1
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Wiedemann S, Heckel R. A deep learning method for simultaneous denoising and missing wedge reconstruction in cryogenic electron tomography. Nat Commun 2024; 15:8255. [PMID: 39313517 PMCID: PMC11420219 DOI: 10.1038/s41467-024-51438-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 08/07/2024] [Indexed: 09/25/2024] Open
Abstract
Cryogenic electron tomography is a technique for imaging biological samples in 3D. A microscope collects a series of 2D projections of the sample, and the goal is to reconstruct the 3D density of the sample called the tomogram. Reconstruction is difficult as the 2D projections are noisy and can not be recorded from all directions, resulting in a missing wedge of information. Tomograms conventionally reconstructed with filtered back-projection suffer from noise and strong artefacts due to the missing wedge. Here, we propose a deep-learning approach for simultaneous denoising and missing wedge reconstruction called DeepDeWedge. The algorithm requires no ground truth data and is based on fitting a neural network to the 2D projections using a self-supervised loss. DeepDeWedge is simpler than current state-of-the-art approaches for denoising and missing wedge reconstruction, performs competitively and produces more denoised tomograms with higher overall contrast.
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Affiliation(s)
- Simon Wiedemann
- Department of Computer Engineering, Technical University of Munich, Munich, Germany
| | - Reinhard Heckel
- Department of Computer Engineering, Technical University of Munich, Munich, Germany.
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2
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Boegholm N, Petriman NA, Tanvir NM, Lorentzen E. Architecture of RabL2-associated complexes at the ciliary base: A structural modeling perspective: Deciphering the structural organization of ciliary RabL2 complexes. Bioessays 2024; 46:e2300222. [PMID: 38991980 DOI: 10.1002/bies.202300222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 06/28/2024] [Accepted: 07/01/2024] [Indexed: 07/13/2024]
Abstract
Cilia are slender, micrometer-long organelles present on the surface of eukaryotic cells. They function in signaling and locomotion and are constructed by intraflagellar transport (IFT). The assembly of IFT complexes into so-called IFT trains to initiate ciliary entry at the base of the cilium remains a matter of debate. Here, we use structural modeling to provide an architectural framework for how RabL2 is anchored at the ciliary base via CEP19 before being handed over to IFT trains for ciliary entry. Our models suggest that the N-terminal domain of CEP43 forms a homo-dimer to anchor at the subdistal appendages of cilia through a direct interaction with CEP350. A long linker region separates the N-terminal domain of CEP43 from the C-terminal domain, which captures CEP19 above the subdistal appendages and close to the distal appendages. Furthermore, we present a structural model for how RabL2-CEP19 associates with the IFT-B complex, providing insight into how RabL2 is handed over from CEP19 to the IFT complex. Interestingly, RabL2 association with the IFT-B complex appears to induce a significant conformational change in the IFT complex via a kink in the coiled-coils of the IFT81/74 proteins, which may prime the IFT machinery for entry into cilia.
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Affiliation(s)
- Niels Boegholm
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Narcis A Petriman
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Niaj M Tanvir
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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3
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Lacey SE, Graziadei A, Pigino G. Extensive structural rearrangement of intraflagellar transport trains underpins bidirectional cargo transport. Cell 2024; 187:4621-4636.e18. [PMID: 39067443 PMCID: PMC11349379 DOI: 10.1016/j.cell.2024.06.041] [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: 02/13/2024] [Revised: 05/06/2024] [Accepted: 06/28/2024] [Indexed: 07/30/2024]
Abstract
Bidirectional transport in cilia is carried out by polymers of the IFTA and IFTB protein complexes, called anterograde and retrograde intraflagellar transport (IFT) trains. Anterograde trains deliver cargoes from the cell to the cilium tip, then convert into retrograde trains for cargo export. We set out to understand how the IFT complexes can perform these two directly opposing roles before and after conversion. We use cryoelectron tomography and in situ cross-linking mass spectrometry to determine the structure of retrograde IFT trains and compare it with the known structure of anterograde trains. The retrograde train is a 2-fold symmetric polymer organized around a central thread of IFTA complexes. We conclude that anterograde-to-retrograde remodeling involves global rearrangements of the IFTA/B complexes and requires complete disassembly of the anterograde train. Finally, we describe how conformational changes to cargo-binding sites facilitate unidirectional cargo transport in a bidirectional system.
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4
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Macarelli V, Harding EC, Gershlick DC, Merkle FT. A Short Sequence Targets Transmembrane Proteins to Primary Cilia. Cells 2024; 13:1156. [PMID: 38995007 PMCID: PMC11240719 DOI: 10.3390/cells13131156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 06/26/2024] [Accepted: 07/02/2024] [Indexed: 07/13/2024] Open
Abstract
Primary cilia are finger-like sensory organelles that extend from the bodies of most cell types and have a distinct lipid and protein composition from the plasma membrane. This partitioning is maintained by a diffusion barrier that restricts the entry of non-ciliary proteins, and allows the selective entry of proteins harboring a ciliary targeting sequence (CTS). However, CTSs are not stereotyped and previously reported sequences are insufficient to drive efficient ciliary localisation across diverse cell types. Here, we describe a short peptide sequence that efficiently targets transmembrane proteins to primary cilia in all tested cell types, including human neurons. We generate human-induced pluripotent stem cell (hiPSC) lines stably expressing a transmembrane construct bearing an extracellular HaloTag and intracellular fluorescent protein, which enables the bright, specific labeling of primary cilia in neurons and other cell types to facilitate studies of cilia in health and disease. We demonstrate the utility of this resource by developing an image analysis pipeline for the automated measurement of primary cilia to detect changes in their length associated with altered signaling or disease state.
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Affiliation(s)
- Viviana Macarelli
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
- Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK
| | - Edward C Harding
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
| | - David C Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Florian T Merkle
- Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, UK
- Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 0AW, UK
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5
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Shao S, Chen Y, Deng H, Pan J. Quantitative proteomics reveals insights into the assembly of IFT trains and ciliary assembly. J Cell Sci 2024; 137:jcs262152. [PMID: 38853670 DOI: 10.1242/jcs.262152] [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: 03/26/2024] [Accepted: 05/28/2024] [Indexed: 06/11/2024] Open
Abstract
Intraflagellar transport (IFT) is required for ciliary assembly. The IFT machinery comprises the IFT motors kinesin-2 and IFT dynein plus IFT-A and IFT-B complexes, which assemble into IFT trains in cilia. To gain mechanistic understanding of IFT and ciliary assembly, here, we performed an absolute quantification of IFT machinery in Chlamydomonas reinhardtii cilium. There are ∼756, ∼532, ∼276 and ∼350 molecules of IFT-B, IFT-A, IFT dynein and kinesin-2, respectively, per cilium. The amount of IFT-B is sufficient to sustain rapid ciliary growth in terms of tubulin delivery. The stoichiometric ratio of IFT-B:IFT-A:dynein is ∼3:2:1 whereas the IFT-B:IFT-A ratio in an IFT dynein mutant is 2:1, suggesting that there is a plastic interaction between IFT-A and IFT-B that can be influenced by IFT dynein. Considering diffusion of kinesin-2 during retrograde IFT, it is estimated that one kinesin-2 molecule drives eight molecules of IFT-B during anterograde IFT. These data provide new insights into the assembly of IFT trains and ciliary assembly.
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Affiliation(s)
- Shangjin Shao
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, Shandong Province 266000, China
| | - Yuling Chen
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Core Facility Center for Biomedical Analysis, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Core Facility Center for Biomedical Analysis, Tsinghua University, Beijing 100084, China
| | - Junmin Pan
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, Shandong Province 266000, China
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6
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Reddy Palicharla V, Mukhopadhyay S. Molecular and structural perspectives on protein trafficking to the primary cilium membrane. Biochem Soc Trans 2024; 52:1473-1487. [PMID: 38864436 PMCID: PMC11346432 DOI: 10.1042/bst20231403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/13/2024]
Abstract
The primary cilium is a dynamic subcellular compartment templated from the mother centriole or basal body. Cilia are solitary and tiny, but remarkably consequential in cellular pathways regulating proliferation, differentiation, and maintenance. Multiple transmembrane proteins such as G-protein-coupled receptors, channels, enzymes, and membrane-associated lipidated proteins are enriched in the ciliary membrane. The precise regulation of ciliary membrane content is essential for effective signal transduction and maintenance of tissue homeostasis. Surprisingly, a few conserved molecular factors, intraflagellar transport complex A and the tubby family adapter protein TULP3, mediate the transport of most membrane cargoes into cilia. Recent advances in cryogenic electron microscopy provide fundamental insights into these molecular players. Here, we review the molecular players mediating cargo delivery into the ciliary membrane through the lens of structural biology. These mechanistic insights into ciliary transport provide a framework for understanding of disease variants in ciliopathies, enable precise manipulation of cilia-mediated pathways, and provide a platform for the development of targeted therapeutics.
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Affiliation(s)
- Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, U.S.A
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, U.S.A
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7
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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.
