1
|
Ewerling A, May-Simera HL. Evolutionary trajectory for nuclear functions of ciliary transport complex proteins. Microbiol Mol Biol Rev 2024:e0000624. [PMID: 38995044 DOI: 10.1128/mmbr.00006-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024] Open
Abstract
SUMMARYCilia and the nucleus were two defining features of the last eukaryotic common ancestor. In early eukaryotic evolution, these structures evolved through the diversification of a common membrane-coating ancestor, the protocoatomer. While in cilia, the descendants of this protein complex evolved into parts of the intraflagellar transport complexes and BBSome, the nucleus gained its selectivity by recruiting protocoatomer-like proteins to the nuclear envelope to form the selective nuclear pore complexes. Recent studies show a growing number of proteins shared between the proteomes of the respective organelles, and it is currently unknown how ciliary transport proteins could acquire nuclear functions and vice versa. The nuclear functions of ciliary proteins are still observable today and remain relevant for the understanding of the disease mechanisms behind ciliopathies. In this work, we review the evolutionary history of cilia and nucleus and their respective defining proteins and integrate current knowledge into theories for early eukaryotic evolution. We postulate a scenario where both compartments co-evolved and that fits current models of eukaryotic evolution, explaining how ciliary proteins and nucleoporins acquired their dual functions.
Collapse
Affiliation(s)
- Alexander Ewerling
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
| | - Helen Louise May-Simera
- Faculty of Biology, Institute of Molecular Physiology, Johannes Gutenberg-University, Mainz, Germany
| |
Collapse
|
2
|
Mercey O, Mukherjee S, Guichard P, Hamel V. The molecular architecture of the ciliary transition zones. Curr Opin Cell Biol 2024; 88:102361. [PMID: 38648677 DOI: 10.1016/j.ceb.2024.102361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/25/2024]
Abstract
Cilia and flagella are specialized eukaryotic organelles projecting from the surface of eukaryotic cells that play a central role in various physiological processes, including cell motility, sensory perception, and signal transduction. At the base of these structures lies the ciliary transition zone, a pivotal region that functions as a gatekeeper and communication hub for ciliary activities. Despite its crucial role, the intricacies of its architecture remain poorly understood, especially given the variations in its organization across different cell types and species. In this review, we explore the molecular architecture of the ciliary transition zone, with a particular focus on recent findings obtained using cryotomography and super-resolution imaging techniques.
Collapse
Affiliation(s)
- Olivier Mercey
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Souradip Mukherjee
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Paul Guichard
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
| | - Virginie Hamel
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
| |
Collapse
|
3
|
Tingey M, Ruba A, Jiang Z, Yang W. Deciphering vesicle-assisted transport mechanisms in cytoplasm to cilium trafficking. Front Cell Neurosci 2024; 18:1379976. [PMID: 38860265 PMCID: PMC11163138 DOI: 10.3389/fncel.2024.1379976] [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: 01/31/2024] [Accepted: 05/13/2024] [Indexed: 06/12/2024] Open
Abstract
The cilium, a pivotal organelle crucial for cell signaling and proper cell function, relies on meticulous macromolecular transport from the cytoplasm for its formation and maintenance. While the intraflagellar transport (IFT) pathway has traditionally been the focus of extensive study concerning ciliogenesis and ciliary maintenance, recent research highlights a complementary and alternative mechanism-vesicle-assisted transport (VAT) in cytoplasm to cilium trafficking. Despite its potential significance, the VAT pathway remains largely uncharacterized. This review explores recent studies providing evidence for the dynamics of vesicle-related diffusion and transport within the live primary cilium, employing high-speed super-resolution light microscopy. Additionally, we analyze the spatial distribution of vesicles in the cilium, mainly relying on electron microscopy data. By scrutinizing the VAT pathways that facilitate cargo transport into the cilium, with a specific emphasis on recent advancements and imaging data, our objective is to synthesize a comprehensive model of ciliary transport through the integration of IFT-VAT mechanisms.
Collapse
Affiliation(s)
| | | | | | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA, United States
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Owens JW, Hopkin RJ, Martin LJ, Kodani A, Simpson BN. Phenotypic variability in Joubert syndrome is partially explained by ciliary pathophysiology. Ann Hum Genet 2024; 88:86-100. [PMID: 37921557 DOI: 10.1111/ahg.12537] [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] [Received: 06/30/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023]
Abstract
INTRODUCTION Joubert syndrome (JS) arises from defects of primary cilia resulting in potential malformations of the brain, kidneys, eyes, liver, and limbs. Several of the 35+ genes associated with JS have recognized genotype/phenotype correlations, but most genes have not had enough reported individuals to draw meaningful conclusions. METHODS A PubMed literature review identified 688 individuals with JS across 32 genes and 112 publications to bolster known genotype/phenotype relationships and identify new correlations. All included patients had the "molar tooth sign" and a confirmed genetic diagnosis. Individuals were categorized by age, ethnicity, sex and the presence of developmental disability/intellectual disability, hypotonia, abnormal eye movements, ataxia, visual impairment, renal impairment, polydactyly, and liver abnormalities. RESULTS Most genes demonstrated unique phenotypic profiles. Grouping proteins based on physiologic interactions established stronger phenotypic relationships that reflect known ciliary pathophysiology. Age-stratified data demonstrated that end-organ disease is progressive in JS. Most genes demonstrated a significant skew towards having variants with either residual protein function or no residual protein function. CONCLUSION This cohort demonstrates that clinically meaningful genotype/phenotype relationships exist within most JS-related genes and can be referenced to allow for more personalized clinical care.
