1
|
Perry JA, Werner ME, Omi S, Heck BW, Maddox PS, Mavrakis M, Maddox AS. Animal septins contain functional transmembrane domains. Curr Biol 2025; 35:1910-1917.e5. [PMID: 40157353 DOI: 10.1016/j.cub.2025.03.004] [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: 09/13/2024] [Revised: 01/17/2025] [Accepted: 03/04/2025] [Indexed: 04/01/2025]
Abstract
Septins are a highly conserved family of proteins that form palindromic hetero-oligomeric rods, which anneal into non-polar filaments. Via association with the plasma membrane, septin filaments recognize micron-scale membrane curvature, create diffusion barriers, and regulate cell morphogenic events via scaffolding other cytoskeletal polymers (i.e., filamentous actin [F-actin] and microtubules) and biochemical regulators of cell division, cell migration, and polarity establishment.1,2 Although interaction with cellular membranes is thought to be crucial for septin polymer dynamics and function, how septins associate with membranes is not understood. Three polybasic regions (PB1, PB2, and PB3) and an amphipathic helix (AH) are each sufficient for membrane interaction in vitro, and while the AH domain has been implicated in conferring membrane curvature sensing in vivo in the filamentous fungus Ashbya, the functionality of these domains in the context of intact septin complexes in vivo is still incompletely defined.3,4,5,6,7,8,9 We identified and characterized an isoform of Caenorhabditis elegans septin UNC-61 that was predicted to contain a transmembrane domain (TMD; UNC-61a). UNC-61a was expressed in a subset of tissues where the known septins act, and the TMD was required for tissue integrity of the egg-laying apparatus. We found predicted TMD-containing septins across much of opisthokont phylogeny and demonstrated that the TMD-containing sequence of a primate TMD-septin is sufficient for localization to cellular membranes. Together, our findings reveal a novel mechanism of septin-membrane association with profound implications for septin dynamics and regulation.
Collapse
Affiliation(s)
- Jenna A Perry
- Department of Biology, the University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Michael E Werner
- Department of Biology, the University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Shizue Omi
- Institut Fresnel, CNRS UMR7249, Aix Marseille University, Centrale Med, 13013 Marseille, France
| | - Bryan W Heck
- Department of Biology, the University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Paul S Maddox
- Department of Biology, the University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Manos Mavrakis
- Institut Fresnel, CNRS UMR7249, Aix Marseille University, Centrale Med, 13013 Marseille, France
| | - Amy S Maddox
- Department of Biology, the University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| |
Collapse
|
2
|
MacTaggart B, Wang J, Tang HY, Kashina A. Arginylation of ⍺-tubulin at E77 regulates microtubule dynamics via MAP1S. J Cell Biol 2025; 224:e202406099. [PMID: 39852692 PMCID: PMC11775831 DOI: 10.1083/jcb.202406099] [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: 06/18/2024] [Revised: 11/26/2024] [Accepted: 01/03/2025] [Indexed: 01/26/2025] Open
Abstract
Arginylation is the posttranslational addition of arginine to a protein by arginyltransferase-1 (ATE1). Previous studies have found that ATE1 targets multiple cytoskeletal proteins, and Ate1 deletion causes cytoskeletal defects, including reduced cell motility and adhesion. Some of these defects have been linked to actin arginylation, but the role of other arginylated cytoskeletal proteins has not been studied. Here, we characterize tubulin arginylation and its role in the microtubule cytoskeleton. We identify ATE1-dependent arginylation of ⍺-tubulin at E77. Ate1-/- cells and cells overexpressing non-arginylatable ⍺-tubulinE77A both show a reduced microtubule growth rate and increased microtubule stability. Additionally, they show an increase in the fraction of the stabilizing protein MAP1S associated with microtubules, suggesting that E77 arginylation directly regulates MAP1S binding. Knockdown of Map1s is sufficient to rescue microtubule growth rate and stability to wild-type levels. Together, these results demonstrate a new type of tubulin regulation by posttranslational arginylation, which modulates microtubule growth rate and stability through the microtubule-associated protein, MAP1S.
Collapse
Affiliation(s)
- Brittany MacTaggart
- University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA
| | - Junling Wang
- University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, Wistar Institute, Philadelphia, PA, USA
| | - Anna Kashina
- University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA, USA
| |
Collapse
|
3
|
Wood LM, Moore JK. β3 accelerates microtubule plus end maturation through a divergent lateral interface. Mol Biol Cell 2025; 36:ar36. [PMID: 39813077 PMCID: PMC12005103 DOI: 10.1091/mbc.e24-08-0354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Revised: 11/26/2024] [Accepted: 01/09/2025] [Indexed: 01/16/2025] Open
Abstract
β-tubulin isotypes exhibit similar sequences but different activities, suggesting that limited sequence divergence is functionally important. We investigated this hypothesis for TUBB3/β3, a β-tubulin linked to aggressive cancers and chemoresistance in humans. We created mutant yeast strains with β-tubulin alleles that mimic variant residues in β3 and find that residues at the lateral interface are sufficient to alter microtubule dynamics and response to microtubule targeting agents. In HeLa cells, β3 overexpression decreases the lifetime of microtubule growth, and this requires residues at the lateral interface. These microtubules exhibit a shorter region of EB binding at the plus end, suggesting faster lattice maturation, and resist stabilization by paclitaxel. Resistance requires the H1-S2 and H2-S3 regions at the lateral interface of β3. Our results identify the mechanistic origins of the unique activity of β3 tubulin and suggest that tubulin isotype expression may tune the rate of lattice maturation at growing microtubule plus ends in cells.
Collapse
Affiliation(s)
- Lisa M. Wood
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Jeffrey K. Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| |
Collapse
|
4
|
Estévez-Gallego J, Blum TB, Ruhnow F, Gili M, Speroni S, García-Castellanos R, Steinmetz MO, Surrey T. Hydrolysis-deficient mosaic microtubules as faithful mimics of the GTP cap. Nat Commun 2025; 16:2396. [PMID: 40064882 PMCID: PMC11893814 DOI: 10.1038/s41467-025-57555-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/20/2025] [Indexed: 03/14/2025] Open
Abstract
A critical feature of microtubules is their GTP cap, a stabilizing GTP-tubulin rich region at growing microtubule ends. Microtubules polymerized in the presence of GTP analogs or from GTP hydrolysis-deficient tubulin mutants have been used as GTP-cap mimics for structural and biochemical studies. However, these analogs and mutants generate microtubules with diverse biochemical properties and lattice structures, leaving it unclear what is the most faithful GTP mimic and hence the structure of the GTP cap. Here, we generate a hydrolysis-deficient human tubulin mutant, αE254Q, with the smallest possible modification. We show that αE254Q-microtubules are stable, but still exhibit mild mutation-induced growth abnormalities. However, mixing two GTP hydrolysis-deficient tubulin mutants, αE254Q and αE254N, at an optimized ratio eliminates growth and lattice abnormalities, indicating that these 'mosaic microtubules' are faithful GTP cap mimics. Their cryo-electron microscopy structure reveals that longitudinal lattice expansion, but not protofilament twist, is the primary structural feature distinguishing the GTP-tubulin containing cap from the GDP-tubulin containing microtubule shaft. However, alterations in protofilament twist may be transiently needed to allow lattice compaction and GTP hydrolysis. Together, our results provide insights into the structural origin of GTP cap stability, the pathway of GTP hydrolysis and hence microtubule dynamic instability.
Collapse
Affiliation(s)
- Juan Estévez-Gallego
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland.
| | - Thorsten B Blum
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland
| | - Felix Ruhnow
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - María Gili
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Silvia Speroni
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Raquel García-Castellanos
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Michel O Steinmetz
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland
- University of Basel, Biozentrum, Basel, Switzerland
| | - Thomas Surrey
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- ICREA, Pg. Lluis Companys 23, Barcelona, Spain.
| |
Collapse
|
5
|
An S, Choi BS. Surface code model for Fibonacci helical pathways of the Orch OR microtubule. Biosystems 2025; 249:105414. [PMID: 39978568 DOI: 10.1016/j.biosystems.2025.105414] [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: 07/25/2024] [Revised: 02/06/2025] [Accepted: 02/07/2025] [Indexed: 02/22/2025]
Abstract
The Objective Reduction (OR) theory suggested by Sir Roger Penrose presented a novel perspective on the measurement problem of quantum mechanics and consciousness. Subsequently, based on the assertion of anesthesiologist Dr. Hameroff, the theory proposed that the phenomenon of OR could also manifest in microtubules within neurons. This would, serve as the trigger for consciousness, thereby forming the basis of Orchestrated OR (Orch OR). The peculiarity of this theory lies in the claim that tubulin and its higher neuronal information structures are not simply additive, rather, they are formed in a topological manner. Specifically, higher information structure of tubulin, helical pathways are presumed to form an intersecting pattern in both left-handed and right-handed directions, following a repeating Fibonacci series (3, 5, 8, 13, …), and are interconnected with each other. There have been attempts to examine these unique characteristics. However, experimenting upon these quantum characteristics in the microtubule appears to be plagued by certain limitations. Therefore, this study proposed a surface code model to implement this biological model on a quantum computer, focusing on its quantum properties. To the best of our knowledge, this is the first study to attempt this. The study emphasizes that interpreting asymmetric Fibonacci helical pathways as logical qubits can stabilize surface code. In addition, we analyzed the conditions required for experimenting with this model based on the development of current quantum computer. Although the experimental feasibility of this study is dependents on future quantum computer development, it provides significant insights into Orch OR research by offering a novel perspective.
Collapse
Affiliation(s)
- Seungju An
- Department of Physics, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan, 48513, Republic of Korea
| | - Byung-Soo Choi
- Department of Scientific Computing, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan, 48513, Republic of Korea.
| |
Collapse
|
6
|
Oeztuerk M, Herebian D, Dipali K, Hentschel A, Rademacher N, Kraft F, Horvath R, Distelmaier F, Meuth SG, Ruck T, Schara-Schmidt U, Roos A. Multi-omics-based phenotyping of AFG3L2-mutant lymphoblasts determines key factors of a pathophysiological interplay between mitochondrial vulnerability and neurodegeneration in spastic ataxia type 5. Front Mol Neurosci 2025; 18:1548255. [PMID: 40051915 PMCID: PMC11882581 DOI: 10.3389/fnmol.2025.1548255] [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: 12/19/2024] [Accepted: 01/29/2025] [Indexed: 03/09/2025] Open
Abstract
Mitochondrial integrity is fundamental to cellular function, upheld by a network of proteases that regulate proteostasis and mitochondrial dynamics. Among these proteases, AFG3L2 is critical due to its roles in maintaining mitochondrial homeostasis, regulating mitochondrial protein quality, and facilitating mitochondrial biogenesis. Mutations in AFG3L2 are implicated in a spectrum of diseases, including spinocerebellar ataxia type 28 (SCA28) and spastic ataxia 5 (SPAX5), as well as other systemic conditions. This study employs a multi-omics approach to investigate the biochemical impact of AFG3L2 mutations in immortalized lymphoblastoid cell lines derived from a patient with biallelic variants leading to spastic ataxia (SPAX5). Our proteomic analysis revealed AFG3L2 impairment, with significant dysregulation of proteins critical for mitochondrial function, cytoskeletal integrity, and cellular metabolism. Specifically, disruptions were observed in mitochondrial dynamics and calcium homeostasis, alongside downregulation of key proteins like COX11, a copper chaperone for complex IV assembly, and NFU1, an iron-sulfur cluster protein linked to spastic paraparesis and infection-related worsening. Lipidomic analysis highlighted substantial alterations in lipid composition, with significant decreases in sphingomyelins, phosphatidylethanolamine, and phosphatidylcholine, reflecting disruptions in lipid metabolism and membrane integrity. Metabolomic profiling did not reveal any significant findings. Our comprehensive investigation into loss of functional AFG3L2 elucidates a pathophysiology extending beyond mitochondrial proteostasis, implicating a wide array of cellular processes. The findings reveal substantial cellular disturbances at multiple levels, contributing to neurodegeneration through disrupted mitochondrial respiratory chain, calcium homeostasis, cytoskeletal integrity, and altered lipid homeostasis. This study underscores the complexity of SPAX5 pathophysiology and the importance of multi-omics approaches in developing effective strategies to address the impact of loss of functional AFG3L2. Our data also highlight the value of immortalized lymphoblastoid cells as a tool for pre-clinical testing and research, offering a detailed biochemical fingerprint that enhances our understanding of SPAX5 and identifies potential areas for further investigation.
