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Xie C, Chen G, Li M, Huang P, Chen Z, Lei K, Li D, Wang Y, Cleetus A, Mohamed MA, Sonar P, Feng W, Ökten Z, Ou G. Neurons dispose of hyperactive kinesin into glial cells for clearance. EMBO J 2024; 43:2606-2635. [PMID: 38806659 PMCID: PMC11217292 DOI: 10.1038/s44318-024-00118-0] [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: 11/22/2023] [Revised: 04/06/2024] [Accepted: 04/25/2024] [Indexed: 05/30/2024] Open
Abstract
Microtubule-based kinesin motor proteins are crucial for intracellular transport, but their hyperactivation can be detrimental for cellular functions. This study investigated the impact of a constitutively active ciliary kinesin mutant, OSM-3CA, on sensory cilia in C. elegans. Surprisingly, we found that OSM-3CA was absent from cilia but underwent disposal through membrane abscission at the tips of aberrant neurites. Neighboring glial cells engulf and eliminate the released OSM-3CA, a process that depends on the engulfment receptor CED-1. Through genetic suppressor screens, we identified intragenic mutations in the OSM-3CA motor domain and mutations inhibiting the ciliary kinase DYF-5, both of which restored normal cilia in OSM-3CA-expressing animals. We showed that conformational changes in OSM-3CA prevent its entry into cilia, and OSM-3CA disposal requires its hyperactivity. Finally, we provide evidence that neurons also dispose of hyperactive kinesin-1 resulting from a clinic variant associated with amyotrophic lateral sclerosis, suggesting a widespread mechanism for regulating hyperactive kinesins.
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Affiliation(s)
- Chao Xie
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Guanghan Chen
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Ming Li
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Peng Huang
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhe Chen
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Kexin Lei
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Dong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, 100101, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yuhe Wang
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China
- State Key Laboratory for Membrane Biology, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Augustine Cleetus
- Physik Department E22, Technische Universitat Munchen, James-Franck-Strasse, Garching, 85748, Germany
| | - Mohamed Aa Mohamed
- Physik Department E22, Technische Universitat Munchen, James-Franck-Strasse, Garching, 85748, Germany
| | - Punam Sonar
- Physik Department E22, Technische Universitat Munchen, James-Franck-Strasse, Garching, 85748, Germany
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, 100101, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Zeynep Ökten
- Physik Department E22, Technische Universitat Munchen, James-Franck-Strasse, Garching, 85748, Germany
| | - Guangshuo Ou
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China.
- Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China.
- McGovern Institute for Brain Research, Tsinghua University, Beijing, China.
- State Key Laboratory for Membrane Biology, Beijing, China.
- School of Life Sciences, Tsinghua University, Beijing, China.
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Mechanisms of Regulation in Intraflagellar Transport. Cells 2022; 11:cells11172737. [PMID: 36078145 PMCID: PMC9454703 DOI: 10.3390/cells11172737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Cilia are eukaryotic organelles essential for movement, signaling or sensing. Primary cilia act as antennae to sense a cell’s environment and are involved in a wide range of signaling pathways essential for development. Motile cilia drive cell locomotion or liquid flow around the cell. Proper functioning of both types of cilia requires a highly orchestrated bi-directional transport system, intraflagellar transport (IFT), which is driven by motor proteins, kinesin-2 and IFT dynein. In this review, we explore how IFT is regulated in cilia, focusing from three different perspectives on the issue. First, we reflect on how the motor track, the microtubule-based axoneme, affects IFT. Second, we focus on the motor proteins, considering the role motor action, cooperation and motor-train interaction plays in the regulation of IFT. Third, we discuss the role of kinases in the regulation of the motor proteins. Our goal is to provide mechanistic insights in IFT regulation in cilia and to suggest directions of future research.
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Rah G, Cha H, Kim J, Song J, Kim H, Oh YK, Ahn C, Kang M, Kim J, Yoo KH, Kim MJ, Ko HW, Ko JY, Park JH. KLC3 Regulates Ciliary Trafficking and Cyst Progression in CILK1 Deficiency-Related Polycystic Kidney Disease. J Am Soc Nephrol 2022; 33:1726-1741. [PMID: 35961787 PMCID: PMC9529174 DOI: 10.1681/asn.2021111455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 05/23/2022] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Ciliogenesis-associated kinase 1 (CILK1) is a ciliary gene that localizes in primary cilia and regulates ciliary transport. Mutations in CILK1 cause various ciliopathies. However, the pathogenesis of CILK1-deficient kidney disease is unknown. METHODS To examine whether CILK1 deficiency causes PKD accompanied by abnormal cilia, we generated mice with deletion of Cilk1 in cells of the renal collecting duct. A yeast two-hybrid system and coimmunoprecipitation (co-IP) were used to identify a novel regulator, kinesin light chain-3 (KLC3), of ciliary trafficking and cyst progression in the Cilk1-deficient model. Immunocytochemistry and co-IP were used to examine the effect of KLC3 on ciliary trafficking of the IFT-B complex and EGFR. We evaluated the effects of these genes on ciliary trafficking and cyst progression by modulating CILK1 and KLC3 expression levels. RESULTS CILK1 deficiency leads to PKD accompanied by abnormal ciliary trafficking. KLC3 interacts with CILK1 at cilia bases and is increased in cyst-lining cells of CILK1-deficient mice. KLC3 overexpression promotes ciliary recruitment of IFT-B and EGFR in the CILK1 deficiency condition, which contributes to the ciliary defect in cystogenesis. Reduction in KLC3 rescued the ciliary defects and inhibited cyst progression caused by CILK1 deficiency. CONCLUSIONS Our findings suggest that CILK1 deficiency in renal collecting ducts leads to PKD and promotes ciliary trafficking via increased KLC3.
