1
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Xie P. Modeling study of kinesin-13 MCAK microtubule depolymerase. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2024:10.1007/s00249-024-01718-8. [PMID: 39093405 DOI: 10.1007/s00249-024-01718-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/18/2024] [Indexed: 08/04/2024]
Abstract
Mitotic centromere-associated kinesin (MCAK) motor protein is a typical member of the kinesin-13 family, which can depolymerize microtubules from both plus and minus ends. A critical issue for the MCAK motor is how it performs the depolymerase activity. To address the issue, the pathway of the MCAK motor moving on microtubules and depolymerizing the microtubules is presented here. On the basis of the pathway, the dynamics of both the wild-type and mutant MCAK motors is studied theoretically, which include the full-length MCAK, the full-length MCAK with mutations in the α4-helix of the motor domain, the mutant full-length MCAK with a neutralized neck, the monomeric MCAK and the mutant monomeric MCAK with a neutralized neck. The studies show that a single dimeric MCAK motor can depolymerize microtubules in a processive manner, with either one tubulin or two tubulins being removed per times. The theoretical results are in agreement with the available experimental data. Moreover, predicted results are provided.
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Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
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2
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Bensel BM, Previs SB, Bookwalter C, Trybus KM, Walcott S, Warshaw DM. Kinesin-1-transported liposomes prefer to go straight in 3D microtubule intersections by a mechanism shared by other molecular motors. Proc Natl Acad Sci U S A 2024; 121:e2407330121. [PMID: 38980901 PMCID: PMC11260143 DOI: 10.1073/pnas.2407330121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Accepted: 05/24/2024] [Indexed: 07/11/2024] Open
Abstract
Kinesin-1 ensembles maneuver vesicular cargoes through the three-dimensional (3D) intracellular microtubule (MT) network. To define how such cargoes navigate MT intersections, we first determined how many kinesins from an ensemble on a lipid-based cargo simultaneously engage a MT, and then determined the directional outcomes (straight, turn, terminate) for liposome cargoes at perpendicular MT intersections. Run lengths of 350-nm diameter liposomes decorated with up to 20, constitutively active, truncated kinesin-1 KIF5B (K543) were longer than single motor transported cargo, suggesting multiple motor engagement. However, detachment forces of lipid-coated beads with ~20 kinesins, measured using an optical trap, showed no more than three simultaneously engaged motors, with a single engaged kinesin predominating, indicating anticooperative MT binding. At two-dimensional (2D) and 3D in vitro MT intersections, liposomes frequently paused (~2 s), suggesting kinesins simultaneously bind both MTs and engage in a tug-of-war. Liposomes showed no directional outcome bias in 2D (1.1 straight:turn ratio) but preferentially went straight (1.8 straight:turn ratio) in 3D intersections. To explain these data, we developed a mathematical model of liposome transport incorporating the known mechanochemistry of kinesins, which diffuse on the liposome surface, and have stiff tails in both compression and extension that impact how motors engage the intersecting MTs. Our model predicts the ~3 engaged motor limit observed in the optical trap and the bias toward going straight in 3D intersections. The striking similarity of these results to our previous study of liposome transport by myosin Va suggests a "universal" mechanism by which cargoes navigate 3D intersections.
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Affiliation(s)
- Brandon M. Bensel
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
| | - Samantha Beck Previs
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
| | - Carol Bookwalter
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
| | - Kathleen M. Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
| | - Sam Walcott
- Department of Mathematical Sciences, and Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA01609
| | - David M. Warshaw
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT05405
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3
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Nasrin SR, Yamashita T, Ikeguchi M, Torisawa T, Oiwa K, Sada K, Kakugo A. Tensile Stress on Microtubules Facilitates Dynein-Driven Cargo Transport. NANO LETTERS 2024. [PMID: 38916205 DOI: 10.1021/acs.nanolett.4c00209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Mechanical stress significantly affects the physiological functions of cells, including tissue homeostasis, cytoskeletal alterations, and intracellular transport. As a major cytoskeletal component, microtubules respond to mechanical stimulation by altering their alignment and polymerization dynamics. Previously, we reported that microtubules may modulate cargo transport by one of the microtubule-associated motor proteins, dynein, under compressive mechanical stress. Despite the critical role of tensile stress in many biological functions, how tensile stress on microtubules regulates cargo transport is yet to be unveiled. The present study demonstrates that the low-level tensile stress-induced microtubule deformation facilitates dynein-driven transport. We validate our experimental findings using all-atom molecular dynamics simulation. Our study may provide important implications for developing new therapies for diseases that involve impaired intracellular transport.
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Affiliation(s)
- Syeda Rubaiya Nasrin
- Graduate School of Science, Department of Physics and Astronomy, Kyoto University, Kyoto, 606-8152, Japan
| | - Takefumi Yamashita
- Department of Physical University, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa-ku, Tokyo, 142-8501, Japan
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, 153-8904, Japan
| | - Mitsunori Ikeguchi
- Graduate School of Medical Life Science, Yokohama City University, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Takayuki Torisawa
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, 411-8540, Japan
- Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, 411-8540, Japan
| | - Kazuhiro Oiwa
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Hyogo 651-2492, Japan
| | - Kazuki Sada
- Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Akira Kakugo
- Graduate School of Science, Department of Physics and Astronomy, Kyoto University, Kyoto, 606-8152, Japan
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4
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Shen Y, Ori-McKenney KM. Microtubule-associated protein MAP7 promotes tubulin posttranslational modifications and cargo transport to enable osmotic adaptation. Dev Cell 2024; 59:1553-1570.e7. [PMID: 38574732 PMCID: PMC11187767 DOI: 10.1016/j.devcel.2024.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/11/2023] [Accepted: 03/12/2024] [Indexed: 04/06/2024]
Abstract
Cells remodel their cytoskeletal networks to adapt to their environment. Here, we analyze the mechanisms utilized by the cell to tailor its microtubule landscape in response to changes in osmolarity that alter macromolecular crowding. By integrating live-cell imaging, ex vivo enzymatic assays, and in vitro reconstitution, we probe the impact of cytoplasmic density on microtubule-associated proteins (MAPs) and tubulin posttranslational modifications (PTMs). We find that human epithelial cells respond to fluctuations in cytoplasmic density by modulating microtubule acetylation, detyrosination, or MAP7 association without differentially affecting polyglutamylation, tyrosination, or MAP4 association. These MAP-PTM combinations alter intracellular cargo transport, enabling the cell to respond to osmotic challenges. We further dissect the molecular mechanisms governing tubulin PTM specification and find that MAP7 promotes acetylation and inhibits detyrosination. Our data identify MAP7 in modulating the tubulin code, resulting in microtubule cytoskeleton remodeling and alteration of intracellular transport as an integrated mechanism of cellular adaptation.
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Affiliation(s)
- Yusheng Shen
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Kassandra M Ori-McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
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5
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Liang X, Agulto R, Eichel K, Taylor CA, Paat VA, Deng H, Ori-McKenney K, Shen K. CRMP/UNC-33 maintains neuronal microtubule arrays by promoting individual microtubule rescue. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596870. [PMID: 38854103 PMCID: PMC11160792 DOI: 10.1101/2024.05.31.596870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Microtubules (MTs) are intrinsically dynamic polymers. In neurons, staggered individual microtubules form stable, polarized acentrosomal MT arrays spanning the axon and dendrite to support long-distance intracellular transport. How the stability and polarity of these arrays are maintained when individual MTs remain highly dynamic is still an open question. Here we visualize MT arrays in vivo in C. elegans neurons with single microtubule resolution. We find that the CRMP family homolog, UNC-33, is essential for the stability and polarity of MT arrays in neurites. In unc-33 mutants, MTs exhibit dramatically reduced rescue after catastrophe, develop gaps in coverage, and lose their polarity, leading to trafficking defects. UNC-33 is stably anchored on the cortical cytoskeleton and forms patch-like structures along the dendritic shaft. These discrete and stable UNC-33 patches concentrate free tubulins and correlate with MT rescue sites. In vitro , purified UNC-33 preferentially associates with MT tips and increases MT rescue frequency. Together, we propose that UNC-33 functions as a microtubule-associated protein (MAP) to promote individual MT rescue locally. Through this activity, UNC-33 prevents the loss of individual MTs, thereby maintaining the coverage and polarity of MT arrays throughout the lifetime of neurons.
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6
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Adams JM, Sawe C, Rogers S, Reid J, Dasari R, Engelke MF. Characterization of the disease-causing mechanism of KIF3B mutations from ciliopathy patients. Front Mol Biosci 2024; 11:1327963. [PMID: 38665936 PMCID: PMC11043552 DOI: 10.3389/fmolb.2024.1327963] [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: 10/25/2023] [Accepted: 03/04/2024] [Indexed: 04/28/2024] Open
Abstract
The heterodimeric kinesin-2 motor (KIF3A/KIF3B with accessory protein KAP3) drives intraflagellar transport, essential for ciliogenesis and ciliary function. Three point mutations in the KIF3B subunit have recently been linked to disease in humans (E250Q and L523P) and Bengal cats (A334T) (Cogné et al., Am. J. Hum. Genet., 2020, 106, 893-904). Patients display retinal atrophy and, in some cases, other ciliopathy phenotypes. However, the molecular mechanism leading to disease is currently unknown. Here, we used Kif3a -/- ;Kif3b -/- (knockout) 3T3 cells, which cannot make cilia, to characterize these mutations. While reexpression of KIF3B(E250Q) and KIF3B(L523P) did not rescue ciliogenesis, reexpression of wildtype or KIF3B(A334T) restored ciliogenesis to wildtype levels. Fluorescent tagging revealed that the E250Q mutant decorated microtubules and thus is a rigor mutation. The L523P mutation, in the alpha-helical stalk domain, surprisingly did not affect formation of the KIF3A/KIF3B/KAP3 complex but instead impaired motility along microtubules. Lastly, expression of the A334T motor was reduced in comparison to all other motors, and this motor displayed an impaired ability to disperse the Golgi complex when artificially linked to this high-load cargo. In summary, this work uses cell-based assays to elucidate the molecular effects of disease-causing mutations in the KIF3B subunit on the kinesin-2 holoenzyme.