Collapse
Affiliation(s)
- Joshua W Owens
- UPMC Children's Hospital of Pittsburgh Division of Genetic and Genomic Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center Division of Human Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Robert J Hopkin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center Division of Human Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Lisa J Martin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center Division of Human Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Andrew Kodani
- Department of Cell and Molecular Biology, Center for Pediatric Neurological Disease Research, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Brittany N Simpson
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center Division of Human Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| |
Collapse
|
6
|
Cideciyan AV, Jacobson SG, Ho AC, Swider M, Sumaroka A, Roman AJ, Wu V, Russell RC, Viarbitskaya I, Garafalo AV, Schwartz MR, Girach A. Durable vision improvement after a single intravitreal treatment with antisense oligonucleotide in CEP290-LCA: Replication in two eyes. Am J Ophthalmol Case Rep 2023; 32:101873. [PMID: 37388818 PMCID: PMC10302566 DOI: 10.1016/j.ajoc.2023.101873] [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: 03/28/2023] [Revised: 05/15/2023] [Accepted: 06/11/2023] [Indexed: 07/01/2023] Open
Abstract
Purpose An intravitreally injected antisense oligonucleotide, sepofarsen, was designed to modulate splicing within retinas of patients with severe vision loss due to deep intronic c.2991 + 1655A > G variant in the CEP290 gene. A previous report showed vision improvements following a single injection in one eye with unexpected durability lasting at least 15 months. The current study evaluated durability of efficacy beyond 15 months in the previously treated left eye. In addition, peak efficacy and durability were evaluated in the treatment-naive right eye, and re-injection of the left eye 4 years after the first injection. Observations Visual function was evaluated with best corrected standard and low-luminance visual acuities, microperimetry, dark-adapted chromatic perimetry, and full-field sensitivity testing. Retinal structure was evaluated with OCT imaging. At the fovea, all visual function measures and IS/OS intensity of the OCT showed transient improvements peaking at 3-6 months, remaining better than baseline at ∼2 years, and returning to baseline by 3-4 years after each single injection. Conclusions and Importance These results suggest that sepofarsen reinjection intervals may need to be longer than 2 years.
Collapse
Affiliation(s)
- Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Allen C. Ho
- Wills Eye Hospital, Thomas Jefferson University, Philadelphia, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C. Russell
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Iryna Viarbitskaya
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexandra V. Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | |
Collapse
|
7
|
Chen Y, Zhang Y, Zhou X. Non-classical functions of nuclear pore proteins in ciliopathy. Front Mol Biosci 2023; 10:1278976. [PMID: 37908226 PMCID: PMC10614291 DOI: 10.3389/fmolb.2023.1278976] [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: 08/17/2023] [Accepted: 10/02/2023] [Indexed: 11/02/2023] Open
Abstract
Nucleoporins (NUPs) constitute integral nuclear pore protein (NPC) elements. Although traditional NUP functions have been extensively researched, evidence of additional vital non-NPC roles, referred to herein as non-classical NUP functions, is also emerging. Several NUPs localise at the ciliary base. Indeed, Nup188, Nup93 or Nup205 knockdown results in cilia loss, impacting cardiac left-right patterning in models and cell lines. Genetic variants of Nup205 and Nup188 have been identified in patients with congenital heart disease and situs inversus totalis or heterotaxy, a prevalent human ciliopathy. These findings link non-classical NUP functions to human diseases. This mini-review summarises pivotal NUP interactions with NIMA-related kinases or nephronophthisis proteins that regulate ciliary function and explores other NUPs potentially implicated in cilia-related disorders. Overall, elucidating the non-classical roles of NUPs will enhance comprehension of ciliopathy aetiology.
Collapse
Affiliation(s)
- Yan Chen
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University Shanghai Medical College, Shanghai, China
| | - Yuan Zhang
- Department of Assisted Reproduction, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiangyu Zhou
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University Shanghai Medical College, Shanghai, China
| |
Collapse
|
8
|
Tingey M, Ruba A, Yang W. High-SPEED super-resolution SPEED microscopy to study primary cilium signaling in vivo. Methods Cell Biol 2023; 176:181-197. [PMID: 37164537 DOI: 10.1016/bs.mcb.2022.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The primary cilium is a surface exposed organelle found in eukaryotic cells that functions to decode a variety of intracellular signals with significant implications in human developmental disorders and diseases. It is therefore highly desirable to obtain in vivo information regarding the dynamic processes occurring within the primary cilium. However, current techniques are limited by either the physical limitations of light microscopy or the static nature of electron microscopy. To overcome these limitations, single-point edge-excitation sub-diffraction (SPEED) microscopy was developed to obtain dynamic in vivo information in subcellular organelles such as cilia and nuclear pore complexes using single-molecule super-resolution light microscopy with a spatiotemporal resolution of 10-20nm and 0.4-2ms. Three-dimensional (3D) structural and dynamic information in these organelles can be further obtained through a post-processing 2D-to-3D transformation algorithm. Here we present a modular step-by-step protocol for studying primary cilium signaling dynamics, including Intraflagellar transport (IFT) via IFT20 and somatostatin g-protein-coupled receptor activity via SSTR3.
Collapse
Affiliation(s)
- Mark Tingey
- Department of Biology, Temple University, Philadelphia, PA, United States
| | - Andrew Ruba
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, United States
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA, United States.
