revealing much about how differentiation proceeds. Basal progenitor cells of the olfactory epithelium transition into nascent OSNs marked by Cxcr4 expression and the initial extension of basal and apical neurites. Nascent OSNs become immature OSNs within 24-48 h. Immature OSN differentiation requires about a week and at least 2 stages. Early-stage immature OSNs initiate expression of genes encoding key transcriptional regulators and structural proteins necessary for further neuritogenesis. Late-stage immature OSNs begin expressing genes encoding proteins important for energy production and neuronal homeostasis that carry over into mature OSNs. The transition to maturity depends on massive expression of one allele of one odorant receptor gene, and this results in expression of the last 8% of genes expressed by mature OSNs. Many of these genes encode proteins necessary for mature function of axons and synapses or for completing the elaboration of non-motile cilia, which began extending from the newly formed dendritic knobs of immature OSNs. The cilia from adjoining OSNs form a meshwork in the olfactory mucus and are the site of olfactory transduction. Immature OSNs also have a primary cilium, but its role is unknown, unlike the critical role in proliferation and differentiation played by the primary cilium of the olfactory epithelium's horizontal basal cell.
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Affiliation(s)
- Timothy S McClintock
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- Correspondence to be sent to: Timothy S. McClintock, Department of Physiology, University of Kentucky, 800 Rose St., Lexington, KY 40536-0298, USA. e-mail:
| | - Naazneen Khan
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Chao Xie
- Department of Pharmacology and Therapeutics, and Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, and Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
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Luo M, He R, Lin Z, Shen Y, Zhang G, Cao Z, Lu C, Meng D, Zhang J, Ma X, Cao M. Novel Compound Heterozygous Variants in MKS1 Leading to Joubert Syndrome. Front Genet 2020; 11:576235. [PMID: 33193692 PMCID: PMC7592398 DOI: 10.3389/fgene.2020.576235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/14/2020] [Indexed: 11/13/2022] Open
Abstract
Joubert syndrome (JBTS) and Meckel-Gruber syndrome (MKS) are rare recessive disorders caused by defects of cilia, and they share overlapping clinical features and allelic loci. Mutations of MKS1 contribute approximately 7% to all MKS cases and are found in some JBTS patients. Here, we describe a JBTS patient with two novel mutations of MKS1. Whole exome sequencing (WES) revealed c.191-1G > A and c.1058delG compound heterozygous variants. The patient presented with typical cerebellar vermis hypoplasia, hypotonia, and developmental delay, but without other renal/hepatic involvement or polydactyly. Functional studies showed that the c.1058delG mutation disrupts the B9 domain of MKS1, attenuates the interactions with B9D2, and impairs its ciliary localization at the transition zone (TZ), indicating that the B9 domain of MKS1 is essential for the integrity of the B9 protein complex and localization of MKS1 at the TZ. This work expands the mutation spectrum of MKS1 and elucidates the clinical heterogeneity of MKS1-related ciliopathies.
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Affiliation(s)
- Minna Luo
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Ruida He
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zaisheng Lin
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue Shen
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Guangyu Zhang
- Department of Children Rehabilitation, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zongfu Cao
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Chao Lu
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Dan Meng
- Tianjin Key Laboratory of Food and Biotechnology, School of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Jing Zhang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xu Ma
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Muqing Cao
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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50
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Yamazoe T, Nagai T, Umeda S, Sugaya Y, Mizuno K. Roles of TOG and jelly-roll domains of centrosomal protein CEP104 in its functions in cilium elongation and Hedgehog signaling. J Biol Chem 2020; 295:14723-14736. [PMID: 32820051 DOI: 10.1074/jbc.ra120.013334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/11/2020] [Indexed: 12/26/2022] Open
Abstract
Primary cilia are generated through the extension of the microtubule-based axoneme. Centrosomal protein 104 (CEP104) localizes to the tip of the elongating axoneme, and CEP104 mutations are linked to a ciliopathy, Joubert syndrome. Thus, CEP104 has been implicated in ciliogenesis. However, the mechanism by which CEP104 regulates ciliogenesis remains elusive. We report here that CEP104 is critical for cilium elongation but not for initiating ciliogenesis. We also demonstrated that the tumor-overexpressed gene (TOG) domain of CEP104 exhibits microtubule-polymerizing activity and that this activity is essential for the cilium-elongating activity of CEP104. Knockdown/rescue experiments showed that the N-terminal jelly-roll (JR) fold partially contributes to cilium-elongating activity of CEP104, but neither the zinc-finger region nor the SXIP motif is required for this activity. CEP104 binds to a centriole-capping protein, CP110, through the zinc-finger region and to a microtubule plus-end-binding protein, EB1, through the SXIP motif, indicating that the binding of CP110 and EB1 is dispensable for the cilium-elongating activity of CEP104. Moreover, CEP104 depletion does not affect CP110 removal from the mother centriole, which suggests that CEP104 functions after the removal of CP110. Last, we also showed that CEP104 is required for the ciliary entry of Smoothened and export of GPR161 upon Hedgehog signal activation and that the TOG domain plays a critical role in this activity. Our results define the roles of the individual domains of CEP104 in its functions in cilium elongation and Hedgehog signaling and should enhance our understanding of the mechanism underlying CEP104 mutation-associated ciliopathies.
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Affiliation(s)
- Takashi Yamazoe
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Tomoaki Nagai
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan; Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima, Japan.
| | - Shinya Umeda
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Yuko Sugaya
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Kensaku Mizuno
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan; Institute of Liberal Arts and Sciences, Tohoku University, Kawauchi, Sendai, Miyagi, Japan.
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