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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.
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8
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Viar GA, Pigino G. Tubulin posttranslational modifications through the lens of new technologies. Curr Opin Cell Biol 2024; 88:102362. [PMID: 38701611 DOI: 10.1016/j.ceb.2024.102362] [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: 01/16/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 05/05/2024]
Abstract
The Tubulin Code revolutionizes our understanding of microtubule dynamics and functions, proposing a nuanced system governed by tubulin isotypes, posttranslational modifications (PTMs) and microtubule-associated proteins (MAPs). Tubulin isotypes, diverse across species, contribute structural complexity, and are thought to influence microtubule functions. PTMs encode dynamic information on microtubules, which are read by several microtubule interacting proteins and impact on cellular processes. Here we discuss recent technological and methodological advances, such as in genome engineering, live cell imaging, expansion microscopy, and cryo-electron microscopy that reveal new elements and levels of complexity of the tubulin code, including new modifying enzymes and nanopatterns of PTMs on individual microtubules. The Tubulin Code's exploration holds transformative potential, guiding therapeutic strategies and illuminating connections to diseases like cancer and neurodegenerative disorders, underscoring its relevance in decoding fundamental cellular language.
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Affiliation(s)
| | - Gaia Pigino
- Human Technopole, via Rita Levi Montalcini 1, Milan, Italy.
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9
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Marshall WF. Chlamydomonas as a model system to study cilia and flagella using genetics, biochemistry, and microscopy. Front Cell Dev Biol 2024; 12:1412641. [PMID: 38872931 PMCID: PMC11169674 DOI: 10.3389/fcell.2024.1412641] [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: 04/05/2024] [Accepted: 05/13/2024] [Indexed: 06/15/2024] Open
Abstract
The unicellular green alga, Chlamydomonas reinhardtii, has played a central role in discovering much of what is currently known about the composition, assembly, and function of cilia and flagella. Chlamydomonas combines excellent genetics, such as the ability to grow cells as haploids or diploids and to perform tetrad analysis, with an unparalleled ability to detach and isolate flagella in a single step without cell lysis. The combination of genetics and biochemistry that is possible in Chlamydomonas has allowed many of the key components of the cilium to be identified by looking for proteins that are missing in a defined mutant. Few if any other model organisms allow such a seamless combination of genetic and biochemical approaches. Other major advantages of Chlamydomonas compared to other systems include the ability to induce flagella to regenerate in a highly synchronous manner, allowing the kinetics of flagellar growth to be measured, and the ability of Chlamydomonas flagella to adhere to glass coverslips allowing Intraflagellar Transport to be easily imaged inside the flagella of living cells, with quantitative precision and single-molecule resolution. These advantages continue to work in favor of Chlamydomonas as a model system going forward, and are now augmented by extensive genomic resources, a knockout strain collection, and efficient CRISPR gene editing. While Chlamydomonas has obvious limitations for studying ciliary functions related to animal development or organ physiology, when it comes to studying the fundamental biology of cilia and flagella, Chlamydomonas is simply unmatched in terms of speed, efficiency, cost, and the variety of approaches that can be brought to bear on a question.
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Affiliation(s)
- Wallace F. Marshall
- Department Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, United States
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10
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Beriashvili D, Zhou J, Liu Y, Folkers GE, Baldus M. Cellular Applications of DNP Solid-State NMR - State of the Art and a Look to the Future. Chemistry 2024; 30:e202400323. [PMID: 38451060 DOI: 10.1002/chem.202400323] [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: 01/25/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/08/2024]
Abstract
Sensitivity enhanced dynamic nuclear polarization solid-state NMR is emerging as a powerful technique for probing the structural properties of conformationally homogenous and heterogenous biomolecular species irrespective of size at atomic resolution within their native environments. Herein we detail advancements that have made acquiring such data, specifically within the confines of intact bacterial and eukaryotic cell a reality and further discuss the type of structural information that can presently be garnered by the technique's exploitation. Subsequently, we discuss bottlenecks that have thus far curbed cellular DNP-ssNMR's broader adoption namely due a lack of sensitivity and spectral resolution. We also explore possible solutions ranging from utilization of new pulse sequences, design of better performing polarizing agents, and application of additional biochemical/ cell biological methodologies.
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Affiliation(s)
- David Beriashvili
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padaulaan 8, 3584 CH, Utrecht, The Netherlands
| | - Jiaxin Zhou
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics, Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics, Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Gert E Folkers
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padaulaan 8, 3584 CH, Utrecht, The Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padaulaan 8, 3584 CH, Utrecht, The Netherlands
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11
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Rao VG, Subramanianbalachandar V, Magaj MM, Redemann S, Kulkarni SS. Mechanisms of cilia regeneration in Xenopus multiciliated epithelium in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.14.544972. [PMID: 37398226 PMCID: PMC10312767 DOI: 10.1101/2023.06.14.544972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cilia regeneration is a physiological event, and while studied extensively in unicellular organisms, it remains poorly understood in vertebrates. In this study, using Xenopus multiciliated cells (MCCs) as a model, we demonstrate that, unlike unicellular organisms, deciliation removes the transition zone (TZ) and the ciliary axoneme. While MCCs immediately begin the regeneration of the ciliary axoneme, surprisingly, the assembly of TZ is delayed. However, ciliary tip proteins, Sentan and Clamp, localize to regenerating cilia without delay. Using cycloheximide (CHX) to block new protein synthesis, we show that the TZ protein B9d1 is not a component of the cilia precursor pool and requires new transcription/translation, providing insights into the delayed repair of TZ. Moreover, MCCs in CHX treatment assemble fewer (∼ 10 vs. ∼150 in controls) but near wild-type length (ranging between 60 to 90%) cilia by gradually concentrating ciliogenesis proteins like IFTs at a select few basal bodies. Using mathematical modeling, we show that cilia length compared to cilia number influences the force generated by MCCs more. In summary, our results question the requirement of TZ in motile cilia assembly and provide insights into how cells determine organelle size and number.
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12
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Werner S, Okenve-Ramos P, Hehlert P, Zitouni S, Priya P, Mendonça S, Sporbert A, Spalthoff C, Göpfert MC, Jana SC, Bettencourt-Dias M. IFT88 maintains sensory function by localising signalling proteins along Drosophila cilia. Life Sci Alliance 2024; 7:e202302289. [PMID: 38373798 PMCID: PMC10876440 DOI: 10.26508/lsa.202302289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/21/2024] Open
Abstract
Ciliary defects cause several ciliopathies, some of which have late onset, suggesting cilia are actively maintained. Still, we have a poor understanding of the mechanisms underlying their maintenance. Here, we show Drosophila melanogaster IFT88 (DmIFT88/nompB) continues to move along fully formed sensory cilia. We further identify Inactive, a TRPV channel subunit involved in Drosophila hearing and negative-gravitaxis behaviour, and a yet uncharacterised Drosophila Guanylyl Cyclase 2d (DmGucy2d/CG34357) as DmIFT88 cargoes. We also show DmIFT88 binding to the cyclase´s intracellular part, which is evolutionarily conserved and mutated in several degenerative retinal diseases, is important for the ciliary localisation of DmGucy2d. Finally, acute knockdown of both DmIFT88 and DmGucy2d in ciliated neurons of adult flies caused defects in the maintenance of cilium function, impairing hearing and negative-gravitaxis behaviour, but did not significantly affect ciliary ultrastructure. We conclude that the sensory ciliary function underlying hearing in the adult fly requires an active maintenance program which involves DmIFT88 and at least two of its signalling transmembrane cargoes, DmGucy2d and Inactive.
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Affiliation(s)
- Sascha Werner
- https://ror.org/04b08hq31 Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Pilar Okenve-Ramos
- https://ror.org/04b08hq31 Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Philip Hehlert
- Department of Cellular Neurobiology, University of Göttingen, Göttingen, Germany
| | - Sihem Zitouni
- https://ror.org/04b08hq31 Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Institut de Génétique Humaine (IGH), UMR, 9002 CNRS, Montpellier, France
| | - Pranjali Priya
- National Centre for Biological Sciences- TIFR, Bangalore, India
| | - Susana Mendonça
- https://ror.org/04b08hq31 Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Anje Sporbert
- Advanced Light Microscopy, Max Delbrück Centrum for Molecular Medicine Berlin in the Helmholtz Association, Berlin, Germany
| | - Christian Spalthoff
- Department of Cellular Neurobiology, University of Göttingen, Göttingen, Germany
| | - Martin C Göpfert
- Department of Cellular Neurobiology, University of Göttingen, Göttingen, Germany
| | - Swadhin Chandra Jana
- https://ror.org/04b08hq31 Instituto Gulbenkian de Ciência, Oeiras, Portugal
- National Centre for Biological Sciences- TIFR, Bangalore, India
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13
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Mitra A, Loseva E, Peterman EJG. IFT cargo and motors associate sequentially with IFT trains to enter cilia of C. elegans. Nat Commun 2024; 15:3456. [PMID: 38658528 PMCID: PMC11043347 DOI: 10.1038/s41467-024-47807-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 04/12/2024] [Indexed: 04/26/2024] Open
Abstract
Intraflagellar transport (IFT) orchestrates entry of proteins into primary cilia. At the ciliary base, assembled IFT trains, driven by kinesin-2 motors, can transport cargo proteins into the cilium, across the crowded transition zone. How trains assemble at the base and how proteins associate with them is far from understood. Here, we use single-molecule imaging in the cilia of C. elegans chemosensory neurons to directly visualize the entry of kinesin-2 motors, kinesin-II and OSM-3, as well as anterograde cargo proteins, IFT dynein and tubulin. Single-particle tracking shows that IFT components associate with trains sequentially, both in time and space. Super-resolution maps of IFT components in wild-type and mutant worms reveal ciliary ultrastructure and show that kinesin-II is essential for axonemal organization. Finally, imaging cilia lacking kinesin-II and/or transition zone function uncovers the interplay of kinesin-II and OSM-3 in driving efficient transport of IFT trains across the transition zone.