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Kruczek K, Qu Z, Welby E, Shimada H, Hiriyanna S, English MA, Zein WM, Brooks BP, Swaroop A. In vitro modeling and rescue of ciliopathy associated with IQCB1/NPHP5 mutations using patient-derived cells. Stem Cell Reports 2022; 17:2172-2186. [PMID: 36084637 PMCID: PMC9561628 DOI: 10.1016/j.stemcr.2022.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/12/2022] [Accepted: 08/12/2022] [Indexed: 11/26/2022] Open
Abstract
Mutations in the IQ calmodulin-binding motif containing B1 (IQCB1)/NPHP5 gene encoding the ciliary protein nephrocystin 5 cause early-onset blinding disease Leber congenital amaurosis (LCA), together with kidney dysfunction in Senior-Løken syndrome. For in vitro disease modeling, we obtained dermal fibroblasts from patients with NPHP5-LCA that were reprogrammed into induced pluripotent stem cells (iPSCs) and differentiated into retinal pigment epithelium (RPE) and retinal organoids. Patient fibroblasts and RPE demonstrated aberrantly elongated ciliary axonemes. Organoids revealed impaired development of outer segment structures, which are modified primary cilia, and mislocalization of visual pigments to photoreceptor cell soma. All patient-derived cells showed reduced levels of CEP290 protein, a critical cilia transition zone component interacting with NPHP5, providing a plausible mechanism for aberrant ciliary gating and cargo transport. Disease phenotype in NPHP5-LCA retinal organoids could be rescued by adeno-associated virus (AAV)-mediated IQCB1/NPHP5 gene augmentation therapy. Our studies thus establish a human disease model and a path for treatment of NPHP5-LCA.
Collapse
Affiliation(s)
- Kamil Kruczek
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Zepeng Qu
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Emily Welby
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Hiroko Shimada
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Suja Hiriyanna
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Milton A English
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
| |
Collapse
|
11
|
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.
Collapse
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.
| |
Collapse
|
12
|
Abstract
Cilia harbor diffusion barriers for soluble and membrane proteins within their proximal-most transition zone (TZ) region and employ an intraflagellar transport (IFT) system to form dynamic motile and signaling compartments. In this issue, De-Castro and colleagues (2021. J. Cell Biol.https://doi.org/10.1083/jcb.202010178) uncover a long-suspected role for the TZ in gating IFT particles.
Collapse
Affiliation(s)
- Kwangjin Park
- Terry Fox Laboratory, BC Cancer, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michel R. Leroux
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
| |
Collapse
|
13
|
Wensel TG, Potter VL, Moye A, Zhang Z, Robichaux MA. Structure and dynamics of photoreceptor sensory cilia. Pflugers Arch 2021; 473:1517-1537. [PMID: 34050409 PMCID: PMC11216635 DOI: 10.1007/s00424-021-02564-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
The rod and cone photoreceptor cells of the vertebrate retina have highly specialized structures that enable them to carry out their function of light detection over a broad range of illumination intensities with optimized spatial and temporal resolution. Most prominent are their unusually large sensory cilia, consisting of outer segments packed with photosensitive disc membranes, a connecting cilium with many features reminiscent of the primary cilium transition zone, and a pair of centrioles forming a basal body which serves as the platform upon which the ciliary axoneme is assembled. These structures form a highway through which an enormous flux of material moves on a daily basis to sustain the continual turnover of outer segment discs and the energetic demands of phototransduction. After decades of study, the details of the fine structure and distribution of molecular components of these structures are still incompletely understood, but recent advances in cellular imaging techniques and animal models of inherited ciliary defects are yielding important new insights. This knowledge informs our understanding both of the mechanisms of trafficking and assembly and of the pathophysiological mechanisms of human blinding ciliopathies.
Collapse
Affiliation(s)
- Theodore G Wensel
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Valencia L Potter
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology and Developmental Biology Graduate Program, Baylor College of Medicine, Houston, TX, 77030, USA
- Medical Scientist Training Program (MSTP), Baylor College of Medicine, Houston, TX, 77030, USA
| | - Abigail Moye
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Zhixian Zhang
- Vera and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Michael A Robichaux
- Departments of Ophthalmology and Biochemistry, West Virginia University, Morgantown, WV, USA
| |
Collapse
|
14
|
Doornbos C, Roepman R. Moonlighting of mitotic regulators in cilium disassembly. Cell Mol Life Sci 2021; 78:4955-4972. [PMID: 33860332 PMCID: PMC8233288 DOI: 10.1007/s00018-021-03827-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/03/2021] [Accepted: 03/27/2021] [Indexed: 02/07/2023]
Abstract
Correct timing of cellular processes is essential during embryological development and to maintain the balance between healthy proliferation and tumour formation. Assembly and disassembly of the primary cilium, the cell’s sensory signalling organelle, are linked to cell cycle timing in the same manner as spindle pole assembly and chromosome segregation. Mitotic processes, ciliary assembly, and ciliary disassembly depend on the centrioles as microtubule-organizing centres (MTOC) to regulate polymerizing and depolymerizing microtubules. Subsequently, other functional protein modules are gathered to potentiate specific protein–protein interactions. In this review, we show that a significant subset of key mitotic regulator proteins is moonlighting at the cilium, among which PLK1, AURKA, CDC20, and their regulators. Although ciliary assembly defects are linked to a variety of ciliopathies, ciliary disassembly defects are more often linked to brain development and tumour formation. Acquiring a better understanding of the overlap in regulators of ciliary disassembly and mitosis is essential in finding therapeutic targets for the different diseases and types of tumours associated with these regulators.