Collapse
Affiliation(s)
- Menekse Oeztuerk
- Department of Neurology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
- Heimer Institute for Muscle Research, BG-University Hospital Bergmannsheil, Bochum, Germany
| | - Diran Herebian
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Kale Dipali
- Leibniz-Institut für Analytische Wissenschaften -ISAS- e.V., Dortmund, Germany
| | - Andreas Hentschel
- Leibniz-Institut für Analytische Wissenschaften -ISAS- e.V., Dortmund, Germany
| | - Nina Rademacher
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, University Duisburg-Essen, Essen, Germany
| | - Florian Kraft
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, Rheinisch-Westfälische Technische Hochschule Aachen University Hospital, Aachen, Germany
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Felix Distelmaier
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Sven G. Meuth
- Department of Neurology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Tobias Ruck
- Department of Neurology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany
- Heimer Institute for Muscle Research, BG-University Hospital Bergmannsheil, Bochum, Germany
| | - Ulrike Schara-Schmidt
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, University Duisburg-Essen, Essen, Germany
| | - Andreas Roos
- Department of Neurology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, University Duisburg-Essen, Essen, Germany
- Brain and Mind Research Institute, Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| |
Collapse
|
7
|
Chew YM, Cross RA. Structural switching of tubulin in the microtubule lattice. Biochem Soc Trans 2025; 53:BST20240360. [PMID: 39910801 DOI: 10.1042/bst20240360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2024] [Revised: 11/28/2024] [Accepted: 12/23/2024] [Indexed: 02/07/2025]
Abstract
Microtubule (MT) dynamic instability, a cycle of growth, catastrophe, shrinkage and rescue, is driven by the switching of tubulin between two structural states, one stabilised by GTP and the other by GDP. Recent work has uncovered the ancient origins of this structural switch and revealed further fundamental elements of microtubule dynamic instability, whereby switching can be brought about by a range of allosteric effectors, propagate deep within the lattice of assembled MTs, and profoundly affect MT function. Here, we review evidence for structural switching within the MT lattice and discuss current ideas about its mechanisms.
Collapse
Affiliation(s)
- Yean-Ming Chew
- Centre for Mechanochemical Cell Biology, University of Warwick, Warwick Medical School, Coventry CV4 7LA, U.K
| | - Robert A Cross
- Centre for Mechanochemical Cell Biology, University of Warwick, Warwick Medical School, Coventry CV4 7LA, U.K
| |
Collapse
|
8
|
Troman L, de Gaulejac E, Biswas A, Stiens J, Kuropka B, Moores CA, Reber S. Mechanistic basis of temperature adaptation in microtubule dynamics across frog species. Curr Biol 2025; 35:612-628.e6. [PMID: 39798564 DOI: 10.1016/j.cub.2024.12.022] [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: 07/22/2024] [Revised: 10/31/2024] [Accepted: 12/09/2024] [Indexed: 01/15/2025]
Abstract
Cellular processes are remarkably effective across diverse temperature ranges, even with highly conserved proteins. In the context of the microtubule cytoskeleton, which is critically involved in a wide range of cellular activities, this is particularly striking, as tubulin is one of the most conserved proteins while microtubule dynamic instability is highly temperature sensitive. Here, we leverage the diversity of natural tubulin variants from three closely related frog species that live at different temperatures. We determine the microtubule structure across all three species at between 3.0 and 3.6 Å resolution by cryo-electron microscopy and find small differences at the β-tubulin lateral interactions. Using in vitro reconstitution assays and quantitative biochemistry, we show that tubulin's free energy scales inversely with temperature. The observed weakening of lateral contacts and the low apparent activation energy for tubulin incorporation provide an explanation for the overall stability and higher growth rates of microtubules in cold-adapted frog species. This study thus broadens our conceptual framework for understanding microtubule dynamics and provides insights into how conserved cellular processes are tailored to different ecological niches.
Collapse
Affiliation(s)
- Luca Troman
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Ella de Gaulejac
- IRI Life Sciences, Humboldt-Universität zu Berlin, Philippstrasse 13, 10115 Berlin, Germany
| | - Abin Biswas
- Max Planck Institute for Infection Biology, Virchowweg 12, 10117 Berlin, Germany; Marine Biological Laboratory, 7 Mbl St., Woods Hole, MA 02543, USA; Max-Planck-Zentrum für Physik und Medizin, Kussmaulallee 2, 91054 Erlangen, Germany
| | - Jennifer Stiens
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Benno Kuropka
- Freie Universität Berlin, Core Facility BioSupraMol, Thielallee 63, 14195 Berlin, Germany
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK.
| | - Simone Reber
- Max Planck Institute for Infection Biology, Virchowweg 12, 10117 Berlin, Germany; Marine Biological Laboratory, 7 Mbl St., Woods Hole, MA 02543, USA; Berliner Hochschule für Technik, Luxemburger Straße 10, 13353 Berlin, Germany.
| |
Collapse
|
9
|
Montecinos F, Eren E, Watts NR, Sackett DL, Wingfield PT. Structure of blood cell-specific tubulin and demonstration of dimer spacing compaction in a single protofilament. J Biol Chem 2025; 301:108132. [PMID: 39725029 PMCID: PMC11791314 DOI: 10.1016/j.jbc.2024.108132] [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: 10/10/2024] [Revised: 12/12/2024] [Accepted: 12/19/2024] [Indexed: 12/28/2024] Open
Abstract
Microtubule (MT) function plasticity originates from its composition of α- and β-tubulin isotypes and the posttranslational modifications of both subunits. Aspects such as MT assembly dynamics, structure, and anticancer drug binding can be modulated by αβ-tubulin heterogeneity. However, the exact molecular mechanism regulating these aspects is only partially understood. A recent insight is the discovery of expansion and compaction of the MT lattice, which can occur via fine modulation of dimer longitudinal spacing mediated by GTP hydrolysis, taxol binding, protein binding, or isotype composition. Here, we report the first structure of the blood cell-specific α1/β1-tubulin isolated from the marginal band of chicken erythrocytes (ChET) determined to a resolution of 3.2 Å by cryo-EM. We show that ChET rings induced with cryptophycin-52 (Cp-52) are smaller in diameter than HeLa cell line tubulin (HeLaT) rings induced with Cp-52 and composed of the same number of heterodimers. We observe compacted interdimer and intradimer curved protofilament interfaces, characterized by shorter distances between ChET subunits and accompanied by conformational changes in the β-tubulin subunit. The compacted ChET interdimer interface brings more residues near the Cp-52 binding site. We measured the Cp-52 apparent binding affinities of ChET and HeLaT by mass photometry, observing small differences, and detected the intermediates of the ring assembly reaction. These findings demonstrate that compaction/expansion of dimer spacing can occur in a single protofilament context and that the subtle structural differences between tubulin isotypes can modulate tubulin small molecule binding.
Collapse
Affiliation(s)
- Felipe Montecinos
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Elif Eren
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Norman R Watts
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Dan L Sackett
- Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
| | - Paul T Wingfield
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA.
| |
Collapse
|
10
|
Henkin G, Reber S. Microtubules: Decoding tubulin diversity with help from an amoeba. Curr Biol 2025; 35:R69-R71. [PMID: 39837274 DOI: 10.1016/j.cub.2024.11.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2025]
Abstract
Eukaryotic cells typically express multiple tubulin isoforms that form the microtubule cytoskeleton. A new study of the evolution and functional diversification of pools of tubulin isoforms suggests that these proteins are part of a co-evolving network that includes the extensive microtubule interactome.
Collapse
Affiliation(s)
- Gil Henkin
- Max Planck Institute for Infection Biology, Berlin, Germany
| | - Simone Reber
- Max Planck Institute for Infection Biology, Berlin, Germany; Berliner Hochschule für Technik, Berlin, Germany.
| |
Collapse
|
11
|
Mahalingan KK, Grotjahn DA, Li Y, Lander GC, Zehr EA, Roll-Mecak A. Structural basis for α-tubulin-specific and modification state-dependent glutamylation. Nat Chem Biol 2024; 20:1493-1504. [PMID: 38658656 PMCID: PMC11529724 DOI: 10.1038/s41589-024-01599-0] [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: 08/01/2023] [Accepted: 03/06/2024] [Indexed: 04/26/2024]
Abstract
Microtubules have spatiotemporally complex posttranslational modification patterns. Tubulin tyrosine ligase-like (TTLL) enzymes introduce the most prevalent modifications on α-tubulin and β-tubulin. How TTLLs specialize for specific substrate recognition and ultimately modification-pattern generation is largely unknown. TTLL6, a glutamylase implicated in ciliopathies, preferentially modifies tubulin α-tails in microtubules. Cryo-electron microscopy, kinetic analysis and single-molecule biochemistry reveal an unprecedented quadrivalent recognition that ensures simultaneous readout of microtubule geometry and posttranslational modification status. By binding to a β-tubulin subunit, TTLL6 modifies the α-tail of the longitudinally adjacent tubulin dimer. Spanning two tubulin dimers along and across protofilaments (PFs) ensures fidelity of recognition of both the α-tail and the microtubule. Moreover, TTLL6 reads out and is stimulated by glutamylation of the β-tail of the laterally adjacent tubulin dimer, mediating crosstalk between α-tail and β-tail. This positive feedback loop can generate localized microtubule glutamylation patterns. Our work uncovers general principles that generate tubulin chemical and topographic complexity.
Collapse
Affiliation(s)
- Kishore K Mahalingan
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Danielle A Grotjahn
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute La Jolla, La Jolla, CA, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute La Jolla, La Jolla, CA, USA
| | - Elena A Zehr
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
- Biochemistry & Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA.
| |
Collapse
|
12
|
Chen L, Chen X, Kashina A. Amino acid-level differences in alpha tubulin sequences are uniquely required for meiosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.11.617919. [PMID: 39416131 PMCID: PMC11482916 DOI: 10.1101/2024.10.11.617919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
Tubulin is the major structural constituent of the microtubule cytoskeleton. Yeast Schizosaccharomyces pombe contain two α- tubulins genes, nda2 and atb2, that are highly functionally distinct: nda2 deletion is lethal, while lack of atb2 does not interfere with cell viability. The functional determinants underlying this distinction are unknown. Here we used CRISPR-Cas9 gene editing to generate a yeast strain expressing Atb2 amino acid sequence utilizing Nda2 codon usage in the native Nda2 locus. Such Nda2-coded Atb2 (NCA) yeast, unlike Nda2 knockout, were viable and displayed no visible abnormalities in cell morphology or vegetative life cycle. However, these NCA yeast showed strong impairments in sporulation and meiosis, including major meiotic delays and high rates of abnormal chromosome segregation. Our data indicate that the amino acid sequence of Nda2 is uniquely required for normal meiosis, and identify a novel determinant that underlies functional distinction between closely related tubulin isoforms.