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Affiliation(s)
- Gyuyeong Rah
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Hwayeon Cha
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Joohee Kim
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Jieun Song
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Hyunho Kim
- Center for Medical Innovation, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Yun Kyu Oh
- Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea
| | - Curie Ahn
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Minyong Kang
- Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jongmin Kim
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Kyung Hyun Yoo
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Min Jung Kim
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Hyuk Wan Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Je Yeong Ko
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
| | - Jong Hoon Park
- Department of Biological Science, Sookmyung Women’s University, Seoul, Korea
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Abstract
Cilia are microtubule-based organelles that power cell motility and regulate sensation and signaling, and abnormal ciliary structure and function cause various ciliopathies. Cilium formation and maintenance requires intraflagellar transport (IFT), during which the kinesin-2 family motor proteins ferry IFT particles carrying axonemal precursors such as tubulins into cilia. Tubulin dimers are loaded to IFT machinery through an interaction between tubulin and the IFT-74/81 module; however, little is known of how tubulins are unloaded when arriving at the ciliary tip. Here, we show that the ciliary kinase DYF-5/MAK phosphorylates multiple sites within the tubulin-binding module of IFT-74, reducing the tubulin-binding affinity of IFT-74/81 approximately sixfold. Ablation or constitutive activation of IFT-74 phosphorylation abnormally elongates or shortens sensory cilia in Caenorhabditis elegans neurons. We propose that DYF-5/MAK-dependent phosphorylation plays a fundamental role in ciliogenesis by regulating tubulin unloading.
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The physiological cargo adaptor of kinesin-2 functions as an evolutionary conserved lockpick. Proc Natl Acad Sci U S A 2022; 119:e2109378119. [PMID: 35947619 PMCID: PMC9388150 DOI: 10.1073/pnas.2109378119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Specific recognition of cellular cargo and efficient transport to its correct intracellular destination is an infrastructural challenge faced by most eukaryotic cells. This remarkable deed is accomplished by processive motor proteins that are subject to robust regulatory mechanisms. The first level of regulation entails the ability of the motor to suppress its own activity. This autoinhibition is eventually relieved by specific cargo binding. To better understand the role of the cargo during motor activation, we dissected the activation mechanism of the ciliary homodimeric kinesin-2 from Caenorhabditis elegans by its physiological cargo. In functional reconstitution assays, we identified two cargo adaptor proteins that together are necessary and sufficient to allosterically activate the autoinhibited motor. Surprisingly, the orthologous adaptor proteins from the unicellular green algae Chlamydomonas reinhardtii also fully activated the kinesin-2 from worm, even though C. reinhardtii itself lacks a homodimeric kinesin-2 motor. The latter suggested that a motor activation mechanism similar to the C. elegans model existed already well before metazoans evolved, and prompted us to scrutinize predicted homodimeric kinesin-2 orthologs in other evolutionarily distant eukaryotes. We show that the ciliate Tetrahymena thermophila not only possesses a homodimeric kinesin-2 but that it also shares the same allosteric activation mechanism that we delineated in the C. elegans model. Our results point to a much more fundamental role of homodimeric kinesin-2 in intraflagellar transport (IFT) than previously thought and warrant further scrutiny of distantly related organisms toward a comprehensive picture of the IFT process and its evolution.
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6
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Unksov IN, Korosec CS, Surendiran P, Verardo D, Lyttleton R, Forde NR, Linke H. Through the Eyes of Creators: Observing Artificial Molecular Motors. ACS NANOSCIENCE AU 2022; 2:140-159. [PMID: 35726277 PMCID: PMC9204826 DOI: 10.1021/acsnanoscienceau.1c00041] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022]
Abstract
![]()
Inspired by molecular
motors in biology, there has been significant
progress in building artificial molecular motors, using a number of
quite distinct approaches. As the constructs become more sophisticated,
there is also an increasing need to directly observe the motion of
artificial motors at the nanoscale and to characterize their performance.