Collapse
Affiliation(s)
- Cenna Doornbos
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands. .,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| |
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
The Transition Zone Protein AHI1 Regulates Neuronal Ciliary Trafficking of MCHR1 and Its Downstream Signaling Pathway. J Neurosci 2021; 41:3932-3943. [PMID: 33741721 DOI: 10.1523/jneurosci.2993-20.2021] [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: 10/24/2020] [Revised: 02/25/2021] [Accepted: 03/10/2021] [Indexed: 11/21/2022] Open
Abstract
The Abelson-helper integration site 1 (AHI1) gene encodes for a ciliary transition zone localizing protein that when mutated causes the human ciliopathy, Joubert syndrome. We prepared and examined neuronal cultures derived from male and female embryonic Ahi1 +/+ and Ahi1 -/- mice (littermates) and found that the distribution of ciliary melanin-concentrating hormone receptor-1 (MchR1) was significantly reduced in Ahi1 -/- neurons; however, the total and surface expression of MchR1 on Ahi1 -/- neurons was similar to controls (Ahi1 +/+). This indicates that a pathway for MchR1 trafficking to the surface plasma membrane is intact, but the process of targeting MchR1 into cilia is impaired in Ahi1-deficient mouse neurons, indicating a role for Ahi1 in localizing MchR1 to the cilium. Mouse Ahi1 -/- neurons that fail to accumulate MchR1 in the ciliary membrane have significant decreases in two downstream MchR1 signaling pathways [cAMP and extracellular signal-regulated kinase (Erk)] on MCH stimulation. These results suggest that the ciliary localization of MchR1 is necessary and critical for MchR1 signaling, with Ahi1 participating in regulating MchR1 localization to cilia, and further supporting cilia as critical signaling centers in neurons.SIGNIFICANCE STATEMENT Our work here demonstrates that neuronal primary cilia are powerful and focused signaling centers for the G-protein-coupled receptor (GPCR), melanin-concentrating hormone receptor-1 (MCHR1), with a role for the ciliary transition zone protein, Abelson-helper integration site 1 (AHI1), in mediating ciliary trafficking of MCHR1. Moreover, our manuscript further expands the repertoire of cilia functions on neurons, a cell type that has not received significant attention in the cilia field. Lastly, our work demonstrates the significant influence of ciliary GPCR signaling in the overall signaling of neurons.
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Huang S, Dougherty LL, Avasthi P. Separable roles for RanGTP in nuclear and ciliary trafficking of a kinesin-2 subunit. J Biol Chem 2021; 296:100117. [PMID: 33234597 PMCID: PMC7948393 DOI: 10.1074/jbc.ra119.010936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023] Open
Abstract
Kinesin is part of the microtubule-binding motor protein superfamily, which serves important roles in cell division and intraorganellar transport. The heterotrimeric kinesin-2, consisting of the heterodimeric motor subunits, kinesin family member 3A/3B (KIF3A/3B), and kinesin-associated protein 3 (KAP3), is highly conserved across species from the unicellular eukaryote Chlamydomonas to humans. It plays diverse roles in cargo transport including anterograde (base to tip) trafficking in cilia. However, the molecular determinants mediating trafficking of heterotrimeric kinesin-2 itself are poorly understood. It has been previously suggested that ciliary transport is analogous to nuclear transport mechanisms. Using Chlamydomonas and human telomerase reverse transcriptase-retinal pigment epithelial cell line, we show that RanGTP, a small GTPase that dictates nuclear transport, regulates ciliary trafficking of KAP3, a key component for functional kinesin-2. We found that the armadillo-repeat region 6 to 9 (ARM6-9) of KAP3, required for its nuclear translocation, is also necessary and sufficient for its targeting to the ciliary base. Given that KAP3 is essential for cilium formation and there are the emerging roles for RanGTP/importin β in ciliary protein targeting, we further investigated the effect of RanGTP in cilium formation and maintenance. We found that precise control of RanGTP levels, revealed by different Ran mutants, is crucial for cilium formation and maintenance. Most importantly, we were able to provide orthogonal support in an algal model system that segregates RanGTP regulation of ciliary protein trafficking from its nuclear roles. Our work provides important support for the model that nuclear import mechanisms have been co-opted for independent roles in ciliary import.
Collapse
Affiliation(s)
- Shengping Huang
- Department of Ophthalmology, University of Kansas Medical Center, Kansas City, Kansas, USA.
| | - Larissa L Dougherty
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire, USA
| | - Prachee Avasthi
- Department of Ophthalmology, University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire, USA.
| |
Collapse
|
19
|
Jühlen R, Martinelli V, Vinci C, Breckpot J, Fahrenkrog B. Centrosome and ciliary abnormalities in fetal akinesia deformation sequence human fibroblasts. Sci Rep 2020; 10:19301. [PMID: 33168876 PMCID: PMC7652866 DOI: 10.1038/s41598-020-76192-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/23/2020] [Indexed: 02/06/2023] Open
Abstract
Ciliopathies are clinical disorders of the primary cilium with widely recognised phenotypic and genetic heterogeneity. Here, we found impaired ciliogenesis in fibroblasts derived from individuals with fetal akinesia deformation sequence (FADS), a broad spectrum of neuromuscular disorders arising from compromised foetal movement. We show that cells derived from FADS individuals have shorter and less primary cilia (PC), in association with alterations in post-translational modifications in α-tubulin. Similarly, siRNA-mediated depletion of two known FADS proteins, the scaffold protein rapsyn and the nucleoporin NUP88, resulted in defective PC formation. Consistent with a role in ciliogenesis, rapsyn and NUP88 localised to centrosomes and PC. Furthermore, proximity-ligation assays confirm the respective vicinity of rapsyn and NUP88 to γ-tubulin. Proximity-ligation assays moreover show that rapsyn and NUP88 are adjacent to each other and that the rapsyn-NUP88 interface is perturbed in the examined FADS cells. We suggest that the perturbed rapsyn-NUP88 interface leads to defects in PC formation and that defective ciliogenesis contributes to the pleiotropic defects seen in FADS.