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Affiliation(s)
- Aniruddha Mitra
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Elizaveta Loseva
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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14
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Weijman JF, Vuolo L, Shak C, Pugnetti A, Mukhopadhyay AG, Hodgson LR, Heesom KJ, Roberts AJ, Stephens DJ. Roles for CEP170 in cilia function and dynein-2 assembly. J Cell Sci 2024; 137:jcs261816. [PMID: 38533689 PMCID: PMC11112123 DOI: 10.1242/jcs.261816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/19/2024] [Indexed: 03/28/2024] Open
Abstract
Primary cilia are essential eukaryotic organelles required for signalling and secretion. Dynein-2 is a microtubule-motor protein complex and is required for ciliogenesis via its role in facilitating retrograde intraflagellar transport (IFT) from the cilia tip to the cell body. Dynein-2 must be assembled and loaded onto IFT trains for entry into cilia for this process to occur, but how dynein-2 is assembled and how it is recycled back into a cilium remain poorly understood. Here, we identify centrosomal protein of 170 kDa (CEP170) as a dynein-2-interacting protein in mammalian cells. We show that loss of CEP170 perturbs intraflagellar transport and hedgehog signalling, and alters the stability of dynein-2 holoenzyme complex. Together, our data indicate a role for CEP170 in supporting cilia function and dynein-2 assembly.
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Affiliation(s)
- Johannes F. Weijman
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Laura Vuolo
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Caroline Shak
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Anna Pugnetti
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | | | - Lorna R. Hodgson
- Wolfson Bioimaging Facility, Faculty of Life Sciences, University Walk, University of Bristol, Bristol BS8 1TD, UK
| | - Kate J. Heesom
- Proteomics Facility, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Anthony J. Roberts
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - David J. Stephens
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
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15
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Mukhopadhyay AG, Toropova K, Daly L, Wells JN, Vuolo L, Mladenov M, Seda M, Jenkins D, Stephens DJ, Roberts AJ. Structure and tethering mechanism of dynein-2 intermediate chains in intraflagellar transport. EMBO J 2024; 43:1257-1272. [PMID: 38454149 PMCID: PMC10987677 DOI: 10.1038/s44318-024-00060-1] [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: 09/05/2023] [Revised: 02/06/2024] [Accepted: 02/09/2024] [Indexed: 03/09/2024] Open
Abstract
Dynein-2 is a large multiprotein complex that powers retrograde intraflagellar transport (IFT) of cargoes within cilia/flagella, but the molecular mechanism underlying this function is still emerging. Distinctively, dynein-2 contains two identical force-generating heavy chains that interact with two different intermediate chains (WDR34 and WDR60). Here, we dissect regulation of dynein-2 function by WDR34 and WDR60 using an integrative approach including cryo-electron microscopy and CRISPR/Cas9-enabled cell biology. A 3.9 Å resolution structure shows how WDR34 and WDR60 use surprisingly different interactions to engage equivalent sites of the two heavy chains. We show that cilia can assemble in the absence of either WDR34 or WDR60 individually, but not both subunits. Dynein-2-dependent distribution of cargoes depends more strongly on WDR60, because the unique N-terminal extension of WDR60 facilitates dynein-2 targeting to cilia. Strikingly, this N-terminal extension can be transplanted onto WDR34 and retain function, suggesting it acts as a flexible tether to the IFT "trains" that assemble at the ciliary base. We discuss how use of unstructured tethers represents an emerging theme in IFT train interactions.
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Affiliation(s)
- Aakash G Mukhopadhyay
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Katerina Toropova
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
| | - Lydia Daly
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
- Randall Centre of Cell & Molecular Biophysics, King's College London, London, UK
| | - Jennifer N Wells
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
- MRC London Institute of Medical Sciences (LMS), London, UK
| | - Laura Vuolo
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Bristol, UK
| | - Miroslav Mladenov
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK
- Cellular Signalling and Cytoskeletal Function Laboratory, The Francis Crick Institute, London, UK
| | - Marian Seda
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Dagan Jenkins
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - David J Stephens
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Bristol, UK
| | - Anthony J Roberts
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, UK.
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16
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Walton T, Doran MH, Brown A. Structural determination and modeling of ciliary microtubules. Acta Crystallogr D Struct Biol 2024; 80:220-231. [PMID: 38451206 PMCID: PMC10994176 DOI: 10.1107/s2059798324001815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 02/24/2024] [Indexed: 03/08/2024] Open
Abstract
The axoneme, a microtubule-based array at the center of every cilium, has been the subject of structural investigations for decades, but only recent advances in cryo-EM and cryo-ET have allowed a molecular-level interpretation of the entire complex to be achieved. The unique properties of the nine doublet microtubules and central pair of singlet microtubules that form the axoneme, including the highly decorated tubulin lattice and the docking of massive axonemal complexes, provide opportunities and challenges for sample preparation, 3D reconstruction and atomic modeling. Here, the approaches used for cryo-EM and cryo-ET of axonemes are reviewed, while highlighting the unique opportunities provided by the latest generation of AI-guided tools that are transforming structural biology.
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Affiliation(s)
- Travis Walton
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Matthew H. Doran
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
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17
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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 PMCID: PMC11380706 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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18
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Rao L, Gennerich A. Structure and Function of Dynein's Non-Catalytic Subunits. Cells 2024; 13:330. [PMID: 38391943 PMCID: PMC10886578 DOI: 10.3390/cells13040330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
Dynein, an ancient microtubule-based motor protein, performs diverse cellular functions in nearly all eukaryotic cells, with the exception of land plants. It has evolved into three subfamilies-cytoplasmic dynein-1, cytoplasmic dynein-2, and axonemal dyneins-each differentiated by their cellular functions. These megadalton complexes consist of multiple subunits, with the heavy chain being the largest subunit that generates motion and force along microtubules by converting the chemical energy of ATP hydrolysis into mechanical work. Beyond this catalytic core, the functionality of dynein is significantly enhanced by numerous non-catalytic subunits. These subunits are integral to the complex, contributing to its stability, regulating its enzymatic activities, targeting it to specific cellular locations, and mediating its interactions with other cofactors. The diversity of non-catalytic subunits expands dynein's cellular roles, enabling it to perform critical tasks despite the conservation of its heavy chains. In this review, we discuss recent findings and insights regarding these non-catalytic subunits.
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Affiliation(s)
- Lu Rao
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Arne Gennerich
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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19
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McCafferty CL, Klumpe S, Amaro RE, Kukulski W, Collinson L, Engel BD. Integrating cellular electron microscopy with multimodal data to explore biology across space and time. Cell 2024; 187:563-584. [PMID: 38306982 DOI: 10.1016/j.cell.2024.01.005] [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: 12/04/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 02/04/2024]
Abstract
Biology spans a continuum of length and time scales. Individual experimental methods only glimpse discrete pieces of this spectrum but can be combined to construct a more holistic view. In this Review, we detail the latest advancements in volume electron microscopy (vEM) and cryo-electron tomography (cryo-ET), which together can visualize biological complexity across scales from the organization of cells in large tissues to the molecular details inside native cellular environments. In addition, we discuss emerging methodologies for integrating three-dimensional electron microscopy (3DEM) imaging with multimodal data, including fluorescence microscopy, mass spectrometry, single-particle analysis, and AI-based structure prediction. This multifaceted approach fills gaps in the biological continuum, providing functional context, spatial organization, molecular identity, and native interactions. We conclude with a perspective on incorporating diverse data into computational simulations that further bridge and extend length scales while integrating the dimension of time.
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Affiliation(s)
| | - Sven Klumpe
- Research Group CryoEM Technology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - Rommie E Amaro
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Wanda Kukulski
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Benjamin D Engel
- Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.
