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Reddy Palicharla V, Mukhopadhyay S. Molecular and structural perspectives on protein trafficking to the primary cilium membrane. Biochem Soc Trans 2024; 52:1473-1487. [PMID: 38864436 DOI: 10.1042/bst20231403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/13/2024]
Abstract
The primary cilium is a dynamic subcellular compartment templated from the mother centriole or basal body. Cilia are solitary and tiny, but remarkably consequential in cellular pathways regulating proliferation, differentiation, and maintenance. Multiple transmembrane proteins such as G-protein-coupled receptors, channels, enzymes, and membrane-associated lipidated proteins are enriched in the ciliary membrane. The precise regulation of ciliary membrane content is essential for effective signal transduction and maintenance of tissue homeostasis. Surprisingly, a few conserved molecular factors, intraflagellar transport complex A and the tubby family adapter protein TULP3, mediate the transport of most membrane cargoes into cilia. Recent advances in cryogenic electron microscopy provide fundamental insights into these molecular players. Here, we review the molecular players mediating cargo delivery into the ciliary membrane through the lens of structural biology. These mechanistic insights into ciliary transport provide a framework for understanding of disease variants in ciliopathies, enable precise manipulation of cilia-mediated pathways, and provide a platform for the development of targeted therapeutics.
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Affiliation(s)
- Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, U.S.A
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, U.S.A
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2
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Patel MB, Griffin PJ, Olson SF, Dai J, Hou Y, Malik T, Das P, Zhang G, Zhao W, Witman GB, Lechtreck KF. Distribution and bulk flow analyses of the intraflagellar transport (IFT) motor kinesin-2 support an "on-demand" model for Chlamydomonas ciliary length control. Cytoskeleton (Hoboken) 2024. [PMID: 38456596 DOI: 10.1002/cm.21851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/09/2024]
Abstract
Most cells tightly control the length of their cilia. The regulation likely involves intraflagellar transport (IFT), a bidirectional motility of multi-subunit particles organized into trains that deliver building blocks into the organelle. In Chlamydomonas, the anterograde IFT motor kinesin-2 consists of the motor subunits FLA8 and FLA10 and the nonmotor subunit KAP. KAP dissociates from IFT at the ciliary tip and diffuses back to the cell body. This observation led to the diffusion-as-a-ruler model of ciliary length control, which postulates that KAP is progressively sequestered into elongating cilia because its return to the cell body will require increasingly more time, limiting motor availability at the ciliary base, train assembly, building block supply, and ciliary growth. Here, we show that Chlamydomonas FLA8 also returns to the cell body by diffusion. However, more than 95% of KAP and FLA8 are present in the cell body and, at a given time, just ~1% of the motor participates in IFT. After repeated photobleaching of both cilia, IFT of fluorescent kinesin subunits continued indicating that kinesin-2 cycles from the large cell-body pool through the cilia and back. Furthermore, growing and full-length cilia contained similar amounts of kinesin-2 subunits and the size of the motor pool at the base changed only slightly with ciliary length. These observations are incompatible with the diffusion-as-a-ruler model, but rather support an "on-demand model," in which the cargo load of the trains is regulated to assemble cilia of the desired length.
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Affiliation(s)
- Mansi B Patel
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Paul J Griffin
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Spencer F Olson
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Jin Dai
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Yuqing Hou
- Department of Radiology, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - Tara Malik
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Poulomi Das
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Gui Zhang
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Winston Zhao
- Department of Radiology, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - George B Witman
- Department of Radiology, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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3
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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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4
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Gupta M, Pazour GJ. Intraflagellar transport: A critical player in photoreceptor development and the pathogenesis of retinal degenerative diseases. Cytoskeleton (Hoboken) 2023:10.1002/cm.21823. [PMID: 38140908 PMCID: PMC11193844 DOI: 10.1002/cm.21823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
In vertebrate vision, photons are detected by highly specialized sensory cilia called outer segments. Photoreceptor outer segments form by remodeling the membrane of a primary cilium into a stack of flattened disks. Intraflagellar transport (IFT) is critical to the formation of most types of eukaryotic cilia including the outer segments. This review covers the state of knowledge of the role of IFT in the formation and maintenance of outer segments and the human diseases that result from mutations in genes encoding the IFT complex and associated motors.