Collapse
|
13
|
Wood LM, Moore JK. β3 accelerates microtubule plus end maturation through a divergent lateral interface. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.17.603993. [PMID: 39071388 PMCID: PMC11275713 DOI: 10.1101/2024.07.17.603993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
β-tubulin isotypes exhibit similar sequences but different activities, suggesting that limited sequence divergence is functionally important. We investigated this hypothesis for TUBB3/β3, a β-tubulin linked to aggressive cancers and chemoresistance in humans. We created mutant yeast strains with β-tubulin alleles that mimic variant residues in β3 and find that residues at the lateral interface are sufficient to alter microtubule dynamics and response to microtubule targeting agents. In HeLa cells, β3 overexpression decreases the lifetime of microtubule growth, and this requires residues at the lateral interface. These microtubules exhibit a shorter region of EB binding at the plus end, suggesting faster lattice maturation, and resist stabilization by paclitaxel. Resistance requires the H1-S2 and H2-S3 regions at the lateral interface of β3. Our results identify the mechanistic origins of the unique activity of β3 tubulin and suggest that tubulin isotype expression may tune the rate of lattice maturation at growing microtubule plus ends in cells.
Collapse
Affiliation(s)
- Lisa M Wood
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| |
Collapse
|
14
|
Chen J, Zehr EA, Gruschus JM, Szyk A, Liu Y, Tanner ME, Tjandra N, Roll-Mecak A. Tubulin code eraser CCP5 binds branch glutamates by substrate deformation. Nature 2024; 631:905-912. [PMID: 39020174 DOI: 10.1038/s41586-024-07699-0] [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: 01/20/2024] [Accepted: 06/11/2024] [Indexed: 07/19/2024]
Abstract
Microtubule function is modulated by the tubulin code, diverse posttranslational modifications that are altered dynamically by writer and eraser enzymes1. Glutamylation-the addition of branched (isopeptide-linked) glutamate chains-is the most evolutionarily widespread tubulin modification2. It is introduced by tubulin tyrosine ligase-like enzymes and erased by carboxypeptidases of the cytosolic carboxypeptidase (CCP) family1. Glutamylation homeostasis, achieved through the balance of writers and erasers, is critical for normal cell function3-9, and mutations in CCPs lead to human disease10-13. Here we report cryo-electron microscopy structures of the glutamylation eraser CCP5 in complex with the microtubule, and X-ray structures in complex with transition-state analogues. Combined with NMR analysis, these analyses show that CCP5 deforms the tubulin main chain into a unique turn that enables lock-and-key recognition of the branch glutamate in a cationic pocket that is unique to CCP family proteins. CCP5 binding of the sequences flanking the branch point primarily through peptide backbone atoms enables processing of diverse tubulin isotypes and non-tubulin substrates. Unexpectedly, CCP5 exhibits inefficient processing of an abundant β-tubulin isotype in the brain. This work provides an atomistic view into glutamate branch recognition and resolution, and sheds light on homeostasis of the tubulin glutamylation syntax.
Collapse
Affiliation(s)
- Jiayi Chen
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Elena A Zehr
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - James M Gruschus
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Agnieszka Szyk
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Yanjie Liu
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin E Tanner
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nico Tjandra
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA.
| |
Collapse
|
15
|
Sewell MT, Legué E, Liem KF. Tubb4b is required for multi-ciliogenesis in the mouse. Development 2024; 151:dev201819. [PMID: 38031972 PMCID: PMC10820790 DOI: 10.1242/dev.201819] [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: 05/01/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023]
Abstract
Cilia are microtubule (MT)-based organelles present on the surface of nearly all vertebrate cells. MTs are polymers of α- and β-tubulins that are each encoded by multiple, individual isotype genes. Tubulin isotype composition is thought to influence MT behaviors. Ciliary MTs differ from other MTs in the cell in terms of organization, stability and post-translational modifications. However, little is known about the tubulin isotypes that build ciliary MTs and the functional requirements for tubulin isotypes in cilia have not been examined in vertebrates. Here, we have tested the role of the β-tubulin isotype genes in the mouse that harbor a conserved amino acid motif associated with ciliated organisms. We found that Tubb4b localizes to cilia in multi-ciliated cells (MCCs) specifically. In respiratory and oviduct MCCs, Tubb4b is asymmetrically localized within multi-cilia, indicating that the tubulin isotype composition changes along the length of the ciliary axonemal MTs. Deletion of Tubb4b resulted in striking structural defects within the axonemes of multi-cilia, without affecting primary cilia. These studies show that Tubb4b is essential for the formation of a specific MT-based subcellular organelle and sheds light on the requirements of tubulin isotypes in cilia.
Collapse
Affiliation(s)
- Mycah T. Sewell
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Emilie Legué
- Vertebrate Developmental Biology Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Karel F. Liem
- Vertebrate Developmental Biology Program, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA
| |
Collapse
|
16
|
Nurmagambetova A, Mustyatsa V, Saidova A, Vorobjev I. Morphological and cytoskeleton changes in cells after EMT. Sci Rep 2023; 13:22164. [PMID: 38092761 PMCID: PMC10719275 DOI: 10.1038/s41598-023-48279-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023] Open
Abstract
Epithelial cells undergoing EMT experience significant alterations at transcriptional and morphological levels. However, changes in the cytoskeleton, especially cytoskeleton dynamics are poorly described. Addressing the question we induced EMT in three cell lines (MCF-7, HaCaT and A-549) and analyzed morphological and cytoskeletal changes there using immunostaining and life cell imaging of cells transfected with microtubule and focal adhesion markers. In all studied cell lines, cell area after EMT increased, MCF-7 and A-549 cells became elongated, while HaCaT cells kept the aspect ratio the same. We next analyzed three components of the cytoskeleton: microtubules, stress fibers and focal adhesions. The following changes were observed after EMT in cultured cells: (i) Organization of microtubules becomes more radial; and the growth rate of microtubule plus ends was accelerated; (ii) Actin stress fibers become co-aligned forming the longitudinal cell axis; and (iii) Focal adhesions had decreased area in all cancer cell lines studied and became more numerous in HaCaT cells. We conclude that among dynamic components of the cytoskeleton, the most significant changes during EMT happen in the regulation of microtubules.
Collapse
Affiliation(s)
- Assel Nurmagambetova
- School of Sciences and Humanities, Nazarbayev University, Kabanbay Batyr Avenue, 53, 010000, Astana, Kazakhstan.
- School of Engineering and Digital Sciences, Nazarbayev University, Kabanbay Batyr Avenue, 53, 010000, Astana, Kazakhstan.
| | - Vadim Mustyatsa
- National Laboratory Astana, Nazarbayev University, Kabanbay Batyr Avenue, 53, 010000, Astana, Kazakhstan
| | - Aleena Saidova
- National Laboratory Astana, Nazarbayev University, Kabanbay Batyr Avenue, 53, 010000, Astana, Kazakhstan
| | - Ivan Vorobjev
- School of Sciences and Humanities, Nazarbayev University, Kabanbay Batyr Avenue, 53, 010000, Astana, Kazakhstan.
- National Laboratory Astana, Nazarbayev University, Kabanbay Batyr Avenue, 53, 010000, Astana, Kazakhstan.
| |
Collapse
|
17
|
Abbaali I, Truong D, Day SD, Mushayeed F, Ganesh B, Haro-Ramirez N, Isles J, Nag H, Pham C, Shah P, Tomar I, Manel-Romero C, Morrissette NS. The tubulin database: Linking mutations, modifications, ligands and local interactions. PLoS One 2023; 18:e0295279. [PMID: 38064432 PMCID: PMC10707541 DOI: 10.1371/journal.pone.0295279] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Microtubules are polymeric filaments, constructed of α-β tubulin heterodimers that underlie critical subcellular structures in eukaryotic organisms. Four homologous proteins (γ-, δ-, ε- and ζ-tubulin) additionally contribute to specialized microtubule functions. Although there is an immense volume of publicly available data pertaining to tubulins, it is difficult to assimilate all potentially relevant information across diverse organisms, isotypes, and categories of data. We previously assembled an extensive web-based catalogue of published missense mutations to tubulins with >1,500 entries that each document a specific substitution to a discrete tubulin, the species where the mutation was described and the associated phenotype with hyperlinks to the amino acid sequence and citation(s) for research. This report describes a significant update and expansion of our online resource (TubulinDB.bio.uci.edu) to nearly 18,000 entries. It now encompasses a cross-referenced catalog of post-translational modifications (PTMs) to tubulin drawn from public datasets, primary literature, and predictive algorithms. In addition, tubulin protein structures were used to define local interactions with bound ligands (GTP, GDP and diverse microtubule-targeting agents) and amino acids at the intradimer interface, within the microtubule lattice and with associated proteins. To effectively cross-reference these datasets, we established a universal tubulin numbering system to map entries into a common framework that accommodates specific insertions and deletions to tubulins. Indexing and cross-referencing permitted us to discern previously unappreciated patterns. We describe previously unlinked observations of loss of PTM sites in the context of cancer cells and tubulinopathies. Similarly, we expanded the set of clinical substitutions that may compromise MAP or microtubule-motor interactions by collecting tubulin missense mutations that alter amino acids at the interface with dynein and doublecortin. By expanding the database as a curated resource, we hope to relate model organism data to clinical findings of pathogenic tubulin variants. Ultimately, we aim to aid researchers in hypothesis generation and design of studies to dissect tubulin function.
Collapse
Affiliation(s)
- Izra Abbaali
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Danny Truong
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Shania Deon Day
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Faliha Mushayeed
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Bhargavi Ganesh
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Nancy Haro-Ramirez
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Juliet Isles
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Hindol Nag
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Catherine Pham
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Priya Shah
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Ishaan Tomar
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Carolina Manel-Romero
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Naomi S. Morrissette
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| |
Collapse
|
18
|
Diao L, Zheng W, Zhao Q, Liu M, Fu Z, Zhang X, Bao L, Cong Y. Cryo-EM of α-tubulin isotype-containing microtubules revealed a contracted structure of α4A/β2A microtubules. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1551-1560. [PMID: 37439022 PMCID: PMC10577476 DOI: 10.3724/abbs.2023130] [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: 03/09/2023] [Accepted: 04/14/2023] [Indexed: 07/14/2023] Open
Abstract
Microtubules are hollow α/β-tubulin heterodimeric polymers that play critical roles in cells. In vertebrates, both α- and β-tubulins have multiple isotypes encoded by different genes, which are intrinsic factors in regulating microtubule functions. However, the structures of microtubules composed of different tubulin isotypes, especially α-tubulin isotypes, remain largely unknown. Here, we purify recombinant tubulin heterodimers composed of different mouse α-tubulin isotypes, including α1A, α1C and α4A, with the β-tubulin isotype β2A. We further assemble and determine the cryo-electron microscopy (cryo-EM) structures of α1A/β2A, α1C/β2A, and α4A/β2A microtubules. Our structural analysis demonstrates that α4A/β2A microtubules exhibit longitudinal contraction between tubulin interdimers compared with α1A/β2A and α1C/β2A microtubules. Collectively, our findings reveal that α-tubulin isotype composition can tune microtubule structures, and also provide evidence for the "tubulin code" hypothesis.