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20
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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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21
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Hwang J, Yanagisawa H, Davis KC, Hunter EL, Fox LA, Jimenez AR, Goodwin RE, Gordon SA, Stuart CDE, Bower R, Porter ME, Dutcher SK, Sale WS, Lechtreck KF, Alford LM. Assembly of FAP93 at the proximal axoneme in Chlamydomonas cilia. Cytoskeleton (Hoboken) 2024. [PMID: 38224153 DOI: 10.1002/cm.21818] [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: 09/19/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 01/16/2024]
Abstract
To identify proteins specific to the proximal ciliary axoneme, we used iTRAQ to compare short (~2 μm) and full-length (~11 μm) axonemes of Chlamydomonas. Known compoents of the proximal axoneme such as minor dynein heavy chains and LF5 kinase as well as the ciliary tip proteins FAP256 (CEP104) and EB1 were enriched in short axonemes whereas proteins present along the length of the axoneme were of similar abundance in both samples. The iTRAQ analysis revealed that FAP93, a protein of unknown function, and protein phosphatase 2A (PP2A) are enriched in the short axonemes. Consistently, immunoblots show enrichment of FAP93 and PP2A in short axonemes and immunofluorescence confirms the localization of FAP93 and enrichment of PP2A at the proximal axoneme. Ciliary regeneration reveals that FAP93 assembles continuously but more slowly than other axonemal structures and terminates at 1.03 μm in steady-state axonemes. The length of FAP93 assembly correlates with ciliary length, demonstrating ciliary length-dependent assembly of FAP93. Dikaryon rescue experiments show that FAP93 can assemble independently of IFT transport. In addition, FRAP analysis of GFP-tagged FAP93 demonstrates that FAP93 is stably anchored in axoneme. FAP93 may function as a scaffold for assembly of other specific proteins at the proximal axoneme.
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Affiliation(s)
- Juyeon Hwang
- Department of Cell Biology, Emory University, Atlanta, Georgia, USA
| | | | - Keira C Davis
- Department of Cell Biology, Emory University, Atlanta, Georgia, USA
- College of Arts & Sciences, Clayton State University, Morrow, Georgia, USA
| | - Emily L Hunter
- Department of Cell Biology, Emory University, Atlanta, Georgia, USA
- Science Communication Group, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Laura A Fox
- Department of Cell Biology, Emory University, Atlanta, Georgia, USA
| | - Ariana R Jimenez
- Division of Natural Sciences, Oglethorpe University, Atlanta, Georgia, USA
| | - Reagan E Goodwin
- Division of Natural Sciences, Oglethorpe University, Atlanta, Georgia, USA
| | - Sarah A Gordon
- Division of Natural Sciences, Oglethorpe University, Atlanta, Georgia, USA
| | | | - Raqual Bower
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mary E Porter
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University St. Louis, St. Louis, Missouri, USA
| | - Winfield S Sale
- Department of Cell Biology, Emory University, Atlanta, Georgia, USA
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Lea M Alford
- Division of Natural Sciences, Oglethorpe University, Atlanta, Georgia, USA
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22
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Li L, Ran J. Regulation of ciliary homeostasis by intraflagellar transport-independent kinesins. Cell Death Dis 2024; 15:47. [PMID: 38218748 PMCID: PMC10787775 DOI: 10.1038/s41419-024-06428-9] [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: 10/01/2023] [Revised: 12/20/2023] [Accepted: 01/02/2024] [Indexed: 01/15/2024]
Abstract
Cilia are highly conserved eukaryotic organelles that protrude from the cell surface and are involved in sensory perception, motility, and signaling. Their proper assembly and function rely on the bidirectional intraflagellar transport (IFT) system, which involves motor proteins, including antegrade kinesins and retrograde dynein. Although the role of IFT-mediated transport in cilia has been extensively studied, recent research has highlighted the contribution of IFT-independent kinesins in ciliary processes. The coordinated activities and interplay between IFT kinesins and IFT-independent kinesins are crucial for maintaining ciliary homeostasis. In this comprehensive review, we aim to delve into the specific contributions and mechanisms of action of the IFT-independent kinesins in cilia. By shedding light on their involvement, we hope to gain a more holistic perspective on ciliogenesis and ciliopathies.
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Affiliation(s)
- Lin Li
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250014, China
| | - Jie Ran
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250014, China.
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23
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Kong D, Luvsanjav D, Loncarek J. Immunolabel-First-Expand-Later Expansion Microscopy Approach Using Stable STED Dyes. Methods Mol Biol 2024; 2725:89-101. [PMID: 37856019 DOI: 10.1007/978-1-0716-3507-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Multiple expansion microscopy approaches have been successfully used in the analysis of centrioles, centrosomes, and cilia, helping to reveal the localization of numerous centrosomal and ciliary proteins at nanoscale resolution. In this chapter, we describe the use of two stable STED dyes in combination with expansion microscopy, which allows the robust detection by conventional and STED microscopy of proteins immunolabeled prior to sample expansion. We demonstrate the stability of these dyes during the crosslinking, polymerization, and denaturation steps of an expansion protocol thereby allowing their use in an immunolabel-first-expand-later approach. Our protocol overcomes the frequent technical limitation of poor, unreproducible binding of primary antibodies to proteins after denaturation. We demonstrate the applicability of this approach by analyzing both a centriole appendage protein Cep164 and a ciliary protein ARL13B.
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Affiliation(s)
- Dong Kong
- Cancer Innovation Laboratory, NIH/NCI/CCR, Frederick, MD, USA
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24
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Wang Y, Yang J, Hu F, Yang Y, Huang K, Zhang K. Cryo-EM reveals how the mastigoneme assembles and responds to environmental signal changes. J Cell Biol 2023; 222:e202301066. [PMID: 37882754 PMCID: PMC10602792 DOI: 10.1083/jcb.202301066] [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: 01/13/2023] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
Mastigonemes are thread-like structures adorning the flagella of protists. In Chlamydomonas reinhardtii, filamentous mastigonemes find their roots in the flagella's distal region, associated with the channel protein PKD2, implying their potential contribution to external signal sensing and flagellar motility control. Here, we present the single-particle cryo-electron microscopy structure of the mastigoneme at 3.4 Å. The filament unit, MST1, consists of nine immunoglobulin-like domains and six Sushi domains, trailed by an elastic polyproline-II helix. Our structure demonstrates that MST1 subunits are periodically assembled to form a centrosymmetric, non-polar filament. Intriguingly, numerous clustered disulfide bonds within a ladder-like spiral configuration underscore structural resilience. While defects in the mastigoneme structure did not noticeably affect general attributes of cell swimming, they did impact specific swimming properties, particularly under varied environmental conditions such as redox shifts and heightened viscosity. Our findings illuminate the potential role of mastigonemes in flagellar motility and suggest their involvement in diverse environmental responses.
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Affiliation(s)
- Yue Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jun Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Fangheng Hu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Yuchen Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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25
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Fung HKH, Hayashi Y, Salo VT, Babenko A, Zagoriy I, Brunner A, Ellenberg J, Müller CW, Cuylen-Haering S, Mahamid J. Genetically encoded multimeric tags for subcellular protein localization in cryo-EM. Nat Methods 2023; 20:1900-1908. [PMID: 37932397 PMCID: PMC10703698 DOI: 10.1038/s41592-023-02053-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 09/19/2023] [Indexed: 11/08/2023]
Abstract
Cryo-electron tomography (cryo-ET) allows for label-free high-resolution imaging of macromolecular assemblies in their native cellular context. However, the localization of macromolecules of interest in tomographic volumes can be challenging. Here we present a ligand-inducible labeling strategy for intracellular proteins based on fluorescent, 25-nm-sized, genetically encoded multimeric particles (GEMs). The particles exhibit recognizable structural signatures, enabling their automated detection in cryo-ET data by convolutional neural networks. The coupling of GEMs to green fluorescent protein-tagged macromolecules of interest is triggered by addition of a small-molecule ligand, allowing for time-controlled labeling to minimize disturbance to native protein function. We demonstrate the applicability of GEMs for subcellular-level localization of endogenous and overexpressed proteins across different organelles in human cells using cryo-correlative fluorescence and cryo-ET imaging. We describe means for quantifying labeling specificity and efficiency, and for systematic optimization for rare and abundant protein targets, with emphasis on assessing the potential effects of labeling on protein function.
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Affiliation(s)
- Herman K H Fung
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Yuki Hayashi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Anastasiia Babenko
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Andreas Brunner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Faculty of Biosciences, Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Sara Cuylen-Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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26
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Wesselman HM, Arceri L, Nguyen TK, Lara CM, Wingert RA. Genetic mechanisms of multiciliated cell development: from fate choice to differentiation in zebrafish and other models. FEBS J 2023. [PMID: 37997009 DOI: 10.1111/febs.17012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 10/17/2023] [Accepted: 11/21/2023] [Indexed: 11/25/2023]
Abstract
Multiciliated cells (MCCS) form bundles of cilia and their activities are essential for the proper development and physiology of many organ systems. Not surprisingly, defects in MCCs have profound consequences and are associated with numerous disease states. Here, we discuss the current understanding of MCC formation, with a special focus on the genetic and molecular mechanisms of MCC fate choice and differentiation. Furthermore, we cast a spotlight on the use of zebrafish to study MCC ontogeny and several recent advances made in understanding MCCs using this vertebrate model to delineate mechanisms of MCC emergence in the developing kidney.