Here, we review the most used methods that tackle those tasks. We
aim to help experimentalists with an overview of the available tools
used for different types of synthetic motors and to choose the method
most suited for the size of a motor and the desired measurements,
such as the generated force or distances in the moving system. Furthermore,
for many envisioned applications of synthetic motors, it will be a
requirement to guide and control directed motions. We therefore also
provide a perspective on how motors can be observed on structures
that allow for directional guidance, such as nanowires and microchannels.
Thus, this Review facilitates the future research on synthetic molecular
motors, where observations at a single-motor level and a detailed
characterization of motion will promote applications.
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Affiliation(s)
- Ivan N. Unksov
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Chapin S. Korosec
- Department of Physics, Simon Fraser University, V5A 1S6 Burnaby, British Columbia, Canada
| | | | - Damiano Verardo
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
- AlignedBio AB, Medicon Village, Scheeletorget 1, 223 63 Lund, Sweden
| | - Roman Lyttleton
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Nancy R. Forde
- Department of Physics, Simon Fraser University, V5A 1S6 Burnaby, British Columbia, Canada
| | - Heiner Linke
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
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Direct imaging of intraflagellar-transport turnarounds reveals that motors detach, diffuse, and reattach to opposite-direction trains. Proc Natl Acad Sci U S A 2021; 118:2115089118. [PMID: 34732580 PMCID: PMC8609318 DOI: 10.1073/pnas.2115089118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2021] [Indexed: 12/16/2022] Open
Abstract
Primary cilia are important organelles that exist in almost all eukaryotic cells. Intraflagellar transport (IFT) is a motor-protein–driven bidirectional intracellular transport mechanism in cilia. Previous studies have shown that motors in Caenorhabditis elegans chemosensory cilia undergo rapid turnarounds to effectively work together in driving orderly IFT. The mechanism of motor turnarounds has, however, remained unclear. Here, using a combination of advanced fluorescence imaging and single-molecule analysis, we directly show that the individual turnarounds are due to motors switching between opposite-direction IFT trains. Furthermore, we show that switching events consist of motors detaching from a train, diffusing to another one followed by attachment. This directly demonstrates that motors switch trains by diffusion, which clarifies the mechanism of motor turnarounds. Intraflagellar transport (IFT), a bidirectional intracellular transport mechanism in cilia, relies on the cooperation of kinesin-2 and IFT-dynein motors. In Caenorhabditis elegans chemosensory cilia, motors undergo rapid turnarounds to effectively work together in driving IFT. Here, we push the envelope of fluorescence imaging to obtain insight into the underlying mechanism of motor turnarounds. We developed an alternating dual-color imaging system that allows simultaneous single-molecule imaging of kinesin-II turnarounds and ensemble imaging of IFT trains. This approach allowed direct visualization of motor detachment and reattachment during turnarounds and accordingly demonstrated that the turnarounds are actually single-motor switching between opposite-direction IFT trains rather than the behaviors of motors moving independently of IFT trains. We further improved the time resolution of single-motor imaging up to 30 ms to zoom into motor turnarounds, revealing diffusion during motor turnarounds, which unveils the mechanism of motor switching trains: detach–diffuse–attach. The subsequent single-molecule analysis of turnarounds unveiled location-dependent diffusion coefficients and diffusion times for both kinesin-2 and IFT-dynein motors. From correlating the diffusion times with IFT train frequencies, we estimated that kinesins tend to attach to the next train passing in the opposite direction. IFT-dynein, however, diffuses longer and lets one or two trains pass before attaching. This might be a direct consequence of the lower diffusion coefficient of the larger IFT-dynein. Our results provide important insights into how motors can cooperate to drive intracellular transport.
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Abstract
The intraflagellar transport (IFT) system is a remarkable molecular machine used by cells to assemble and maintain the cilium, a long organelle extending from eukaryotic cells that gives rise to motility, sensing and signaling. IFT plays a critical role in building the cilium by shuttling structural components and signaling receptors between the ciliary base and tip. To provide effective transport, IFT-A and IFT-B adaptor protein complexes assemble into highly repetitive polymers, called IFT trains, that are powered by the motors kinesin-2 and IFT-dynein to move bidirectionally along the microtubules. This dynamic system must be precisely regulated to shuttle different cargo proteins between the ciliary tip and base. In this Cell Science at a Glance article and the accompanying poster, we discuss the current structural and mechanistic understanding of IFT trains and how they function as macromolecular machines to assemble the structure of the cilium.