Collapse
Affiliation(s)
- Ramona Jühlen
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 6041, Gosselies, Belgium.,Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, 52074, Aachen, Germany
| | - Valérie Martinelli
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 6041, Gosselies, Belgium
| | - Chiara Vinci
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 6041, Gosselies, Belgium
| | - Jeroen Breckpot
- Center for Human Genetics, University Hospitals Leuven, Catholic University Leuven, Leuven, Belgium
| | - Birthe Fahrenkrog
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 6041, Gosselies, Belgium. .,Biozentrum, University of Basel, 4056, Basel, Switzerland.
| |
Collapse
|
20
|
Yu T, Matsuda M. Epb41l5 interacts with Iqcb1 and regulates ciliary function in zebrafish embryos. J Cell Sci 2020; 133:jcs240648. [PMID: 32501287 PMCID: PMC7338265 DOI: 10.1242/jcs.240648] [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: 10/21/2019] [Accepted: 05/13/2020] [Indexed: 11/20/2022] Open
Abstract
Erythrocyte protein band 4.1 like 5 (EPB41L5) is an adaptor protein beneath the plasma membrane that functions to control epithelial morphogenesis. Here we report a previously uncharacterized role of EPB41L5 in controlling ciliary function. We found that EPB41L5 forms a complex with IQCB1 (previously known as NPHP5), a ciliopathy protein. Overexpression of EPB41L5 reduced IQCB1 localization at the ciliary base in cultured mammalian epithelial cells. Conversely, epb41l5 knockdown increased IQCB1 localization at the ciliary base. epb41l5-deficient zebrafish embryos or embryos expressing C-terminally modified forms of Epb41l5 developed cilia with reduced motility and exhibited left-right patterning defects, an outcome of abnormal ciliary function. We observed genetic synergy between epb41l5 and iqcb1. Moreover, EPB41L5 decreased IQCB1 interaction with CEP290, another ciliopathy protein and a component of the ciliary base and centrosome. Together, these observations suggest that EPB41L5 regulates the composition of the ciliary base and centrosome through IQCB1 and CEP290.
Collapse
Affiliation(s)
- Tiffany Yu
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07302, USA
| | - Miho Matsuda
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07302, USA
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| |
Collapse
|
21
|
Nagao Y, Sakamoto M, Chinen T, Okada Y, Takao D. Robust classification of cell cycle phase and biological feature extraction by image-based deep learning. Mol Biol Cell 2020; 31:1346-1354. [PMID: 32320349 PMCID: PMC7353138 DOI: 10.1091/mbc.e20-03-0187] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Across the cell cycle, the subcellular organization undergoes major spatiotemporal changes that could in principle contain biological features that could potentially represent cell cycle phase. We applied convolutional neural network-based classifiers to extract such putative features from the fluorescence microscope images of cells stained for the nucleus, the Golgi apparatus, and the microtubule cytoskeleton. We demonstrate that cell images can be robustly classified according to G1/S and G2 cell cycle phases without the need for specific cell cycle markers. Grad-CAM analysis of the classification models enabled us to extract several pairs of quantitative parameters of specific subcellular features as good classifiers for the cell cycle phase. These results collectively demonstrate that machine learning-based image processing is useful to extract biological features underlying cellular phenomena of interest in an unbiased and data-driven manner.
Collapse
Affiliation(s)
- Yukiko Nagao
- Faculty of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Mika Sakamoto
- Genome Informatics Laboratory, National Institute of Genetics, Mishima 411-8540, Japan
| | - Takumi Chinen
- Faculty of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yasushi Okada
- Department of Cell Biology and Anatomy and International Research Center for Neurointelligence (WPI-IRCN), Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.,Department of Physics and Universal Biology Institute (UBI), Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.,Laboratory for Cell Polarity Regulation, Center for Biosystems Dynamics Research (BDR), RIKEN, Osaka 565-0874, Japan
| | - Daisuke Takao
- Department of Cell Biology and Anatomy and International Research Center for Neurointelligence (WPI-IRCN), Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| |
Collapse
|
22
|
Establishing and regulating the composition of cilia for signal transduction. Nat Rev Mol Cell Biol 2020; 20:389-405. [PMID: 30948801 DOI: 10.1038/s41580-019-0116-4] [Citation(s) in RCA: 244] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The primary cilium is a hair-like surface-exposed organelle of the eukaryotic cell that decodes a variety of signals - such as odorants, light and Hedgehog morphogens - by altering the local concentrations and activities of signalling proteins. Signalling within the cilium is conveyed through a diverse array of second messengers, including conventional signalling molecules (such as cAMP) and some unusual intermediates (such as sterols). Diffusion barriers at the ciliary base establish the unique composition of this signalling compartment, and cilia adapt their proteome to signalling demands through regulated protein trafficking. Much progress has been made on the molecular understanding of regulated ciliary trafficking, which encompasses not only exchanges between the cilium and the rest of the cell but also the shedding of signalling factors into extracellular vesicles.
Collapse
|
23
|
Sumaroka A, Garafalo AV, Semenov EP, Sheplock R, Krishnan AK, Roman AJ, Jacobson SG, Cideciyan AV. Treatment Potential for Macular Cone Vision in Leber Congenital Amaurosis Due to CEP290 or NPHP5 Mutations: Predictions From Artificial Intelligence. Invest Ophthalmol Vis Sci 2019; 60:2551-2562. [PMID: 31212307 PMCID: PMC6586080 DOI: 10.1167/iovs.19-27156] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Purpose To use supervised machine learning to predict visual function from retinal structure in retinitis pigmentosa (RP) and apply these estimates to CEP290- and NPHP5-associated Leber congenital amaurosis (LCA) to determine the potential for functional improvement. Methods Patients with RP (n = 20) and LCA due to CEP290 (n = 12) or NPHP5 (n = 6) mutations were studied. A patient with CEP290 mutations but mild retinal degeneration was included. RP patients had cone-mediated macular function. A machine learning technique was used to associate perimetric sensitivities to local structure in RP patients. Models trained on RP data were applied to predict visual function in LCA. Results The RP and LCA patients had comparable retinal structure. RP patients had peak sensitivity at the fovea surrounded by decreasing sensitivity. Machine learning could successfully predict perimetry results from segmented or unsegmented optical coherence tomography (OCT) input. Application of machine learning predictions to LCA within the residual macular island of photoreceptor structure showed differences between predicted and measured sensitivities defining treatment potential. In patients with retained vision, the treatment potential was 4.6 ± 2.9 dB at the fovea but 16.4 ± 4.4 dB at the parafovea. In patients with limited or no vision, the treatment potential was 17.6 ± 9.4 dB. Conclusions Cone vision improvement potential in LCA due to CEP290 or NPHP5 mutations is predictable from retinal structure using a machine learning approach. This should allow individual prediction of the maximal efficacy in clinical trials and guide decisions about dosing. Similar strategies can be used in other retinal degenerations to estimate the extent and location of treatment potential.
