1
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Heber S, McClintock MA, Simon B, Mehtab E, Lapouge K, Hennig J, Bullock SL, Ephrussi A. Tropomyosin 1-I/C coordinates kinesin-1 and dynein motors during oskar mRNA transport. Nat Struct Mol Biol 2024; 31:476-488. [PMID: 38297086 PMCID: PMC10948360 DOI: 10.1038/s41594-024-01212-x] [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] [Accepted: 01/02/2024] [Indexed: 02/02/2024]
Abstract
Dynein and kinesin motors mediate long-range intracellular transport, translocating towards microtubule minus and plus ends, respectively. Cargoes often undergo bidirectional transport by binding to both motors simultaneously. However, it is not known how motor activities are coordinated in such circumstances. In the Drosophila female germline, sequential activities of the dynein-dynactin-BicD-Egalitarian (DDBE) complex and of kinesin-1 deliver oskar messenger RNA from nurse cells to the oocyte, and within the oocyte to the posterior pole. We show through in vitro reconstitution that Tm1-I/C, a tropomyosin-1 isoform, links kinesin-1 in a strongly inhibited state to DDBE-associated oskar mRNA. Nuclear magnetic resonance spectroscopy, small-angle X-ray scattering and structural modeling indicate that Tm1-I/C suppresses kinesin-1 activity by stabilizing its autoinhibited conformation, thus preventing competition with dynein until kinesin-1 is activated in the oocyte. Our work reveals a new strategy for ensuring sequential activity of microtubule motors.
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Affiliation(s)
- Simone Heber
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Mark A McClintock
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Bernd Simon
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Eve Mehtab
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Karine Lapouge
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Biochemistry IV, Biophysical Chemistry, University of Bayreuth, Bayreuth, Germany
| | - Simon L Bullock
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK.
| | - Anne Ephrussi
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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2
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Carrington G, Fatima U, Caramujo I, Lewis T, Casas-Mao D, Peckham M. A multiscale approach reveals the molecular architecture of the autoinhibited kinesin KIF5A. J Biol Chem 2024; 300:105713. [PMID: 38309508 PMCID: PMC10907169 DOI: 10.1016/j.jbc.2024.105713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/05/2024] Open
Abstract
Kinesin-1 is a microtubule motor that transports cellular cargo along microtubules. KIF5A is one of three kinesin-1 isoforms in humans, all of which are autoinhibited by an interaction between the motor and an IAK motif in the proximal region of the C-terminal tail. The C-terminal tail of KIF5A is ∼80 residues longer than the other two kinesin-1 isoforms (KIF5B and KIF5C) and it is unclear if it contributes to autoinhibition. Mutations in KIF5A cause neuronal diseases and could affect autoinhibition, as reported for a mutation that skips exon 27, altering its C-terminal sequence. Here, we combined negative-stain electron microscopy, crosslinking mass spectrometry (XL-MS) and AlphaFold2 structure prediction to determine the molecular architecture of the full-length autoinhibited KIF5A homodimer, in the absence of light chains. We show that KIF5A forms a compact, bent conformation, through a bend between coiled-coils 2 and 3, around P687. XL-MS of WT KIF5A revealed extensive interactions between residues in the motor, between coiled-coil 1 and the motor, between coiled-coils 1 and 2, with coiled-coils 3 and 4, and the proximal region of the C-terminal tail and the motor in the autoinhibited state, but not between the distal C-terminal region and the rest of the molecule. While negative-stain electron microscopy of exon-27 KIF5A splice mutant showed the presence of autoinhibited molecules, XL-MS analysis suggested that its autoinhibited state is more labile. Our model offers a conceptual framework for understanding how mutations within the motor and stalk domain may affect motor activity.
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Affiliation(s)
- Glenn Carrington
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Uzrama Fatima
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Ines Caramujo
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Tarek Lewis
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - David Casas-Mao
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Michelle Peckham
- Faculty of Biological Sciences, Astbury Centre for Structural Biology and the School of Molecular and Cellular Biology, University of Leeds, Leeds, UK.
