1
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Xiong GJ, Sheng ZH. Presynaptic perspective: Axonal transport defects in neurodevelopmental disorders. J Cell Biol 2024; 223:e202401145. [PMID: 38568173 PMCID: PMC10988239 DOI: 10.1083/jcb.202401145] [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: 01/27/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/05/2024] Open
Abstract
Disruption of synapse assembly and maturation leads to a broad spectrum of neurodevelopmental disorders. Presynaptic proteins are largely synthesized in the soma, where they are packaged into precursor vesicles and transported into distal axons to ensure precise assembly and maintenance of presynapses. Due to their morphological features, neurons face challenges in the delivery of presynaptic cargos to nascent boutons. Thus, targeted axonal transport is vital to build functional synapses. A growing number of mutations in genes encoding the transport machinery have been linked to neurodevelopmental disorders. Emerging lines of evidence have started to uncover presynaptic mechanisms underlying axonal transport defects, thus broadening the view of neurodevelopmental disorders beyond postsynaptic mechanisms. In this review, we discuss presynaptic perspectives of neurodevelopmental disorders by focusing on impaired axonal transport and disturbed assembly and maintenance of presynapses. We also discuss potential strategies for restoring axonal transport as an early therapeutic intervention.
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Affiliation(s)
- Gui-Jing Xiong
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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2
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Schutt KL, Queen KA, Fisher K, Budington O, Mao W, Liu W, Gu X, Xiao Y, Aswad F, Joseph J, Stumpff J. Identification of the KIF18A alpha-4 helix as a therapeutic target for chromosomally unstable tumor cells. Front Mol Biosci 2024; 11:1328077. [PMID: 38410188 PMCID: PMC10896213 DOI: 10.3389/fmolb.2024.1328077] [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: 10/26/2023] [Accepted: 01/08/2024] [Indexed: 02/28/2024] Open
Abstract
Background: The mitotic kinesin, KIF18A, is required for proliferation of cancer cells that exhibit chromosome instability (CIN), implicating it as a promising target for treatment of a subset of aggressive tumor types. Determining regions of the KIF18A protein to target for inhibition will be important for the design and optimization of effective small molecule inhibitors. Methods: In this study, we used cultured cell models to investigate the effects of mutating S284 within the alpha-4 helix of KIF18A, which was previously identified as a phosphorylated residue. Results: Mutations in S284 cause relocalization of KIF18A from the plus-ends of spindle microtubules to the spindle poles. Furthermore, KIF18A S284 mutants display loss of KIF18A function and fail to support proliferation in CIN tumor cells. Interestingly, similar effects on KIF18A localization and function were seen after treatment of CIN cells with KIF18A inhibitory compounds that are predicted to interact with residues within the alpha-4 helix. Conclusion: These data implicate the KIF18A alpha-4 helix as an effective target for inhibition and demonstrate that small molecules targeting KIF18A selectively limit CIN tumor cell proliferation and result in phenotypically similar effects on mitosis at the single cell level compared to genetic perturbations.
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Affiliation(s)
- Katherine L Schutt
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, United States
| | - Katelyn A Queen
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, United States
| | - Kira Fisher
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, United States
| | - Olivia Budington
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, United States
| | | | - Wei Liu
- Apeiron Therapeutics, Shanghai, China
| | | | | | - Fred Aswad
- Apeiron Therapeutics, Burlingame, CA, United States
| | - James Joseph
- Apeiron Therapeutics, Burlingame, CA, United States
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, United States
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3
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Queen KA, Cario A, Berger CL, Stumpff J. Modification of the neck-linker of KIF18A alters Microtubule subpopulation preference. Mol Biol Cell 2024; 35:ar3. [PMID: 37903223 PMCID: PMC10881168 DOI: 10.1091/mbc.e23-05-0167] [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: 05/12/2023] [Revised: 10/13/2023] [Accepted: 10/19/2023] [Indexed: 11/01/2023] Open
Abstract
Kinesins support many diverse cellular processes, including facilitating cell division through mechanical regulation of the mitotic spindle. However, how kinesin activity is controlled to facilitate this process is not well understood. Interestingly, posttranslational modifications have been identified within the enzymatic region of all 45 mammalian kinesins, but the significance of these modifications has gone largely unexplored. Given the critical role of the enzymatic region in facilitating nucleotide and microtubule binding, it may serve as a primary site for kinesin regulation. Consistent with this idea, a phosphomimetic mutation at S357 in the neck-linker of KIF18A alters the localization of KIF18A within the spindle from kinetochore microtubules to nonkinetochore microtubules at the periphery of the spindle. Changes in localization of KIF18A-S357D are accompanied by defects in mitotic spindle positioning and the ability to promote mitotic progression. This altered localization pattern is mimicked by a shortened neck-linker mutant, suggesting that KIF18A-S357D may cause the motor to adopt a shortened neck-linker-like state that decreases KIF18A accumulation at the plus-ends of kinetochore microtubules. These findings demonstrate that posttranslational modifications in the enzymatic region of kinesins could be important for biasing their localization to particular microtubule subpopulations.