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Affiliation(s)
| | - Liana Arceri
- Department of Biological Sciences, University of Notre Dame, IN, USA
| | - Thanh Khoa Nguyen
- Department of Biological Sciences, University of Notre Dame, IN, USA
| | - Caroline M Lara
- Department of Biological Sciences, University of Notre Dame, IN, USA
| | - Rebecca A Wingert
- Department of Biological Sciences, University of Notre Dame, IN, USA
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27
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Kruczek K, Swaroop A. Patient stem cell-derived in vitro disease models for developing novel therapies of retinal ciliopathies. Curr Top Dev Biol 2023; 155:127-163. [PMID: 38043950 DOI: 10.1016/bs.ctdb.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Primary cilia are specialized organelles on the surface of almost all cells in vertebrate tissues and are primarily involved in the detection of extracellular stimuli. In retinal photoreceptors, cilia are uniquely modified to form outer segments containing components required for the detection of light in stacks of membrane discs. Not surprisingly, vision impairment is a frequent phenotype associated with ciliopathies, a heterogeneous class of conditions caused by mutations in proteins required for formation, maintenance and/or function of primary cilia. Traditionally, immortalized cell lines and model organisms have been used to provide insights into the biology of ciliopathies. The advent of methods for reprogramming human somatic cells into pluripotent stem cells has enabled the generation of in vitro disease models directly from patients suffering from ciliopathies. Such models help us in investigating pathological mechanisms specific to human physiology and in developing novel therapeutic approaches. In this article, we review current protocols to differentiate human pluripotent stem cells into retinal cell types, and discuss how these cellular and/or organoid models can be utilized to interrogate pathobiology of ciliopathies affecting the retina and for testing prospective treatments.
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Affiliation(s)
- Kamil Kruczek
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, United States.
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, United States.
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28
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McCafferty CL, Papoulas O, Lee C, Bui KH, Taylor DW, Marcotte EM, Wallingford JB. An amino acid-resolution interactome for motile cilia illuminates the structure and function of ciliopathy protein complexes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.09.548259. [PMID: 37781579 PMCID: PMC10541116 DOI: 10.1101/2023.07.09.548259] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Motile cilia are ancient, evolutionarily conserved organelles whose dysfunction underlies motile ciliopathies, a broad class of human diseases. Motile cilia contain myriad different proteins that assemble into an array of distinct machines, so understanding the interactions and functional hierarchies among them presents an important challenge. Here, we defined the protein interactome of motile axonemes using cross-linking mass spectrometry (XL/MS) in Tetrahymena thermophila. From over 19,000 XLs, we identified 4,757 unique amino acid interactions among 1,143 distinct proteins, providing both macromolecular and atomic-scale insights into diverse ciliary machines, including the Intraflagellar Transport system, axonemal dynein arms, radial spokes, the 96 nm ruler, and microtubule inner proteins, among others. Guided by this dataset, we used vertebrate multiciliated cells to reveal novel functional interactions among several poorly-defined human ciliopathy proteins. The dataset therefore provides a powerful resource for studying the basic biology of an ancient organelle and the molecular etiology of human genetic disease.
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Affiliation(s)
- Caitlyn L. McCafferty
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Ophelia Papoulas
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - Chanjae Lee
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences McGill University, Québec, Canada
| | - David W. Taylor
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - Edward M. Marcotte
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - John B. Wallingford
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
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29
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Boegholm N, Petriman NA, Loureiro‐López M, Wang J, Vela MIS, Liu B, Kanie T, Ng R, Jackson PK, Andersen JS, Lorentzen E. The IFT81-IFT74 complex acts as an unconventional RabL2 GTPase-activating protein during intraflagellar transport. EMBO J 2023; 42:e111807. [PMID: 37606072 PMCID: PMC10505919 DOI: 10.15252/embj.2022111807] [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: 06/04/2022] [Revised: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 08/23/2023] Open
Abstract
Cilia are important cellular organelles for signaling and motility and are constructed via intraflagellar transport (IFT). RabL2 is a small GTPase that localizes to the basal body of cilia via an interaction with the centriolar protein CEP19 before downstream association with the IFT machinery, which is followed by initiation of IFT. We reconstituted and purified RabL2 with CEP19 or IFT proteins to show that a reconstituted pentameric IFT complex containing IFT81/74 enhances the GTP hydrolysis rate of RabL2. The binding site on IFT81/74 that promotes GTP hydrolysis in RabL2 was mapped to a 70-amino-acid-long coiled-coil region of IFT81/74. We present structural models for RabL2-containing IFT complexes that we validate in vitro and in cellulo and demonstrate that Chlamydomonas IFT81/74 enhances GTP hydrolysis of human RabL2, suggesting an ancient evolutionarily conserved activity. Our results provide an architectural understanding of how RabL2 is incorporated into the IFT complex and a molecular rationale for why RabL2 dissociates from anterograde IFT trains soon after departure from the ciliary base.
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Affiliation(s)
- Niels Boegholm
- Department of Molecular Biology and GeneticsAarhus UniversityAarhus CDenmark
| | - Narcis A Petriman
- Department of Molecular Biology and GeneticsAarhus UniversityAarhus CDenmark
| | - Marta Loureiro‐López
- Department for Biochemistry and Molecular BiologyUniversity of Southern DenmarkOdense MDenmark
| | - Jiaolong Wang
- Department of Molecular Biology and GeneticsAarhus UniversityAarhus CDenmark
| | | | - Beibei Liu
- Department of Cell BiologyUniversity of Oklahoma Health Science CenterOklahomaOKUSA
| | - Tomoharu Kanie
- Department of Cell BiologyUniversity of Oklahoma Health Science CenterOklahomaOKUSA
- Baxter Laboratory, Department of Microbiology & ImmunologyStanford University School of MedicineStanfordCAUSA
| | - Roy Ng
- Baxter Laboratory, Department of Microbiology & ImmunologyStanford University School of MedicineStanfordCAUSA
| | - Peter K Jackson
- Baxter Laboratory, Department of Microbiology & ImmunologyStanford University School of MedicineStanfordCAUSA
- Department of PathologyStanford University School of MedicineStanfordCAUSA
| | - Jens S Andersen
- Department for Biochemistry and Molecular BiologyUniversity of Southern DenmarkOdense MDenmark
| | - Esben Lorentzen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhus CDenmark
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30
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King SM. Inherently disordered regions of axonemal dynein assembly factors. Cytoskeleton (Hoboken) 2023:10.1002/cm.21789. [PMID: 37712517 PMCID: PMC10940205 DOI: 10.1002/cm.21789] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/16/2023]
Abstract
The dynein-driven beating of cilia is required to move individual cells and to generate fluid flow across surfaces and within cavities. These motor enzymes are highly complex and can contain upwards of 20 different protein components with a total mass approaching 2 MDa. The dynein heavy chains are enormous proteins consisting of ~4500 residues and ribosomes take approximately 15 min to synthesize one. Studies in a broad array of organisms ranging from the green alga Chlamydomonas to humans has identified 19 cytosolic factors (DNAAFs) that are needed to specifically build axonemal dyneins; defects in many of these proteins lead to primary ciliary dyskinesia in mammals which can result in infertility, severe bronchial problems, and situs inversus. How all these factors cooperate in a spatially and temporally regulated manner to promote dynein assembly in cytoplasm remains very uncertain. These DNAAFs contain a variety of well-folded domains many of which provide protein interaction surfaces. However, many also exhibit large regions that are predicted to be inherently disordered. Here I discuss the nature of these unstructured segments, their predicted propensity for driving protein phase separation, and their potential for adopting more defined conformations during the dynein assembly process.
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Affiliation(s)
- Stephen M. King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, Connecticut 06030-3305, USA
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31
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Klena N, Maltinti G, Batman U, Pigino G, Guichard P, Hamel V. An In-depth Guide to the Ultrastructural Expansion Microscopy (U-ExM) of Chlamydomonas reinhardtii. Bio Protoc 2023; 13:e4792. [PMID: 37719077 PMCID: PMC10502176 DOI: 10.21769/bioprotoc.4792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 05/25/2023] [Accepted: 06/01/2023] [Indexed: 09/19/2023] Open
Abstract
Expansion microscopy is an innovative method that enables super-resolution imaging of biological materials using a simple confocal microscope. The principle of this method relies on the physical isotropic expansion of a biological specimen cross-linked to a swellable polymer, stained with antibodies, and imaged. Since its first development, several improved versions of expansion microscopy and adaptations for different types of samples have been produced. Here, we show the application of ultrastructure expansion microscopy (U-ExM) to investigate the 3D organization of the green algae Chlamydomonas reinhardtii cellular ultrastructure, with a particular emphasis on the different types of sample fixation that can be used, as well as compatible staining procedures including membranes. Graphical overview.