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Affiliation(s)
| | | | | | | | | | - Martin F. Engelke
- School of Biological Sciences, Cell Physiology, Illinois State University, Normal, IL, United States
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7
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Luchniak A, Roy PS, Kumar A, Schneider IC, Gelfand VI, Jernigan RL, Gupta ML. Tubulin CFEOM mutations both inhibit or activate kinesin motor activity. Mol Biol Cell 2024; 35:ar32. [PMID: 38170592 PMCID: PMC10916880 DOI: 10.1091/mbc.e23-01-0020] [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: 01/23/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Kinesin-mediated transport along microtubules is critical for axon development and health. Mutations in the kinesin Kif21a, or the microtubule subunit β-tubulin, inhibit axon growth and/or maintenance resulting in the eye-movement disorder congenital fibrosis of the extraocular muscles (CFEOM). While most examined CFEOM-causing β-tubulin mutations inhibit kinesin-microtubule interactions, Kif21a mutations activate the motor protein. These contrasting observations have led to opposed models of inhibited or hyperactive Kif21a in CFEOM. We show that, contrary to other CFEOM-causing β-tubulin mutations, R380C enhances kinesin activity. Expression of β-tubulin-R380C increases kinesin-mediated peroxisome transport in S2 cells. The binding frequency, percent motile engagements, run length and plus-end dwell time of Kif21a are also elevated on β-tubulin-R380C compared with wildtype microtubules in vitro. This conserved effect persists across tubulins from multiple species and kinesins from different families. The enhanced activity is independent of tail-mediated kinesin autoinhibition and thus utilizes a mechanism distinct from CFEOM-causing Kif21a mutations. Using molecular dynamics, we visualize how β-tubulin-R380C allosterically alters critical structural elements within the kinesin motor domain, suggesting a basis for the enhanced motility. These findings resolve the disparate models and confirm that inhibited or increased kinesin activity can both contribute to CFEOM. They also demonstrate the microtubule's role in regulating kinesins and highlight the importance of balanced transport for cellular and organismal health.
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Affiliation(s)
- Anna Luchniak
- Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011
| | - Pallavi Sinha Roy
- Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011
| | - Ambuj Kumar
- Bioinformatics and Computational Biology Program, Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Ian C. Schneider
- Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011
| | - Vladimir I. Gelfand
- Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611
| | - Robert L. Jernigan
- Bioinformatics and Computational Biology Program, Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Mohan L. Gupta
- Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011
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8
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Ori-McKenney KM, McKenney RJ. Tau oligomerization on microtubules in health and disease. Cytoskeleton (Hoboken) 2024; 81:35-40. [PMID: 37747123 PMCID: PMC10841430 DOI: 10.1002/cm.21785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023]
Affiliation(s)
- Kassandra M Ori-McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, California, USA
| | - Richard J McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, California, USA
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9
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Volkov VA, Akhmanova A. Phase separation on microtubules: from droplet formation to cellular function? Trends Cell Biol 2024; 34:18-30. [PMID: 37453878 DOI: 10.1016/j.tcb.2023.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Microtubules are cytoskeletal polymers that play important roles in numerous cellular processes, ranging from the control of cell shape and polarity to cell division and intracellular transport. Many of these roles rely on proteins that bind to microtubule ends and shafts, carry intrinsically disordered regions, and form complex multivalent interaction networks. A flurry of recent studies demonstrated that these properties allow diverse microtubule-binding proteins to undergo liquid-liquid phase separation (LLPS) in vitro. It is proposed that LLPS could potentially affect multiple microtubule-related processes, such as microtubule nucleation, control of microtubule dynamics and organization, and microtubule-based transport. Here, we discuss the evidence in favor and against the occurrence of LLPS and its functional significance for microtubule-based processes in cells.
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Affiliation(s)
- Vladimir A Volkov
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, E1 4NS, UK.
| | - Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.
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10
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Bensel BM, Previs S, Bookwalter C, Trybus KM, Walcott S, Warshaw DM. "Spatial Relationships Matter: Kinesin-1 Molecular Motors Transport Liposome Cargo Through 3D Microtubule Intersections In Vitro". BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569616. [PMID: 38076816 PMCID: PMC10705568 DOI: 10.1101/2023.12.01.569616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Kinesin-1 ensembles maneuver vesicular cargoes through intersections in the 3-dimensional (3D) intracellular microtubule (MT) network. To characterize directional outcomes (straight, turn, terminate) at MT intersections, we challenge 350 nm fluid-like liposomes transported by ~10 constitutively active, truncated kinesin-1 KIF5B (K543) with perpendicular 2-dimensional (2D) and 3D intersections in vitro. Liposomes frequently pause at 2D and 3D intersections (~2s), suggesting that motor teams can simultaneously engage each MT and undergo a tug-of-war. Once resolved, the directional outcomes at 2D MT intersections have a straight to turn ratio of 1.1; whereas at 3D MT intersections, liposomes more frequently go straight (straight to turn ratio of 1.8), highlighting that spatial relationships at intersections bias directional outcomes. Using 3D super-resolution microscopy (STORM), we define the gap between intersecting MTs and the liposome azimuthal approach angle heading into the intersection. We develop an in silico model in which kinesin-1 motors diffuse on the liposome surface, simultaneously engage the intersecting MTs, generate forces and detach from MTs governed by the motors' mechanochemical cycle, and undergo a tug-of-war with the winning team determining the directional outcome in 3D. The model predicts that 1-3 motors typically engage the MT, consistent with optical trapping measurements. Modeled liposomes also predominantly go straight through 3D intersections over a range of intersection gaps and liposome approach angles, even when obstructed by the crossing MT. Our observations and modeling offer mechanistic insights into how cells might tune the MT cytoskeleton, cargo, and motors to modulate cargo transport.
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Affiliation(s)
- Brandon M Bensel
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT 05405
| | - Samantha Previs
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT 05405
| | - Carol Bookwalter
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT 05405
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT 05405
| | - Sam Walcott
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA 01609
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of Medicine, Burlington, VT 05405
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11
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Lawrence EJ, Chatterjee S, Zanic M. More is different: Reconstituting complexity in microtubule regulation. J Biol Chem 2023; 299:105398. [PMID: 37898404 PMCID: PMC10694663 DOI: 10.1016/j.jbc.2023.105398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 10/13/2023] [Accepted: 10/18/2023] [Indexed: 10/30/2023] Open
Abstract
Microtubules are dynamic cytoskeletal filaments that undergo stochastic switching between phases of polymerization and depolymerization-a behavior known as dynamic instability. Many important cellular processes, including cell motility, chromosome segregation, and intracellular transport, require complex spatiotemporal regulation of microtubule dynamics. This coordinated regulation is achieved through the interactions of numerous microtubule-associated proteins (MAPs) with microtubule ends and lattices. Here, we review the recent advances in our understanding of microtubule regulation, focusing on results arising from biochemical in vitro reconstitution approaches using purified multiprotein ensembles. We discuss how the combinatory effects of MAPs affect both the dynamics of individual microtubule ends, as well as the stability and turnover of the microtubule lattice. In addition, we highlight new results demonstrating the roles of protein condensates in microtubule regulation. Our overall intent is to showcase how lessons learned from reconstitution approaches help unravel the regulatory mechanisms at play in complex cellular environments.
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Affiliation(s)
- Elizabeth J Lawrence
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Saptarshi Chatterjee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Marija Zanic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA.
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12
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Romeiro Motta M, Biswas S, Schaedel L. Beyond uniformity: Exploring the heterogeneous and dynamic nature of the microtubule lattice. Eur J Cell Biol 2023; 102:151370. [PMID: 37922811 DOI: 10.1016/j.ejcb.2023.151370] [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: 08/14/2023] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023] Open
Abstract
A fair amount of research on microtubules since their discovery in 1963 has focused on their dynamic tips. In contrast, the microtubule lattice was long believed to be highly regular and static, and consequently received far less attention. Yet, as it turned out, the microtubule lattice is neither as regular, nor as static as previously believed: structural studies uncovered the remarkable wealth of different conformations the lattice can accommodate. In the last decade, the microtubule lattice was shown to be labile and to spontaneously undergo renovation, a phenomenon that is intimately linked to structural defects and was called "microtubule self-repair". Following this breakthrough discovery, further recent research provided a deeper understanding of the lattice self-repair mechanism, which we review here. Instrumental to these discoveries were in vitro microtubule reconstitution assays, in which microtubules are grown from the minimal components required for their dynamics. In this review, we propose a shift from the term "lattice self-repair" to "lattice dynamics", since this phenomenon is an inherent property of microtubules and can happen without microtubule damage. We focus on how in vitro microtubule reconstitution assays helped us learn (1) which types of structural variations microtubules display, (2) how these structural variations influence lattice dynamics and microtubule damage caused by mechanical stress, (3) how lattice dynamics impact tip dynamics, and (4) how microtubule-associated proteins (MAPs) can play a role in structuring the lattice. Finally, we discuss the unanswered questions about lattice dynamics and how technical advances will help us tackle these questions.
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Affiliation(s)
- Mariana Romeiro Motta
- Department of Physics, Center for Biophysics, Campus A2 4, Saarland University, 66123 Saarbrücken, Germany; Laboratoire Reproduction et Développement des Plantes, Université de Lyon, École normale supérieure de Lyon, Lyon 69364, France
| | - Subham Biswas
- Department of Physics, Center for Biophysics, Campus A2 4, Saarland University, 66123 Saarbrücken, Germany
| | - Laura Schaedel
- Department of Physics, Center for Biophysics, Campus A2 4, Saarland University, 66123 Saarbrücken, Germany.