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3
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Dutta S, Farhadifar R, Lu W, Kabacaoğlu G, Blackwell R, Stein DB, Lakonishok M, Gelfand VI, Shvartsman SY, Shelley MJ. Self-organized intracellular twisters. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.04.534476. [PMID: 37066165 PMCID: PMC10104069 DOI: 10.1101/2023.04.04.534476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Life in complex systems, such as cities and organisms, comes to a standstill when global coordination of mass, energy, and information flows is disrupted. Global coordination is no less important in single cells, especially in large oocytes and newly formed embryos, which commonly use fast fluid flows for dynamic reorganization of their cytoplasm. Here, we combine theory, computing, and imaging to investigate such flows in the Drosophila oocyte, where streaming has been proposed to spontaneously arise from hydrodynamic interactions among cortically anchored microtubules loaded with cargo-carrying molecular motors. We use a fast, accurate, and scalable numerical approach to investigate fluid-structure interactions of 1000s of flexible fibers and demonstrate the robust emergence and evolution of cell-spanning vortices, or twisters. Dominated by a rigid body rotation and secondary toroidal components, these flows are likely involved in rapid mixing and transport of ooplasmic components.
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Affiliation(s)
- Sayantan Dutta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ
- Center of Computational Biology, Flatiron Institute, New York, NY
| | - Reza Farhadifar
- Center of Computational Biology, Flatiron Institute, New York, NY
| | - Wen Lu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | | | - Robert Blackwell
- Center of Computational Biology, Flatiron Institute, New York, NY
| | - David B Stein
- Center of Computational Biology, Flatiron Institute, New York, NY
| | - Margot Lakonishok
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Vladimir I Gelfand
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Stanislav Y Shvartsman
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ
- Center of Computational Biology, Flatiron Institute, New York, NY
- Department of Molecular Biology and Lewis Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ
| | - Michael J Shelley
- Center of Computational Biology, Flatiron Institute, New York, NY
- Courant Institute of Mathematical Sciences, New York University, New York, NY
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4
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Qiu R, Zhang J, Xiang X. Kinesin-1 autoinhibition facilitates the initiation of dynein cargo transport. J Biophys Biochem Cytol 2022; 222:213766. [PMID: 36524956 PMCID: PMC9802684 DOI: 10.1083/jcb.202205136] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 11/04/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
The functional significance of Kinesin-1 autoinhibition has been unclear. Kinesin-1 transports multiple cargoes including cytoplasmic dynein to microtubule plus ends. From a genetic screen for Aspergillus mutants defective in dynein-mediated early endosome transport, we identified a kinesin-1 mutation kinAK895* at the C-terminal IAK motif involved in autoinhibition. The kinA∆IAK and kinAK895E mutants exhibited a similar defect in dynein-mediated early endosome transport, verifying the importance of kinesin-1 autoinhibition in dynein-mediated transport. Kinesin-1 autoinhibition is not critical for dynein accumulation at microtubule plus ends or for the secretory vesicle cargoes of kinesin-1 to reach the hyphal tip. However, it facilitates dynein to initiate early endosome transport. This is unrelated to a direct competition between dynein and kinesin-1 on early endosomes because kinesin-3 rather than kinesin-1 drives the plus-end-directed early endosome movement. This effect of kinesin-1 autoinhibition on dynein-mediated early endosome transport is related to cargo adapter-mediated dynein activation but at a step beyond the switching of dynein from its autoinhibited conformation.