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Affiliation(s)
- Mareike A Jordan
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstraße 108, 01307 Dresden, Germany.,Human Technopole, Via Cristina Belgioioso 171, 20157 Milan, Italy
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9
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Zhang Y, Zhang X, Dai Y, Song M, Zhou Y, Zhou J, Yan X, Shen Y. The decrease of intraflagellar transport impairs sensory perception and metabolism in ageing. Nat Commun 2021; 12:1789. [PMID: 33741976 PMCID: PMC7979750 DOI: 10.1038/s41467-021-22065-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 02/26/2021] [Indexed: 12/22/2022] Open
Abstract
Sensory perception and metabolic homeostasis are known to deteriorate with ageing, impairing the health of aged animals, while mechanisms underlying their deterioration remain poorly understood. The potential interplay between the declining sensory perception and the impaired metabolism during ageing is also barely explored. Here, we report that the intraflagellar transport (IFT) in the cilia of sensory neurons is impaired in the aged nematode Caenorhabditis elegans due to a daf-19/RFX-modulated decrease of IFT components. We find that the reduced IFT in sensory cilia thus impairs sensory perception with ageing. Moreover, we demonstrate that whereas the IFT-dependent decrease of sensory perception in aged worms has a mild impact on the insulin/IGF-1 signalling, it remarkably suppresses AMP-activated protein kinase (AMPK) signalling across tissues. We show that upregulating daf-19/RFX effectively enhances IFT, sensory perception, AMPK activity and autophagy, promoting metabolic homeostasis and longevity. Our study determines an ageing pathway causing IFT decay and sensory perception deterioration, which in turn disrupts metabolism and healthy ageing.
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Affiliation(s)
- Yincong Zhang
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiaona Zhang
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yumin Dai
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mengjiao Song
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yifei Zhou
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jun Zhou
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, Shandong, China
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiumin Yan
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yidong Shen
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
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10
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Webb S, Mukhopadhyay AG, Roberts AJ. Intraflagellar transport trains and motors: Insights from structure. Semin Cell Dev Biol 2020; 107:82-90. [PMID: 32684327 PMCID: PMC7561706 DOI: 10.1016/j.semcdb.2020.05.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 11/17/2022]
Abstract
Intraflagellar transport (IFT) sculpts the proteome of cilia and flagella; the antenna-like organelles found on the surface of virtually all human cell types. By delivering proteins to the growing ciliary tip, recycling turnover products, and selectively transporting signalling molecules, IFT has critical roles in cilia biogenesis, quality control, and signal transduction. IFT involves long polymeric arrays, termed IFT trains, which move to and from the ciliary tip under the power of the microtubule-based motor proteins kinesin-II and dynein-2. Recent top-down and bottom-up structural biology approaches are converging on the molecular architecture of the IFT train machinery. Here we review these studies, with a focus on how kinesin-II and dynein-2 assemble, attach to IFT trains, and undergo precise regulation to mediate bidirectional transport.
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Affiliation(s)
- Stephanie Webb
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom
| | - Aakash G Mukhopadhyay
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom
| | - Anthony J Roberts
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom.
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11
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Vitre B, Guesdon A, Delaval B. Non-ciliary Roles of IFT Proteins in Cell Division and Polycystic Kidney Diseases. Front Cell Dev Biol 2020; 8:578239. [PMID: 33072760 PMCID: PMC7536321 DOI: 10.3389/fcell.2020.578239] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/26/2020] [Indexed: 12/30/2022] Open
Abstract
Cilia are small organelles present at the surface of most differentiated cells where they act as sensors for mechanical or biochemical stimuli. Cilia assembly and function require the Intraflagellar Transport (IFT) machinery, an intracellular transport system that functions in association with microtubules and motors. If IFT proteins have long been studied for their ciliary roles, recent evidences indicate that their functions are not restricted to the cilium. Indeed, IFT proteins are found outside the ciliary compartment where they are involved in a variety of cellular processes in association with non-ciliary motors. Recent works also provide evidence that non-ciliary roles of IFT proteins could be responsible for the development of ciliopathies related phenotypes including polycystic kidney diseases. In this review, we will discuss the interactions of IFT proteins with microtubules and motors as well as newly identified non-ciliary functions of IFT proteins, focusing on their roles in cell division. We will also discuss the potential contribution of non-ciliary IFT proteins functions to the etiology of kidney diseases.
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12
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Nakayama K, Katoh Y. Architecture of the IFT ciliary trafficking machinery and interplay between its components. Crit Rev Biochem Mol Biol 2020; 55:179-196. [PMID: 32456460 DOI: 10.1080/10409238.2020.1768206] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cilia and flagella serve as cellular antennae and propellers in various eukaryotic cells, and contain specific receptors and ion channels as well as components of axonemal microtubules and molecular motors to achieve their sensory and motile functions. Not only the bidirectional trafficking of specific proteins within cilia but also their selective entry and exit across the ciliary gate is mediated by the intraflagellar transport (IFT) machinery with the aid of motor proteins. The IFT-B complex, which is powered by the kinesin-2 motor, mediates anterograde protein trafficking from the base to the tip of cilia, whereas the IFT-A complex together with the dynein-2 complex mediates retrograde protein trafficking. The BBSome complex connects ciliary membrane proteins to the IFT machinery. Defects in any component of this trafficking machinery lead to abnormal ciliogenesis and ciliary functions, and results in a broad spectrum of disorders, collectively called the ciliopathies. In this review article, we provide an overview of the architectures of the components of the IFT machinery and their functional interplay in ciliary protein trafficking.