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13
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Hoshino A, Clemente V, Shetty M, Castle B, Odde D, Bazzaro M. The microtubule-severing protein UNC-45A preferentially binds to curved microtubules and counteracts the microtubule-straightening effects of Taxol. J Biol Chem 2023; 299:105355. [PMID: 37858676 PMCID: PMC10654038 DOI: 10.1016/j.jbc.2023.105355] [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: 02/22/2023] [Revised: 09/28/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023] Open
Abstract
Uncoordinated protein 45A (UNC-45A) is the only known ATP-independent microtubule (MT)-severing protein. Thus, it severs MTs via a novel mechanism. In vitro and in cells, UNC-45A-mediated MT severing is preceded by the appearance of MT bends. While MTs are stiff biological polymers, in cells, they often curve, and the result of this curving can be breaking off. The contribution of MT-severing proteins on MT lattice curvature is largely undefined. Here, we show that UNC-45A curves MTs. Using in vitro biophysical reconstitution and total internal fluorescence microscopy analysis, we show that UNC-45A is enriched in the areas where MTs are curved versus the areas where MTs are straight. In cells, we show that UNC-45A overexpression increases MT curvature and its depletion has the opposite effect. We also show that this effect occurs is independent of actomyosin contractility. Lastly, we show for the first time that in cells, Paclitaxel straightens MTs, and that UNC-45A can counteracts the MT-straightening effects of the drug.
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Affiliation(s)
- Asumi Hoshino
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Valentino Clemente
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mihir Shetty
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Brian Castle
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - David Odde
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Martina Bazzaro
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Health, University of Minnesota, Minneapolis, Minnesota, USA.
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14
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Yue Y, Hotta T, Higaki T, Verhey KJ, Ohi R. Microtubule detyrosination by VASH1/SVBP is regulated by the conformational state of tubulin in the lattice. Curr Biol 2023; 33:4111-4123.e7. [PMID: 37716348 PMCID: PMC10592207 DOI: 10.1016/j.cub.2023.07.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 09/18/2023]
Abstract
Tubulin, a heterodimer of α- and β-tubulin, is a GTPase that assembles into microtubule (MT) polymers whose dynamic properties are intimately coupled to nucleotide hydrolysis. In cells, the organization and dynamics of MTs are further tuned by post-translational modifications (PTMs), which control the ability of MT-associated proteins (MAPs) and molecular motors to engage MTs. Detyrosination is a PTM of α-tubulin, wherein its C-terminal tyrosine residue is enzymatically removed by either the vasohibin (VASH) or MT-associated tyrosine carboxypeptidase (MATCAP) peptidases. How these enzymes generate specific patterns of MT detyrosination in cells is not known. Here, we use a novel antibody-based probe to visualize the formation of detyrosinated MTs in real time and employ single-molecule imaging of VASH1 bound to its regulatory partner small-vasohibin binding protein (SVBP) to understand the process of MT detyrosination in vitro and in cells. We demonstrate that the activity, but not binding, of VASH1/SVBP is much greater on mimics of guanosine triphosphate (GTP)-MTs than on guanosine diphosphate (GDP)-MTs. Given emerging data showing that tubulin subunits in GTP-MTs are in expanded conformation relative to tubulin subunits in GDP-MTs, we reasoned that the lattice conformation of MTs is a key factor that gates the activity of VASH1/SVBP. We show that Taxol, a drug known to expand the MT lattice, promotes MT detyrosination and that CAMSAP2 and CAMSAP3 are two MAPs that spatially regulate detyrosination in cells. Collectively, our work shows that VASH1/SVBP detyrosination is regulated by the conformational state of tubulin in the MT lattice and that this is spatially determined in cells by the activity of MAPs.
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Affiliation(s)
- Yang Yue
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Takashi Hotta
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Takumi Higaki
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan; International Research Organization in Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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15
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Chew YM, Cross RA. Taxol acts differently on different tubulin isotypes. Commun Biol 2023; 6:946. [PMID: 37717119 PMCID: PMC10505170 DOI: 10.1038/s42003-023-05306-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 08/31/2023] [Indexed: 09/18/2023] Open
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.
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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.
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16
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Hoshino A, Clemente V, Shetty M, Castle B, Odde D, Bazzaro M. The Microtubule Severing Protein UNC-45A Counteracts the Microtubule Straightening Effects of Taxol. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557417. [PMID: 37745537 PMCID: PMC10515786 DOI: 10.1101/2023.09.12.557417] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
UNC-45A is the only known ATP-independent microtubule (MT) severing protein. Thus, it severs MTs via a novel mechanism. In vitro and in cells UNC-45A-mediated MT severing is preceded by the appearance of MT bends. While MTs are stiff biological polymers, in cells, they often curve, and the result of this curving can be breaking off. The contribution of MT severing proteins on MT lattice curvature is largely undefined. Here we show that UNC-45A curves MTs. Using in vitro biophysical reconstitution and TIRF microscopy analysis, we show that UNC-45A is enriched in the areas where MTs are curved versus the areas where MTs are straight. In cells, we show that UNC-45A overexpression increases MT curvature and its depletion has the opposite effect. We also show that this effect occurs is independent of actomyosin contractility. Lastly, we show for the first time that in cells, Paclitaxel straightens MTs, and that UNC-45A can counteracts the MT straightening effects of the drug. Significance: Our findings reveal for the first time that UNC-45A increases MT curvature. This hints that UNC-45A-mediated MT severing could be due to the worsening of MT curvature and provide a mechanistic understanding of how this MT-severing protein may act. UNC-45A is the only MT severing protein expressed in human cancers, including paclitaxel-resistant ovarian cancer. Our finding that UNC-45A counteracts the paclitaxel-straightening effects of MTs in cells suggests an additional mechanism through which cancer cells escape drug treatment.
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17
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Smith G, Sweeney ST, O’Kane CJ, Prokop A. How neurons maintain their axons long-term: an integrated view of axon biology and pathology. Front Neurosci 2023; 17:1236815. [PMID: 37564364 PMCID: PMC10410161 DOI: 10.3389/fnins.2023.1236815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery-all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the 'dependency cycle of local axon homeostasis' as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases.
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Affiliation(s)
- Gaynor Smith
- Cardiff University, School of Medicine, College of Biomedical and Life Sciences, Cardiff, United Kingdom
| | - Sean T. Sweeney
- Department of Biology, University of York and York Biomedical Research Institute, York, United Kingdom
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, The University of Manchester, Manchester, United Kingdom
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18
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Szebényi K, Barrio-Hernandez I, Gibbons GM, Biasetti L, Troakes C, Beltrao P, Lakatos A. A human proteogenomic-cellular framework identifies KIF5A as a modulator of astrocyte process integrity with relevance to ALS. Commun Biol 2023; 6:678. [PMID: 37386082 PMCID: PMC10310856 DOI: 10.1038/s42003-023-05041-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 06/13/2023] [Indexed: 07/01/2023] Open
Abstract
Genome-wide association studies identified several disease-causing mutations in neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). However, the contribution of genetic variants to pathway disturbances and their cell type-specific variations, especially in glia, is poorly understood. We integrated ALS GWAS-linked gene networks with human astrocyte-specific multi-omics datasets to elucidate pathognomonic signatures. It predicts that KIF5A, a motor protein kinesin-1 heavy-chain isoform, previously detected only in neurons, can also potentiate disease pathways in astrocytes. Using postmortem tissue and super-resolution structured illumination microscopy in cell-based perturbation platforms, we provide evidence that KIF5A is present in astrocyte processes and its deficiency disrupts structural integrity and mitochondrial transport. We show that this may underly cytoskeletal and trafficking changes in SOD1 ALS astrocytes characterised by low KIF5A levels, which can be rescued by c-Jun N-terminal Kinase-1 (JNK1), a kinesin transport regulator. Altogether, our pipeline reveals a mechanism controlling astrocyte process integrity, a pre-requisite for synapse maintenance and suggests a targetable loss-of-function in ALS.
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Affiliation(s)
- Kornélia Szebényi
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0PY, UK
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, 1117, Hungary
| | | | - George M Gibbons
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0PY, UK
| | - Luca Biasetti
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
| | - Claire Troakes
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
| | - Pedro Beltrao
- European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD, UK.
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, 8093, Switzerland.
| | - András Lakatos
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0PY, UK.
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK.
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19
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Shen Y, Ori-McKenney KM. Macromolecular Crowding Tailors the Microtubule Cytoskeleton Through Tubulin Modifications and Microtubule-Associated Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.14.544846. [PMID: 37398431 PMCID: PMC10312695 DOI: 10.1101/2023.06.14.544846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Cells remodel their cytoskeletal networks to adapt to their environment. Here, we analyze the mechanisms utilized by the cell to tailor its microtubule landscape in response to changes in osmolarity that alter macromolecular crowding. By integrating live cell imaging, ex vivo enzymatic assays, and in vitro reconstitution, we probe the impact of acute perturbations in cytoplasmic density on microtubule-associated proteins (MAPs) and tubulin posttranslational modifications (PTMs), unraveling the molecular underpinnings of cellular adaptation via the microtubule cytoskeleton. We find that cells respond to fluctuations in cytoplasmic density by modulating microtubule acetylation, detyrosination, or MAP7 association, without differentially affecting polyglutamylation, tyrosination, or MAP4 association. These MAP-PTM combinations alter intracellular cargo transport, enabling the cell to respond to osmotic challenges. We further dissect the molecular mechanisms governing tubulin PTM specification, and find that MAP7 promotes acetylation by biasing the conformation of the microtubule lattice, and directly inhibits detyrosination. Acetylation and detyrosination can therefore be decoupled and utilized for distinct cellular purposes. Our data reveal that the MAP code dictates the tubulin code, resulting in remodeling of the microtubule cytoskeleton and alteration of intracellular transport as an integrated mechanism of cellular adaptation.