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Affiliation(s)
- Rongde Qiu
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MA, USA
| | - Jun Zhang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MA, USA
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MA, USA,Correspondence to Xin Xiang:
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5
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Blasius TL, Yue Y, Prasad R, Liu X, Gennerich A, Verhey KJ. Sequences in the stalk domain regulate auto-inhibition and ciliary tip localization of the immotile kinesin-4 KIF7. J Cell Sci 2021; 134:269104. [PMID: 34114033 DOI: 10.1242/jcs.258464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/27/2021] [Indexed: 12/31/2022] Open
Abstract
The kinesin-4 member KIF7 plays critical roles in Hedgehog signaling in vertebrate cells. KIF7 is an atypical kinesin as it binds to microtubules but is immotile. We demonstrate that, like conventional kinesins, KIF7 is regulated by auto-inhibition, as the full-length protein is inactive for microtubule binding in cells. We identify a segment, the inhibitory coiled coil (inhCC), that is required for auto-inhibition of KIF7, whereas the adjacent regulatory coiled coil (rCC) that contributes to auto-inhibition of the motile kinesin-4s KIF21A and KIF21B is not sufficient for KIF7 auto-inhibition. Disease-associated mutations in the inhCC relieve auto-inhibition and result in strong microtubule binding. Surprisingly, uninhibited KIF7 proteins did not bind preferentially to or track the plus ends of growing microtubules in cells, as suggested by previous in vitro work, but rather bound along cytosolic and axonemal microtubules. Localization to the tip of the primary cilium also required the inhCC, and could be increased by disease-associated mutations regardless of the auto-inhibition state of the protein. These findings suggest that loss of KIF7 auto-inhibition and/or altered cilium tip localization can contribute to the pathogenesis of human disease.
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Affiliation(s)
- T Lynne Blasius
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yang Yue
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - RaghuRam Prasad
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Xinglei Liu
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Arne Gennerich
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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6
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Dimitrova-Paternoga L, Jagtap PKA, Cyrklaff A, Vaishali, Lapouge K, Sehr P, Perez K, Heber S, Löw C, Hennig J, Ephrussi A. Molecular basis of mRNA transport by a kinesin-1-atypical tropomyosin complex. Genes Dev 2021; 35:976-991. [PMID: 34140355 PMCID: PMC8247599 DOI: 10.1101/gad.348443.121] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/14/2021] [Indexed: 11/24/2022]
Abstract
Here, Dimitrova-Paternoga et al. present the high-resolution crystal structure of Khc–aTm1 (Drosophila kinesin-1, also called kinesin heavy chain [Khc], in complex with a putative cargo adaptor, the atypical tropomyosin [aTm1]), which mediates transport of oskar mRNA to the posterior pole of the Drosophila oocyte. They show that aTm1 binds to an evolutionarily conserved cargo binding site on Khc, demonstrate that Khc binds RNA directly, and show that aTm1 plays a stabilizing role in the interaction of Khc with RNA, which distinguishes aTm1 from classical motor adaptors. Kinesin-1 carries cargos including proteins, RNAs, vesicles, and pathogens over long distances within cells. The mechanochemical cycle of kinesins is well described, but how they establish cargo specificity is not fully understood. Transport of oskar mRNA to the posterior pole of the Drosophila oocyte is mediated by Drosophila kinesin-1, also called kinesin heavy chain (Khc), and a putative cargo adaptor, the atypical tropomyosin, aTm1. How the proteins cooperate in mRNA transport is unknown. Here, we present the high-resolution crystal structure of a Khc–aTm1 complex. The proteins form a tripartite coiled coil comprising two in-register Khc chains and one aTm1 chain, in antiparallel orientation. We show that aTm1 binds to an evolutionarily conserved cargo binding site on Khc, and mutational analysis confirms the importance of this interaction for mRNA transport in vivo. Furthermore, we demonstrate that Khc binds RNA directly and that it does so via its alternative cargo binding domain, which forms a positively charged joint surface with aTm1, as well as through its adjacent auxiliary microtubule binding domain. Finally, we show that aTm1 plays a stabilizing role in the interaction of Khc with RNA, which distinguishes aTm1 from classical motor adaptors.