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Affiliation(s)
- Katelyn A. Queen
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
| | - Alisa Cario
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
| | - Christopher L. Berger
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
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4
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Schutt K, Queen KA, Fisher K, Budington O, Mao W, Liu W, Xiao Y, Aswad F, Joseph J, Stumpff J. Identification of the KIF18A alpha-4 helix as a therapeutic target for chromosomally unstable tumor cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562576. [PMID: 37905069 PMCID: PMC10614886 DOI: 10.1101/2023.10.16.562576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The mitotic kinesin, KIF18A, is required for proliferation of cancer cells that exhibit chromosome instability (CIN), implicating it as a promising target for treatment of a subset of aggressive tumor types. Determining regions of the KIF18A protein to target for inhibition will be important for the design and optimization of effective small molecule inhibitors. In this study, we investigated the effects of mutating S284 within the alpha-4 helix of KIF18A, which was previously identified as a phosphorylated residue. Mutations in S284 cause relocalization of KIF18A from the plus-ends of spindle microtubules to the spindle poles. Furthermore, KIF18A S284 mutants display loss of KIF18A function and fail to support proliferation in CIN tumor cells. Interestingly, similar effects on KIF18A localization and function were seen after treatment of CIN cells with KIF18A inhibitory compounds that are predicted to interact with residues within the alpha-4 helix. These data implicate the KIF18A alpha-4 helix as an effective target for inhibition and demonstrate that small molecules targeting KIF18A selectively limit CIN tumor cell proliferation and result in phenotypically similar effects on mitosis at the single cell level compared to genetic perturbations.
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Affiliation(s)
- Katherine Schutt
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Katelyn A Queen
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Kira Fisher
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Olivia Budington
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | | | - Wei Liu
- Apeiron Therapeutics, Shanghai, CN
| | | | | | | | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
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5
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Benoit MP, Hunter B, Allingham JS, Sosa H. New insights into the mechanochemical coupling mechanism of kinesin-microtubule complexes from their high-resolution structures. Biochem Soc Trans 2023; 51:1505-1520. [PMID: 37560910 PMCID: PMC10586761 DOI: 10.1042/bst20221238] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023]
Abstract
Kinesin motor proteins couple mechanical movements in their motor domain to the binding and hydrolysis of ATP in their nucleotide-binding pocket. Forces produced through this 'mechanochemical' coupling are typically used to mobilize kinesin-mediated transport of cargos along microtubules or microtubule cytoskeleton remodeling. This review discusses the recent high-resolution structures (<4 Å) of kinesins bound to microtubules or tubulin complexes that have resolved outstanding questions about the basis of mechanochemical coupling, and how family-specific modifications of the motor domain can enable its use for motility and/or microtubule depolymerization.
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Affiliation(s)
| | - Byron Hunter
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - John S. Allingham
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Hernando Sosa
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, U.S.A
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6
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Queen KA, Cario A, Berger CL, Stumpff J. Modification of the Neck Linker of KIF18A Alters Microtubule Subpopulation Preference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539080. [PMID: 37205510 PMCID: PMC10187232 DOI: 10.1101/2023.05.02.539080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Kinesins support many diverse cellular processes, including facilitating cell division through mechanical regulation of the mitotic spindle. However, how kinesin activity is controlled to facilitate this process is not well understood. Interestingly, post-translational modifications have been identified within the enzymatic region of all 45 mammalian kinesins, but the significance of these modifications has gone largely unexplored. Given the critical role of the enzymatic region in facilitating nucleotide and microtubule binding, it may serve as a primary site for kinesin regulation. Consistent with this idea, a phosphomimetic mutation at S357 in the neck-linker of KIF18A alters the localization of KIF18A within the spindle from kinetochore microtubules to peripheral microtubules. Changes in localization of KIF18A-S357D are accompanied by defects in mitotic spindle positioning and the ability to promote mitotic progression. This altered localization pattern is mimicked by a shortened neck-linker mutant, suggesting that KIF18A-S357D may cause the motor to adopt a shortened neck-linker like state that prevents KIF18A from accumulating at the plus-ends of kinetochore microtubules. These findings demonstrate that post-translational modifications in the enzymatic region of kinesins could be important for biasing their localization to particular microtubule subpopulations.