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Affiliation(s)
- Yusheng Shen
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Kassandra M Ori-McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
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20
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Liu H, Shima T. Preference of CAMSAP3 for expanded microtubule lattice contributes to stabilization of the minus end. Life Sci Alliance 2023; 6:e202201714. [PMID: 36894175 PMCID: PMC9998277 DOI: 10.26508/lsa.202201714] [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: 09/06/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 03/11/2023] Open
Abstract
CAMSAPs are proteins that show microtubule minus-end-specific localization, decoration, and stabilization. Although the mechanism for minus-end recognition via their C-terminal CKK domain has been well described in recent studies, it is unclear how CAMSAPs stabilize microtubules. Our several binding assays revealed that the D2 region of CAMSAP3 specifically binds to microtubules with the expanded lattice. To investigate the relationship between this preference and the stabilization effect of CAMSAP3, we precisely measured individual microtubule lengths and found that D2 binding expanded the microtubule lattice by ∼3%. Consistent with the notion that the expanded lattice is a common feature of stable microtubules, the presence of D2 slowed the microtubule depolymerization rate to ∼1/20, suggesting that the D2-triggered lattice expansion stabilizes microtubules. Combining these results, we propose that CAMSAP3 stabilizes microtubules by lattice expansion upon D2 binding, which further accelerates the recruitment of other CAMSAP3 molecules. Because only CAMSAP3 has D2 and the highest microtubule-stabilizing effect among mammalian CAMSAPs, our model also explains the molecular basis for the functional diversity of CAMSAP family members.
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Affiliation(s)
- Hanjin Liu
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tomohiro Shima
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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21
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Jansen KI, Iwanski MK, Burute M, Kapitein LC. A live-cell marker to visualize the dynamics of stable microtubules throughout the cell cycle. J Cell Biol 2023; 222:213914. [PMID: 36880745 PMCID: PMC9998657 DOI: 10.1083/jcb.202106105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 01/08/2022] [Accepted: 02/13/2023] [Indexed: 03/08/2023] Open
Abstract
The microtubule (MT) cytoskeleton underlies processes such as intracellular transport and cell division. Immunolabeling for posttranslational modifications of tubulin has revealed the presence of different MT subsets, which are believed to differ in stability and function. Whereas dynamic MTs can readily be studied using live-cell plus-end markers, the dynamics of stable MTs have remained obscure due to a lack of tools to directly visualize these MTs in living cells. Here, we present StableMARK (Stable Microtubule-Associated Rigor-Kinesin), a live-cell marker to visualize stable MTs with high spatiotemporal resolution. We demonstrate that a rigor mutant of Kinesin-1 selectively binds to stable MTs without affecting MT organization and organelle transport. These MTs are long-lived, undergo continuous remodeling, and often do not depolymerize upon laser-based severing. Using this marker, we could visualize the spatiotemporal regulation of MT stability before, during, and after cell division. Thus, this live-cell marker enables the exploration of different MT subsets and how they contribute to cellular organization and transport.
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Affiliation(s)
- Klara I Jansen
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University , Utrecht, Netherlands
| | - Malina K Iwanski
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University , Utrecht, Netherlands
| | - Mithila Burute
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University , Utrecht, Netherlands
| | - Lukas C Kapitein
- Department of Biology, Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University , Utrecht, Netherlands
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22
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Verhey KJ, Ohi R. Causes, costs and consequences of kinesin motors communicating through the microtubule lattice. J Cell Sci 2023; 136:293511. [PMID: 36866642 PMCID: PMC10022682 DOI: 10.1242/jcs.260735] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
Microtubules are critical for a variety of important functions in eukaryotic cells. During intracellular trafficking, molecular motor proteins of the kinesin superfamily drive the transport of cellular cargoes by stepping processively along the microtubule surface. Traditionally, the microtubule has been viewed as simply a track for kinesin motility. New work is challenging this classic view by showing that kinesin-1 and kinesin-4 proteins can induce conformational changes in tubulin subunits while they are stepping. These conformational changes appear to propagate along the microtubule such that the kinesins can work allosterically through the lattice to influence other proteins on the same track. Thus, the microtubule is a plastic medium through which motors and other microtubule-associated proteins (MAPs) can communicate. Furthermore, stepping kinesin-1 can damage the microtubule lattice. Damage can be repaired by the incorporation of new tubulin subunits, but too much damage leads to microtubule breakage and disassembly. Thus, the addition and loss of tubulin subunits are not restricted to the ends of the microtubule filament but rather, the lattice itself undergoes continuous repair and remodeling. This work leads to a new understanding of how kinesin motors and their microtubule tracks engage in allosteric interactions that are critical for normal cell physiology.
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Affiliation(s)
- Kristen J. Verhey
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Author for correspondence ()
| | - Ryoma Ohi
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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23
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Chiba K, Kita T, Anazawa Y, Niwa S. Insight into the regulation of axonal transport from the study of KIF1A-associated neurological disorder. J Cell Sci 2023; 136:286709. [PMID: 36655764 DOI: 10.1242/jcs.260742] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Neuronal function depends on axonal transport by kinesin superfamily proteins (KIFs). KIF1A is the molecular motor that transports synaptic vesicle precursors, synaptic vesicles, dense core vesicles and active zone precursors. KIF1A is regulated by an autoinhibitory mechanism; many studies, as well as the crystal structure of KIF1A paralogs, support a model whereby autoinhibited KIF1A is monomeric in solution, whereas activated KIF1A is dimeric on microtubules. KIF1A-associated neurological disorder (KAND) is a broad-spectrum neuropathy that is caused by mutations in KIF1A. More than 100 point mutations have been identified in KAND. In vitro assays show that most mutations are loss-of-function mutations that disrupt the motor activity of KIF1A, whereas some mutations disrupt its autoinhibition and abnormally hyperactivate KIF1A. Studies on disease model worms suggests that both loss-of-function and gain-of-function mutations cause KAND by affecting the axonal transport and localization of synaptic vesicles. In this Review, we discuss how the analysis of these mutations by molecular genetics, single-molecule assays and force measurements have helped to reveal the physiological significance of KIF1A function and regulation, and what physical parameters of KIF1A are fundamental to axonal transport.
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Affiliation(s)
- Kyoko Chiba
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan
| | - Tomoki Kita
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, 2-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Yuzu Anazawa
- Graduate School of Life Sciences, Tohoku University, 2-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Shinsuke Niwa
- Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan.,Department of Applied Physics, Graduate School of Engineering, Tohoku University, 2-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8578, Japan.,Graduate School of Life Sciences, Tohoku University, 2-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8578, Japan
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24
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Iwanski MK, Kapitein LC. Cellular cartography: Towards an atlas of the neuronal microtubule cytoskeleton. Front Cell Dev Biol 2023; 11:1052245. [PMID: 37035244 PMCID: PMC10073685 DOI: 10.3389/fcell.2023.1052245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 02/28/2023] [Indexed: 04/11/2023] Open
Abstract
Microtubules, one of the major components of the cytoskeleton, play a crucial role during many aspects of neuronal development and function, such as neuronal polarization and axon outgrowth. Consequently, the microtubule cytoskeleton has been implicated in many neurodevelopmental and neurodegenerative disorders. The polar nature of microtubules is quintessential for their function, allowing them to serve as tracks for long-distance, directed intracellular transport by kinesin and dynein motors. Most of these motors move exclusively towards either the plus- or minus-end of a microtubule and some have been shown to have a preference for either dynamic or stable microtubules, those bearing a particular post-translational modification or those decorated by a specific microtubule-associated protein. Thus, it becomes important to consider the interplay of these features and their combinatorial effects on transport, as well as how different types of microtubules are organized in the cell. Here, we discuss microtubule subsets in terms of tubulin isotypes, tubulin post-translational modifications, microtubule-associated proteins, microtubule stability or dynamicity, and microtubule orientation. We highlight techniques used to study these features of the microtubule cytoskeleton and, using the information from these studies, try to define the composition, role, and organization of some of these subsets in neurons.
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25
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Taguchi S, Nakano J, Imasaki T, Kita T, Saijo-Hamano Y, Sakai N, Shigematsu H, Okuma H, Shimizu T, Nitta E, Kikkawa S, Mizobuchi S, Niwa S, Nitta R. Structural model of microtubule dynamics inhibition by kinesin-4 from the crystal structure of KLP-12 -tubulin complex. eLife 2022; 11:77877. [PMID: 36065637 PMCID: PMC9451533 DOI: 10.7554/elife.77877] [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: 02/14/2022] [Accepted: 08/01/2022] [Indexed: 12/02/2022] Open
Abstract
Kinesin superfamily proteins are microtubule-based molecular motors driven by the energy of ATP hydrolysis. Among them, the kinesin-4 family is a unique motor that inhibits microtubule dynamics. Although mutations of kinesin-4 cause several diseases, its molecular mechanism is unclear because of the difficulty of visualizing the high-resolution structure of kinesin-4 working at the microtubule plus-end. Here, we report that KLP-12, a C. elegans kinesin-4 ortholog of KIF21A and KIF21B, is essential for proper length control of C. elegans axons, and its motor domain represses microtubule polymerization in vitro. The crystal structure of the KLP-12 motor domain complexed with tubulin, which represents the high-resolution structural snapshot of the inhibition state of microtubule-end dynamics, revealed the bending effect of KLP-12 for tubulin. Comparison with the KIF5B-tubulin and KIF2C-tubulin complexes, which represent the elongation and shrinking forms of microtubule ends, respectively, showed the curvature of tubulin introduced by KLP-12 is in between them. Taken together, KLP-12 controls the proper length of axons by modulating the curvature of the microtubule ends to inhibit the microtubule dynamics. From meter-long structures that allow nerve cells to stretch across a body to miniscule ‘hairs’ required for lung cells to clear mucus, many life processes rely on cells sporting projections which have the right size for their role. Networks of hollow filaments known as microtubules shape these structures and ensure that they have the appropriate dimensions. Controlling the length of microtubules is therefore essential for organisms, yet how this process takes place is still not fully elucidated. Previous research has shown that microtubules continue to grow when their end is straight but stop when it is curved. A family of molecular motors known as kinesin-4 participate in this process, but the exact mechanisms at play remain unclear. To investigate, Tuguchi, Nakano, Imasaki et al. focused on the KLP-12 protein, a kinesin-4 equivalent which helps to controls the length of microtubules in the tiny worm Caenorhabditis elegans. They performed genetic manipulations and imaged the interactions between KLP-12 and the growing end of a microtubule using X-ray crystallography. This revealed that KLP-12 controls the length of neurons by inhibiting microtubule growth. It does so by modulating the curvature of the growing end of the filament to suppress its extension. A ‘snapshot’ of KLP-12 binding to a microtubule at the resolution of the atom revealed exactly how the protein helps to bend the end of the filament to prevent it from growing further. These results will help to understand how nerve cells are shaped. This may also provide insights into the molecular mechanisms for various neurodegenerative disorders caused by problems with the human equivalents of KLP-12, potentially leading to new therapies.