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Affiliation(s)
- Mohona Gupta
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Suite 213 Biotech II, 373 Plantation Street, Worcester MA USA 01605
- Morningside Graduate School of Biological Sciences, University of Massachusetts Chan Medical School, 55 Lake Avenue North, Worcester MA USA 01655
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Suite 213 Biotech II, 373 Plantation Street, Worcester MA USA 01605
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5
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Ghanaeian A, Majhi S, McCafferty CL, Nami B, Black CS, Yang SK, Legal T, Papoulas O, Janowska M, Valente-Paterno M, Marcotte EM, Wloga D, Bui KH. Integrated modeling of the Nexin-dynein regulatory complex reveals its regulatory mechanism. Nat Commun 2023; 14:5741. [PMID: 37714832 PMCID: PMC10504270 DOI: 10.1038/s41467-023-41480-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023] Open
Abstract
Cilia are hairlike protrusions that project from the surface of eukaryotic cells and play key roles in cell signaling and motility. Ciliary motility is regulated by the conserved nexin-dynein regulatory complex (N-DRC), which links adjacent doublet microtubules and regulates and coordinates the activity of outer doublet complexes. Despite its critical role in cilia motility, the assembly and molecular basis of the regulatory mechanism are poorly understood. Here, using cryo-electron microscopy in conjunction with biochemical cross-linking and integrative modeling, we localize 12 DRC subunits in the N-DRC structure of Tetrahymena thermophila. We also find that the CCDC96/113 complex is in close contact with the DRC9/10 in the linker region. In addition, we reveal that the N-DRC is associated with a network of coiled-coil proteins that most likely mediates N-DRC regulatory activity.
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Affiliation(s)
- Avrin Ghanaeian
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Sumita Majhi
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Caitlyn L McCafferty
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, USA
| | - Babak Nami
- Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, Canada
| | - Corbin S Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Shun Kai Yang
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Ophelia Papoulas
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, USA
| | - Martyna Janowska
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
- Laboratory of Immunology, Mossakowski Institute of Experimental and Clinical Medicine, Polish Academy of Science, Pawinskiego 5, 02-106, Warsaw, Poland
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, USA
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada.
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6
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Linnert J, Knapp B, Güler BE, Boldt K, Ueffing M, Wolfrum U. Usher syndrome proteins ADGRV1 (USH2C) and CIB2 (USH1J) interact and share a common interactome containing TRiC/CCT-BBS chaperonins. Front Cell Dev Biol 2023; 11:1199069. [PMID: 37427378 PMCID: PMC10323441 DOI: 10.3389/fcell.2023.1199069] [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: 04/02/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
The human Usher syndrome (USH) is the most common form of a sensory hereditary ciliopathy characterized by progressive vision and hearing loss. Mutations in the genes ADGRV1 and CIB2 have been associated with two distinct sub-types of USH, namely, USH2C and USH1J. The proteins encoded by the two genes belong to very distinct protein families: the adhesion G protein-coupled receptor ADGRV1 also known as the very large G protein-coupled receptor 1 (VLGR1) and the Ca2+- and integrin-binding protein 2 (CIB2), respectively. In the absence of tangible knowledge of the molecular function of ADGRV1 and CIB2, pathomechanisms underlying USH2C and USH1J are still unknown. Here, we aimed to enlighten the cellular functions of CIB2 and ADGRV1 by the identification of interacting proteins, a knowledge that is commonly indicative of cellular functions. Applying affinity proteomics by tandem affinity purification in combination with mass spectrometry, we identified novel potential binding partners of the CIB2 protein and compared these with the data set we previously obtained for ADGRV1. Surprisingly, the interactomes of both USH proteins showed a high degree of overlap indicating their integration in common networks, cellular pathways and functional modules which we confirmed by GO term analysis. Validation of protein interactions revealed that ADGRV1 and CIB2 mutually interact. In addition, we showed that the USH proteins also interact with the TRiC/CCT chaperonin complex and the Bardet Biedl syndrome (BBS) chaperonin-like proteins. Immunohistochemistry on retinal sections demonstrated the co-localization of the interacting partners at the photoreceptor cilia, supporting the role of USH proteins ADGRV1 and CIB2 in primary cilia function. The interconnection of protein networks involved in the pathogenesis of both syndromic retinal dystrophies BBS and USH suggest shared pathomechanisms for both syndromes on the molecular level.