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Affiliation(s)
- Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yohei Katoh
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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13
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Xie C, Li L, Li M, Shao W, Zuo Q, Huang X, Chen R, Li W, Brunnbauer M, Ökten Z, Chen L, Ou G. Optimal sidestepping of intraflagellar transport kinesins regulates structure and function of sensory cilia. EMBO J 2020; 39:e103955. [PMID: 32338401 DOI: 10.15252/embj.2019103955] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 03/20/2020] [Accepted: 03/27/2020] [Indexed: 02/06/2023] Open
Abstract
Cytoskeletal-based molecular motors produce force perpendicular to their direction of movement. However, it remains unknown whether and why motor proteins generate sidesteps movement along their filamentous tracks in vivo. Using Hessian structured illumination microscopy, we located green fluorescent protein (GFP)-labeled intraflagellar transport (IFT) particles inside sensory cilia of live Caenorhabditis elegans with 3-6-nanometer accuracy and 3.4-ms resolution. We found that IFT particles took sidesteps along axoneme microtubules, demonstrating that IFT motors generate torque in a living animal. Kinesin-II and OSM-3-kinesin collaboratively drive anterograde IFT. We showed that the deletion of kinesin-II, a torque-generating motor protein, reduced sidesteps, whereas the increase of neck flexibility of OSM-3-kinesin upregulated sidesteps. Either increase or decrease of sidesteps of IFT kinesins allowed ciliogenesis to the regular length, but changed IFT speeds, disrupted axonemal ninefold symmetry, and inhibited sensory cilia-dependent animal behaviors. Thus, an optimum level of IFT kinesin sidestepping is associated with the structural and functional fidelity of cilia.
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Affiliation(s)
- Chao Xie
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Liuju Li
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Ming Li
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Wenxin Shao
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Qingyu Zuo
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Xiaoshuai Huang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Riwang Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Wei Li
- School of Medicine, Tsinghua University, Beijing, China
| | - Melanie Brunnbauer
- Physik Department E22, Technische Universitat Munchen, Garching, Germany
| | - Zeynep Ökten
- Physik Department E22, Technische Universitat Munchen, Garching, Germany
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Guangshuo Ou
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
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14
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Vitre B, Taulet N, Guesdon A, Douanier A, Dosdane A, Cisneros M, Maurin J, Hettinger S, Anguille C, Taschner M, Lorentzen E, Delaval B. IFT proteins interact with HSET to promote supernumerary centrosome clustering in mitosis. EMBO Rep 2020; 21:e49234. [PMID: 32270908 PMCID: PMC7271317 DOI: 10.15252/embr.201949234] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/25/2020] [Accepted: 03/12/2020] [Indexed: 11/10/2022] Open
Abstract
Centrosome amplification is a hallmark of cancer, and centrosome clustering is essential for cancer cell survival. The mitotic kinesin HSET is an essential contributor to this process. Recent studies have highlighted novel functions for intraflagellar transport (IFT) proteins in regulating motors and mitotic processes. Here, using siRNA knock‐down of various IFT proteins or AID‐inducible degradation of endogenous IFT88 in combination with small‐molecule inhibition of HSET, we show that IFT proteins together with HSET are required for efficient centrosome clustering. We identify a direct interaction between the kinesin HSET and IFT proteins, and we define how IFT proteins contribute to clustering dynamics during mitosis using high‐resolution live imaging of centrosomes. Finally, we demonstrate the requirement of IFT88 for efficient centrosome clustering in a variety of cancer cell lines naturally harboring supernumerary centrosomes and its importance for cancer cell proliferation. Overall, our data unravel a novel role for the IFT machinery in centrosome clustering during mitosis in cells harboring supernumerary centrosomes.
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Affiliation(s)
- Benjamin Vitre
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Nicolas Taulet
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Audrey Guesdon
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Audrey Douanier
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Aurelie Dosdane
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Melanie Cisneros
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Justine Maurin
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Sabrina Hettinger
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Christelle Anguille
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
| | - Michael Taschner
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Benedicte Delaval
- CRBM, University of Montpellier, CNRS, Montpellier, France.,Centrosome, Cilia and Pathologies Lab, Montpellier, France
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15
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Mitra A, Peterman EJG. Motor Proteins: It Runs in the Family, but at Different Speeds. Curr Biol 2020; 30:R282-R285. [PMID: 32208157 DOI: 10.1016/j.cub.2020.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The velocity of intraflagellar transport among evolutionarily distant organisms differs substantially, while the transport machinery is well conserved. A new in vitro study finds that the velocity difference is encoded in the motor proteins driving transport.