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Affiliation(s)
- Shinya Taguchi
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan.,Division of Anesthesiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Juri Nakano
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Tsuyoshi Imasaki
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoki Kita
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Yumiko Saijo-Hamano
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | | | - Hiromichi Okuma
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takahiro Shimizu
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eriko Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Satoshi Kikkawa
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Satoshi Mizobuchi
- Division of Anesthesiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinsuke Niwa
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan.,Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Japan.,Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Sendai, Japan
| | - Ryo Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
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26
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Siahaan V, Tan R, Humhalova T, Libusova L, Lacey SE, Tan T, Dacy M, Ori-McKenney KM, McKenney RJ, Braun M, Lansky Z. Microtubule lattice spacing governs cohesive envelope formation of tau family proteins. Nat Chem Biol 2022; 18:1224-1235. [PMID: 35996000 PMCID: PMC9613621 DOI: 10.1038/s41589-022-01096-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 06/24/2022] [Indexed: 01/28/2023]
Abstract
Tau is an intrinsically disordered microtubule-associated protein (MAP) implicated in neurodegenerative disease. On microtubules, tau molecules segregate into two kinetically distinct phases, consisting of either independently diffusing molecules or interacting molecules that form cohesive 'envelopes' around microtubules. Envelopes differentially regulate lattice accessibility for other MAPs, but the mechanism of envelope formation remains unclear. Here we find that tau envelopes form cooperatively, locally altering the spacing of tubulin dimers within the microtubule lattice. Envelope formation compacted the underlying lattice, whereas lattice extension induced tau envelope disassembly. Investigating other members of the tau family, we find that MAP2 similarly forms envelopes governed by lattice spacing, whereas MAP4 cannot. Envelopes differentially biased motor protein movement, suggesting that tau family members could spatially divide the microtubule surface into functionally distinct regions. We conclude that the interdependent allostery between lattice spacing and cooperative envelope formation provides the molecular basis for spatial regulation of microtubule-based processes by tau and MAP2.
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Affiliation(s)
- Valerie Siahaan
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prague West, Czech Republic
| | - Ruensern Tan
- Department of Molecular and Cellular Biology, University of California - Davis, Davis, CA, USA.,Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Tereza Humhalova
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lenka Libusova
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Samuel E Lacey
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK.,Human Technopole, Milan, Italy
| | - Tracy Tan
- Department of Molecular and Cellular Biology, University of California - Davis, Davis, CA, USA
| | - Mariah Dacy
- Department of Molecular and Cellular Biology, University of California - Davis, Davis, CA, USA
| | | | - Richard J McKenney
- Department of Molecular and Cellular Biology, University of California - Davis, Davis, CA, USA.
| | - Marcus Braun
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prague West, Czech Republic.
| | - Zdenek Lansky
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prague West, Czech Republic.
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27
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Abstract
Coupling of motor proteins within arrays drives muscle contraction, flagellar beating, chromosome segregation, and other biological processes. Current models of motor coupling invoke either direct mechanical linkage or protein crowding, which rely on short-range motor-motor interactions. In contrast, coupling mechanisms that act at longer length scales remain largely unexplored. Here we report that microtubules can physically couple motor movement in the absence of detectable short-range interactions. The human kinesin-4 Kif4A changes the run length and velocity of other motors on the same microtubule in the dilute binding limit, when approximately 10-nm-sized motors are much farther apart than the motor size. This effect does not depend on specific motor-motor interactions because similar changes in Kif4A motility are induced by kinesin-1 motors. A micrometer-scale attractive interaction potential between motors is sufficient to recreate the experimental results in a biophysical model. Unexpectedly, our theory suggests that long-range microtubule-mediated coupling affects not only binding kinetics but also motor mechanochemistry. Therefore, the model predicts that motors can sense and respond to motors bound several micrometers away on a microtubule. Our results are consistent with a paradigm in which long-range motor interactions along the microtubule enable additional forms of collective motor behavior, possibly due to changes in the microtubule lattice.
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28
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Sabo J, Lansky Z. Molecular motors: Turning kinesin-1 into a microtubule destroyer. Curr Biol 2022; 32:R518-R520. [PMID: 35671724 DOI: 10.1016/j.cub.2022.04.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinesin-1 is a typical microtubule-associated molecular motor that drives cargo transport in the cell. New work now shows that small changes in its structure can bring out unforeseen powers in this motor, turning it into a microtubule destroyer and highlighting the interdependencies between the biological motor and its track.
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Affiliation(s)
- Jan Sabo
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prague West, Czech Republic
| | - Zdenek Lansky
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Prague West, Czech Republic.
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29
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Budaitis BG, Badieyan S, Yue Y, Blasius TL, Reinemann DN, Lang MJ, Cianfrocco MA, Verhey KJ. A kinesin-1 variant reveals motor-induced microtubule damage in cells. Curr Biol 2022; 32:2416-2429.e6. [PMID: 35504282 PMCID: PMC9993403 DOI: 10.1016/j.cub.2022.04.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 03/11/2022] [Accepted: 04/08/2022] [Indexed: 12/16/2022]
Abstract
Kinesins drive the transport of cellular cargoes as they walk along microtubule tracks; however, recent work has suggested that the physical act of kinesins walking along microtubules can stress the microtubule lattice. Here, we describe a kinesin-1 KIF5C mutant with an increased ability to generate damage sites in the microtubule lattice as compared with the wild-type motor. The expression of the mutant motor in cultured cells resulted in microtubule breakage and fragmentation, suggesting that kinesin-1 variants with increased damage activity would have been selected against during evolution. The increased ability to damage microtubules is not due to the enhanced motility properties of the mutant motor, as the expression of the kinesin-3 motor KIF1A, which has similar single-motor motility properties, also caused increased microtubule pausing, bending, and buckling but not breakage. In cells, motor-induced microtubule breakage could not be prevented by increased α-tubulin K40 acetylation, a post-translational modification known to increase microtubule flexibility. In vitro, lattice damage induced by wild-type KIF5C was repaired by soluble tubulin and resulted in increased rescues and overall microtubule growth, whereas lattice damage induced by the KIF5C mutant resulted in larger repair sites that made the microtubule vulnerable to breakage and fragmentation when under mechanical stress. These results demonstrate that kinesin-1 motility causes defects in and damage to the microtubule lattice in cells. While cells have the capacity to repair lattice damage, conditions that exceed this capacity result in microtubule breakage and fragmentation and may contribute to human disease.
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Affiliation(s)
- Breane G Budaitis
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Somayesadat Badieyan
- Department of Biological Chemistry and Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yang Yue
- Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - T Lynne Blasius
- Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dana N Reinemann
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37240, USA
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37240, USA
| | - Michael A Cianfrocco
- Department of Biological Chemistry and Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kristen J Verhey
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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30
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Vu HT, Zhang Z, Tehver R, Thirumalai D. Plus and minus ends of microtubules respond asymmetrically to kinesin binding by a long-range directionally driven allosteric mechanism. SCIENCE ADVANCES 2022; 8:eabn0856. [PMID: 35417226 PMCID: PMC9007332 DOI: 10.1126/sciadv.abn0856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Although it is known that majority of kinesin motors walk predominantly toward the plus end of microtubules (MTs) in a hand-over-hand manner, the structural origin of the stepping directionality is not understood. To resolve this issue, we modeled the structures of kinesin-1 (Kin1), MT, and the Kin1-MT complex using the elastic network model and calculated the residue-dependent responses to a local perturbation in the constructs. Kin1 binding elicits an asymmetric response that is pronounced in α/β-tubulin dimers in the plus end of the MT. Kin1 opens the clefts of multiple plus end α/β-tubulin dimers, creating binding-competent conformations, which is required for processivity. Reciprocally, MT induces correlations between switches I and II in the motor and enhances fluctuations in adenosine 5'-diphosphate and the residues in the binding pocket. Our findings explain both the directionality of stepping and MT effects on a key step in the catalytic cycle of kinesin.
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Affiliation(s)
- Huong T. Vu
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry CV4 7AL, UK
| | - Zhechun Zhang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Riina Tehver
- Department of Physics, Denison University, Granville, OH 43023, USA
| | - D. Thirumalai
- Department of Chemistry, University of Texas, Austin, TX 78702, USA
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31
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Akhmanova A, Kapitein LC. Mechanisms of microtubule organization in differentiated animal cells. Nat Rev Mol Cell Biol 2022; 23:541-558. [PMID: 35383336 DOI: 10.1038/s41580-022-00473-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 02/08/2023]
Abstract
Microtubules are polarized cytoskeletal filaments that serve as tracks for intracellular transport and form a scaffold that positions organelles and other cellular components and modulates cell shape and mechanics. In animal cells, the geometry, density and directionality of microtubule networks are major determinants of cellular architecture, polarity and proliferation. In dividing cells, microtubules form bipolar spindles that pull chromosomes apart, whereas in interphase cells, microtubules are organized in a cell type-specific fashion, which strongly correlates with cell physiology. In motile cells, such as fibroblasts and immune cells, microtubules are organized as radial asters, whereas in immotile epithelial and neuronal cells and in muscles, microtubules form parallel or antiparallel arrays and cortical meshworks. Here, we review recent work addressing how the formation of such microtubule networks is driven by the plethora of microtubule regulatory proteins. These include proteins that nucleate or anchor microtubule ends at different cellular structures and those that sever or move microtubules, as well as regulators of microtubule elongation, stability, bundling or modifications. The emerging picture, although still very incomplete, shows a remarkable diversity of cell-specific mechanisms that employ conserved building blocks to adjust microtubule organization in order to facilitate different cellular functions.