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Affiliation(s)
- Lyudmila Dimitrova-Paternoga
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany.,Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany.,Centre for Structural Systems Biology (CSSB), Deutsches Elektronen-Synchrotron (DESY), EMBL Hamburg, 22607 Hamburg, Germany
| | | | - Anna Cyrklaff
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Vaishali
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Karine Lapouge
- Protein Expression and Purification Core Facility, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Peter Sehr
- Chemical Biology Core Facility, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Kathryn Perez
- Protein Expression and Purification Core Facility, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Simone Heber
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB), Deutsches Elektronen-Synchrotron (DESY), EMBL Hamburg, 22607 Hamburg, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Anne Ephrussi
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL) Heidelberg, 69117 Heidelberg, Germany
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7
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Stein DB, De Canio G, Lauga E, Shelley MJ, Goldstein RE. Swirling Instability of the Microtubule Cytoskeleton. PHYSICAL REVIEW LETTERS 2021; 126:028103. [PMID: 33512217 PMCID: PMC7616086 DOI: 10.1103/physrevlett.126.028103] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/29/2020] [Indexed: 05/12/2023]
Abstract
In the cellular phenomena of cytoplasmic streaming, molecular motors carrying cargo along a network of microtubules entrain the surrounding fluid. The piconewton forces produced by individual motors are sufficient to deform long microtubules, as are the collective fluid flows generated by many moving motors. Studies of streaming during oocyte development in the fruit fly Drosophila melanogaster have shown a transition from a spatially disordered cytoskeleton, supporting flows with only short-ranged correlations, to an ordered state with a cell-spanning vortical flow. To test the hypothesis that this transition is driven by fluid-structure interactions, we study a discrete-filament model and a coarse-grained continuum theory for motors moving on a deformable cytoskeleton, both of which are shown to exhibit a swirling instability to spontaneous large-scale rotational motion, as observed.
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Affiliation(s)
- David B. Stein
- Center for Computational Biology, Flatiron Institute, 162 5th Avenue, New York, New York 10010, USA
| | - Gabriele De Canio
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Eric Lauga
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Michael J. Shelley
- Center for Computational Biology, Flatiron Institute, 162 5th Avenue, New York, New York 10010, USA
- Courant Institute, New York University, 251 Mercer Street, New York, New York 10012, USA
| | - Raymond E. Goldstein
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge CB3 0WA, United Kingdom
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8
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Drechsler M, Lang LF, Al-Khatib L, Dirks H, Burger M, Schönlieb CB, Palacios IM. Optical flow analysis reveals that Kinesin-mediated advection impacts the orientation of microtubules in the Drosophila oocyte. Mol Biol Cell 2020; 31:1246-1258. [PMID: 32267197 PMCID: PMC7353148 DOI: 10.1091/mbc.e19-08-0440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The orientation of microtubule (MT) networks is exploited by motors to deliver cargoes to specific intracellular destinations and is thus essential for cell polarity and function. Reconstituted in vitro systems have largely contributed to understanding the molecular framework regulating the behavior of MT filaments. In cells, however, MTs are exposed to various biomechanical forces that might impact on their orientation, but little is known about it. Oocytes, which display forceful cytoplasmic streaming, are excellent model systems to study the impact of motion forces on cytoskeletons in vivo. Here we implement variational optical flow analysis as a new approach to analyze the polarity of MTs in the Drosophila oocyte, a cell that displays distinct Kinesin-dependent streaming. After validating the method as robust for describing MT orientation from confocal movies, we find that increasing the speed of flows results in aberrant plus end growth direction. Furthermore, we find that in oocytes where Kinesin is unable to induce cytoplasmic streaming, the growth direction of MT plus ends is also altered. These findings lead us to propose that cytoplasmic streaming - and thus motion by advection – contributes to the correct orientation of MTs in vivo. Finally, we propose a possible mechanism for a specialized cytoplasmic actin network (the actin mesh) to act as a regulator of flow speeds to counteract the recruitment of Kinesin to MTs.