Collapse
Affiliation(s)
- Lei Diao
- State Key Laboratory of Cell BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
| | - Wei Zheng
- State Key Laboratory of Molecular BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
| | - Qiaoyu Zhao
- State Key Laboratory of Molecular BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
| | - Mingyi Liu
- State Key Laboratory of Cell BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Zhenglin Fu
- State Key Laboratory of Molecular BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
| | - Xu Zhang
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
- Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai201210China
| | - Lan Bao
- State Key Laboratory of Cell BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Yao Cong
- State Key Laboratory of Molecular BiologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200031China
| |
Collapse
|
19
|
McKenna ED, Sarbanes SL, Cummings SW, Roll-Mecak A. The Tubulin Code, from Molecules to Health and Disease. Annu Rev Cell Dev Biol 2023; 39:331-361. [PMID: 37843925 DOI: 10.1146/annurev-cellbio-030123-032748] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Microtubules are essential dynamic polymers composed of α/β-tubulin heterodimers. They support intracellular trafficking, cell division, cellular motility, and other essential cellular processes. In many species, both α-tubulin and β-tubulin are encoded by multiple genes with distinct expression profiles and functionality. Microtubules are further diversified through abundant posttranslational modifications, which are added and removed by a suite of enzymes to form complex, stereotyped cellular arrays. The genetic and chemical diversity of tubulin constitute a tubulin code that regulates intrinsic microtubule properties and is read by cellular effectors, such as molecular motors and microtubule-associated proteins, to provide spatial and temporal specificity to microtubules in cells. In this review, we synthesize the rapidly expanding tubulin code literature and highlight limitations and opportunities for the field. As complex microtubule arrays underlie essential physiological processes, a better understanding of how cells employ the tubulin code has important implications for human disease ranging from cancer to neurological disorders.
Collapse
Affiliation(s)
- Elizabeth D McKenna
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
| | - Stephanie L Sarbanes
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
| | - Steven W Cummings
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA;
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
| |
Collapse
|
20
|
Abstract
Taxol is a small molecule effector that allosterically locks tubulin into the microtubule lattice. We show here that taxol has different effects on different single-isotype microtubule lattices. Using in vitro reconstitution, we demonstrate that single-isotype α1β4 GDP-tubulin lattices are stabilised and expanded by 10 µM taxol, as reported by accelerated microtubule gliding in kinesin motility assays, whereas single-isotype α1β3 GDP-tubulin lattices are stabilised but not expanded. This isotype-specific action of taxol drives gliding of segmented-isotype GDP-taxol microtubules along convoluted, sinusoidal paths, because their expanded α1β4 segments try to glide faster than their compacted α1β3 segments. In GMPCPP, single-isotype α1β3 and α1β4 lattices both show accelerated gliding, indicating that both can in principle be driven to expand. We therefore propose that taxol-induced lattice expansion requires a higher taxol occupancy than taxol-induced stabilisation, and that higher taxol occupancies are accessible to α1β4 but not α1β3 single-isotype lattices.
Collapse
Affiliation(s)
- Yean Ming Chew
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, CV4 7LA, UK
| | - Robert A Cross
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, CV4 7LA, UK.
| |
Collapse
|
21
|
Nicot S, Gillard G, Impheng H, Joachimiak E, Urbach S, Mochizuki K, Wloga D, Juge F, Rogowski K. A family of carboxypeptidases catalyzing α- and β-tubulin tail processing and deglutamylation. SCIENCE ADVANCES 2023; 9:eadi7838. [PMID: 37703372 PMCID: PMC10499314 DOI: 10.1126/sciadv.adi7838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 08/10/2023] [Indexed: 09/15/2023]
Abstract
Tubulin posttranslational modifications represent an important mechanism involved in the regulation of microtubule functions. The most widespread among them are detyrosination, α∆2-tubulin, and polyglutamylation. Here, we describe a family of tubulin-modifying enzymes composed of two closely related proteins, KIAA0895L and KIAA0895, which have tubulin metallocarboxypeptidase activity and thus were termed TMCP1 and TMCP2, respectively. We show that TMCP1 (also known as MATCAP) acts as α-tubulin detyrosinase that also catalyzes α∆2-tubulin. In contrast, TMCP2 preferentially modifies βI-tubulin by removing three amino acids from its C terminus, generating previously unknown βI∆3 modification. We show that βI∆3-tubulin is mostly found on centrioles and mitotic spindles and in cilia. Moreover, we demonstrate that TMCPs also remove posttranslational polyglutamylation and thus act as tubulin deglutamylases. Together, our study describes the identification and comprehensive biochemical analysis of a previously unknown type of tubulin-modifying enzymes involved in the processing of α- and β-tubulin C-terminal tails and deglutamylation.
Collapse
Affiliation(s)
- Simon Nicot
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Ghislain Gillard
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Hathaichanok Impheng
- Department of Physiology, Faculty of Medical science, Naresuan University, Phitsanulok 65000, Thailand
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Serge Urbach
- Functional Proteomics Platform (FPP), IGF, Université Montpellier, CNRS, INSERM, Montpellier, France
| | - Kazufumi Mochizuki
- Epigenetic Chromatin Regulation team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - François Juge
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| | - Krzysztof Rogowski
- Tubulin Code team, Institute of Human Genetics, Université Montpellier, CNRS, Montpellier, France
| |
Collapse
|
22
|
Marien J, Prévost C, Sacquin-Mora S. It Takes Tau to Tango: Investigating the Fuzzy Interaction between the R2-Repeat Domain and Tubulin C-Terminal Tails. Biochemistry 2023; 62:2492-2502. [PMID: 37499261 DOI: 10.1021/acs.biochem.3c00092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The microtubule-associated protein (MAP) tau plays a key role in the regulation of microtubule assembly and spatial organization. Tau hyperphosphorylation affects its binding on the tubulin surface and has been shown to be involved in several pathologies such as Alzheimer's disease. As the tau binding site on the microtubule lays close to the disordered and highly flexible tubulin C-terminal tails (CTTs), these are likely to impact the tau-tubulin interaction. Since the disordered tubulin CTTs are missing from the available experimental structures, we used homology modeling to build two complete models of tubulin heterotrimers with different isotypes for the β-tubulin subunit (βI/αI/βI and βIII/αI/βIII). We then performed long timescale classical Molecular Dynamics simulations for the tau-R2/tubulin assembly (in systems with and without CTTs) and analyzed the resulting trajectories to obtain a detailed view of the protein interface in the complex and the impact of the CTTs on the stability of this assembly. Additional analyses of the CTT mobility in the presence, or in the absence, of tau also highlight how tau might modulate the CTT activity as hooks that are involved in the recruitment of several MAPs. In particular, we observe a wrapping phenomenon, where the β-tubulin CTTs form a loop over tau-R2, thus stabilizing its interaction with the tubulin surface and simultaneously reducing the CTT availability for interactions with other MAPs.
Collapse
Affiliation(s)
- Jules Marien
- CNRS, UPR 9080, Laboratoire de Biochimie Théorique, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France
- Institut de Biologie Physico-Chimique-Fondation Edmond de Rotschild, PSL Research University, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Chantal Prévost
- CNRS, UPR 9080, Laboratoire de Biochimie Théorique, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France
- Institut de Biologie Physico-Chimique-Fondation Edmond de Rotschild, PSL Research University, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Sophie Sacquin-Mora
- CNRS, UPR 9080, Laboratoire de Biochimie Théorique, Université de Paris, 13 rue Pierre et Marie Curie, 75005 Paris, France
- Institut de Biologie Physico-Chimique-Fondation Edmond de Rotschild, PSL Research University, 13 rue Pierre et Marie Curie, 75005 Paris, France
| |
Collapse
|
23
|
Puri D, Barry BJ, Engle EC. TUBB3 and KIF21A in neurodevelopment and disease. Front Neurosci 2023; 17:1226181. [PMID: 37600020 PMCID: PMC10436312 DOI: 10.3389/fnins.2023.1226181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Neuronal migration and axon growth and guidance require precise control of microtubule dynamics and microtubule-based cargo transport. TUBB3 encodes the neuronal-specific β-tubulin isotype III, TUBB3, a component of neuronal microtubules expressed throughout the life of central and peripheral neurons. Human pathogenic TUBB3 missense variants result in altered TUBB3 function and cause errors either in the growth and guidance of cranial and, to a lesser extent, central axons, or in cortical neuronal migration and organization, and rarely in both. Moreover, human pathogenic missense variants in KIF21A, which encodes an anterograde kinesin motor protein that interacts directly with microtubules, alter KIF21A function and cause errors in cranial axon growth and guidance that can phenocopy TUBB3 variants. Here, we review reported TUBB3 and KIF21A variants, resulting phenotypes, and corresponding functional studies of both wildtype and mutant proteins. We summarize the evidence that, in vitro and in mouse models, loss-of-function and missense variants can alter microtubule dynamics and microtubule-kinesin interactions. Lastly, we highlight additional studies that might contribute to our understanding of the relationship between specific tubulin isotypes and specific kinesin motor proteins in health and disease.
Collapse
Affiliation(s)
- Dharmendra Puri
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA, United States
- Howard Hughes Medical Institute, Chevy Chase, MD, United States
| | - Brenda J. Barry
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA, United States
- Howard Hughes Medical Institute, Chevy Chase, MD, United States
| | - Elizabeth C. Engle
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA, United States
- Howard Hughes Medical Institute, Chevy Chase, MD, United States
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
24
|
Ramesh Babu PB. Prediction of anti-microtubular target proteins of tubulins and their interacting proteins using Gene Ontology tools. J Genet Eng Biotechnol 2023; 21:78. [PMID: 37466845 DOI: 10.1186/s43141-023-00531-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 07/01/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND Tubulins are highly conserved globular proteins involved in stabilization of cellular cytoskeletal microtubules during cell cycle. Different isoforms of tubulins are differentially expressed in various cell types, and their protein-protein interactions (PPIs) analysis will help in identifying the anti-microtubular drug targets for cancer and neurological disorders. Numerous web-based PPIs analysis methods are recently being used, and in this paper, I used Gene Ontology (GO) tools, e.g., Stringbase, ProteomeHD, GeneMANIA, and ShinyGO, to identify anti-microtubular target proteins by selecting strongly interacting proteins of tubulins. RESULTS I used 6 different human tubulin isoforms (two from each of α-, β-, and γ-tubulin) and found several thousands of node-to-node protein interactions (highest 4956 in GeneMANIA) and selected top 10 strongly interacting node-to-node interactions with highest score, which included 7 tubulin family protein and 6 non-tubulin family proteins (total 13). Functional enrichment analysis indicated a significant role of these 13 proteins in nucleation, polymerization or depolymerization of microtubules, membrane tethering and docking, dorsal root ganglion development, mitotic cycle, and cytoskeletal organization. I found γ-tubulins (TUBG1, TUBGCP4, and TUBBGCP6) were known to contribute majorly for tubulin-associated functions followed by α-tubulin (TUBA1A) and β-tubulins (TUBB AND TUBB3). In PPI results, I found several non-tubular proteins interacting with tubulins, and six of them (HTT, DPYSL2, SKI, UNC5C, NINL, and DDX41) were found closely associated with their functions. CONCLUSIONS Increasing number of regulatory proteins and subpopulation of tubulin proteins are being reported with poor understanding in their association with microtubule assembly and disassembly. The functional enrichment analysis of tubulin isoforms using recent GO tools resulted in identification of γ-tubulins playing a key role in microtubule functions and observed non-tubulin family of proteins HTT, DPYSL2, SKI, UNC5C, NINL, and DDX41 strongly interacting functional proteins of tubulins. The present study yields a promising model system using GO tools to narrow down tubulin-associated proteins as a drug target in cancer, Alzheimer's, neurological disorders, etc.