Collapse
Affiliation(s)
- Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alexandra V Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Evelyn P Semenov
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Arun K Krishnan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alejandro J Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| |
Collapse
|
24
|
Blasius TL, Takao D, Verhey KJ. NPHP proteins are binding partners of nucleoporins at the base of the primary cilium. PLoS One 2019; 14:e0222924. [PMID: 31553752 PMCID: PMC6760808 DOI: 10.1371/journal.pone.0222924] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/09/2019] [Indexed: 12/21/2022] Open
Abstract
Cilia are microtubule-based organelles that protrude from the surface of eukaryotic cells to generate motility and to sense and respond to environmental cues. In order to carry out these functions, the complement of proteins in the cilium must be specific for the organelle. Regulation of protein entry into primary cilia has been shown to utilize mechanisms and components of nuclear gating, including nucleoporins of the nuclear pore complex (NPC). We show that nucleoporins also localize to the base of motile cilia on the surface of trachea epithelial cells. How nucleoporins are anchored at the cilium base has been unclear as transmembrane nucleoporins, which anchor nucleoporins at the nuclear envelope, have not been found to localize at the cilium. Here we use the directed yeast two-hybrid assay to identify direct interactions between nucleoporins and nephronophthisis proteins (NPHPs) which localize to the cilium base and contribute to cilium assembly and identity. We validate NPHP-nucleoporin interactions in mammalian cells using the knocksideways assay and demonstrate that the interactions occur at the base of the primary cilium using bimolecular fluorescence complementation. We propose that NPHP proteins anchor nucleoporins at the base of primary cilia to regulate protein entry into the organelle.
Collapse
Affiliation(s)
- T. Lynne Blasius
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Daisuke Takao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Kristen J. Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
| |
Collapse
|
25
|
Muñoz-Estrada J, Ferland RJ. Ahi1 promotes Arl13b ciliary recruitment, regulates Arl13b stability and is required for normal cell migration. J Cell Sci 2019; 132:jcs.230680. [PMID: 31391239 DOI: 10.1242/jcs.230680] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/24/2019] [Indexed: 12/14/2022] Open
Abstract
Mutations in the Abelson-helper integration site 1 (AHI1) gene are associated with neurological/neuropsychiatric disorders, and cause the neurodevelopmental ciliopathy Joubert syndrome (JBTS). Here, we show that deletion of the transition zone (TZ) protein Ahi1 in mouse embryonic fibroblasts (MEFs) has a small effect on cilia formation. However, Ahi1 loss in these cells results in: (1) reduced localization of the JBTS-associated protein Arl13b to the ciliary membrane, (2) decreased sonic hedgehog signaling, (3) and an abnormally elongated ciliary axoneme accompanied by an increase in ciliary IFT88 concentrations. While no changes in Arl13b levels are detected in crude cell membrane extracts, loss of Ahi1 significantly reduced the level of non-membrane-associated Arl13b and its stability via the proteasome pathway. Exogenous expression of Ahi1-GFP in Ahi1-/- MEFs restored ciliary length, increased ciliary recruitment of Arl13b and augmented Arl13b stability. Finally, Ahi1-/- MEFs displayed defects in cell motility and Pdgfr-α-dependent migration. Overall, our findings support molecular mechanisms underlying JBTS etiology that involve: (1) disruptions at the TZ resulting in defects of membrane- and non-membrane-associated proteins to localize to primary cilia, and (2) defective cell migration.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Jesús Muñoz-Estrada
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA .,Department of Neurology, Albany Medical College, Albany, NY 12208, USA
| |
Collapse
|
26
|
Jack B, Mueller DM, Fee AC, Tetlow AL, Avasthi P. Partially Redundant Actin Genes in Chlamydomonas Control Transition Zone Organization and Flagellum-Directed Traffic. Cell Rep 2019; 27:2459-2467.e3. [PMID: 31116988 PMCID: PMC6541019 DOI: 10.1016/j.celrep.2019.04.087] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/03/2018] [Accepted: 04/18/2019] [Indexed: 11/16/2022] Open
Abstract
The unicellular green alga Chlamydomonas reinhardtii is a biflagellated cell with two actin genes: one encoding a conventional actin (IDA5) and the other encoding a divergent novel actin-like protein (NAP1). Here, we probe how actin redundancy contributes to flagellar assembly. Disrupting a single actin allows complete flagellar assembly. However, when disrupting both actins using latrunculin B (LatB) treatment on the nap1 mutant background, we find that actins are necessary for flagellar growth from newly synthesized limiting flagellar proteins. Under total actin disruption, transmission electron microscopy identified an accumulation of Golgi-adjacent vesicles. We also find that there is a mislocalization of a key transition zone gating and ciliopathy protein, NPHP-4. Our experiments demonstrate that each stage of flagellar biogenesis requires redundant actin function to varying degrees, with an absolute requirement for these actins in transport of Golgi-adjacent vesicles and flagellar incorporation of newly synthesized proteins.