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Affiliation(s)
- Aniruddha Mitra
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erwin J G Peterman
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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16
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Sonar P, Youyen W, Cleetus A, Wisanpitayakorn P, Mousavi SI, Stepp WL, Hancock WO, Tüzel E, Ökten Z. Kinesin-2 from C. reinhardtii Is an Atypically Fast and Auto-inhibited Motor that Is Activated by Heterotrimerization for Intraflagellar Transport. Curr Biol 2020; 30:1160-1166.e5. [PMID: 32142698 DOI: 10.1016/j.cub.2020.01.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/04/2019] [Accepted: 01/14/2020] [Indexed: 11/17/2022]
Abstract
Construction and function of virtually all cilia require the universally conserved process of intraflagellar transport (IFT) [1, 2]. During the atypically fast IFT in the green alga C. reinhardtii, on average, 10 kinesin-2 motors "line up" in a tight assembly on the trains [3], provoking the question of how these motors coordinate their action to ensure smooth and fast transport along the flagellum without standing in each other's way. Here, we show that the heterodimeric FLA8/10 kinesin-2 alone is responsible for the atypically fast IFT in C. reinhardtii. Notably, in single-molecule studies, FLA8/10 moved at speeds matching those of in vivo IFT [4] but additionally displayed a slow velocity distribution, indicative of auto-inhibition. Addition of the KAP subunit to generate the heterotrimeric FLA8/10/KAP relieved this inhibition, thus providing a mechanistic rationale for heterotrimerization with the KAP subunit fully activating FLA8/10 for IFT in vivo. Finally, we linked fast FLA8/10 and slow KLP11/20 kinesin-2 from C. reinhardtii and C. elegans through a DNA tether to understand the molecular underpinnings of motor coordination during IFT in vivo. For motor pairs from both species, the co-transport velocities very nearly matched the single-molecule velocities, and both complexes spent roughly 80% of the time with only one of the two motors attached to the microtubule. Thus, irrespective of phylogeny and kinetic properties, kinesin-2 motors work mostly alone without sacrificing efficiency. Our findings thus offer a simple mechanism for how efficient IFT is achieved across diverse organisms despite being carried out by motors with different properties.
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Affiliation(s)
- Punam Sonar
- Physik Department E22, Technische Universität München, Garching 85748, Germany
| | - Wiphu Youyen
- Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Augustine Cleetus
- Physik Department E22, Technische Universität München, Garching 85748, Germany
| | | | - Sayed I Mousavi
- Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Willi L Stepp
- Physik Department E22, Technische Universität München, Garching 85748, Germany
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Erkan Tüzel
- Bioengineering Department, College of Engineering, Temple University, Philadelphia, PA 19122, USA
| | - Zeynep Ökten
- Physik Department E22, Technische Universität München, Garching 85748, Germany.
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17
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Abstract
Cross-talk between the microtubule and actin networks has come under intense scrutiny following the realization that it is crucial for numerous essential processes, ranging from cytokinesis to cell migration. It is becoming increasingly clear that proteins long-considered highly specific for one or the other cytoskeletal system do, in fact, make use of both filament types. How this functional duality of "shared proteins" has evolved and how their coadaptation enables cross-talk at the molecular level remain largely unknown. We previously discovered that the mammalian adaptor protein melanophilin of the actin-associated myosin motor is one such "shared protein," which also interacts with microtubules in vitro. In a hypothesis-driven in vitro and in silico approach, we turn to early and lower vertebrates and ask two fundamental questions. First, is the capability of interacting with microtubules and actin filaments unique to mammalian melanophilin or did it evolve over time? Second, what is the functional consequence of being able to interact with both filament types at the cellular level? We describe the emergence of a protein domain that confers the capability of interacting with both filament types onto melanophilin. Strikingly, our computational modeling demonstrates that the regulatory power of this domain on the microscopic scale alone is sufficient to recapitulate previously observed behavior of pigment organelles in amphibian melanophores. Collectively, our dissection provides a molecular framework for explaining the underpinnings of functional cross-talk and its potential to orchestrate the cell-wide redistribution of organelles on the cytoskeleton.