Collapse
Affiliation(s)
- Polani B Ramesh Babu
- Center for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Bharath Institute of Science and Technology, Selaiyur, Tambaram, Chennai, India.
| |
Collapse
|
25
|
Ebberink E, Fernandes S, Hatzopoulos G, Agashe N, Chang PH, Guidotti N, Reichart TM, Reymond L, Velluz MC, Schneider F, Pourroy C, Janke C, Gönczy P, Fierz B, Aumeier C. Tubulin engineering by semi-synthesis reveals that polyglutamylation directs detyrosination. Nat Chem 2023:10.1038/s41557-023-01228-8. [PMID: 37386282 DOI: 10.1038/s41557-023-01228-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 04/28/2023] [Indexed: 07/01/2023]
Abstract
Microtubules, a critical component of the cytoskeleton, carry post-translational modifications (PTMs) that are important for the regulation of key cellular processes. Long-lived microtubules, in neurons particularly, exhibit both detyrosination of α-tubulin and polyglutamylation. Dysregulation of these PTMs can result in developmental defects and neurodegeneration. Owing to a lack of tools to study the regulation and function of these PTMs, the mechanisms that govern such PTM patterns are not well understood. Here we produce fully functional tubulin carrying precisely defined PTMs within its C-terminal tail. We ligate synthetic α-tubulin tails-which are site-specifically glutamylated-to recombinant human tubulin heterodimers by applying a sortase- and intein-mediated tandem transamidation strategy. Using microtubules reconstituted with these designer tubulins, we find that α-tubulin polyglutamylation promotes its detyrosination by enhancing the activity of the tubulin tyrosine carboxypeptidase vasohibin/small vasohibin-binding protein in a manner dependent on the length of polyglutamyl chains. We also find that modulating polyglutamylation levels in cells results in corresponding changes in detyrosination, corroborating the link between the detyrosination cycle to polyglutamylation.
Collapse
Affiliation(s)
- Eduard Ebberink
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland
| | - Simon Fernandes
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Georgios Hatzopoulos
- Swiss Institute for Experimental Cancer Research (ISREC), EPFL, Lausanne, Switzerland
| | - Ninad Agashe
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland
| | - Po-Han Chang
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland
| | - Nora Guidotti
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland
| | - Timothy M Reichart
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland
| | - Luc Reymond
- Biomolecular Screening Facility, EPFL, Lausanne, Switzerland
| | | | - Fabian Schneider
- Swiss Institute for Experimental Cancer Research (ISREC), EPFL, Lausanne, Switzerland
| | - Cédric Pourroy
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland
| | - Carsten Janke
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), EPFL, Lausanne, Switzerland
| | - Beat Fierz
- École Polytechnique Fédérale de Lausanne (EPFL), SB ISIC LCBM, Lausanne, Switzerland.
| | - Charlotte Aumeier
- Department of Biochemistry, University of Geneva, Geneva, Switzerland.
- National Center for Competence in Research Chemical Biology, University of Geneva, Geneva, Switzerland.
| |
Collapse
|
26
|
Fu G, Yan S, Khoo CJ, Chao VC, Liu Z, Mukhi M, Hervas R, Li XD, Ti SC. Integrated regulation of tubulin tyrosination and microtubule stability by human α-tubulin isotypes. Cell Rep 2023; 42:112653. [PMID: 37379209 DOI: 10.1016/j.celrep.2023.112653] [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: 07/28/2022] [Revised: 05/03/2023] [Accepted: 05/31/2023] [Indexed: 06/30/2023] Open
Abstract
Tubulin isotypes are critical for the functions of cellular microtubules, which exhibit different stability and harbor various post-translational modifications. However, how tubulin isotypes determine the activities of regulators for microtubule stability and modifications remains unknown. Here, we show that human α4A-tubulin, a conserved genetically detyrosinated α-tubulin isotype, is a poor substrate for enzymatic tyrosination. To examine the stability of microtubules reconstituted with defined tubulin compositions, we develop a strategy to site-specifically label recombinant human tubulin for single-molecule TIRF microscopy-based in vitro assays. The incorporation of α4A-tubulin into the microtubule lattice stabilizes the polymers from passive and MCAK-stimulated depolymerization. Further characterization reveals that the compositions of α-tubulin isotypes and tyrosination/detyrosination states allow graded control for the microtubule binding and the depolymerization activities of MCAK. Together, our results uncover the tubulin isotype-dependent enzyme activity for an integrated regulation of α-tubulin tyrosination/detyrosination states and microtubule stability, two well-correlated features of cellular microtubules.
Collapse
Affiliation(s)
- Guoling Fu
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Shan Yan
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Chen Jing Khoo
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Victor C Chao
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Zheng Liu
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, China
| | - Mayur Mukhi
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Rubén Hervas
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Xiang David Li
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, China
| | - Shih-Chieh Ti
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, China.
| |
Collapse
|
27
|
Chen J, Roll-Mecak A. Glutamylation is a negative regulator of microtubule growth. Mol Biol Cell 2023; 34:ar70. [PMID: 37074962 PMCID: PMC10295482 DOI: 10.1091/mbc.e23-01-0030] [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: 01/30/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/20/2023] Open
Abstract
Microtubules are noncovalent polymers built from αβ-tubulin dimers. The disordered C-terminal tubulin tails are functionalized with multiple glutamate chains of variable lengths added and removed by tubulin tyrosine ligases (TTLLs) and carboxypeptidases (CCPs). Glutamylation is abundant on stable microtubule arrays such as in axonemes and axons, and its dysregulation leads to human pathologies. Despite this, the effects of glutamylation on intrinsic microtubule dynamics are unclear. Here we generate tubulin with short and long glutamate chains and show that glutamylation slows the rate of microtubule growth and increases catastrophes as a function of glutamylation levels. This implies that the higher stability of glutamylated microtubules in cells is due to effectors. Interestingly, EB1 is minimally affected by glutamylation and thus can report on the growth rates of both unmodified and glutamylated microtubules. Finally, we show that glutamate removal by CCP1 and 5 is synergistic and occurs preferentially on soluble tubulin, unlike TTLL enzymes that prefer microtubules. This substrate preference establishes an asymmetry whereby once the microtubule depolymerizes, the released tubulin is reset to a less-modified state, while polymerized tubulin accumulates the glutamylation mark. Our work shows that a modification on the disordered tubulin tails can directly affect microtubule dynamics and furthers our understanding of the mechanistic underpinnings of the tubulin code.
Collapse
Affiliation(s)
- Jiayi Chen
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, and
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, and
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
| |
Collapse
|
28
|
Naren P, Samim KS, Tryphena KP, Vora LK, Srivastava S, Singh SB, Khatri DK. Microtubule acetylation dyshomeostasis in Parkinson's disease. Transl Neurodegener 2023; 12:20. [PMID: 37150812 PMCID: PMC10165769 DOI: 10.1186/s40035-023-00354-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 04/06/2023] [Indexed: 05/09/2023] Open
Abstract
The inter-neuronal communication occurring in extensively branched neuronal cells is achieved primarily through the microtubule (MT)-mediated axonal transport system. This mechanistically regulated system delivers cargos (proteins, mRNAs and organelles such as mitochondria) back and forth from the soma to the synapse. Motor proteins like kinesins and dynein mechanistically regulate polarized anterograde (from the soma to the synapse) and retrograde (from the synapse to the soma) commute of the cargos, respectively. Proficient axonal transport of such cargos is achieved by altering the microtubule stability via post-translational modifications (PTMs) of α- and β-tubulin heterodimers, core components constructing the MTs. Occurring within the lumen of MTs, K40 acetylation of α-tubulin via α-tubulin acetyl transferase and its subsequent deacetylation by HDAC6 and SIRT2 are widely scrutinized PTMs that make the MTs highly flexible, which in turn promotes their lifespan. The movement of various motor proteins, including kinesin-1 (responsible for axonal mitochondrial commute), is enhanced by this PTM, and dyshomeostasis of neuronal MT acetylation has been observed in a variety of neurodegenerative conditions, including Alzheimer's disease and Parkinson's disease (PD). PD is the second most common neurodegenerative condition and is closely associated with impaired MT dynamics and deregulated tubulin acetylation levels. Although the relationship between status of MT acetylation and progression of PD pathogenesis has become a chicken-and-egg question, our review aims to provide insights into the MT-mediated axonal commute of mitochondria and dyshomeostasis of MT acetylation in PD. The enzymatic regulators of MT acetylation along with their synthetic modulators have also been briefly explored. Moving towards a tubulin-based therapy that enhances MT acetylation could serve as a disease-modifying treatment in neurological conditions that lack it.
Collapse
Affiliation(s)
- Padmashri Naren
- Molecular and Cellular Neuroscience Lab, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Khan Sabiya Samim
- Molecular and Cellular Neuroscience Lab, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Kamatham Pushpa Tryphena
- Molecular and Cellular Neuroscience Lab, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Lalitkumar K Vora
- School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, UK.
| | - Saurabh Srivastava
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India.
| | - Shashi Bala Singh
- Molecular and Cellular Neuroscience Lab, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India
| | - Dharmendra Kumar Khatri
- Molecular and Cellular Neuroscience Lab, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, Telangana, 500037, India.
| |
Collapse
|
29
|
Zocchi R, Compagnucci C, Bertini E, Sferra A. Deciphering the Tubulin Language: Molecular Determinants and Readout Mechanisms of the Tubulin Code in Neurons. Int J Mol Sci 2023; 24:ijms24032781. [PMID: 36769099 PMCID: PMC9917122 DOI: 10.3390/ijms24032781] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/17/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Microtubules (MTs) are dynamic components of the cell cytoskeleton involved in several cellular functions, such as structural support, migration and intracellular trafficking. Despite their high similarity, MTs have functional heterogeneity that is generated by the incorporation into the MT lattice of different tubulin gene products and by their post-translational modifications (PTMs). Such regulations, besides modulating the tubulin composition of MTs, create on their surface a "biochemical code" that is translated, through the action of protein effectors, into specific MT-based functions. This code, known as "tubulin code", plays an important role in neuronal cells, whose highly specialized morphologies and activities depend on the correct functioning of the MT cytoskeleton and on its interplay with a myriad of MT-interacting proteins. In recent years, a growing number of mutations in genes encoding for tubulins, MT-interacting proteins and enzymes that post-translationally modify MTs, which are the main players of the tubulin code, have been linked to neurodegenerative processes or abnormalities in neural migration, differentiation and connectivity. Nevertheless, the exact molecular mechanisms through which the cell writes and, downstream, MT-interacting proteins decipher the tubulin code are still largely uncharted. The purpose of this review is to describe the molecular determinants and the readout mechanisms of the tubulin code, and briefly elucidate how they coordinate MT behavior during critical neuronal events, such as neuron migration, maturation and axonal transport.
Collapse
Affiliation(s)
- Riccardo Zocchi
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
| | - Claudia Compagnucci
- Molecular Genetics and Functional Genomics, Bambino Gesù Children’s Research Hospital, IRCCS, 00146 Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
- Correspondence: (E.B.); or (A.S.); Tel.: +39-06-6859-2104 (E.B. & A.S.)
| | - Antonella Sferra
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy
- Correspondence: (E.B.); or (A.S.); Tel.: +39-06-6859-2104 (E.B. & A.S.)
| |
Collapse
|
30
|
Pinho-Correia LM, Prokop A. Maintaining essential microtubule bundles in meter-long axons: a role for local tubulin biogenesis? Brain Res Bull 2023; 193:131-145. [PMID: 36535305 DOI: 10.1016/j.brainresbull.2022.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Axons are the narrow, up-to-meter long cellular processes of neurons that form the biological cables wiring our nervous system. Most axons must survive for an organism's lifetime, i.e. up to a century in humans. Axonal maintenance depends on loose bundles of microtubules that run without interruption all along axons. The continued turn-over and the extension of microtubule bundles during developmental, regenerative or plastic growth requires the availability of α/β-tubulin heterodimers up to a meter away from the cell body. The underlying regulation in axons is poorly understood and hardly features in past and contemporary research. Here we discuss potential mechanisms, particularly focussing on the possibility of local tubulin biogenesis in axons. Current knowledge might suggest that local translation of tubulin takes place in axons, but far less is known about the post-translational machinery of tubulin biogenesis involving three chaperone complexes: prefoldin, CCT and TBC. We discuss functional understanding of these chaperones from a range of model organisms including yeast, plants, flies and mice, and explain what is known from human diseases. Microtubules across species depend on these chaperones, and they are clearly required in the nervous system. However, most chaperones display a high degree of functional pleiotropy, partly through independent functions of individual subunits outside their complexes, thus posing a challenge to experimental studies. Notably, we found hardly any studies that investigate their presence and function particularly in axons, thus highlighting an important gap in our understanding of axon biology and pathology.