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Affiliation(s)
- Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
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32
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Microtubule Dumbbells to Assess the Effect of Force Geometry on Single Kinesin Motors. Methods Mol Biol 2022; 2478:559-583. [PMID: 36063334 PMCID: PMC9987583 DOI: 10.1007/978-1-0716-2229-2_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The cytoskeletal motors myosin, kinesin, and dynein and their corresponding tracks, actin and microtubules, are force generating ATPases responsible for motility and morphological changes at the intracellular, cellular, and tissue levels. The pioneering application of optical tweezers to measure the force-producing properties of cytoskeletal motors has provided an unparalleled understanding of their mechanochemistry. The mechanosensitivity of processive, microtubule-based motors has largely been studied in the optical trap using the "single-bead" assay, where a bead-attached motor is held adjacent to a cytoskeletal filament as it processively steps along it. However, because of the geometrical constraints in the conventional single-bead assay, the motor-filament bond is not only loaded parallel to the long axis of the filament, but also perpendicular to the long axis of the filament. This perpendicular force, which is inherent in the conventional single-bead assay, accelerates the motor-filament detachment and has not been carefully considered in prior experiments. An alternative approach is the "three-bead" assay, which was developed for the study of non-processive myosin motors. The vertical force component is minimized in this assay, and the total opposing force is mainly parallel to the microtubule. Experiments with kinesin show that microtubule attachment durations can be highly variable and last for up to tenfold longer times in the three-bead assay, compared to the single-bead assay. Thus, the ability of kinesin to bear mechanical load and remain attached to microtubules depends on the forces in more than one dimension. In this chapter, we provide detailed methods for preparing the proteins, buffers, flow chambers, and bead-filament assemblies for performing the three-bead assay with microtubules and their motors.
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33
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Motor usage imprints microtubule stability along the shaft. Dev Cell 2021; 57:5-18.e8. [PMID: 34883065 DOI: 10.1016/j.devcel.2021.11.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/27/2021] [Accepted: 11/15/2021] [Indexed: 12/22/2022]
Abstract
Tubulin dimers assemble into dynamic microtubules, which are used by molecular motors as tracks for intracellular transport. Organization and dynamics of the microtubule network are commonly thought to be regulated at the polymer ends, where tubulin dimers can be added or removed. Here, we show that molecular motors running on microtubules cause exchange of dimers along the shaft in vitro and in cells. These sites of dimer exchange act as rescue sites where depolymerizing microtubules stop shrinking and start re-growing. Consequently, the average length of microtubules increases depending on how frequently they are used as motor tracks. An increase of motor activity densifies the cellular microtubule network and enhances cell polarity. Running motors leave marks in the shaft, serving as traces of microtubule usage to organize the polarity landscape of the cell.
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34
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Masucci EM, Relich PK, Lakadamyali M, Ostap EM, Holzbaur ELF. Microtubule dynamics influence the retrograde biased motility of kinesin-4 motor teams in neuronal dendrites. Mol Biol Cell 2021; 33:ar52. [PMID: 34705476 PMCID: PMC9265162 DOI: 10.1091/mbc.e21-10-0480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Microtubules establish the directionality of intracellular transport by kinesins and dynein through polarized assembly, but it remains unclear how directed transport occurs along microtubules organized with mixed polarity. We investigated the ability of the plus end–directed kinesin-4 motor KIF21B to navigate mixed polarity microtubules in mammalian dendrites. Reconstitution assays with recombinant KIF21B and engineered microtubule bundles or extracted neuronal cytoskeletons indicate that nucleotide-independent microtubule-binding regions of KIF21B modulate microtubule dynamics and promote directional switching on antiparallel microtubules. Optogenetic recruitment of KIF21B to organelles in live neurons induces unidirectional transport in axons but bidirectional transport with a net retrograde bias in dendrites. Removal of the secondary microtubule-binding regions of KIF21B or dampening of microtubule dynamics with low concentrations of nocodazole eliminates retrograde bias in live dendrites. Further exploration of the contribution of microtubule dynamics in dendrites to directionality revealed plus end–out microtubules to be more dynamic than plus end–in microtubules, with nocodazole preferentially stabilizing the plus end–out population. We propose a model in which both nucleotide-sensitive and -insensitive microtubule-binding sites of KIF21B motors contribute to the search and selection of stable plus end–in microtubules within the mixed polarity microtubule arrays characteristic of mammalian dendrites to achieve net retrograde movement of KIF21B-bound cargoes.
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Affiliation(s)
- Erin M Masucci
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Peter K Relich
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Melike Lakadamyali
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - E Michael Ostap
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
| | - Erika L F Holzbaur
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
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35
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Fiorenza SA, Steckhahn DG, Betterton MD. Modeling spatiotemporally varying protein-protein interactions in CyLaKS, the Cytoskeleton Lattice-based Kinetic Simulator. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:105. [PMID: 34406510 PMCID: PMC10202044 DOI: 10.1140/epje/s10189-021-00097-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/21/2021] [Indexed: 05/24/2023]
Abstract
Interaction of cytoskeletal filaments, motor proteins, and crosslinking proteins drives important cellular processes such as cell division and cell movement. Cytoskeletal networks also exhibit nonequilibrium self-assembly in reconstituted systems. An emerging problem in cytoskeletal modeling and simulation is spatiotemporal alteration of the dynamics of filaments, motors, and associated proteins. This can occur due to motor crowding, obstacles along the filament, motor interactions and direction switching, and changes, defects, or heterogeneity in the filament binding lattice. How such spatiotemporally varying cytoskeletal filaments and motor interactions affect their collective properties is not fully understood. We developed the Cytoskeleton Lattice-based Kinetic Simulator (CyLaKS) to investigate such problems. The simulation model builds on previous work by incorporating motor mechanochemistry into a simulation with many interacting motors and/or associated proteins on a discretized lattice. CyLaKS also includes detailed balance in binding kinetics, movement, and lattice heterogeneity. The simulation framework is flexible and extensible for future modeling work and is available on GitHub for others to freely use or build upon. Here we illustrate the use of CyLaKS to study long-range motor interactions, microtubule lattice heterogeneity, motion of a heterodimeric motor, and how changing crosslinker number affects filament separation.
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Affiliation(s)
- Shane A Fiorenza
- Department of Physics, University of Colorado Boulder, Boulder, USA
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36
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Ciorîță A, Bugiel M, Sudhakar S, Schäffer E, Jannasch A. Single depolymerizing and transport kinesins stabilize microtubule ends. Cytoskeleton (Hoboken) 2021; 78:177-184. [PMID: 34310069 DOI: 10.1002/cm.21681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/14/2021] [Accepted: 07/19/2021] [Indexed: 11/07/2022]
Abstract
Microtubules are highly dynamic cellular filaments and an accurate control of their length is important for many intracellular processes like cell division. Among other factors, microtubule length is actively modulated by motors from the kinesin superfamily. For example, yeast kinesin-8, Kip3, motors depolymerize microtubules by a cooperative, force- and length-dependent mechanism. However, whether single motors can also depolymerize microtubules is unclear. Here, we measured how single kinesin motors influenced the stability of microtubules in an in vitro assay. Using label-free interference reflection microscopy, we determined the spontaneous microtubule depolymerization rate of stabilized microtubules in the presence of kinesins. Surprisingly, we found that both single Kip3 and nondepolymerizing kinesin-1 transport motors, used as a control, stabilized microtubules further. For Kip3, this behavior is contrary to the collective force-dependent depolymerization activity of multiple motors. Because of the control measurement, the finding may hint at a more general stabilization mechanism. The complex, concentration-dependent interaction with microtubule ends provides new insights into the molecular mechanism of kinesin-8 and its regulatory function of microtubule length.
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Affiliation(s)
- Alexandra Ciorîță
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany.,National Institute for Research and Development of Isotopic and Molecular Technologies, Integrated Electron Microscopy Laboratory, Cluj-Napoca, Romania
| | - Michael Bugiel
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
| | - Swathi Sudhakar
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany.,MRC London Institute of Medical Science, Imperial College London, London, UK
| | - Erik Schäffer
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
| | - Anita Jannasch
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
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37
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Mani N, Wijeratne SS, Subramanian R. Micron-scale geometrical features of microtubules as regulators of microtubule organization. eLife 2021; 10:e63880. [PMID: 34114950 PMCID: PMC8195601 DOI: 10.7554/elife.63880] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/02/2021] [Indexed: 12/20/2022] Open
Abstract
The organization of micron-sized, multi-microtubule arrays from individual microtubules is essential for diverse cellular functions. The microtubule polymer is largely viewed as a passive building block during the organization process. An exception is the 'tubulin code' where alterations to tubulin at the amino acid level can influence the activity of microtubule-associated proteins. Recent studies reveal that micron-scale geometrical features of individual microtubules and polymer networks, such as microtubule length, overlap length, contact angle, and lattice defects, can also regulate the activity of microtubule-associated proteins and modulate polymer dynamics. We discuss how the interplay between such geometrical properties of the microtubule lattice and the activity of associated proteins direct multiple aspects of array organization, from microtubule nucleation and coalignment to specification of array dimensions and remodeling of dynamic networks. The mechanisms reviewed here highlight micron-sized features of microtubules as critical parameters to be routinely investigated in the study of microtubule self-organization.