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Affiliation(s)
- Maik Drechsler
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.,Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom.,Department of Zoology and Developmental Biology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Lukas F Lang
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Layla Al-Khatib
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Hendrik Dirks
- Institute for Computational and Applied Mathematics, University of Münster, 48149 Münster, Germany
| | - Martin Burger
- Department of Mathematics, Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Carola-Bibiane Schönlieb
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Isabel M Palacios
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.,Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
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9
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Lu W, Lakonishok M, Liu R, Billington N, Rich A, Glotzer M, Sellers JR, Gelfand VI. Competition between kinesin-1 and myosin-V defines Drosophila posterior determination. eLife 2020; 9:54216. [PMID: 32057294 PMCID: PMC7112953 DOI: 10.7554/elife.54216] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 02/14/2020] [Indexed: 12/05/2022] Open
Abstract
Local accumulation of oskar (osk) mRNA in the Drosophila oocyte determines the posterior pole of the future embryo. Two major cytoskeletal components, microtubules and actin filaments, together with a microtubule motor, kinesin-1, and an actin motor, myosin-V, are essential for osk mRNA posterior localization. In this study, we use Staufen, an RNA-binding protein that colocalizes with osk mRNA, as a proxy for osk mRNA. We demonstrate that posterior localization of osk/Staufen is determined by competition between kinesin-1 and myosin-V. While kinesin-1 removes osk/Staufen from the cortex along microtubules, myosin-V anchors osk/Staufen at the cortex. Myosin-V wins over kinesin-1 at the posterior pole due to low microtubule density at this site, while kinesin-1 wins at anterior and lateral positions because they have high density of cortically-anchored microtubules. As a result, posterior determinants are removed from the anterior and lateral cortex but retained at the posterior pole. Thus, posterior determination of Drosophila oocytes is defined by kinesin-myosin competition, whose outcome is primarily determined by cortical microtubule density. One of the most fundamental steps of embryonic development is deciding which end of the body should be the head, and which should be the tail. Known as 'axis specification', this process depends on the location of genetic material called mRNAs. In fruit flies, for example, the tail-end of the embryo accumulates an mRNA called oskar. If this mRNA is missing, the embryo will not develop an abdomen. The build-up of oskar mRNA happens before the egg is even fertilized and depends on two types of scaffold proteins in the egg cell called microtubules and microfilaments. These scaffolds act like ‘train tracks’ in the cell and have associated protein motors, which work a bit like trains, carrying cargo as they travel up and down along the scaffolds. For microtubules, one of the motors is a protein called kinesin-1, whereas for microfilaments, the motors are called myosins. Most microtubules in the egg cell are pointing away from the membrane, while microfilament tracks form a dense network of randomly oriented filaments just underneath the membrane. It was already known that kinesin-1 and a myosin called myosin-V are important for localizing oskar mRNA to the posterior of the egg. However, it was not clear why the mRNA only builds up in that area. To find out, Lu et al. used a probe to track oskar mRNA, while genetically manipulating each of the motors so that their ability to transport cargo changed. Modulating the balance of activity between the two motors revealed that kinesin-1 and myosin-V engage in a tug-of-war inside the egg: myosin-V tries to keep oskar mRNA underneath the membrane of the cell, while kinesin-1 tries to pull it away from the membrane along microtubules. The winner of this molecular battle depends on the number of microtubule tracks available in the local area of the cell. In most parts of the cell, there are abundant microtubules, so kinesin-1 wins and pulls oskar mRNA away from the membrane. But at the posterior end of the cell there are fewer microtubules, so myosin-V wins, allowing oskar mRNA to localize in this area. Artificially 'shaving' some microtubules in a local area immediately changed the outcome of this tug-of-war creating a build-up of oskar mRNA in the 'shaved' patch. This is the first time a molecular tug-of-war has been shown in an egg cell, but in other types of cell, such as neurons and pigment cells, myosins compete with kinesins to position other molecular cargoes. Understanding these processes more clearly sheds light not only on embryo development, but also on cell biology in general.