Collapse
Affiliation(s)
- Liliana Maria Pinho-Correia
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, Manchester, UK
| | - Andreas Prokop
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, Manchester, UK.
| |
Collapse
|
31
|
Ahmed MB, Islam SU, Alghamdi AAA, Kamran M, Ahsan H, Lee YS. Phytochemicals as Chemo-Preventive Agents and Signaling Molecule Modulators: Current Role in Cancer Therapeutics and Inflammation. Int J Mol Sci 2022; 23:15765. [PMID: 36555406 PMCID: PMC9779495 DOI: 10.3390/ijms232415765] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/02/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
Cancer is one of the deadliest non communicable diseases. Numerous anticancer medications have been developed to target the molecular pathways driving cancer. However, there has been no discernible increase in the overall survival rate in cancer patients. Therefore, innovative chemo-preventive techniques and agents are required to supplement standard cancer treatments and boost their efficacy. Fruits and vegetables should be tapped into as a source of compounds that can serve as cancer therapy. Phytochemicals play an important role as sources of new medication in cancer treatment. Some synthetic and natural chemicals are effective for cancer chemoprevention, i.e., the use of exogenous medicine to inhibit or impede tumor development. They help regulate molecular pathways linked to the development and spread of cancer. They can enhance antioxidant status, inactivating carcinogens, suppressing proliferation, inducing cell cycle arrest and death, and regulating the immune system. While focusing on four main categories of plant-based anticancer agents, i.e., epipodophyllotoxin, camptothecin derivatives, taxane diterpenoids, and vinca alkaloids and their mode of action, we review the anticancer effects of phytochemicals, like quercetin, curcumin, piperine, epigallocatechin gallate (EGCG), and gingerol. We examine the different signaling pathways associated with cancer and how inflammation as a key mechanism is linked to cancer growth.
Collapse
Affiliation(s)
- Muhammad Bilal Ahmed
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Salman Ul Islam
- Department of Pharmacy, Cecos University, Peshawar, Street 1, Sector F 5 Phase 6 Hayatabad, Peshawar 25000, Pakistan
| | | | - Muhammad Kamran
- School of Molecular Sciences, The University of Western Australia, M310, 35 Stirling Hwy, Perth, WA 6009, Australia
| | - Haseeb Ahsan
- Department of Pharmacy, Faculty of Life and Environmental Sciences, University of Peshawar, Peshawar 25120, Pakistan
| | - Young Sup Lee
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| |
Collapse
|
32
|
Qian H, Beltran AS. Mesoscience in cell biology and cancer research. CANCER INNOVATION 2022; 1:271-284. [PMID: 38089088 PMCID: PMC10686186 DOI: 10.1002/cai2.33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 10/15/2024]
Abstract
Mesoscale characteristics and their interdimensional correlation are the focus of contemporary interdisciplinary research. Mesoscience is a discipline that has the potential to radically update the existing knowledge structure, which differs from the conventional unit-scale and system-scale research models, revealing a previously untouchable area for scientific research. Integrative biology research aims to dissect the complex problems of life systems by conducting comprehensive research and integrating various disciplines from all biological levels of the living organism. However, the mesoscientific issues between different research units are neglected and challenging. Mesoscale research in biology requires the integration of research theories and methods from other disciplines (mathematics, physics, engineering, and even visual imaging) to investigate theoretical and frontier questions of biological processes through experiments, computations, and modeling. We reviewed integrative paradigms and methods for the biological mesoscale problems (focusing on oncology research) and prospected the potential of their multiple dimensions and upcoming challenges. We expect to establish an interactive and collaborative theoretical platform for further expanding the depth and width of our understanding on the nature of biology.
Collapse
Affiliation(s)
- Haili Qian
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Adriana Sujey Beltran
- Department of Pharmacology, University of North Carolina at Chapel HillChapel HillNCUSA
| |
Collapse
|
33
|
Kletter T, Biswas A, Reber S. Engineering metaphase spindles: Construction site and building blocks. Curr Opin Cell Biol 2022; 79:102143. [PMID: 36436307 DOI: 10.1016/j.ceb.2022.102143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/08/2022] [Accepted: 10/21/2022] [Indexed: 11/27/2022]
Abstract
In an active, crowded cytoplasm, eukaryotic cells construct metaphase spindles from conserved building blocks to segregate chromosomes. Yet, spindles execute their function in a stunning variety of cell shapes and sizes across orders of magnitude. Thus, the current challenge is to understand how unique mesoscale spindle characteristics emerge from the interaction of molecular collectives. Key components of these collectives are tubulin dimers, which polymerise into microtubules. Despite all conservation, tubulin is a genetically and biochemically complex protein family, and we only begin to uncover how tubulin diversity affects microtubule dynamics and thus spindle assembly. Moreover, it is increasingly appreciated that spindles are dynamically intertwined with the cytoplasm that itself exhibits cell-type specific emergent properties with yet mostly unexplored consequences for spindle construction. Therefore, on our way toward a quantitative picture of spindle function, we need to understand molecular behaviour of the building blocks and connect it to the entire cellular context.
Collapse
Affiliation(s)
- Tobias Kletter
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Abin Biswas
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; Max-Planck-Institute for the Science of Light, 91058 Erlangen, Germany
| | - Simone Reber
- IRI Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; University of Applied Sciences Berlin, 13353 Berlin, Germany.
| |
Collapse
|
34
|
Szczesna E, Zehr EA, Cummings SW, Szyk A, Mahalingan KK, Li Y, Roll-Mecak A. Combinatorial and antagonistic effects of tubulin glutamylation and glycylation on katanin microtubule severing. Dev Cell 2022; 57:2497-2513.e6. [PMID: 36347241 PMCID: PMC9665884 DOI: 10.1016/j.devcel.2022.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/17/2022] [Accepted: 10/11/2022] [Indexed: 11/09/2022]
Abstract
Microtubules have spatiotemporally complex posttranslational modification patterns. How cells interpret this tubulin modification code is largely unknown. We show that C. elegans katanin, a microtubule severing AAA ATPase mutated in microcephaly and critical for cell division, axonal elongation, and cilia biogenesis, responds precisely, differentially, and combinatorially to three chemically distinct tubulin modifications-glycylation, glutamylation, and tyrosination-but is insensitive to acetylation. Glutamylation and glycylation are antagonistic rheostats with glycylation protecting microtubules from severing. Katanin exhibits graded and divergent responses to glutamylation on the α- and β-tubulin tails, and these act combinatorially. The katanin hexamer central pore constrains the polyglutamate chain patterns on β-tails recognized productively. Elements distal to the katanin AAA core sense α-tubulin tyrosination, and detyrosination downregulates severing. The multivalent microtubule recognition that enables katanin to read multiple tubulin modification inputs explains in vivo observations and illustrates how effectors can integrate tubulin code signals to produce diverse functional outcomes.
Collapse
Affiliation(s)
- Ewa Szczesna
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Elena A Zehr
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Steven W Cummings
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Agnieszka Szyk
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Kishore K Mahalingan
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Yan Li
- Proteomic Core Facility, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA; Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, Bethesda, MD 20892, USA.
| |
Collapse
|
35
|
Hoff KJ, Neumann AJ, Moore JK. The molecular biology of tubulinopathies: Understanding the impact of variants on tubulin structure and microtubule regulation. Front Cell Neurosci 2022; 16:1023267. [PMID: 36406756 PMCID: PMC9666403 DOI: 10.3389/fncel.2022.1023267] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/30/2022] [Indexed: 11/24/2022] Open
Abstract
Heterozygous, missense mutations in both α- and β-tubulin genes have been linked to an array of neurodevelopment disorders, commonly referred to as "tubulinopathies." To date, tubulinopathy mutations have been identified in three β-tubulin isotypes and one α-tubulin isotype. These mutations occur throughout the different genetic domains and protein structures of these tubulin isotypes, and the field is working to address how this molecular-level diversity results in different cellular and tissue-level pathologies. Studies from many groups have focused on elucidating the consequences of individual mutations; however, the field lacks comprehensive models for the molecular etiology of different types of tubulinopathies, presenting a major gap in diagnosis and treatment. This review highlights recent advances in understanding tubulin structural dynamics, the roles microtubule-associated proteins (MAPs) play in microtubule regulation, and how these are inextricably linked. We emphasize the value of investigating interactions between tubulin structures, microtubules, and MAPs to understand and predict the impact of tubulinopathy mutations at the cell and tissue levels. Microtubule regulation is multifaceted and provides a complex set of controls for generating a functional cytoskeleton at the right place and right time during neurodevelopment. Understanding how tubulinopathy mutations disrupt distinct subsets of those controls, and how that ultimately disrupts neurodevelopment, will be important for establishing mechanistic themes among tubulinopathies that may lead to insights in other neurodevelopment disorders and normal neurodevelopment.
Collapse
Affiliation(s)
| | | | - Jeffrey K. Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| |
Collapse
|
36
|
Radwitz J, Hausrat TJ, Heisler FF, Janiesch PC, Pechmann Y, Rübhausen M, Kneussel M. Tubb3 expression levels are sensitive to neuronal activity changes and determine microtubule growth and kinesin-mediated transport. Cell Mol Life Sci 2022; 79:575. [DOI: 10.1007/s00018-022-04607-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 11/03/2022]
Abstract
AbstractMicrotubules are dynamic polymers of α/β-tubulin. They regulate cell structure, cell division, cell migration, and intracellular transport. However, functional contributions of individual tubulin isotypes are incompletely understood. The neuron-specific β-tubulin Tubb3 displays highest expression around early postnatal periods characterized by exuberant synaptogenesis. Although Tubb3 mutations are associated with neuronal disease, including abnormal inhibitory transmission and seizure activity in patients, molecular consequences of altered Tubb3 levels are largely unknown. Likewise, it is unclear whether neuronal activity triggers Tubb3 expression changes in neurons. In this study, we initially asked whether chemical protocols to induce long-term potentiation (cLTP) affect microtubule growth and the expression of individual tubulin isotypes. We found that growing microtubules and Tubb3 expression are sensitive to changes in neuronal activity and asked for consequences of Tubb3 downregulation in neurons. Our data revealed that reduced Tubb3 levels accelerated microtubule growth in axons and dendrites. Remarkably, Tubb3 knockdown induced a specific upregulation of Tubb4 gene expression, without changing other tubulin isotypes. We further found that Tubb3 downregulation reduces tubulin polyglutamylation, increases KIF5C motility and boosts the transport of its synaptic cargo N-Cadherin, which is known to regulate synaptogenesis and long-term potentiation. Due to the large number of tubulin isotypes, we developed and applied a computational model based on a Monte Carlo simulation to understand consequences of tubulin expression changes in silico. Together, our data suggest a feedback mechanism with neuronal activity regulating tubulin expression and consequently microtubule dynamics underlying the delivery of synaptic cargoes.