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18
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Abstract
Primary cilia project in a single copy from the surface of most vertebrate cell types; they detect and transmit extracellular cues to regulate diverse cellular processes during development and to maintain tissue homeostasis. The sensory capacity of primary cilia relies on the coordinated trafficking and temporal localization of specific receptors and associated signal transduction modules in the cilium. The canonical Hedgehog (HH) pathway, for example, is a bona fide ciliary signalling system that regulates cell fate and self-renewal in development and tissue homeostasis. Specific receptors and associated signal transduction proteins can also localize to primary cilia in a cell type-dependent manner; available evidence suggests that the ciliary constellation of these proteins can temporally change to allow the cell to adapt to specific developmental and homeostatic cues. Consistent with important roles for primary cilia in signalling, mutations that lead to their dysfunction underlie a pleiotropic group of diseases and syndromic disorders termed ciliopathies, which affect many different tissues and organs of the body. In this Review, we highlight central mechanisms by which primary cilia coordinate HH, G protein-coupled receptor, WNT, receptor tyrosine kinase and transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP) signalling and illustrate how defects in the balanced output of ciliary signalling events are coupled to developmental disorders and disease progression.
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19
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Stepp WL, Ökten Z. Resolving kinesin stepping: one head at a time. Life Sci Alliance 2019; 2:2/5/e201900456. [PMID: 31601622 PMCID: PMC6788457 DOI: 10.26508/lsa.201900456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/27/2019] [Accepted: 09/27/2019] [Indexed: 11/24/2022] Open
Abstract
Kinesins are well known to power diverse long-range transport processes in virtually all eukaryotic cells. The ATP-dependent processive stepping as well as the regulation of kinesin' activity have, thus, been the focus of extensive studies over the past decades. It is widely accepted that kinesin motors can self-regulate their activity by suppressing the catalytic activity of the "heads." The distal random coil at the C terminus, termed "tail domain," is proposed to mediate this autoinhibition; however, a direct regulatory influence of the tail on the processive stepping of kinesin proved difficult to capture. Here, we simultaneously tracked the two distinct head domains in the kinesin-2 motor using dual-color super resolution microscopy (dcFIONA) and reveal for the first time their individual properties during processive stepping. We show that the autoinhibitory wild-type conformation selectively impacts one head in the heterodimer but not the other. Our results provide insights into the regulated kinesin stepping that had escaped experimental scrutiny so far.
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Affiliation(s)
- Willi L Stepp
- Physik Department E22, Technische Universität München, Garching, Germany
| | - Zeynep Ökten
- Physik Department E22, Technische Universität München, Garching, Germany .,Munich Center for Integrated Protein Science, Munich, Germany
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20
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Taulet N, Douanier A, Vitre B, Anguille C, Maurin J, Dromard Y, Georget V, Delaval B. IFT88 controls NuMA enrichment at k-fibers minus-ends to facilitate their re-anchoring into mitotic spindles. Sci Rep 2019; 9:10311. [PMID: 31312011 PMCID: PMC6635507 DOI: 10.1038/s41598-019-46605-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 07/02/2019] [Indexed: 02/06/2023] Open
Abstract
To build and maintain mitotic spindle architecture, molecular motors exert spatially regulated forces on microtubules (MT) minus-ends. This spatial regulation is required to allow proper chromosomes alignment through the organization of kinetochore fibers (k-fibers). NuMA was recently shown to target dynactin to MT minus-ends and thus to spatially regulate dynein activity. However, given that k-fibers are embedded in the spindle, our understanding of the machinery involved in the targeting of proteins to their minus-ends remains limited. Intraflagellar transport (IFT) proteins were primarily studied for their ciliary roles but they also emerged as key regulators of cell division. Taking advantage of MT laser ablation, we show here that IFT88 concentrates at k-fibers minus-ends and is required for their re-anchoring into spindles by controlling NuMA accumulation. Indeed, IFT88 interacts with NuMA and is required for its enrichment at newly generated k-fibers minus-ends. Combining nocodazole washout experiments and IFT88 depletion, we further show that IFT88 is required for the reorganization of k-fibers into spindles and thus for efficient chromosomes alignment in mitosis. Overall, we propose that IFT88 could serve as a mitotic MT minus-end adaptor to concentrate NuMA at minus-ends thus facilitating k-fibers incorporation into the main spindle.
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Affiliation(s)
- Nicolas Taulet
- CRBM, CNRS, Univ. Montpellier, Centrosome, cilia and pathologies Lab, 1919 Route de Mende, 34293, Montpellier, France.
| | - Audrey Douanier
- CRBM, CNRS, Univ. Montpellier, Centrosome, cilia and pathologies Lab, 1919 Route de Mende, 34293, Montpellier, France
| | - Benjamin Vitre
- CRBM, CNRS, Univ. Montpellier, Centrosome, cilia and pathologies Lab, 1919 Route de Mende, 34293, Montpellier, France
| | - Christelle Anguille
- CRBM, CNRS, Univ. Montpellier, Centrosome, cilia and pathologies Lab, 1919 Route de Mende, 34293, Montpellier, France
| | - Justine Maurin
- CRBM, CNRS, Univ. Montpellier, Centrosome, cilia and pathologies Lab, 1919 Route de Mende, 34293, Montpellier, France
| | - Yann Dromard
- Montpellier Ressources Imagerie, CRBM, CNRS, Univ. Montpellier, 1919 Route de Mende, 34293, Montpellier, France
| | - Virginie Georget
- Montpellier Ressources Imagerie, CRBM, CNRS, Univ. Montpellier, 1919 Route de Mende, 34293, Montpellier, France
| | - Benedicte Delaval
- CRBM, CNRS, Univ. Montpellier, Centrosome, cilia and pathologies Lab, 1919 Route de Mende, 34293, Montpellier, France.