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Affiliation(s)
- Katelyn A. Queen
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
| | - Alisa Cario
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
- Current Institution: Department of Cell and Developmental Biology, Vanderbilt School of Medicine, Nashville, TN
| | - Christopher L. Berger
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, 05401
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7
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Cushion TD, Leca I, Keays DA. MAPping tubulin mutations. Front Cell Dev Biol 2023; 11:1136699. [PMID: 36875768 PMCID: PMC9975266 DOI: 10.3389/fcell.2023.1136699] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
Microtubules are filamentous structures that play a critical role in a diverse array of cellular functions including, mitosis, nuclear translocation, trafficking of organelles and cell shape. They are composed of α/β-tubulin heterodimers which are encoded by a large multigene family that has been implicated in an umbrella of disease states collectively known as the tubulinopathies. De novo mutations in different tubulin genes are known to cause lissencephaly, microcephaly, polymicrogyria, motor neuron disease, and female infertility. The diverse clinical features associated with these maladies have been attributed to the expression pattern of individual tubulin genes, as well as their distinct Functional repertoire. Recent studies, however, have highlighted the impact of tubulin mutations on microtubule-associated proteins (MAPs). MAPs can be classified according to their effect on microtubules and include polymer stabilizers (e.g., tau, MAP2, doublecortin), destabilizers (e.g., spastin, katanin), plus-end binding proteins (e.g., EB1-3, XMAP215, CLASPs) and motor proteins (e.g., dyneins, kinesins). In this review we analyse mutation-specific disease mechanisms that influence MAP binding and their phenotypic consequences, and discuss methods by which we can exploit genetic variation to identify novel MAPs.
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Affiliation(s)
- Thomas D Cushion
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Ines Leca
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - David A Keays
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.,Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Munich, Germany
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8
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Portet S, Etienne-Manneville S, Leduc C, Dallon JC. Impact of noise on the regulation of intracellular transport of intermediate filaments. J Theor Biol 2022; 547:111183. [PMID: 35667486 DOI: 10.1016/j.jtbi.2022.111183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 11/26/2022]
Abstract
Noise affects all biological processes from molecules to cells, organisms and populations. Although the effect of noise on these processes is highly variable, evidence is accumulating which shows natural stochastic fluctuations (noise) can facilitate biological functions. Herein, we investigate the effect of noise on the transport of intermediate filaments in cells by comparing the stochastic and deterministic formalizations of the bidirectional transport of intermediate filaments, long elastic polymers transported along microtubules by antagonistic motor proteins Dallon et al., 2019; Portet et al., 2019. By numerically exploring discrepancies in timescales and attractors between both formalizations, we characterize the impact of stochastic fluctuations on the individual and ensemble transport. Biologically, we find that noise promotes the collective movement of intermediate filaments and increases the efficiency of its regulation by the biochemical properties of motor-cargo interactions. While stochastic fluctuations reduce the impact of the initial distributions of motor proteins in cells, the number of binding sites and the affinity of motor-cargo interactions are the key parameters controlling transport efficiency and efficacy.
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Affiliation(s)
- Stéphanie Portet
- Department of Mathematics, University of Manitoba, Winnipeg, MB, Canada.
| | - Sandrine Etienne-Manneville
- Cell Polarity, Migration and Cancer Unit, Institut Pasteur, Paris, UMR3691 CNRS. Equipe Labellisée Ligue Contre le Cancer, F-75015, Paris, France.
| | - Cécile Leduc
- Institut Jacques Monod, 15 rue Hélène Brion, 75013 Paris, France.
| | - J C Dallon
- Department of Mathematics, Brigham Young University, Provo, Utah, USA.