Collapse
|
37
|
Disruption of tubulin-alpha4a polyglutamylation prevents aggregation of hyper-phosphorylated tau and microglia activation in mice. Nat Commun 2022; 13:4192. [PMID: 35858909 PMCID: PMC9300677 DOI: 10.1038/s41467-022-31776-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/30/2022] [Indexed: 11/14/2022] Open
Abstract
Dissociation of hyper-phosphorylated Tau from neuronal microtubules and its pathological aggregates, are hallmarks in the etiology of tauopathies. The Tau-microtubule interface is subject to polyglutamylation, a reversible posttranslational modification, increasing negative charge at tubulin C-terminal tails. Here, we asked whether tubulin polyglutamylation may contribute to Tau pathology in vivo. Since polyglutamylases modify various proteins other than tubulin, we generated a knock-in mouse carrying gene mutations to abolish Tuba4a polyglutamylation in a substrate-specific manner. We found that Tuba4a lacking C-terminal polyglutamylation prevents the binding of Tau and GSK3 kinase to neuronal microtubules, thereby strongly reducing phospho-Tau levels. Notably, crossbreeding of the Tuba4a knock-in mouse with the hTau tauopathy model, expressing a human Tau transgene, reversed hyper-phosphorylation and oligomerization of Tau and normalized microglia activation in brain. Our data highlight tubulin polyglutamylation as a potential therapeutic strategy in fighting tauopathies. Pathologic oligomerization of hyper-phosphorylated Tau is a hallmark of tauopathies. Here the authors show that the loss of tubulin a4 polyglutamylation reverses tau hyperphosphorylation, oligomerization and microglia activation in a tauopathy mouse.
Collapse
|
38
|
Costa AC, Sousa MM. The Role of Spastin in Axon Biology. Front Cell Dev Biol 2022; 10:934522. [PMID: 35865632 PMCID: PMC9294387 DOI: 10.3389/fcell.2022.934522] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/07/2022] [Indexed: 12/05/2022] Open
Abstract
Neurons are highly polarized cells with elaborate shapes that allow them to perform their function. In neurons, microtubule organization—length, density, and dynamics—are essential for the establishment of polarity, growth, and transport. A mounting body of evidence shows that modulation of the microtubule cytoskeleton by microtubule-associated proteins fine tunes key aspects of neuronal cell biology. In this respect, microtubule severing enzymes—spastin, katanin and fidgetin—a group of microtubule-associated proteins that bind to and generate internal breaks in the microtubule lattice, are emerging as key modulators of the microtubule cytoskeleton in different model systems. In this review, we provide an integrative view on the latest research demonstrating the key role of spastin in neurons, specifically in the context of axonal cell biology. We focus on the function of spastin in the regulation of microtubule organization, and axonal transport, that underlie its importance in the intricate control of axon growth, branching and regeneration.
Collapse
Affiliation(s)
- Ana Catarina Costa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
| | - Monica Mendes Sousa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
| |
Collapse
|
39
|
Bera A, Gupta ML. Microtubules in Microorganisms: How Tubulin Isotypes Contribute to Diverse Cytoskeletal Functions. Front Cell Dev Biol 2022; 10:913809. [PMID: 35865635 PMCID: PMC9294176 DOI: 10.3389/fcell.2022.913809] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/15/2022] [Indexed: 11/19/2022] Open
Abstract
The cellular functions of the microtubule (MT) cytoskeleton range from relatively simple to amazingly complex. Assembled from tubulin, a heterodimeric protein with α- and β-tubulin subunits, microtubules are long, hollow cylindrical filaments with inherent polarity. They are intrinsically dynamic polymers that utilize GTP binding by tubulin, and subsequent hydrolysis, to drive spontaneous assembly and disassembly. Early studies indicated that cellular MTs are composed of multiple variants, or isotypes, of α- and β-tubulins, and that these multi-isotype polymers are further diversified by a range of posttranslational modifications (PTMs) to tubulin. These findings support the multi-tubulin hypothesis whereby individual, or combinations of tubulin isotypes possess unique properties needed to support diverse MT structures and/or cellular processes. Beginning 40 years ago researchers have sought to address this hypothesis, and the role of tubulin isotypes, by exploiting experimentally accessible, genetically tractable and functionally conserved model systems. Among these systems, important insights have been gained from eukaryotic microbial models. In this review, we illustrate how using microorganisms yielded among the earliest evidence that tubulin isotypes harbor distinct properties, as well as recent insights as to how they facilitate specific cellular processes. Ongoing and future research in microorganisms will likely continue to reveal basic mechanisms for how tubulin isotypes facilitate MT functions, along with valuable perspectives on how they mediate the range of conserved and diverse processes observed across eukaryotic microbes.
Collapse
|
40
|
Chun Fang G, Kaiwei D, Lingkong Z, Xuwei T. Diaphragmatic paralysis in a neonate with circumferential skin creases Kunze type. Mol Genet Genomic Med 2022; 10:e2003. [PMID: 35747986 PMCID: PMC9482402 DOI: 10.1002/mgg3.2003] [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: 12/25/2021] [Revised: 05/05/2022] [Accepted: 06/08/2022] [Indexed: 11/07/2022] Open
Abstract
Background A range of clinical features have been confirmed with heterozygous mutations in Beta Tubulin (TUBB), including skin creases, facial deformities, abnormal cerebral structures, and intellectual disability, and were defined as Circumferential Skin Creases Kunze type (CSC‐KT). Methods Clinical information was obtained retrospectively on a neonate hospitalized in the Neonatal Intensive Care Unit, Wuhan Children’s Hospital. Genomic DNA was extracted from circulating leukocytes of the proband according to standard procedures. Results The neonate presented dyspnea resulting from diaphragmatic paralysis, accompanied by other typical features of CSC‐KT. Additionally, exome sequencing confirmed a new variant (NM_178,014. 4: c. 1114 A > G) in TUBB. We also summarized features described in previous cases, thus representing phenotype extension of CSC‐KT. Conclusion Our report is the youngest confirmed case, which could extend the current phenotype of CSC‐KT as well as the clinical diagnostic approach.
Collapse
Affiliation(s)
- Gao Chun Fang
- Department of Neonatology, Wuhan Children's Hospital of Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Ding Kaiwei
- Department of Neonatology, Wuhan Children's Hospital of Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Zeng Lingkong
- Department of Neonatology, Wuhan Children's Hospital of Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Tao Xuwei
- Department of Neonatology, Wuhan Children's Hospital of Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| |
Collapse
|
41
|
Gasic I. Regulation of Tubulin Gene Expression: From Isotype Identity to Functional Specialization. Front Cell Dev Biol 2022; 10:898076. [PMID: 35721507 PMCID: PMC9204600 DOI: 10.3389/fcell.2022.898076] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/11/2022] [Indexed: 12/14/2022] Open
Abstract
Genomes of higher eukaryotes encode a large tubulin gene superfamily consisting of at least six α and six β-tubulin isotypes. While some α and β-tubulin isotypes are ubiquitously expressed, others are cell-type specific. The subset of α and β-tubulins that is expressed in a given cell type is defined transcriptionally. But the precise mechanisms of how cells choose which α and β isotypes to express and at what level remain poorly understood. Differential expression of tubulin isotypes is particularly prominent during development and in specialized cells, suggesting that some isotypes are better suited for certain cell type-specific functions. Recent studies begin to rationalize this phenomenon, uncovering important differences in tubulin isotype behavior and their impact on the biomechanical properties of the microtubule cytoskeleton. I summarize our understanding of the regulation of tubulin isotype expression, focusing on the role of these complex regulatory pathways in building a customized microtubule network best suited for cellular needs.
Collapse
Affiliation(s)
- Ivana Gasic
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| |
Collapse
|
42
|
Andreu-Carbó M, Fernandes S, Aumeier C. Two-color in vitro assay to visualize and quantify microtubule shaft dynamics. STAR Protoc 2022; 3:101320. [PMID: 35496777 PMCID: PMC9043774 DOI: 10.1016/j.xpro.2022.101320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Microtubules are dynamic polymers where tubulin exchanges not only at the ends but also all along the microtubule shaft. In vitro reconstitutions are a vital approach to study microtubule tip dynamics, while direct observation of shaft dynamics is challenging. Here, we describe a dual-color in vitro assay to visualize microtubule shaft dynamics using purified, labeled bovine brain tubulin. With this assay, we can quantitatively address how proteins or small molecules impact the dynamics at the microtubule shaft. For complete details on the use and execution of this protocol, please refer to Andreu-Carbó et al. (2022).
Collapse
Affiliation(s)
| | - Simon Fernandes
- Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland
| | - Charlotte Aumeier
- Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland
- National Center for Competence in Research Chemical Biology, University of Geneva, 1211 Geneva, Switzerland
| |
Collapse
|
43
|
Multiple roles for the cytoskeleton in ALS. Exp Neurol 2022; 355:114143. [PMID: 35714755 PMCID: PMC10163623 DOI: 10.1016/j.expneurol.2022.114143] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 06/05/2022] [Accepted: 06/08/2022] [Indexed: 11/20/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by more than sixty genes identified through classic linkage analysis and new sequencing methods. Yet no clear mechanism of onset, cure, or effective treatment is known. Popular discourse classifies the proteins encoded from ALS-related genes into four disrupted processes: proteostasis, mitochondrial function and ROS, nucleic acid regulation, and cytoskeletal dynamics. Surprisingly, the mechanisms detailing the contribution of the neuronal cytoskeletal in ALS are the least explored, despite involvement in these cell processes. Eight genes directly regulate properties of cytoskeleton function and are essential for the health and survival of motor neurons, including: TUBA4A, SPAST, KIF5A, DCTN1, NF, PRPH, ALS2, and PFN1. Here we review the properties and studies exploring the contribution of each of these genes to ALS.
Collapse
|
44
|
Maliekal TT, Dharmapal D, Sengupta S. Tubulin Isotypes: Emerging Roles in Defining Cancer Stem Cell Niche. Front Immunol 2022; 13:876278. [PMID: 35693789 PMCID: PMC9179084 DOI: 10.3389/fimmu.2022.876278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
Although the role of microtubule dynamics in cancer progression is well-established, the roles of tubulin isotypes, their cargos and their specific function in the induction and sustenance of cancer stem cells (CSCs) were poorly explored. But emerging reports urge to focus on the transport function of tubulin isotypes in defining orchestrated expression of functionally critical molecules in establishing a stem cell niche, which is the key for CSC regulation. In this review, we summarize the role of specific tubulin isotypes in the transport of functional molecules that regulate metabolic reprogramming, which leads to the induction of CSCs and immune evasion. Recently, the surface expression of GLUT1 and GRP78 as well as voltage-dependent anion channel (VDAC) permeability, regulated by specific isotypes of β-tubulins have been shown to impart CSC properties to cancer cells, by implementing a metabolic reprogramming. Moreover, βIVb tubulin is shown to be critical in modulating EphrinB1signaling to sustain CSCs in oral carcinoma. These tubulin-interacting molecules, Ephrins, GLUT1 and GRP78, are also important regulators of immune evasion, by evoking PD-L1 mediated T-cell suppression. Thus, the recent advances in the field implicate that tubulins play a role in the controlled transport of molecules involved in CSC niche. The indication of tubulin isotypes in the regulation of CSCs offers a strategy to specifically target those tubulin isotypes to eliminate CSCs, rather than the general inhibition of microtubules, which usually leads to therapy resistance.