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Affiliation(s)
- Wen Lu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Margot Lakonishok
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Rong Liu
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Neil Billington
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Ashley Rich
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
| | - James R Sellers
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Vladimir I Gelfand
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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10
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Kelliher MT, Yue Y, Ng A, Kamiyama D, Huang B, Verhey KJ, Wildonger J. Autoinhibition of kinesin-1 is essential to the dendrite-specific localization of Golgi outposts. J Cell Biol 2018; 217:2531-2547. [PMID: 29728423 PMCID: PMC6028532 DOI: 10.1083/jcb.201708096] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 03/01/2018] [Accepted: 04/16/2018] [Indexed: 12/20/2022] Open
Abstract
Neuronal polarity relies on the axon- or dendrite-specific localization of cargo by molecular motors such as kinesin-1. This study shows how autoinhibition regulates both kinesin-1 activity and localization to keep dendritic Golgi outposts from entering axons. Neuronal polarity relies on the selective localization of cargo to axons or dendrites. The molecular motor kinesin-1 moves cargo into axons but is also active in dendrites. This raises the question of how kinesin-1 activity is regulated to maintain the compartment-specific localization of cargo. Our in vivo structure–function analysis of endogenous Drosophila melanogaster kinesin-1 reveals a novel role for autoinhibition in enabling the dendrite-specific localization of Golgi outposts. Mutations that disrupt kinesin-1 autoinhibition result in the axonal mislocalization of Golgi outposts. Autoinhibition also regulates kinesin-1 localization. Uninhibited kinesin-1 accumulates in axons and is depleted from dendrites, correlating with the change in outpost distribution and dendrite growth defects. Genetic interaction tests show that a balance of kinesin-1 inhibition and dynein activity is necessary to localize Golgi outposts to dendrites and keep them from entering axons. Our data indicate that kinesin-1 activity is precisely regulated by autoinhibition to achieve the selective localization of dendritic cargo.
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Affiliation(s)
- Michael T Kelliher
- Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, WI.,Biochemistry Department, University of Wisconsin-Madison, Madison, WI
| | - Yang Yue
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Ashley Ng
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI.,Biochemistry Scholars Program, University of Wisconsin-Madison, Madison, WI
| | - Daichi Kamiyama
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA
| | - Bo Huang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Jill Wildonger
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI
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11
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Drechsler M, Giavazzi F, Cerbino R, Palacios IM. Active diffusion and advection in Drosophila oocytes result from the interplay of actin and microtubules. Nat Commun 2017; 8:1520. [PMID: 29142223 PMCID: PMC5688094 DOI: 10.1038/s41467-017-01414-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 09/14/2017] [Indexed: 11/23/2022] Open
Abstract
Transport in cells occurs via a delicate interplay of passive and active processes, including diffusion, directed transport and advection. Despite progress in super-resolution microscopy, discriminating and quantifying these processes is a challenge, requiring tracking of rapidly moving, sub-diffraction objects in a crowded, noisy environment. Here we use differential dynamic microscopy with different contrast mechanisms to provide a thorough characterization of the dynamics in the Drosophila oocyte. We study the movement of vesicles and the elusive motion of a cytoplasmic F-actin mesh, a known regulator of cytoplasmic flows. We find that cytoplasmic motility constitutes a combination of directed motion and random diffusion. While advection is mainly attributed to microtubules, we find that active diffusion is driven by the actin cytoskeleton, although it is also enhanced by the flow. We also find that an important dynamic link exists between vesicles and cytoplasmic F-actin motion, as recently suggested in mouse oocytes. Intracellular transport is facilitated by a combination of processes including directed transport, advection and diffusion. Here the authors microscopically characterise the dynamics of the Drosophila oocyte and find distinct contributions of cytoskeletal components to advection and active diffusion.
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Affiliation(s)
- Maik Drechsler
- Department of Zoology, University of Cambridge, CB2 3EJ, Cambridge, UK
| | - Fabio Giavazzi
- Department BIOMETRA, University of Milan, 20090, Segrate, Milan, Italy
| | - Roberto Cerbino
- Department BIOMETRA, University of Milan, 20090, Segrate, Milan, Italy.