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Affiliation(s)
| | | | - Umut Batman
- Department of Molecular and Cellular Biology, Section of Biology, University of Geneva, Geneva, Switzerland
| | | | - Paul Guichard
- Department of Molecular and Cellular Biology, Section of Biology, University of Geneva, Geneva, Switzerland
| | - Virginie Hamel
- Department of Molecular and Cellular Biology, Section of Biology, University of Geneva, Geneva, Switzerland
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32
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Eisenstein M. Catching proteins at play: the method revealing the cell's inner mysteries. Nature 2023; 621:646-648. [PMID: 37723291 DOI: 10.1038/d41586-023-02909-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
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33
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Findinier J, Grossman AR. Chlamydomonas: Fast tracking from genomics. JOURNAL OF PHYCOLOGY 2023; 59:644-652. [PMID: 37417760 DOI: 10.1111/jpy.13356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 07/08/2023]
Abstract
Elucidating biological processes has relied on the establishment of model organisms, many of which offer advantageous features such as rapid axenic growth, extensive knowledge of their physiological features and gene content, and the ease with which they can be genetically manipulated. The unicellular green alga Chlamydomonas reinhardtii has been an exemplary model that has enabled many scientific breakthroughs over the decades, especially in the fields of photosynthesis, cilia function and biogenesis, and the acclimation of photosynthetic organisms to their environment. Here, we discuss recent molecular/technological advances that have been applied to C. reinhardtii and how they have further fostered its development as a "flagship" algal system. We also explore the future promise of this alga in leveraging advances in the fields of genomics, proteomics, imaging, and synthetic biology for addressing critical future biological issues.
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Affiliation(s)
- Justin Findinier
- The Carnegie Institution for Science, Biosphere Science and Engineering, Stanford, California, USA
| | - Arthur R Grossman
- The Carnegie Institution for Science, Biosphere Science and Engineering, Stanford, California, USA
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34
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Tan ZY, Cai S, Noble AJ, Chen JK, Shi J, Gan L. Heterogeneous non-canonical nucleosomes predominate in yeast cells in situ. eLife 2023; 12:RP87672. [PMID: 37503920 PMCID: PMC10382156 DOI: 10.7554/elife.87672] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023] Open
Abstract
Nuclear processes depend on the organization of chromatin, whose basic units are cylinder-shaped complexes called nucleosomes. A subset of mammalian nucleosomes in situ (inside cells) resembles the canonical structure determined in vitro 25 years ago. Nucleosome structure in situ is otherwise poorly understood. Using cryo-electron tomography (cryo-ET) and 3D classification analysis of budding yeast cells, here we find that canonical nucleosomes account for less than 10% of total nucleosomes expected in situ. In a strain in which H2A-GFP is the sole source of histone H2A, class averages that resemble canonical nucleosomes both with and without GFP densities are found ex vivo (in nuclear lysates), but not in situ. These data suggest that the budding yeast intranuclear environment favors multiple non-canonical nucleosome conformations. Using the structural observations here and the results of previous genomics and biochemical studies, we propose a model in which the average budding yeast nucleosome's DNA is partially detached in situ.
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Affiliation(s)
- Zhi Yang Tan
- Department of Biological Sciences and Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Shujun Cai
- Department of Biological Sciences and Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Alex J Noble
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology CenterNew YorkUnited States
| | - Jon K Chen
- Department of Biological Sciences and Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Jian Shi
- Department of Biological Sciences and Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
| | - Lu Gan
- Department of Biological Sciences and Center for BioImaging Sciences, National University of SingaporeSingaporeSingapore
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35
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Curtis AJ, Zhu J, Penny CJ, Gold MG. Molecular basis of interactions between CaMKII and α-actinin-2 that underlie dendritic spine enlargement. eLife 2023; 12:e85008. [PMID: 37489746 PMCID: PMC10484527 DOI: 10.7554/elife.85008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 07/24/2023] [Indexed: 07/26/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is essential for long-term potentiation (LTP) of excitatory synapses that is linked to learning and memory. In this study, we focused on understanding how interactions between CaMKIIα and the actin-crosslinking protein α-actinin-2 underlie long-lasting changes in dendritic spine architecture. We found that association of the two proteins was unexpectedly elevated within 2 minutes of NMDA receptor stimulation that triggers structural LTP in primary hippocampal neurons. Furthermore, disruption of interactions between the two proteins prevented the accumulation of enlarged mushroom-type dendritic spines following NMDA receptor activation. α-Actinin-2 binds to the regulatory segment of CaMKII. Calorimetry experiments, and a crystal structure of α-actinin-2 EF hands 3 and 4 in complex with the CaMKII regulatory segment, indicate that the regulatory segment of autoinhibited CaMKII is not fully accessible to α-actinin-2. Pull-down experiments show that occupation of the CaMKII substrate-binding groove by GluN2B markedly increases α-actinin-2 access to the CaMKII regulatory segment. Furthermore, in situ labelling experiments are consistent with the notion that recruitment of CaMKII to NMDA receptors contributes to elevated interactions between the kinase and α-actinin-2 during structural LTP. Overall, our study provides new mechanistic insight into the molecular basis of structural LTP and reveals an added layer of sophistication to the function of CaMKII.
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Affiliation(s)
- Ashton J Curtis
- Department of Neuroscience, Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Jian Zhu
- Department of Neuroscience, Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Christopher J Penny
- Department of Neuroscience, Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Matthew G Gold
- Department of Neuroscience, Physiology and Pharmacology, University College LondonLondonUnited Kingdom
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36
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Hiyamizu S, Qiu H, Tsurumi Y, Hamada Y, Katoh Y, Nakayama K. Dynein-2-driven intraciliary retrograde trafficking indirectly requires multiple interactions of IFT54 in the IFT-B complex with the dynein-2 complex. Biol Open 2023; 12:bio059976. [PMID: 37309605 PMCID: PMC10320715 DOI: 10.1242/bio.059976] [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: 04/17/2023] [Accepted: 06/05/2023] [Indexed: 06/14/2023] Open
Abstract
Within cilia, the dynein-2 complex needs to be transported as an anterograde cargo to achieve its role as a motor to drive retrograde trafficking of the intraflagellar transport (IFT) machinery containing IFT-A and IFT-B complexes. We previously showed that interactions of WDR60 and the DYNC2H1-DYNC2LI1 dimer of dynein-2 with multiple IFT-B subunits, including IFT54, are required for the trafficking of dynein-2 as an IFT cargo. However, specific deletion of the IFT54-binding site from WDR60 demonstrated only a minor effect on dynein-2 trafficking and function. We here show that the C-terminal coiled-coil region of IFT54, which participates in its interaction with the DYNC2H1-DYNC2LI1 dimer of dynein-2 and with IFT20 of the IFT-B complex, is essential for IFT-B function, and suggest that the IFT54 middle linker region between the N-terminal WDR60-binding region and the C-terminal coiled-coil is required for ciliary retrograde trafficking, probably by mediating the effective binding of IFT-B to the dynein-2 complex, and thereby ensuring dynein-2 loading onto the anterograde IFT trains. The results presented here agree with the notion predicted from the previous structural models that the dynein-2 loading onto the anterograde IFT train relies on intricate, multivalent interactions between the dynein-2 and IFT-B complexes.
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Affiliation(s)
- Shunya Hiyamizu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hantian Qiu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuta Tsurumi
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Hamada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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37
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Xing H, Taniguchi R, Khusainov I, Kreysing JP, Welsch S, Turoňová B, Beck M. Translation dynamics in human cells visualized at high resolution reveal cancer drug action. Science 2023; 381:70-75. [PMID: 37410833 DOI: 10.1126/science.adh1411] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/05/2023] [Indexed: 07/08/2023]
Abstract
Ribosomes catalyze protein synthesis by cycling through various functional states. These states have been extensively characterized in vitro, but their distribution in actively translating human cells remains elusive. We used a cryo-electron tomography-based approach and resolved ribosome structures inside human cells with high resolution. These structures revealed the distribution of functional states of the elongation cycle, a Z transfer RNA binding site, and the dynamics of ribosome expansion segments. Ribosome structures from cells treated with Homoharringtonine, a drug used against chronic myeloid leukemia, revealed how translation dynamics were altered in situ and resolve the small molecules within the active site of the ribosome. Thus, structural dynamics and drug effects can be assessed at high resolution within human cells.