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Affiliation(s)
- Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Barbara Knapp
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Baran E. Güler
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Karsten Boldt
- Institute for Ophthalmic Research, Eberhard Karls University of Tuebingen, Tubingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Eberhard Karls University of Tuebingen, Tubingen, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
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7
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Ghanaeian A, Majhi S, McCaffrey CL, Nami B, Black CS, Yang SK, Legal T, Papoulas O, Janowska M, Valente-Paterno M, Marcotte EM, Wloga D, Bui KH. Integrated modeling of the Nexin-dynein regulatory complex reveals its regulatory mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543107. [PMID: 37398254 PMCID: PMC10312493 DOI: 10.1101/2023.05.31.543107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cilia are hairlike protrusions that project from the surface of eukaryotic cells and play key roles in cell signaling and motility. Ciliary motility is regulated by the conserved nexin-dynein regulatory complex (N-DRC), which links adjacent doublet microtubules and regulates and coordinates the activity of outer doublet complexes. Despite its critical role in cilia motility, the assembly and molecular basis of the regulatory mechanism are poorly understood. Here, utilizing cryo-electron microscopy in conjunction with biochemical cross-linking and integrative modeling, we localized 12 DRC subunits in the N-DRC structure of Tetrahymena thermophila . We also found that the CCDC96/113 complex is in close contact with the N-DRC. In addition, we revealed that the N-DRC is associated with a network of coiled-coil proteins that most likely mediates N-DRC regulatory activity.
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Affiliation(s)
- Avrin Ghanaeian
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Sumita Majhi
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Caitie L McCaffrey
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, United States
| | - Babak Nami
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Corbin S Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Shun Kai Yang
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Ophelia Papoulas
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, United States
| | - Martyna Janowska
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
- current address: Laboratory of Immunology, Mossakowski Institute of Experimental and Clinical Medicine, Polish Academy of Science, Pawinskiego 5, 02-106 Warsaw, Poland
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, United States
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
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8
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Lee C, Ma Y, Tu F, Wallingford JB. Ordered deployment of distinct ciliary beating machines in growing axonemes of vertebrate multiciliated cells. Differentiation 2023; 131:49-58. [PMID: 37120964 PMCID: PMC10523804 DOI: 10.1016/j.diff.2023.03.001] [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: 11/08/2022] [Revised: 02/14/2023] [Accepted: 03/11/2023] [Indexed: 05/02/2023]
Abstract
The beating of motile cilia requires the coordinated action of diverse machineries that include not only the axonemal dynein arms, but also the central apparatus, the radial spokes, and the microtubule inner proteins. These machines exhibit complex radial and proximodistal patterns in mature axonemes, but little is known about the interplay between them during motile ciliogenesis. Here, we describe and quantify the relative rates of axonemal deployment for these diverse cilia beating machineries during the final stages of differentiation of Xenopus epidermal multiciliated cells.
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Affiliation(s)
- Chanjae Lee
- Dept. of Molecular Biosciences, University of Texas at Austin, USA
| | - Yun Ma
- Dept. of Molecular Biosciences, University of Texas at Austin, USA
| | - Fan Tu
- Dept. of Molecular Biosciences, University of Texas at Austin, USA
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9
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Saravanan S, Trischler D, Bower R, Porter M, Lechtreck K. In vivo imaging reveals independent intraflagellar transport of the nexin-dynein regulatory complex subunits DRC2 and DRC4. Mol Biol Cell 2023; 34:br2. [PMID: 36598807 PMCID: PMC9930527 DOI: 10.1091/mbc.e22-11-0524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/19/2022] [Accepted: 12/23/2022] [Indexed: 01/05/2023] Open
Abstract
Many axonemal proteins enter cilia and flagella on intraflagellar transport (IFT) trains, which move bidirectionally along the axonemal microtubules. Certain axonemal substructures including the radial spokes and outer dynein arms are preassembled in the cell body and transported as multisubunit complexes into flagella by IFT. Here, we used in vivo imaging to analyze the transport and assembly of DRC2 and DRC4, two core subunits of the nexin-dynein regulatory complex (N-DRC). Tagged DRC2 moved by IFT in mutants lacking DRC4 and vice versa, showing that they do not depend on each other for IFT. Simultaneous imaging of tagged DRC2 and DRC4, expressed from transgenes that rescue a corresponding double mutant, mostly showed transport on separate IFT trains, but occasional cotransports were also observed. The results demonstrate that DRC2 and DRC4 are transported largely independently of each other into flagella. These studies suggest that the N-DRC assembles onto the axoneme by the stepwise addition of subunits.