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Affiliation(s)
- Nandini Mani
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Sithara S Wijeratne
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
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38
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Triclin S, Inoue D, Gaillard J, Htet ZM, DeSantis ME, Portran D, Derivery E, Aumeier C, Schaedel L, John K, Leterrier C, Reck-Peterson SL, Blanchoin L, Théry M. Self-repair protects microtubules from destruction by molecular motors. NATURE MATERIALS 2021; 20:883-891. [PMID: 33479528 PMCID: PMC7611741 DOI: 10.1038/s41563-020-00905-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 12/09/2020] [Indexed: 05/30/2023]
Abstract
Microtubule instability stems from the low energy of tubulin dimer interactions, which sets the growing polymer close to its disassembly conditions. Molecular motors use ATP hydrolysis to produce mechanical work and move on microtubules. This raises the possibility that the mechanical work produced by walking motors can break dimer interactions and trigger microtubule disassembly. We tested this hypothesis by studying the interplay between microtubules and moving molecular motors in vitro. Our results show that molecular motors can remove tubulin dimers from the lattice and rapidly destroy microtubules. We also found that dimer removal by motors was compensated for by the insertion of free tubulin dimers into the microtubule lattice. This self-repair mechanism allows microtubules to survive the damage induced by molecular motors as they move along their tracks. Our study reveals the existence of coupling between the motion of molecular motors and the renewal of the microtubule lattice.
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Affiliation(s)
- Sarah Triclin
- Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Daisuke Inoue
- Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
- Department of Human Science, Faculty of Design, Kyushu University, Fukuoka, Japan
| | - Jérémie Gaillard
- Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Zaw Min Htet
- Deptartment of Cellular and Molecular Medicine, and Cell and Developmental Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Morgan E DeSantis
- Deptartment of Cellular and Molecular Medicine, and Cell and Developmental Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Didier Portran
- CRBM, University of Montpellier, CNRS, Montpellier, France
| | - Emmanuel Derivery
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Charlotte Aumeier
- Department of Biochemistry, University of Geneva, Genève, Switzerland
| | - Laura Schaedel
- Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Karin John
- Laboratoire Interdisciplinaire de Physique, University of Grenoble-Alpes, CNRS, Grenoble, France
| | | | - Samara L Reck-Peterson
- Deptartment of Cellular and Molecular Medicine, and Cell and Developmental Biology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Laurent Blanchoin
- Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France.
- Institut de Recherche Saint Louis, U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France.
| | - Manuel Théry
- Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France.
- Institut de Recherche Saint Louis, U976 Human Immunology Pathophysiology Immunotherapy (HIPI), CytoMorpho Lab, University of Paris, INSERM, CEA, Paris, France.
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39
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Abstract
Microtubules are dynamic cytoskeletal filaments composed of αβ-tubulin heterodimers. Historically, the dynamics of single tubulin interactions at the growing microtubule tip have been inferred from steady-state growth kinetics. However, recent advances in the production of recombinant tubulin and in high-resolution optical and cryo-electron microscopies have opened new windows into understanding the impacts of specific intermolecular interactions during growth. The microtubule lattice is held together by lateral and longitudinal tubulin-tubulin interactions, and these interactions are in turn regulated by the GTP hydrolysis state of the tubulin heterodimer. Furthermore, tubulin can exist in either an extended or a compacted state in the lattice. Growing evidence has led to the suggestion that binding of microtubule-associated proteins (MAPs) or motors can induce changes in tubulin conformation and that this information can be communicated through the microtubule lattice. Progress in understanding how dynamic tubulin-tubulin interactions control dynamic instability has benefitted from visualizing structures of growing microtubule plus ends and through stochastic biochemical models constrained by experimental data. Here, we review recent insights into the molecular basis of microtubule growth and discuss how MAPs and regulatory proteins alter tubulin-tubulin interactions to exert their effects on microtubule growth and stability.
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Affiliation(s)
- Joseph M Cleary
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA.
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40
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Dexamethasone accelerates muscle regeneration by modulating kinesin-1-mediated focal adhesion signals. Cell Death Discov 2021; 7:35. [PMID: 33597503 PMCID: PMC7889929 DOI: 10.1038/s41420-021-00412-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 01/11/2023] Open
Abstract
During differentiation, skeletal muscle develops mature multinucleated muscle fibers, which could contract to exert force on a substrate. Muscle dysfunction occurs progressively in patients with muscular dystrophy, leading to a loss of the ability to walk and eventually to death. The synthetic glucocorticoid dexamethasone (Dex) has been used therapeutically to treat muscular dystrophy by an inhibition of inflammation, followed by slowing muscle degeneration and stabilizing muscle strength. Here, in mice with muscle injury, we found that Dex significantly promotes muscle regeneration via promoting kinesin-1 motor activity. Nevertheless, how Dex promotes myogenesis through kinesin-1 motors remains unclear. We found that Dex directly increases kinesin-1 motor activity, which is required for the expression of a myogenic marker (muscle myosin heavy chain 1/2), and also for the process of myoblast fusion and the formation of polarized myotubes. Upon differentiation, kinesin-1 mediates the recruitment of integrin β1 onto microtubules allowing delivery of the protein into focal adhesions. Integrin β1-mediated focal adhesion signaling then guides myoblast fusion towards a polarized morphology. By imposing geometric constrains via micropatterns, we have proved that cell adhesion is able to rescue the defects caused by kinesin-1 inhibition during the process of myogenesis. These discoveries reveal a mechanism by which Dex is able to promote myogenesis, and lead us towards approaches that are more efficient in improving skeletal muscle regeneration.
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Atomistic Basis of Microtubule Dynamic Instability Assessed Via Multiscale Modeling. Ann Biomed Eng 2021; 49:1716-1734. [PMID: 33537926 PMCID: PMC8302526 DOI: 10.1007/s10439-020-02715-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 12/24/2020] [Indexed: 02/07/2023]
Abstract
Microtubule “dynamic instability,” the abrupt switching from assembly to disassembly caused by the hydrolysis of GTP to GDP within the β subunit of the αβ-tubulin heterodimer, is necessary for vital cellular processes such as mitosis and migration. Despite existing high-resolution structural data, the key mechanochemical differences between the GTP and GDP states that mediate dynamic instability behavior remain unclear. Starting with a published atomic-level structure as an input, we used multiscale modeling to find that GTP hydrolysis results in both longitudinal bond weakening (~ 4 kBT) and an outward bending preference (~ 1.5 kBT) to both drive dynamic instability and give rise to the microtubule tip structures previously observed by light and electron microscopy. More generally, our study provides an example where atomic level structural information is used as the sole input to predict cellular level dynamics without parameter adjustment.
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42
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Tsitkov S, Song Y, Rodriguez JB, Zhang Y, Hess H. Kinesin-Recruiting Microtubules Exhibit Collective Gliding Motion while Forming Motor Trails. ACS NANO 2020; 14:16547-16557. [PMID: 33054177 DOI: 10.1021/acsnano.0c03263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Microtubules gliding on surfaces coated with kinesin motors are minimalist experimental systems for studying collective behavior. Collective behavior in these systems arises from interactions between filaments, for example, from steric interactions, depletion forces, or cross-links. To maximize the utilization of system components and the production of work, it is desirable to achieve mutualistic interactions leading to the congregations of both types of agents, that is, cytoskeletal filaments and molecular motors. To this end, we used a microtubule-kinesin system, where motors reversibly bind to the surface via an interaction between a hexahistidine (His6) tag on the motor and a Ni(II)-nitrilotriacetic acid (Ni-NTA) moiety on the surface. The surface density of binding sites for kinesin motors was increased relative to our earlier work, driving the motors from the solution to the surface. Characterization of the motor-surface interactions in the absence of microtubules yielded kinetic parameters consistent with previous data and revealed the capacity of the surface to support two-dimensional motor diffusion. The motor density gradually fell over 2 h, presumably due to the stripping of Ni(II) from the NTA moieties on the surface. Microtubules gliding on these reversibly bound motors were unable to cross each other and at high enough densities began to align and form long, dense bundles. The kinesin motors accumulated in trails surrounding the microtubule bundles and participated in microtubule transport.
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Affiliation(s)
- Stanislav Tsitkov
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
| | - Yuchen Song
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
- Department of Biomedical Engineering, Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Juan B Rodriguez
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
| | - Yifei Zhang
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
| | - Henry Hess
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
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43
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Monzon GA, Scharrel L, DSouza A, Henrichs V, Santen L, Diez S. Stable tug-of-war between kinesin-1 and cytoplasmic dynein upon different ATP and roadblock concentrations. J Cell Sci 2020; 133:133/22/jcs249938. [PMID: 33257498 DOI: 10.1242/jcs.249938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 10/18/2020] [Indexed: 11/20/2022] Open
Abstract
The maintenance of intracellular processes, like organelle transport and cell division, depend on bidirectional movement along microtubules. These processes typically require kinesin and dynein motor proteins, which move with opposite directionality. Because both types of motors are often simultaneously bound to the cargo, regulatory mechanisms are required to ensure controlled directional transport. Recently, it has been shown that parameters like mechanical motor activation, ATP concentration and roadblocks on the microtubule surface differentially influence the activity of kinesin and dynein motors in distinct manners. However, how these parameters affect bidirectional transport systems has not been studied. Here, we investigate the regulatory influence of these three parameters using in vitro gliding motility assays and stochastic simulations. We find that the number of active kinesin and dynein motors determines the transport direction and velocity, but that variations in ATP concentration and roadblock density have no significant effect. Thus, factors influencing the force balance between opposite motors appear to be important, whereas the detailed stepping kinetics and bypassing capabilities of the motors only have a small effect.