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Affiliation(s)
- Huaipeng Xing
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
- Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Reiya Taniguchi
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Iskander Khusainov
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Jan Philipp Kreysing
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
- IMPRS on Cellular Biophysics, 60438 Frankfurt am Main, Germany
| | - Sonja Welsch
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Beata Turoňová
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Martin Beck
- Department of Molecular Sociology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
- Institute of Biochemistry, Goethe University Frankfurt, Frankfurt am Main, Germany
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38
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Mill P, Christensen ST, Pedersen LB. Primary cilia as dynamic and diverse signalling hubs in development and disease. Nat Rev Genet 2023; 24:421-441. [PMID: 37072495 PMCID: PMC7615029 DOI: 10.1038/s41576-023-00587-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 04/20/2023]
Abstract
Primary cilia, antenna-like sensory organelles protruding from the surface of most vertebrate cell types, are essential for regulating signalling pathways during development and adult homeostasis. Mutations in genes affecting cilia cause an overlapping spectrum of >30 human diseases and syndromes, the ciliopathies. Given the immense structural and functional diversity of the mammalian cilia repertoire, there is a growing disconnect between patient genotype and associated phenotypes, with variable severity and expressivity characteristic of the ciliopathies as a group. Recent technological developments are rapidly advancing our understanding of the complex mechanisms that control biogenesis and function of primary cilia across a range of cell types and are starting to tackle this diversity. Here, we examine the structural and functional diversity of primary cilia, their dynamic regulation in different cellular and developmental contexts and their disruption in disease.
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Affiliation(s)
- Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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39
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Polino AJ, Sviben S, Melena I, Piston DW, Hughes JW. Scanning electron microscopy of human islet cilia. Proc Natl Acad Sci U S A 2023; 120:e2302624120. [PMID: 37205712 PMCID: PMC10235940 DOI: 10.1073/pnas.2302624120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/12/2023] [Indexed: 05/21/2023] Open
Abstract
Human islet primary cilia are vital glucose-regulating organelles whose structure remains uncharacterized. Scanning electron microscopy (SEM) is a useful technique for studying the surface morphology of membrane projections like cilia, but conventional sample preparation does not reveal the submembrane axonemal structure, which holds key implications for ciliary function. To overcome this challenge, we combined SEM with membrane-extraction techniques to examine primary cilia in native human islets. Our data show well-preserved cilia subdomains which demonstrate both expected and unexpected ultrastructural motifs. Morphometric features were quantified when possible, including axonemal length and diameter, microtubule conformations, and chirality. We further describe a ciliary ring, a structure that may be a specialization in human islets. Key findings are correlated with fluorescence microscopy and interpreted in the context of cilia function as a cellular sensor and communications locus in pancreatic islets.
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Affiliation(s)
- Alexander J. Polino
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO63110
| | - Sanja Sviben
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Saint Louis, MO63110
| | - Isabella Melena
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO63110
| | - David W. Piston
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO63110
| | - Jing W. Hughes
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO63110
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO63110
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40
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Ishikawa T. Architecture of intraflagellar transport complexes. Nat Struct Mol Biol 2023; 30:570-573. [PMID: 37198269 DOI: 10.1038/s41594-023-00986-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Affiliation(s)
- Takashi Ishikawa
- Department of Biology and Chemistry, Paul Scherrer Institute Villigen, Villigen, Switzerland.
- Department of Biology, ETH Zurich, Zurich, Switzerland.
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41
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Purnell C, Heebner J, Swulius MT, Hylton R, Kabonick S, Grillo M, Grigoryev S, Heberle F, Waxham MN, Swulius MT. Rapid Synthesis of Cryo-ET Data for Training Deep Learning Models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.28.538636. [PMID: 37162972 PMCID: PMC10168359 DOI: 10.1101/2023.04.28.538636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Deep learning excels at cryo-tomographic image restoration and segmentation tasks but is hindered by a lack of training data. Here we introduce cryo-TomoSim (CTS), a MATLAB-based software package that builds coarse-grained models of macromolecular complexes embedded in vitreous ice and then simulates transmitted electron tilt series for tomographic reconstruction. We then demonstrate the effectiveness of these simulated datasets in training different deep learning models for use on real cryotomographic reconstructions. Computer-generated ground truth datasets provide the means for training models with voxel-level precision, allowing for unprecedented denoising and precise molecular segmentation of datasets. By modeling phenomena such as a three-dimensional contrast transfer function, probabilistic detection events, and radiation-induced damage, the simulated cryo-electron tomograms can cover a large range of imaging content and conditions to optimize training sets. When paired with small amounts of training data from real tomograms, networks become incredibly accurate at segmenting in situ macromolecular assemblies across a wide range of biological contexts.
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42
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Kubo S, Black CS, Joachimiak E, Yang SK, Legal T, Peri K, Khalifa AAZ, Ghanaeian A, McCafferty CL, Valente-Paterno M, De Bellis C, Huynh PM, Fan Z, Marcotte EM, Wloga D, Bui KH. Native doublet microtubules from Tetrahymena thermophila reveal the importance of outer junction proteins. Nat Commun 2023; 14:2168. [PMID: 37061538 PMCID: PMC10105768 DOI: 10.1038/s41467-023-37868-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 04/03/2023] [Indexed: 04/17/2023] Open
Abstract
Cilia are ubiquitous eukaryotic organelles responsible for cellular motility and sensory functions. The ciliary axoneme is a microtubule-based cytoskeleton consisting of two central singlets and nine outer doublet microtubules. Cryo-electron microscopy-based studies have revealed a complex network inside the lumen of both tubules composed of microtubule-inner proteins (MIPs). However, the functions of most MIPs remain unknown. Here, we present single-particle cryo-EM-based analyses of the Tetrahymena thermophila native doublet microtubule and identify 42 MIPs. These data shed light on the evolutionarily conserved and diversified roles of MIPs. In addition, we identified MIPs potentially responsible for the assembly and stability of the doublet outer junction. Knockout of the evolutionarily conserved outer junction component CFAP77 moderately diminishes Tetrahymena swimming speed and beat frequency, indicating the important role of CFAP77 and outer junction stability in cilia beating generation and/or regulation.
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Affiliation(s)
- Shintaroh Kubo
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Corbin S Black
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Shun Kai Yang
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Katya Peri
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ahmad Abdelzaher Zaki Khalifa
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Avrin Ghanaeian
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Caitlyn L McCafferty
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Chelsea De Bellis
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Phuong M Huynh
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Zhe Fan
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, 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, McGill University, Montreal, QC, Canada.
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada.
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43
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Jiang M, Palicharla VR, Miller D, Hwang SH, Zhu H, Hixson P, Mukhopadhyay S, Sun J. Human IFT-A complex structures provide molecular insights into ciliary transport. Cell Res 2023; 33:288-298. [PMID: 36775821 PMCID: PMC10066299 DOI: 10.1038/s41422-023-00778-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/11/2023] [Indexed: 02/14/2023] Open
Abstract
Intraflagellar transport (IFT) complexes, IFT-A and IFT-B, form bidirectional trains that move along the axonemal microtubules and are essential for assembling and maintaining cilia. Mutations in IFT subunits lead to numerous ciliopathies involving multiple tissues. However, how IFT complexes assemble and mediate cargo transport lacks mechanistic understanding due to missing high-resolution structural information of the holo-complexes. Here we report cryo-EM structures of human IFT-A complexes in the presence and absence of TULP3 at overall resolutions of 3.0-3.9 Å. IFT-A adopts a "lariat" shape with interconnected core and peripheral subunits linked by structurally vital zinc-binding domains. TULP3, the cargo adapter, interacts with IFT-A through its N-terminal region, and interface mutations disrupt cargo transport. We also determine the molecular impacts of disease mutations on complex formation and ciliary transport. Our work reveals IFT-A architecture, sheds light on ciliary transport and IFT train formation, and enables the rationalization of disease mutations in ciliopathies.
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Affiliation(s)
- Meiqin Jiang
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Darcie Miller
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sun-Hee Hwang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hanwen Zhu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Patricia Hixson
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Ji Sun
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
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44
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Laporte MH, Bertiaux É, Hamel V, Guichard P. [Closer to the native architecture of the cell using Cryo-ExM]. Med Sci (Paris) 2023; 39:351-358. [PMID: 37094268 DOI: 10.1051/medsci/2023052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Most cellular imaging techniques, such as light or electron microscopy, require that the biological sample is first fixed by chemical cross-linking agents. This necessary step is also known to damage molecular nanostructures or even sub-cellular organization. To overcome this problem, another fixation approach was invented more than 40 years ago, which consists in cryo-fixing biological samples, thus allowing to preserve their native state. However, this method has been scarcely used in light microscopy due to the complexity of its implementation. In this review, we present a recently developed super-resolution method called expansion microscopy, which, when coupled with cryo-fixation, allows to visualize at a nanometric resolution the cell architecture as close as possible to its native state.