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9
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Selective motor activation in organelle transport along axons. Nat Rev Mol Cell Biol 2022; 23:699-714. [DOI: 10.1038/s41580-022-00491-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2022] [Indexed: 12/17/2022]
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10
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Tymanskyj SR, Curran BM, Ma L. Selective axonal transport through branch junctions is directed by growth cone signaling and mediated by KIF1/kinesin-3 motors. Cell Rep 2022; 39:110748. [PMID: 35476993 PMCID: PMC9097860 DOI: 10.1016/j.celrep.2022.110748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/27/2022] [Accepted: 04/06/2022] [Indexed: 11/16/2022] Open
Abstract
Development and function of nerve cells rely on the orchestration of microtubule-based transport from the cell body into distal axonal terminals. Neurons often have highly elaborate branches innervating multiple targets, but how protein or membrane cargos navigate through branch junctions to specific branch targets is unknown. Here, we demonstrate that anterograde transport of membrane vesicles through axonal branch junctions is highly selective, which is influenced by branch length and more strongly by growth cone motility. Using an optogenetic tool, we demonstrate that signaling from the growth cone can rapidly direct transport through branch junctions. We further demonstrate that such transport selectivity is differentially regulated for different vesicles and mediated by the KIF1/kinesin-3 family motors. We propose that this transport regulation through branch junctions could broadly impact neuronal development, function, and regeneration.
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Affiliation(s)
- Stephen R Tymanskyj
- Department of Neuroscience, Jefferson Center for Synaptic Biology, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Bridget M Curran
- Department of Neuroscience, Jefferson Center for Synaptic Biology, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Le Ma
- Department of Neuroscience, Jefferson Center for Synaptic Biology, Vickie and Jack Farber Institute for Neuroscience, Sydney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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11
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Guo W, Sun S, Sanchez JE, Lopez-Hernandez AE, Ale TA, Chen J, Afrin T, Qiu W, Xie Y, Li L. Using a comprehensive approach to investigate the interaction between Kinesin-5/Eg5 and the microtubule. Comput Struct Biotechnol J 2022; 20:4305-4314. [PMID: 36051882 PMCID: PMC9396395 DOI: 10.1016/j.csbj.2022.08.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 01/02/2023] Open
Abstract
Kinesins are microtubule-based motor proteins that play important roles ranging from intracellular transport to cell division. Human Kinesin-5 (Eg5) is essential for mitotic spindle assembly during cell division. By combining molecular dynamics (MD) simulations with other multi-scale computational approaches, we systematically studied the interaction between Eg5 and the microtubule. We find the electrostatic feature on the motor domains of Eg5 provides attractive interactions to the microtubule. Additionally, the folding and binding energy analysis reveals that the Eg5 motor domain performs its functions best when in a weak acidic environment. Molecular dynamics analyses of hydrogen bonds and salt bridges demonstrate that, on the binding interfaces of Eg5 and the tubulin heterodimer, salt bridges play the most significant role in holding the complex. The salt bridge residues on the binding interface of Eg5 are mostly positive, while salt bridge residues on the binding interface of tubulin heterodimer are mostly negative. Such salt bridge residue distribution is consistent with electrostatic potential calculations. In contrast, the interface between α and β-tubulins is dominated by hydrogen bonds rather than salt bridges. Compared to the Eg5/α-tubulin interface, the Eg5/β-tubulin interface has a greater number of salt bridges and higher occupancy for salt bridges. This asymmetric salt bridge distribution may play a significant role in Eg5′s directionality. The residues involved in hydrogen bonds and salt bridges are identified in this work and may be helpful for anticancer drug design.
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Affiliation(s)
- Wenhan Guo
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | - Shengjie Sun
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | - Jason E. Sanchez
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | | | - Tolulope A. Ale
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
| | - Jiawei Chen
- Department of Physics, University of Texas at El Paso, El Paso, TX, USA
| | - Tanjina Afrin
- Department of Physics, University of Texas at El Paso, El Paso, TX, USA
- Department of Physics, Oregon State University, Corvallis, OR, USA
| | - Weihong Qiu
- Department of Physics, Oregon State University, Corvallis, OR, USA
| | - Yixin Xie
- Department of Information Technology, Kennesaw State University, Kennesaw, GA, USA
| | - Lin Li
- Computational Science Program, University of Texas at El Paso, El Paso, TX, USA
- Department of Physics, University of Texas at El Paso, El Paso, TX, USA
- Corresponding author.