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21
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Trafficking of ciliary membrane proteins by the intraflagellar transport/BBSome machinery. Essays Biochem 2018; 62:753-763. [PMID: 30287585 DOI: 10.1042/ebc20180030] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/04/2018] [Accepted: 09/19/2018] [Indexed: 12/13/2022]
Abstract
Bardet-Biedl syndrome (BBS) is a rare inherited disease caused by defects in the BBSome, an octameric complex of BBS proteins. The BBSome is conserved in most organisms with cilia, which are microtubule (MT)-based cell organelles that protrude from the cell surface and function in motility and sensing. Cilia assembly, maintenance, and function require intraflagellar transport (IFT), a bidirectional motility of multi-megadalton IFT trains propelled by molecular motors along the ciliary MTs. IFT has been shown to transport structural proteins, including tubulin, into growing cilia. The BBSome is an adapter for the transport of ciliary membrane proteins and cycles through cilia via IFT. While both the loss and the abnormal accumulation of ciliary membrane proteins have been observed in bbs mutants, recent data converge on a model where the BBSome mainly functions as a cargo adapter for the removal of certain transmembrane and peripheral membrane proteins from cilia. Here, we review recent data on the ultrastructure of the BBSome and how the BBSome recognizes its cargoes and mediates their removal from cilia.
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22
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Tang F, Pan MH, Wan X, Lu Y, Zhang Y, Sun SC. Kif18a regulates Sirt2-mediated tubulin acetylation for spindle organization during mouse oocyte meiosis. Cell Div 2018; 13:9. [PMID: 30459823 PMCID: PMC6234775 DOI: 10.1186/s13008-018-0042-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/26/2018] [Indexed: 12/17/2022] Open
Abstract
Background During oocyte meiosis, the cytoskeleton dynamics, especially spindle organization, are critical for chromosome congression and segregation. However, the roles of the kinesin superfamily in this process are still largely unknown. Results In the present study, Kif18a, a member of the kinesin-8 family, regulated spindle organization through its effects on tubulin acetylation in mouse oocyte meiosis. Our results showed that Kif18a is expressed and mainly localized in the spindle region. Knock down of Kif18a caused the failure of first polar body extrusion, dramatically affecting spindle organization and resulting in severe chromosome misalignment. Further analysis showed that the disruption of Kif18a caused an increase in acetylated tubulin level, which might be the reason for the spindle organization defects after Kif18a knock down in oocyte meiosis, and the decreased expression of deacetylase Sirt2 was found after Kif18a knock down. Moreover, microinjections of tubulin K40R mRNA, which could induce tubulin deacetylation, protected the oocytes from the effects of Kif18a downregulation, resulting in normal spindle morphology in Kif18a-knock down oocytes. Conclusions Taken together, our results showed that Kif18a affected Sirt2-mediated tubulin acetylation level for spindle organization during mouse oocyte meiosis. Our results not only revealed the critical effect of Kif18a on microtubule stability, but also extended our understanding of kinesin activity in meiosis.
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Affiliation(s)
- Feng Tang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Meng-Hao Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Xiang Wan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yujie Lu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Yu Zhang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095 China
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23
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Morthorst SK, Christensen ST, Pedersen LB. Regulation of ciliary membrane protein trafficking and signalling by kinesin motor proteins. FEBS J 2018; 285:4535-4564. [PMID: 29894023 DOI: 10.1111/febs.14583] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/09/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022]
Abstract
Primary cilia are antenna-like sensory organelles that regulate a substantial number of cellular signalling pathways in vertebrates, both during embryonic development as well as in adulthood, and mutations in genes coding for ciliary proteins are causative of an expanding group of pleiotropic diseases known as ciliopathies. Cilia consist of a microtubule-based axoneme core, which is subtended by a basal body and covered by a bilayer lipid membrane of unique protein and lipid composition. Cilia are dynamic organelles, and the ability of cells to regulate ciliary protein and lipid content in response to specific cellular and environmental cues is crucial for balancing ciliary signalling output. Here we discuss mechanisms involved in regulation of ciliary membrane protein trafficking and signalling, with main focus on kinesin-2 and kinesin-3 family members.
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