Collapse
Affiliation(s)
- Tessy Thomas Maliekal
- Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
- Regional Centre for Biotechnology, Faridabad, India
- *Correspondence: Tessy Thomas Maliekal, ; Suparna Sengupta,
| | - Dhrishya Dharmapal
- Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
- University of Kerala, Department of Biotechnology, Thiruvananthapuram, India
| | - Suparna Sengupta
- Cancer Research, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
- Regional Centre for Biotechnology, Faridabad, India
- University of Kerala, Department of Biotechnology, Thiruvananthapuram, India
- *Correspondence: Tessy Thomas Maliekal, ; Suparna Sengupta,
| |
Collapse
|
45
|
Abstract
The microtubule cytoskeleton is assembled from the α- and β-tubulin subunits of the canonical tubulin heterodimer, which polymerizes into microtubules, and a small number of other family members, such as γ-tubulin, with specialized functions. Overall, microtubule function involves the collective action of multiple α- and β-tubulin isotypes. However, despite 40 years of awareness that most eukaryotes harbor multiple tubulin isotypes, their role in the microtubule cytoskeleton has remained relatively unclear. Various model organisms offer specific advantages for gaining insight into the role of tubulin isotypes. Whereas simple unicellular organisms such as yeast provide experimental tractability that can facilitate deeper access to mechanistic details, more complex organisms, such as the fruit fly, nematode and mouse, can be used to discern potential specialized functions of tissue- and structure-specific isotypes. Here, we review the role of α- and β-tubulin isotypes in microtubule function and in associated tubulinopathies with an emphasis on the advances gained using model organisms. Overall, we argue that studying tubulin isotypes in a range of organisms can reveal the fundamental mechanisms by which they mediate microtubule function. It will also provide valuable perspectives on how these mechanisms underlie the functional and biological diversity of the cytoskeleton.
Collapse
Affiliation(s)
- Emmanuel T Nsamba
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Mohan L Gupta
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
| |
Collapse
|
46
|
Ti SC. Reconstituting Microtubules: A Decades-Long Effort From Building Block Identification to the Generation of Recombinant α/β-Tubulin. Front Cell Dev Biol 2022; 10:861648. [PMID: 35573669 PMCID: PMC9096264 DOI: 10.3389/fcell.2022.861648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Microtubules are cytoskeletal filaments underlying the morphology and functions of all eukaryotic cells. In higher eukaryotes, the basic building blocks of these non-covalent polymers, ɑ- and β-tubulins, are encoded by expanded tubulin family genes (i.e., isotypes) at distinct loci in the genome. While ɑ/β-tubulin heterodimers have been isolated and examined for more than 50 years, how tubulin isotypes contribute to the microtubule organization and functions that support diverse cellular architectures remains a fundamental question. To address this knowledge gap, in vitro reconstitution of microtubules with purified ɑ/β-tubulin proteins has been employed for biochemical and biophysical characterization. These in vitro assays have provided mechanistic insights into the regulation of microtubule dynamics, stability, and interactions with other associated proteins. Here we survey the evolving strategies of generating purified ɑ/β-tubulin heterodimers and highlight the advances in tubulin protein biochemistry that shed light on the roles of tubulin isotypes in determining microtubule structures and properties.
Collapse
|
47
|
Cleary JM, Kim T, Cook ASI, McCormick LA, Hancock WO, Rice LM. Measurements and simulations of microtubule growth imply strong longitudinal interactions and reveal a role for GDP on the elongating end. eLife 2022; 11:75931. [PMID: 35420545 PMCID: PMC9064298 DOI: 10.7554/elife.75931] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Microtubule polymerization dynamics result from the biochemical interactions of αβ-tubulin with the polymer end, but a quantitative understanding has been challenging to establish. We used interference reflection microscopy to make improved measurements of microtubule growth rates and growth fluctuations in the presence and absence of GTP hydrolysis. In the absence of GTP hydrolysis, microtubules grew steadily with very low fluctuations. These data were best described by a computational model implementing slow assembly kinetics, such that the rate of microtubule elongation is primarily limited by the rate of αβ-tubulin associations. With GTPase present, microtubules displayed substantially larger growth fluctuations than expected based on the no GTPase measurements. Our modeling showed that these larger fluctuations occurred because exposure of GDP-tubulin on the microtubule end transiently 'poisoned' growth, yielding a wider range of growth rates compared to GTP only conditions. Our experiments and modeling point to slow association kinetics (strong longitudinal interactions), such that drugs and regulatory proteins that alter microtubule dynamics could do so by modulating either the association or dissociation rate of tubulin from the microtubule tip. By causing slower growth, exposure of GDP tubulin at the growing microtubule end may be an important early event determining catastrophe.
Collapse
Affiliation(s)
- Joseph M Cleary
- Department of Biomedical Engineering, Pennsylvania State University, University Park, United States
| | - Tae Kim
- Departments of Biophysics and Biochemistry, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Annan S I Cook
- Department of Biomedical Engineering, Pennsylvania State University, University Park, United States
| | - Lauren A McCormick
- Departments of Biophysics and Biochemistry, The University of Texas Southwestern Medical Center, Dallas, United States
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, United States
| | - Luke M Rice
- Departments of Biophysics and Biochemistry, The University of Texas Southwestern Medical Center, Dallas, United States
| |
Collapse
|
48
|
Xie Y, Wu Z, Sun L, Zhou L, Xiao L, Wang H, Wang G. Swimming exercise reverses chronic unpredictable mild stress-induced depression-like behaviors and alleviates neuroinflammation and collapsing response mediator protein-2-mediated neuroplasticity injury in adult male mice. Neuroreport 2022; 33:272-282. [PMID: 35383656 PMCID: PMC9354724 DOI: 10.1097/wnr.0000000000001779] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/10/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Impaired neuroplasticity and neuroinflammation are vital in the mechanisms of depression. Exercise alleviates depressive symptoms and ameliorates body functions. Swimming is one of the most common exercises; however, whether swimming alters depressive behaviors and the underlying mechanism has not been fully elucidated. METHODS Male C57/BL6J mice were exposed to chronic unpredictable mild stress (CUMS) for 6 weeks and then were subjected to a 5-week swimming program. Behavioral test, including sucrose preference test (SPT), open field test (OFT), elevated plus-maze (EPM) test, and tail suspension test (TST), was conducted to assess the anxiety-like and depressive behaviors. Western blotting and immunofluorescence staining were carried out after tissue collection. RESULTS This study showed that CUMS-induced depressive behaviors but swimming exercise increased sucrose preference in SPT, increased time and velocity in the center on OFT, decreased time in the closed arm, increased time in the open arm in EPM, and decreased immobility time in TST. We further found swimming exercise increased hippocampal collapsing response mediator protein-2 (CRMP2) expression and decreased p-CRMP2 expression in CUMS mice. CUMS inhibited the levels of α-tubulin and CRMP2, and the expression of ionized calcium-binding adaptor molecule 1 and caspase-1, whereas swimming reversed them in CUMS-exercised mice. CONCLUSION Our study confirmed that swimming exercise reverses CUMS-induced depressive behaviors, and neuroinflammation and CRMP2-mediated neuroplasticity are involved, which may provide a new insight into the antidepression therapy of exercise.
Collapse
Affiliation(s)
- Yumeng Xie
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| | - Zuotian Wu
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| | - Limin Sun
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| | - Lin Zhou
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| | - Ling Xiao
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| | - Huiling Wang
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| | - Gaohua Wang
- Department of Psychiatry, Renmin Hospital of Wuhan University, Hubei, PR China
| |
Collapse
|
49
|
Guan Y, Chen X, Zhao B, Shi Y, Han F. What Happened in the Hippocampal Axon in a Rat Model of Posttraumatic Stress Disorder. Cell Mol Neurobiol 2022; 42:723-737. [PMID: 32930942 PMCID: PMC11441271 DOI: 10.1007/s10571-020-00960-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/03/2020] [Indexed: 01/01/2023]
Abstract
Studies from postmortem and animal models have revealed altered synapse morphology and function in the brain of posttraumatic stress disorder (PTSD). And the effects of PTSD on dendrites and spines have been reported, however, the effection on axon include microtubule (MT) and synaptic vesicles of presynaptic elements remains unknown. Hippocampus is involved in abnormal memory in PTSD. In the present study, we used the single prolonged stress (SPS) model to mimic PTSD. Quantitative real-time polymerase chain reaction (RT-qPCR) and high-throughput sequencing (GSE153081) were utilized to analyze differentially expressed genes (DEGs) in the hippocampus of control and SPS rats. Immunofluorescence and western blotting were performed to examine change in axon-related proteins. Synaptic function was evaluated by measuring miniature excitatory postsynaptic currents (mEPSCs). RNA-sequencing analysis revealed 230 significantly DEGs between the control and SPS groups. Gene Ontology analysis revealed upregulation in axonemal assembly, MT formation, or movement, but downregulation in axon initial segment and synaptic vesicles fusion in the hippocampus of SPS rats. Increased expression in tau, β-tubulin MAP1B, KIF9, CCDC40, DNAH12 and decreased expression in p-tau, stathmin suggested SPS induced axon extension. Increased protein expression in VAMP, STX1A, Munc18-1 and decreased expression in synaptotagmin-1 suggested SPS induced more SNARE complex formation but decreased ability in synaptic vesicle fusion to presynaptic active zone membrane in the hippocampus of SPS rats. Further, low mEPSC frequency in SPS rats indicated dysfunction in presynaptic membrane. These results suggest that axon extension and synaptic vesicles fusion abnormality are involved in dysfunction of PTSD.
Collapse
Affiliation(s)
- Yadi Guan
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical University, China Medical University, Shenyang, 110122, China
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, 110022, Liaoning Province, China
| | - Xinzhao Chen
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical University, China Medical University, Shenyang, 110122, China
| | - Beiying Zhao
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical University, China Medical University, Shenyang, 110122, China
| | - Yuxiu Shi
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical University, China Medical University, Shenyang, 110122, China
| | - Fang Han
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical University, China Medical University, Shenyang, 110122, China.
| |
Collapse
|
50
|
Atherton J, Stouffer M, Francis F, Moores CA. Visualising the cytoskeletal machinery in neuronal growth cones using cryo-electron tomography. J Cell Sci 2022; 135:274968. [PMID: 35383828 PMCID: PMC9016625 DOI: 10.1242/jcs.259234] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/02/2022] [Indexed: 12/12/2022] Open
Abstract
Neurons extend axons to form the complex circuitry of the mature brain. This depends on the coordinated response and continuous remodelling of the microtubule and F-actin networks in the axonal growth cone. Growth cone architecture remains poorly understood at nanoscales. We therefore investigated mouse hippocampal neuron growth cones using cryo-electron tomography to directly visualise their three-dimensional subcellular architecture with molecular detail. Our data showed that the hexagonal arrays of actin bundles that form filopodia penetrate and terminate deep within the growth cone interior. We directly observed the modulation of these and other growth cone actin bundles by alteration of individual F-actin helical structures. Microtubules with blunt, slightly flared or gently curved ends predominated in the growth cone, frequently contained lumenal particles and exhibited lattice defects. Investigation of the effect of absence of doublecortin, a neurodevelopmental cytoskeleton regulator, on growth cone cytoskeleton showed no major anomalies in overall growth cone organisation or in F-actin subpopulations. However, our data suggested that microtubules sustained more structural defects, highlighting the importance of microtubule integrity during growth cone migration. Summary: Cryo-electron tomographic reconstruction of neuronal growth cone subdomains reveals distinctive F-actin and microtubule cytoskeleton architectures and modulation at molecular detail.
Collapse
Affiliation(s)
- Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King's College, London SE1 1YR, UK.,Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
| | - Melissa Stouffer
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France.,Institute of Science and Technology Austria, Am campus 1, 3400 Klosterneuberg, Austria
| | - Fiona Francis
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
| |
Collapse
|