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12
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Solon AL, Tan Z, Schutt KL, Jepsen L, Haynes SE, Nesvizhskii AI, Sept D, Stumpff J, Ohi R, Cianfrocco MA. Kinesin-binding protein remodels the kinesin motor to prevent microtubule binding. SCIENCE ADVANCES 2021; 7:eabj9812. [PMID: 34797717 PMCID: PMC8604404 DOI: 10.1126/sciadv.abj9812] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/29/2021] [Indexed: 05/30/2023]
Abstract
Kinesins are regulated in space and time to ensure activation only in the presence of cargo. Kinesin-binding protein (KIFBP), which is mutated in Goldberg-Shprintzen syndrome, binds to and inhibits the catalytic motor heads of 8 of 45 kinesin superfamily members, but the mechanism remains poorly defined. Here, we used cryo–electron microscopy and cross-linking mass spectrometry to determine high-resolution structures of KIFBP alone and in complex with two mitotic kinesins, revealing structural remodeling of kinesin by KIFBP. We find that KIFBP remodels kinesin motors and blocks microtubule binding (i) via allosteric changes to kinesin and (ii) by sterically blocking access to the microtubule. We identified two regions of KIFBP necessary for kinesin binding and cellular regulation during mitosis. Together, this work further elucidates the molecular mechanism of KIFBP-mediated kinesin inhibition and supports a model in which structural rearrangement of kinesin motor domains by KIFBP abrogates motor protein activity.
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Affiliation(s)
- April L. Solon
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Zhenyu Tan
- Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Katherine L. Schutt
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Lauren Jepsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Sarah E. Haynes
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Alexey I. Nesvizhskii
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - David Sept
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Michael A. Cianfrocco
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
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13
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Atherton J, Moores CA. Cryo-EM of kinesin-binding protein: challenges and opportunities from protein-surface interactions. Acta Crystallogr D Struct Biol 2021; 77:411-423. [PMID: 33825702 PMCID: PMC8025885 DOI: 10.1107/s2059798321001935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/17/2021] [Indexed: 11/10/2022] Open
Abstract
Kinesin-binding protein (KBP) is an important selective inhibitor of specific kinesin family members and its genetic disruption causes Goldberg-Shprintzen syndrome. Cryo-electron microscopy (cryo-EM) has recently been used to reveal the structure of KBP alone (72 kDa) and in complex with the motor domain of the mitotic kinesin-12 KIF15 (110 kDa). KBP is an α-solenoid, tetratricopeptide-repeat protein that interacts with the microtubule-binding region of the kinesin motor domain and blocks microtubule attachment. Numerous challenges arose relating to the behavior of KBP and KBP-kinesin complexes during cryo-EM sample preparation. These included the partial denaturation of KBP by air-water interfaces, protein aggregation resulting from carbon interaction and preferential orientation. Sample preparation with a graphene oxide substrate enabled the eventual structure determination. Here, experiences with preparing these samples are detailed, bringing attention to some of the challenges and opportunities that are likely to arise from protein-surface interactions.
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Affiliation(s)
- Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
| | - Carolyn A. Moores
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
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14
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Abstract
Mitochondria are multifunctional organelles that not only produce energy for the cell, but are also important for cell signalling, apoptosis and many biosynthetic pathways. In most cell types, they form highly dynamic networks that are constantly remodelled through fission and fusion events, repositioned by motor-dependent transport and degraded when they become dysfunctional. Motor proteins and their tracks are key regulators of mitochondrial homeostasis, and in this Review, we discuss the diverse functions of the three classes of motor proteins associated with mitochondria - the actin-based myosins, as well as the microtubule-based kinesins and dynein. In addition, Miro and TRAK proteins act as adaptors that link kinesin-1 and dynein, as well as myosin of class XIX (MYO19), to mitochondria and coordinate microtubule- and actin-based motor activities. Here, we highlight the roles of motor proteins and motor-linked track dynamics in the transporting and docking of mitochondria, and emphasize their adaptations in specialized cells. Finally, we discuss how motor-cargo complexes mediate changes in mitochondrial morphology through fission and fusion, and how they modulate the turnover of damaged organelles via quality control pathways, such as mitophagy. Understanding the importance of motor proteins for mitochondrial homeostasis will help to elucidate the molecular basis of a number of human diseases.
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Affiliation(s)
- Antonina J Kruppa
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, Cambridge Biomedical Campus, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Folma Buss
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, Cambridge Biomedical Campus, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
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