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Affiliation(s)
- Gina A Monzon
- Center for Biophysics, Department of Physics, Saarland University, D-66123, Saarbrücken, Germany
| | - Lara Scharrel
- B CUBE Center for Molecular Bioengineering and Cluster of Excellence Physics of Life, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Ashwin DSouza
- B CUBE Center for Molecular Bioengineering and Cluster of Excellence Physics of Life, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Verena Henrichs
- B CUBE Center for Molecular Bioengineering and Cluster of Excellence Physics of Life, Technische Universität Dresden, D-01307 Dresden, Germany.,Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, CZ-25250 Prague West, Czech Republic
| | - Ludger Santen
- Center for Biophysics, Department of Physics, Saarland University, D-66123, Saarbrücken, Germany
| | - Stefan Diez
- B CUBE Center for Molecular Bioengineering and Cluster of Excellence Physics of Life, Technische Universität Dresden, D-01307 Dresden, Germany .,Max Planck Institute of Molecular Cell Biology and Genetics, D-01307 Dresden, Germany
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44
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Théry M, Blanchoin L. Microtubule self-repair. Curr Opin Cell Biol 2020; 68:144-154. [PMID: 33217636 DOI: 10.1016/j.ceb.2020.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/07/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
The stochastic switching between microtubule growth and shrinkage is a fascinating and unique process in the regulation of the cytoskeleton. To understand it, almost all attention has been focused on the microtubule ends. However, recent research has revived the idea that tubulin dimers can also be exchanged in protofilaments along the microtubule shaft, thus repairing the microtubule and protecting it from disassembly. Here, we review the research describing this phenomenon, the mechanisms regulating the removal and insertion of tubulin dimers, as well as the potential implications for key functions of the microtubule network, such as intracellular transport and cell polarization.
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Affiliation(s)
- Manuel Théry
- University of Grenoble-Alpes, CEA, CNRS, INRA, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, Grenoble, 38054, France; University of Paris, INSERM, CEA, Institut de Recherche Saint Louis, U976, HIPI, CytoMorpho Lab, Paris, 75010, France.
| | - Laurent Blanchoin
- University of Grenoble-Alpes, CEA, CNRS, INRA, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab, Grenoble, 38054, France; University of Paris, INSERM, CEA, Institut de Recherche Saint Louis, U976, HIPI, CytoMorpho Lab, Paris, 75010, France.
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45
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Toleikis A, Carter NJ, Cross RA. Backstepping Mechanism of Kinesin-1. Biophys J 2020; 119:1984-1994. [PMID: 33091340 PMCID: PMC7732724 DOI: 10.1016/j.bpj.2020.09.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 01/19/2023] Open
Abstract
Kinesin-1 is an ATP-driven molecular motor that transports cellular cargo along microtubules. At low loads, kinesin-1 almost always steps forward, toward microtubule plus ends, but at higher loads, it can also step backward. Backsteps are usually 8 nm but can be larger. These larger backward events of 16 nm, 24 nm, or more are thought to be slips rather than steps because they are too fast to consist of multiple, tightly coupled 8-nm steps. Here, we propose that not only these larger backsteps, but all kinesin-1 backsteps, are slips. We show first that kinesin waits before forward steps for less time than before backsteps and detachments; second, we show that kinesin waits for the same amount of time before backsteps and detachments; and third, we show that by varying the microtubule type, we can change the ratio of backsteps to detachments without affecting forward stepping. Our findings indicate that backsteps and detachments originate from the same state and that this state arises later in the mechanochemical cycle than the state that gives rise to forward steps. To explain our data, we propose that, in each cycle of ATP turnover, forward kinesin steps can only occur before Pi release, whereas backslips and detachments can only occur after Pi release. In the scheme we propose, Pi release gates access to a weak binding K⋅ADP-K⋅ADP state that can slip back along the microtubule, re-engage, release ADP, and try again to take an ATP-driven forward step. We predict that this rescued detachment pathway is key to maintaining kinesin processivity under load.
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Affiliation(s)
- Algirdas Toleikis
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom
| | - Nicholas J Carter
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom
| | - Robert A Cross
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom.
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46
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Knossow M, Campanacci V, Khodja LA, Gigant B. The Mechanism of Tubulin Assembly into Microtubules: Insights from Structural Studies. iScience 2020; 23:101511. [PMID: 32920486 PMCID: PMC7491153 DOI: 10.1016/j.isci.2020.101511] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/03/2020] [Accepted: 08/25/2020] [Indexed: 11/26/2022] Open
Abstract
Microtubules are cytoskeletal components involved in pivotal eukaryotic functions such as cell division, ciliogenesis, and intracellular trafficking. They assemble from αβ-tubulin heterodimers and disassemble in a process called dynamic instability, which is driven by GTP hydrolysis. Structures of the microtubule and of soluble tubulin have been determined by cryo-EM and by X-ray crystallography, respectively. Altogether, these data define the mechanism of tubulin assembly-disassembly at atomic or near-atomic level. We review here the structural changes that occur during assembly, tubulin switching from a curved conformation in solution to a straight one in the microtubule core. We also present more subtle changes associated with GTP binding, leading to tubulin activation for assembly. Finally, we show how cryo-EM and X-ray crystallography are complementary methods to characterize the interaction of tubulin with proteins involved either in intracellular transport or in microtubule dynamics regulation.
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Affiliation(s)
- Marcel Knossow
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Valérie Campanacci
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Liza Ammar Khodja
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Benoît Gigant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
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47
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Jose R, Santen L. Self-Organized Lane Formation in Bidirectional Transport by Molecular Motors. PHYSICAL REVIEW LETTERS 2020; 124:198103. [PMID: 32469583 DOI: 10.1103/physrevlett.124.198103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 04/17/2020] [Indexed: 06/11/2023]
Abstract
Within cells, vesicles and proteins are actively transported several micrometers along the cytoskeletal filaments. The transport along microtubules is propelled by dynein and kinesin motors, which carry the cargo in opposite directions. Bidirectional intracellular transport is performed with great efficiency, even under strong confinement, as for example in the axon. For this kind of transport system, one would expect generically cluster formation. In this Letter, we discuss the effect of the recently observed self-enhanced binding affinity along the kinesin trajectories on the microtubule. We introduce a stochastic lattice-gas model, where the enhanced binding affinity is realized via a floor field. From Monte Carlo simulations and a mean-field analysis we show that this mechanism can lead to self-organized symmetry breaking and lane formation that indeed leads to efficient bidirectional transport in narrow environments.
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Affiliation(s)
- Robin Jose
- Department of Theoretical Physics & Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - Ludger Santen
- Department of Theoretical Physics & Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
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48
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Abstract
The intracellular transport system in neurons is specialized to an extraordinary degree, enabling the delivery of critical cargo to sites in axons or dendrites that are far removed from the cell center. Vesicles formed in the cell body are actively transported by kinesin motors along axonal microtubules to presynaptic sites that can be located more than a meter away. Both growth factors and degradative vesicles carrying aged organelles or aggregated proteins take the opposite route, driven by dynein motors. Distance is not the only challenge; precise delivery of cargos to sites of need must also be accomplished. For example, localized delivery of presynaptic components to hundreds of thousands of "en passant" synapses distributed along the length of a single axon in some neuronal subtypes provides a layer of complexity that must be successfully navigated to maintain synaptic transmission. We review recent advances in the field of axonal transport, with a focus on conceptual developments, and highlight our growing quantitative understanding of neuronal trafficking and its role in maintaining the synaptic function that underlies higher cognitive processes such as learning and memory.
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Affiliation(s)
- Pedro Guedes-Dias
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Institute of Neuronal Cell Biology, Technische Universität München, 80802 Munich, Germany
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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49
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Kabir AMR, Sada K, Kakugo A. Breaking of buckled microtubules is mediated by kinesins. Biochem Biophys Res Commun 2020; 524:249-254. [PMID: 31983434 DOI: 10.1016/j.bbrc.2020.01.082] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 01/14/2020] [Indexed: 11/28/2022]
Abstract
Microtubule is the most rigid component of eukaryotic cytoskeleton that plays pivotal roles in many important cellular events. Microtubules are known to undergo bending or buckling in cells which often results in breaking of this cytoskeletal protein filament. Various cellular events such as cell migration, chromosome segregation, etc. are dependent on the buckling induced breaking of microtubules. However, the reason behind the breaking of buckled microtubules in cell has remained obscure yet. In this work, we have demonstrated breaking of microtubules on a 2D elastic medium by applying compressive stress. The applied compressive stress caused buckling of the microtubules which ultimately resulted in their breaking. We show that breaking of the buckled microtubules cannot be accounted for by considering the changes in curvature of the microtubules due to mechanical deformation. Our results confirm that, it is the interaction of kinesin, a microtubule-associated motor protein, with microtubules which plays the key role in breaking of the buckled microtubules on the 2D elastic medium. The breaking of buckled microtubules is ascribed to decrease in rigidity of microtubules upon interaction with kinesins. This work for the first time confirms the involvement of a microtubule-associated motor protein in breaking of microtubules under compressive stress, which will help further clarify the mechanism of breaking of buckled microtubules in cells and its significance in the cellular events.
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Affiliation(s)
| | - Kazuki Sada
- Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan; Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-0810, Japan
| | - Akira Kakugo
- Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan; Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-0810, Japan.
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50
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Nasrin SR, Afrin T, Kabir AMR, Inoue D, Torisawa T, Oiwa K, Sada K, Kakugo A. Regulation of Biomolecular-Motor-Driven Cargo Transport by Microtubules under Mechanical Stress. ACS APPLIED BIO MATERIALS 2020; 3:1875-1883. [DOI: 10.1021/acsabm.9b01010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Syeda Rubaiya Nasrin
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Tanjina Afrin
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | | | - Daisuke Inoue
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Takayuki Torisawa
- Cell Architecture Laboratory, Structural Biology Center, National Institute of Genetics, Mishima 411-8540, Japan
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima 411-8540, Japan
| | - Kazuhiro Oiwa
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe 651-2492, Hyogo, Japan
| | - Kazuki Sada
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
| | - Akira Kakugo
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
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