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Affiliation(s)
- Marine H Laporte
- Department of Molecular and Cellular Biology, Université de Genève, 30 quai Ernest Ansermet, 1211 Genève, Suisse
| | - Éloïse Bertiaux
- Department of Molecular and Cellular Biology, Université de Genève, 30 quai Ernest Ansermet, 1211 Genève, Suisse
| | - Virginie Hamel
- Department of Molecular and Cellular Biology, Université de Genève, 30 quai Ernest Ansermet, 1211 Genève, Suisse
| | - Paul Guichard
- Department of Molecular and Cellular Biology, Université de Genève, 30 quai Ernest Ansermet, 1211 Genève, Suisse
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45
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Ma Y, He J, Li S, Yao D, Huang C, Wu J, Lei M. Structural insight into the intraflagellar transport complex IFT-A and its assembly in the anterograde IFT train. Nat Commun 2023; 14:1506. [PMID: 36932088 PMCID: PMC10023715 DOI: 10.1038/s41467-023-37208-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
Intraflagellar transport (IFT) trains, the polymers composed of two multi-subunit complexes, IFT-A and IFT-B, carry out bidirectional intracellular transport in cilia, vital for cilia biogenesis and signaling. IFT-A plays crucial roles in the ciliary import of membrane proteins and the retrograde cargo trafficking. However, the molecular architecture of IFT-A and the assembly mechanism of the IFT-A into the IFT trains in vivo remains elusive. Here, we report the cryo-electron microscopic structures of the IFT-A complex from protozoa Tetrahymena thermophila. We find that IFT-A complexes present two distinct, elongated and folded states. Remarkably, comparison with the in situ cryo-electron tomography structure of the anterograde IFT train unveils a series of adjustments of the flexible arms in apo IFT-A when incorporated into the anterograde train. Our results provide an atomic-resolution model for the IFT-A complex and valuable insights into the assembly mechanism of anterograde IFT trains.
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Affiliation(s)
- Yuanyuan Ma
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China
| | - Jun He
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China
| | - Shaobai Li
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China
| | - Deqiang Yao
- Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Chenhui Huang
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China
| | - Jian Wu
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China.
| | - Ming Lei
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China.
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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46
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Arora S, Rana M, Sachdev A, D’Souza JS. Appearing and disappearing acts of cilia. J Biosci 2023. [DOI: 10.1007/s12038-023-00326-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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47
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Palicharla VR, Hwang SH, Somatilaka BN, Legué E, Shimada IS, Familiari NE, Tran VM, Woodruff JB, Liem KF, Mukhopadhyay S. Interactions between TULP3 tubby domain and ARL13B amphipathic helix promote lipidated protein transport to cilia. Mol Biol Cell 2023; 34:ar18. [PMID: 36652335 PMCID: PMC10011728 DOI: 10.1091/mbc.e22-10-0473] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The primary cilium is a nexus for cell signaling and relies on specific protein trafficking for function. The tubby family protein TULP3 transports integral membrane proteins into cilia through interactions with the intraflagellar transport complex-A (IFT-A) and phosphoinositides. It was previously shown that short motifs called ciliary localization sequences (CLSs) are necessary and sufficient for TULP3-dependent ciliary trafficking of transmembrane cargoes. However, the mechanisms by which TULP3 regulates ciliary compartmentalization of nonintegral, membrane-associated proteins and whether such trafficking requires TULP3-dependent CLSs is unknown. Here we show that TULP3 is required for ciliary transport of the Joubert syndrome-linked palmitoylated GTPase ARL13B through a CLS. An N-terminal amphipathic helix, preceding the GTPase domain of ARL13B, couples with the TULP3 tubby domain for ciliary trafficking, irrespective of palmitoylation. ARL13B transport requires TULP3 binding to IFT-A but not to phosphoinositides, indicating strong membrane-proximate interactions, unlike transmembrane cargo transport requiring both properties of TULP3. TULP3-mediated trafficking of ARL13B also regulates ciliary enrichment of farnesylated and myristoylated downstream effectors of ARL13B. The lipidated cargoes show distinctive depletion kinetics from kidney epithelial cilia with relation to Tulp3 deletion-induced renal cystogenesis. Overall, these findings indicate an expanded role of the tubby domain in capturing analogous helical secondary structural motifs from diverse cargoes.
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Affiliation(s)
- Vivek Reddy Palicharla
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Sun-Hee Hwang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | | | - Emilie Legué
- Vertebrate Developmental Biology Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520
| | - Issei S Shimada
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Nicole E Familiari
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Vanna M Tran
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jeffrey B Woodruff
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Karel F Liem
- Vertebrate Developmental Biology Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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48
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Hiyamizu S, Qiu H, Vuolo L, Stevenson NL, Shak C, Heesom KJ, Hamada Y, Tsurumi Y, Chiba S, Katoh Y, Stephens DJ, Nakayama K. Multiple interactions of the dynein-2 complex with the IFT-B complex are required for effective intraflagellar transport. J Cell Sci 2023; 136:286934. [PMID: 36632779 PMCID: PMC10110421 DOI: 10.1242/jcs.260462] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 01/04/2023] [Indexed: 01/13/2023] Open
Abstract
The dynein-2 complex must be transported anterogradely within cilia to then drive retrograde trafficking of the intraflagellar transport (IFT) machinery containing IFT-A and IFT-B complexes. Here, we screened for potential interactions between the dynein-2 and IFT-B complexes and found multiple interactions among the dynein-2 and IFT-B subunits. In particular, WDR60 (also known as DYNC2I1) and the DYNC2H1-DYNC2LI1 dimer from dynein-2, and IFT54 (also known as TRAF3IP1) and IFT57 from IFT-B contribute to the dynein-2-IFT-B interactions. WDR60 interacts with IFT54 via a conserved region N-terminal to its light chain-binding regions. Expression of the WDR60 constructs in WDR60-knockout (KO) cells revealed that N-terminal truncation mutants lacking the IFT54-binding site fail to rescue abnormal phenotypes of WDR60-KO cells, such as aberrant accumulation of the IFT machinery around the ciliary tip and on the distal side of the transition zone. However, a WDR60 construct specifically lacking just the IFT54-binding site substantially restored the ciliary defects. In line with the current docking model of dynein-2 with the anterograde IFT trains, these results indicate that extensive interactions involving multiple subunits from the dynein-2 and IFT-B complexes participate in their connection.
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Affiliation(s)
- Shunya Hiyamizu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hantian Qiu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Laura Vuolo
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Nicola L Stevenson
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Caroline Shak
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Kate J Heesom
- Proteomics Facility, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Yuki Hamada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuta Tsurumi
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shuhei Chiba
- Department of Genetic Disease Research, Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka 545-8585, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - David J Stephens
- Cell Biology Laboratories, School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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49
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Weiss LE, Love JF, Yoon J, Comerci CJ, Milenkovic L, Kanie T, Jackson PK, Stearns T, Gustavsson AK. Single-molecule imaging in the primary cilium. Methods Cell Biol 2023; 176:59-83. [PMID: 37164543 PMCID: PMC10509820 DOI: 10.1016/bs.mcb.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The primary cilium is an important signaling organelle critical for normal development and tissue homeostasis. Its small dimensions and complexity necessitate advanced imaging approaches to uncover the molecular mechanisms behind its function. Here, we outline how single-molecule fluorescence microscopy can be used for tracking molecular dynamics and interactions and for super-resolution imaging of nanoscale structures in the primary cilium. Specifically, we describe in detail how to capture and quantify the 2D dynamics of individual transmembrane proteins PTCH1 and SMO and how to map the 3D nanoscale distributions of the inversin compartment proteins INVS, ANKS6, and NPHP3. This protocol can, with minor modifications, be adapted for studies of other proteins and cell lines to further elucidate the structure and function of the primary cilium at the molecular level.
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Affiliation(s)
- Lucien E Weiss
- Department of Engineering Physics, Polytechnique Montréal, Montreal, QC, Canada.
| | - Julia F Love
- Department of Chemistry, Rice University, Houston, TX, United States
| | | | - Colin J Comerci
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States
| | | | - Tomoharu Kanie
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, OK, United States
| | - Peter K Jackson
- Baxter Laboratory, Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, United States; Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States
| | - Tim Stearns
- Department of Biology, Stanford University, Stanford, CA, United States; Rockefeller University, New York City, NY, United States
| | - Anna-Karin Gustavsson
- Department of Chemistry, Rice University, Houston, TX, United States; Department of BioSciences, Rice University, Houston, TX, United States; Institute of Biosciences and Bioengineering, Rice University, Houston, TX, United States; Smalley-Curl Institute, Rice University, Houston, TX, United States.
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50
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Polino AJ, Sviben S, Melena I, Piston DW, Hughes J. Scanning electron microscopy of human islet cilia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528685. [PMID: 36824775 PMCID: PMC9949088 DOI: 10.1101/2023.02.15.528685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Human islet primary cilia are vital glucose-regulating organelles whose structure remains uncharacterized. Scanning electron microscopy (SEM) is a useful technique for studying the surface morphology of membrane projections like primary cilia, but conventional sample preparation does not reveal the sub-membrane axonemal structure which holds key implications for cilia function. To overcome this challenge, we combined SEM with membrane-extraction techniques to examine cilia in native human islets. Our data show well-preserved cilia subdomains which demonstrate both expected and unexpected ultrastructural motifs. Morphometric features were quantified when possible, including axonemal length and diameter, microtubule conformations and chirality. We further describe a novel ciliary ring, a structure that may be a specialization in human islets. Key findings are correlated with fluorescence microscopy and interpreted in the context of cilia function as a cellular sensor and communications locus in pancreatic islets.
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