Collapse
Affiliation(s)
- Brittany Jack
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - David M Mueller
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Ann C Fee
- University of Missouri-Kansas City, School of Medicine, Kansas City, MO 64110, USA
| | - Ashley L Tetlow
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Prachee Avasthi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Ophthalmology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| |
Collapse
|
27
|
Sensory primary cilium is a responsive cAMP microdomain in renal epithelia. Sci Rep 2019; 9:6523. [PMID: 31024067 PMCID: PMC6484033 DOI: 10.1038/s41598-019-43002-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/12/2019] [Indexed: 02/07/2023] Open
Abstract
Primary cilia are hair-like cellular extensions that sense microenvironmental signals surrounding cells. The role of adenylyl cyclases in ciliary function has been of interest because the product of adenylyl cyclase activity, cAMP, is relevant to cilia-related diseases. In the present study, we show that vasopressin receptor type-2 (V2R) is localized to cilia in kidney epithelial cells. Pharmacologic inhibition of V2R with tolvaptan increases ciliary length and mechanosensory function. Genetic knockdown of V2R, however, does not have any effect on ciliary length, although the effect of tolvaptan on ciliary length is dampened. Our study reveals that tolvaptan may have a cilia-specific effect independent of V2R or verapamil-sensitive calcium channels. Live-imaging of single cilia shows that V2R activation increases cilioplasmic and cytoplasmic cAMP levels, whereas tolvaptan mediates cAMP changes only in a cilia-specific manner. Furthermore, fluid-shear stress decreases cilioplasmic, but not cytoplasmic cAMP levels. Our data indicate that cilioplasmic and cytoplasmic cAMP levels are differentially modulated. We propose that the cilium is a critical sensor acting as a responsive cAMP microcompartment during physiologically relevant stimuli.
Collapse
|
28
|
The Nuclear Arsenal of Cilia. Dev Cell 2019; 49:161-170. [DOI: 10.1016/j.devcel.2019.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 12/07/2018] [Accepted: 03/08/2019] [Indexed: 12/31/2022]
|
29
|
Jensen VL, Lambacher NJ, Li C, Mohan S, Williams CL, Inglis PN, Yoder BK, Blacque OE, Leroux MR. Role for intraflagellar transport in building a functional transition zone. EMBO Rep 2018; 19:e45862. [PMID: 30429209 PMCID: PMC6280794 DOI: 10.15252/embr.201845862] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 10/22/2018] [Accepted: 10/26/2018] [Indexed: 12/21/2022] Open
Abstract
Genetic disorders caused by cilia dysfunction, termed ciliopathies, frequently involve the intraflagellar transport (IFT) system. Mutations in IFT subunits-including IFT-dynein motor DYNC2H1-impair ciliary structures and Hedgehog signalling, typically leading to "skeletal" ciliopathies such as Jeune asphyxiating thoracic dystrophy. Intriguingly, IFT gene mutations also cause eye, kidney and brain ciliopathies often linked to defects in the transition zone (TZ), a ciliary gate implicated in Hedgehog signalling. Here, we identify a C. elegans temperature-sensitive (ts) IFT-dynein mutant (che-3; human DYNC2H1) and use it to show a role for retrograde IFT in anterograde transport and ciliary maintenance. Unexpectedly, correct TZ assembly and gating function for periciliary proteins also require IFT-dynein. Using the reversibility of the novel ts-IFT-dynein, we show that restoring IFT in adults (post-developmentally) reverses defects in ciliary structure, TZ protein localisation and ciliary gating. Notably, this ability to reverse TZ defects declines as animals age. Together, our findings reveal a previously unknown role for IFT in TZ assembly in metazoans, providing new insights into the pathomechanism and potential phenotypic overlap between IFT- and TZ-associated ciliopathies.
Collapse
Affiliation(s)
- Victor L Jensen
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Nils J Lambacher
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Chunmei Li
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Swetha Mohan
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Corey L Williams
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham Medical School, Birmingham, AL, USA
| | - Peter N Inglis
- Department of Biology, Kwantlen Polytechnic University, Surrey, BC, Canada
| | - Bradley K Yoder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham Medical School, Birmingham, AL, USA
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Michel R Leroux
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| |
Collapse
|
30
|
The Roles of Primary Cilia in Cardiovascular Diseases. Cells 2018; 7:cells7120233. [PMID: 30486394 PMCID: PMC6315816 DOI: 10.3390/cells7120233] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 02/07/2023] Open
Abstract
Primary cilia are microtubule-based organelles found in most mammalian cell types. Cilia act as sensory organelles that transmit extracellular clues into intracellular signals for molecular and cellular responses. Biochemical and molecular defects in primary cilia are associated with a wide range of diseases, termed ciliopathies, with phenotypes ranging from polycystic kidney disease, liver disorders, mental retardation, and obesity to cardiovascular diseases. Primary cilia in vascular endothelia protrude into the lumen of blood vessels and function as molecular switches for calcium (Ca2+) and nitric oxide (NO) signaling. As mechanosensory organelles, endothelial cilia are involved in blood flow sensing. Dysfunction in endothelial cilia contributes to aberrant fluid-sensing and thus results in vascular disorders, including hypertension, aneurysm, and atherosclerosis. This review focuses on the most recent findings on the roles of endothelial primary cilia within vascular biology and alludes to the possibility of primary cilium as a therapeutic target for cardiovascular disorders.
Collapse
|
31
|
Scheidel N, Blacque OE. Intraflagellar Transport Complex A Genes Differentially Regulate Cilium Formation and Transition Zone Gating. Curr Biol 2018; 28:3279-3287.e2. [PMID: 30293716 DOI: 10.1016/j.cub.2018.08.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 06/08/2018] [Accepted: 08/07/2018] [Indexed: 02/03/2023]
Abstract
Cilia are found on most eukaryotic cell types, serving motility, environment sensing, and signaling (cell-cell) functions, and defects cause genetic diseases (ciliopathies), affecting the development of many tissues [1]. Cilia are built by intraflagellar transport (IFT), a bidirectional microtubule-based motility driven by kinesin-2 anterograde (toward ciliary tip) and IFT-dynein retrograde (toward ciliary base) motors together with IFT-A and IFT-B cargo adaptor complexes that control retrograde and anterograde IFT, respectively [2]. Ciliary composition is also facilitated by the transition zone (TZ) at the ciliary base and the associated Meckel-Gruber syndrome (MKS) and nephronophthisis (NPHP) modules that establish protein diffusion barriers and regulate cilium structure [3]. Although the molecular architecture of the IFT machine is emerging [2], how individual components contribute to cilium subtype formation and IFT remains relatively unexplored, especially in vivo. In addition, little is known about functional interactions between IFT and TZ modules. Here, in Caenorhabditis elegans (roundworms), we identify cell-type-specific mechanisms by which IFT-A sculpts the structures of discrete ciliary subtypes and regulates IFT. We also uncover differential roles for IFT-A subunits in controlling the TZ restriction of MKS module components and ciliary exclusion (gating) of periciliary membrane proteins, with IFT-140 controlling their ciliary entry and IFT-43/121/139 controlling their ciliary removal. Furthermore, we determine that IFT-A and MKS module components synergistically interact to determine cilium structure. Overall, this work provides insight into the functional architecture of a metazoan IFT-A complex in different cell types and uncovers new relationships between ciliopathy-associated IFT-A and TZ modules.