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Affiliation(s)
- Sahana Saravanan
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Douglas Trischler
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Raqual Bower
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Mary Porter
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
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10
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Meleppattu S, Zhou H, Dai J, Gui M, Brown A. Mechanism of IFT-A polymerization into trains for ciliary transport. Cell 2022; 185:4986-4998.e12. [PMID: 36563665 PMCID: PMC9794116 DOI: 10.1016/j.cell.2022.11.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/14/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022]
Abstract
Intraflagellar transport (IFT) is the highly conserved process by which proteins are transported along ciliary microtubules by a train-like polymeric assembly of IFT-A and IFT-B complexes. IFT-A is sandwiched between IFT-B and the ciliary membrane, consistent with its putative role in transporting transmembrane and membrane-associated cargoes. Here, we have used single-particle analysis electron cryomicroscopy (cryo-EM) to determine structures of native IFT-A complexes. We show that subcomplex rearrangements enable IFT-A to polymerize laterally on anterograde IFT trains, revealing a cooperative assembly mechanism. Surprisingly, we discover that binding of IFT-A to IFT-B shields the preferred lipid-binding interface from the ciliary membrane but orients an interconnected network of β-propeller domains with the capacity to accommodate diverse cargoes toward the ciliary membrane. This work provides a mechanistic basis for understanding IFT-train assembly and cargo interactions.
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Affiliation(s)
- Shimi Meleppattu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Haixia Zhou
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Jin Dai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Miao Gui
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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11
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Petriman NA, Loureiro-López M, Taschner M, Zacharia NK, Georgieva MM, Boegholm N, Wang J, Mourão A, Russell RB, Andersen JS, Lorentzen E. Biochemically validated structural model of the 15-subunit intraflagellar transport complex IFT-B. EMBO J 2022; 41:e112440. [PMID: 36354106 PMCID: PMC9753473 DOI: 10.15252/embj.2022112440] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022] Open
Abstract
Cilia are ubiquitous eukaryotic organelles impotant for cellular motility, signaling, and sensory reception. Cilium formation requires intraflagellar transport of structural and signaling components and involves 22 different proteins organized into intraflagellar transport (IFT) complexes IFT-A and IFT-B that are transported by molecular motors. The IFT-B complex constitutes the backbone of polymeric IFT trains carrying cargo between the cilium and the cell body. Currently, high-resolution structures are only available for smaller IFT-B subcomplexes leaving > 50% structurally uncharacterized. Here, we used Alphafold to structurally model the 15-subunit IFT-B complex. The model was validated using cross-linking/mass-spectrometry data on reconstituted IFT-B complexes, X-ray scattering in solution, diffraction from crystals as well as site-directed mutagenesis and protein-binding assays. The IFT-B structure reveals an elongated and highly flexible complex consistent with cryo-electron tomographic reconstructions of IFT trains. The IFT-B complex organizes into IFT-B1 and IFT-B2 parts with binding sites for ciliary cargo and the inactive IFT dynein motor, respectively. Interestingly, our results are consistent with two different binding sites for IFT81/74 on IFT88/70/52/46 suggesting the possibility of different structural architectures for the IFT-B1 complex. Our data present a structural framework to understand IFT-B complex assembly, function, and ciliopathy variants.