| | - Isabel M Palacios
- Department of Zoology, University of Cambridge, CB2 3EJ, Cambridge, UK. .,School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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12
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Gáspár I, Sysoev V, Komissarov A, Ephrussi A. An RNA-binding atypical tropomyosin recruits kinesin-1 dynamically to oskar mRNPs. EMBO J 2016; 36:319-333. [PMID: 28028052 PMCID: PMC5286366 DOI: 10.15252/embj.201696038] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 11/14/2022] Open
Abstract
Localization and local translation of oskar mRNA at the posterior pole of the Drosophila oocyte directs abdominal patterning and germline formation in the embryo. The process requires recruitment and precise regulation of motor proteins to form transport‐competent mRNPs. We show that the posterior‐targeting kinesin‐1 is loaded upon nuclear export of oskar mRNPs, prior to their dynein‐dependent transport from the nurse cells into the oocyte. We demonstrate that kinesin‐1 recruitment requires the DmTropomyosin1‐I/C isoform, an atypical RNA‐binding tropomyosin that binds directly to dimerizing oskar 3′UTRs. Finally, we show that a small but dynamically changing subset of oskar mRNPs gets loaded with inactive kinesin‐1 and that the motor is activated during mid‐oogenesis by the functionalized spliced oskar RNA localization element. This inefficient, dynamic recruitment of Khc decoupled from cargo‐dependent motor activation constitutes an optimized, coordinated mechanism of mRNP transport, by minimizing interference with other cargo‐transport processes and between the cargo‐associated dynein and kinesin‐1.
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Affiliation(s)
- Imre Gáspár
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Vasiliy Sysoev
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Artem Komissarov
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Anne Ephrussi
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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13
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Veeranan-Karmegam R, Boggupalli DP, Liu G, Gonsalvez GB. A new isoform of Drosophila non-muscle Tropomyosin 1 interacts with Kinesin-1 and functions in oskar mRNA localization. J Cell Sci 2016; 129:4252-4264. [PMID: 27802167 DOI: 10.1242/jcs.194332] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/05/2016] [Indexed: 12/16/2022] Open
Abstract
Recent studies have revealed that diverse cell types use mRNA localization as a means to establish polarity. Despite the prevalence of this phenomenon, much less is known regarding the mechanism by which mRNAs are localized. The Drosophila melanogaster oocyte provides a useful model for examining the process of mRNA localization. oskar (osk) mRNA is localized at the posterior of the oocyte, thus restricting the expression of Oskar protein to this site. The localization of osk mRNA is microtubule dependent and requires the plus-end-directed motor Kinesin-1. Unlike most Kinesin-1 cargoes, localization of osk mRNA requires the Kinesin heavy chain (Khc) motor subunit, but not the Kinesin light chain (Klc) adaptor. In this report, we demonstrate that a newly discovered isoform of Tropomyosin 1, referred to as Tm1C, directly interacts with Khc and functions in concert with this microtubule motor to localize osk mRNA. Apart from osk mRNA localization, several additional Khc-dependent processes in the oocyte are unaffected upon loss of Tm1C. Our results therefore suggest that the Tm1C-Khc interaction is specific for the osk localization pathway.
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Affiliation(s)
- Rajalakshmi Veeranan-Karmegam
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd, Augusta, GA 30912, USA
| | - Devi Prasad Boggupalli
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd, Augusta, GA 30912, USA
| | - Guojun Liu
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd, Augusta, GA 30912, USA
| | - Graydon B Gonsalvez
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd, Augusta, GA 30912, USA
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14
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Microtubule-microtubule sliding by kinesin-1 is essential for normal cytoplasmic streaming in Drosophila oocytes. Proc Natl Acad Sci U S A 2016; 113:E4995-5004. [PMID: 27512034 DOI: 10.1073/pnas.1522424113] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytoplasmic streaming in Drosophila oocytes is a microtubule-based bulk cytoplasmic movement. Streaming efficiently circulates and localizes mRNAs and proteins deposited by the nurse cells across the oocyte. This movement is driven by kinesin-1, a major microtubule motor. Recently, we have shown that kinesin-1 heavy chain (KHC) can transport one microtubule on another microtubule, thus driving microtubule-microtubule sliding in multiple cell types. To study the role of microtubule sliding in oocyte cytoplasmic streaming, we used a Khc mutant that is deficient in microtubule sliding but able to transport a majority of cargoes. We demonstrated that streaming is reduced by genomic replacement of wild-type Khc with this sliding-deficient mutant. Streaming can be fully rescued by wild-type KHC and partially rescued by a chimeric motor that cannot move organelles but is active in microtubule sliding. Consistent with these data, we identified two populations of microtubules in fast-streaming oocytes: a network of stable microtubules anchored to the actin cortex and free cytoplasmic microtubules that moved in the ooplasm. We further demonstrated that the reduced streaming in sliding-deficient oocytes resulted in posterior determination defects. Together, we propose that kinesin-1 slides free cytoplasmic microtubules against cortically immobilized microtubules, generating forces that contribute to cytoplasmic streaming and are essential for the refinement of posterior determinants.