Collapse
Affiliation(s)
- Noémie Scheidel
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Oliver E Blacque
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| |
Collapse
|
32
|
Tusk SE, Delalez NJ, Berry RM. Subunit Exchange in Protein Complexes. J Mol Biol 2018; 430:4557-4579. [DOI: 10.1016/j.jmb.2018.06.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/21/2018] [Accepted: 06/21/2018] [Indexed: 01/09/2023]
|
33
|
Hossain D, Tsang WY. The role of ubiquitination in the regulation of primary cilia assembly and disassembly. Semin Cell Dev Biol 2018; 93:145-152. [PMID: 30213760 DOI: 10.1016/j.semcdb.2018.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 01/02/2023]
Abstract
The primary cilium is a cellular antenna found on the surface of many eukaryotic cells, whose main role is to sense and transduce signals that regulate growth, development, and differentiation. Although once believed to be a vestigial organelle without important function, it has become clear that defects in primary cilium are responsible for a wide variety of genetic diseases affecting many organs and tissues, including the brain, eyes, heart, kidneys, liver, and pancreas. The primary cilium is mainly present in quiescent and differentiated cells, and controls must exist to ensure that this organelle is assembled or disassembled at the right time. Although many protein components required for building the cilium have been identified, mechanistic details of how these proteins are spatially and temporally regulated and how these regulations are connected to external cues are beginning to emerge. This review article highlights the role of ubiquitination and in particular, E3 ubiquitin ligases and deubiquitinases, in the control of primary cilia assembly and disassembly.
Collapse
Affiliation(s)
- Delowar Hossain
- Institut de recherches cliniques de Montréal, Montreal, Quebec, H2W 1R7, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, H4A 3J1, Canada
| | - William Y Tsang
- Institut de recherches cliniques de Montréal, Montreal, Quebec, H2W 1R7, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, H4A 3J1, Canada; Department of Pathology and Cell Biology, Université de Montréal, Montreal, Quebec, H3C 3J7, Canada.
| |
Collapse
|
34
|
Endicott SJ, Brueckner M. NUP98 Sets the Size-Exclusion Diffusion Limit through the Ciliary Base. Curr Biol 2018; 28:1643-1650.e3. [PMID: 29731308 DOI: 10.1016/j.cub.2018.04.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/14/2018] [Accepted: 04/04/2018] [Indexed: 12/16/2022]
Abstract
The primary cilium maintains a well-regulated complement of soluble and membrane proteins, allowing it to mediate a variety of signaling pathways that are essential for development and tissue homeostasis [1-3]. Entry into the cilium is regulated at the base, where a complex containing nucleoporins, referred to as the "ciliary pore complex" (CPC), has been proposed to set a size-exclusion limit for soluble molecule diffusion into the cilium [4-6]. Here, using a fluorescence-based diffusion trap system, we demonstrate that NUP98, a component of the phenylalanine-glycine (FG) hydrogel permeability barrier at the nuclear pore complex [7, 8], limits the diffusion of soluble molecules >70 kDa into the cilium in cultured mammalian cells. Small interfering RNA (siRNA)-mediated knockdown of NUP98 increases the rate of diffusion of molecules >100 kDa into the cilium. The tubulin heterodimer, the building block of the axoneme [9, 10], is approximately 100 kDa in size. After knockdown of NUP98, cilia become shorter, and their length is more sensitive to changes in cytoplasmic soluble tubulin levels. These data indicate a novel function of the ciliary pore complex, limiting diffusion of soluble tubulin between the ciliary matrix and the cytosol, allowing the cilium to regulate its length independently of cytosolic microtubule dynamics.
Collapse
Affiliation(s)
- S Joseph Endicott
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Martina Brueckner
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
| |
Collapse
|
35
|
Bembenek JN, Meshik X, Tsarouhas V. Meeting report - Cellular dynamics: membrane-cytoskeleton interface. J Cell Sci 2017; 130:2775-2779. [PMID: 29360626 DOI: 10.1242/jcs.208660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The first ever 'Cellular Dynamics' meeting on the membrane-cytoskeleton interface took place in Southbridge, MA on May 21-24, 2017 and was co-organized by Michael Way, Elizabeth Chen, Margaret Gardel and Jennifer Lippincott-Schwarz. Investigators from around the world studying a broad range of related topics shared their insights into the function and regulation of the cytoskeleton and membrane compartments. This provided great opportunities to learn about key questions in various cellular processes, from the basic organization and operation of the cell to higher-order interactions in adhesion, migration, metastasis, division and immune cell interactions in different model organisms. This unique and diverse mix of research interests created a stimulating and educational meeting that will hopefully continue to be a successful meeting for years to come.
Collapse
Affiliation(s)
- Joshua N Bembenek
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Xenia Meshik
- Department of Anesthesiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
| | - Vasilios Tsarouhas
- Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden
| |
Collapse
|