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Affiliation(s)
- Narcis A Petriman
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Marta Loureiro-López
- Department for Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Michael Taschner
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Nevin K Zacharia
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | | | - Niels Boegholm
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Jiaolong Wang
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - André Mourão
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Jens S Andersen
- Department for Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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12
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Abstract
The assembly and maintenance of most cilia and eukaryotic flagella depends on intraflagellar transport (IFT), the bidirectional movement of multi-megadalton IFT trains along the axonemal microtubules. These IFT trains function as carriers, moving ciliary proteins between the cell body and the organelle. Whereas tubulin, the principal protein of cilia, binds directly to IFT particle proteins, the transport of other ciliary proteins and complexes requires adapters that link them to the trains. Large axonemal substructures, such as radial spokes, outer dynein arms and inner dynein arms, assemble in the cell body before attaching to IFT trains, using the adapters ARMC2, ODA16 and IDA3, respectively. Ciliary import of several membrane proteins involves the putative adapter tubby-like protein 3 (TULP3), whereas membrane protein export involves the BBSome, an octameric complex that co-migrates with IFT particles. Thus, cells employ a variety of adapters, each of which is substoichiometric to the core IFT machinery, to expand the cargo range of the IFT trains. This Review summarizes the individual and shared features of the known cargo adapters and discusses their possible role in regulating the transport capacity of the IFT pathway.
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Affiliation(s)
- Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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13
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Wang J, Wang W, Shen L, Zheng A, Meng Q, Li H, Yang S. Clinical detection, diagnosis and treatment of morphological abnormalities of sperm flagella: A review of literature. Front Genet 2022; 13:1034951. [PMID: 36425067 PMCID: PMC9679630 DOI: 10.3389/fgene.2022.1034951] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/28/2022] [Indexed: 11/12/2023] Open
Abstract
Sperm carries male genetic information, and flagella help move the sperm to reach oocytes. When the ultrastructure of the flagella is abnormal, the sperm is unable to reach the oocyte and achieve insemination. Multiple morphological abnormalities of sperm flagella (MMAF) is a relatively rare idiopathic condition that is mainly characterized by multiple defects in sperm flagella. In the last decade, with the development of high-throughput DNA sequencing approaches, many genes have been revealed to be related to MMAF. However, the differences in sperm phenotypes and reproductive outcomes in many cases are attributed to different pathogenic genes or different pathogenic mutations in the same gene. Here, we will review information about the various phenotypes resulting from different pathogenic genes, including sperm ultrastructure and encoding proteins with their location and functions as well as assisted reproductive technology (ART) outcomes. We will share our clinical detection and diagnosis experience to provide additional clinical views and broaden the understanding of this disease.
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Affiliation(s)
| | | | | | | | | | | | - Shenmin Yang
- Center for Reproduction and Genetics, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Gusu School, Nanjing Medical University, Suzhou, China
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Martinez G, Coutton C, Loeuillet C, Cazin C, Muroňová J, Boguenet M, Lambert E, Dhellemmes M, Chevalier G, Hograindleur JP, Vilpreux C, Neirijnck Y, Kherraf ZE, Escoffier J, Nef S, Ray PF, Arnoult C. Oligogenic heterozygous inheritance of sperm abnormalities in mouse. eLife 2022; 11:75373. [PMID: 35451961 PMCID: PMC9071268 DOI: 10.7554/elife.75373] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
Male infertility is an important health concern that is expected to have a major genetic etiology. Although high-throughput sequencing has linked gene defects to more than 50% of rare and severe sperm anomalies, less than 20% of common and moderate forms are explained. We hypothesized that this low success rate could at least be partly due to oligogenic defects – the accumulation of several rare heterozygous variants in distinct, but functionally connected, genes. Here, we compared fertility and sperm parameters in male mice harboring one to four heterozygous truncating mutations of genes linked to multiple morphological anomalies of the flagellum (MMAF) syndrome. Results indicated progressively deteriorating sperm morphology and motility with increasing numbers of heterozygous mutations. This first evidence of oligogenic inheritance in failed spermatogenesis strongly suggests that oligogenic heterozygosity could explain a significant proportion of asthenoteratozoospermia cases. The findings presented pave the way to further studies in mice and man.
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Affiliation(s)
| | | | - Corinne Loeuillet
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | | | - Jana Muroňová
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Magalie Boguenet
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Emeline Lambert
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Magali Dhellemmes
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Geneviève Chevalier
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | | | - Charline Vilpreux
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Yasmine Neirijnck
- Department of Genetic Medicine and Development, University of Geneva Medical School, Genève, Switzerland
| | - Zine Eddine Kherraf
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Jessica Escoffier
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Serge Nef
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Pierre F Ray
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
| | - Christophe Arnoult
- Institute for Advanced Biosciences, INSERM, CNRS, University Grenoble-Alpes, Grenoble, France
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