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15
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Abstract
Objects are commonly moved within the cell by either passive diffusion or active directed transport. A third possibility is advection, in which objects within the cytoplasm are moved with the flow of the cytoplasm. Bulk movement of the cytoplasm, or streaming, as required for advection, is more common in large cells than in small cells. For example, streaming is observed in elongated plant cells and the oocytes of several species. In the Drosophila oocyte, two stages of streaming are observed: relatively slow streaming during mid-oogenesis and streaming that is approximately ten times faster during late oogenesis. These flows are implicated in two processes: polarity establishment and mixing. In this review, I discuss the underlying mechanism of streaming, how slow and fast streaming are differentiated, and what we know about the physiological roles of the two types of streaming.
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Affiliation(s)
- Margot E Quinlan
- Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California, Los Angeles, California 90095;
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16
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Twelvetrees AE, Pernigo S, Sanger A, Guedes-Dias P, Schiavo G, Steiner RA, Dodding MP, Holzbaur ELF. The Dynamic Localization of Cytoplasmic Dynein in Neurons Is Driven by Kinesin-1. Neuron 2016; 90:1000-15. [PMID: 27210554 PMCID: PMC4893161 DOI: 10.1016/j.neuron.2016.04.046] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/11/2016] [Accepted: 04/18/2016] [Indexed: 12/01/2022]
Abstract
Cytoplasmic dynein, the major motor driving retrograde axonal transport, must be actively localized to axon terminals. This localization is critical as dynein powers essential retrograde trafficking events required for neuronal survival, such as neurotrophic signaling. Here, we demonstrate that the outward transport of dynein from soma to axon terminal is driven by direct interactions with the anterograde motor kinesin-1. In developing neurons, we find that dynein dynamically cycles between neurites, following kinesin-1 and accumulating in the nascent axon coincident with axon specification. In established axons, dynein is constantly transported down the axon at slow axonal transport speeds; inhibition of the kinesin-1-dynein interaction effectively blocks this process. In vitro and live-imaging assays to investigate the underlying mechanism lead us to propose a new model for the slow axonal transport of cytosolic cargos, based on short-lived direct interactions of cargo with a highly processive anterograde motor. VIDEO ABSTRACT.
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Affiliation(s)
- Alison E Twelvetrees
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA; Molecular NeuroPathobiology Laboratory, Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Stefano Pernigo
- Randall Division of Cell and Molecular Biophysics, King's College London, London, SE1 1UL, UK
| | - Anneri Sanger
- Randall Division of Cell and Molecular Biophysics, King's College London, London, SE1 1UL, UK
| | - Pedro Guedes-Dias
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Giampietro Schiavo
- Molecular NeuroPathobiology Laboratory, Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Roberto A Steiner
- Randall Division of Cell and Molecular Biophysics, King's College London, London, SE1 1UL, UK
| | - Mark P Dodding
- Randall Division of Cell and Molecular Biophysics, King's College London, London, SE1 1UL, UK
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA.
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17
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Ng BF, Selvaraj GK, Santa-Cruz Mateos C, Grosheva I, Alvarez-Garcia I, Martín-Bermudo MD, Palacios IM. α-Spectrin and integrins act together to regulate actomyosin and columnarization, and to maintain a monolayered follicular epithelium. Development 2016; 143:1388-99. [PMID: 26952981 PMCID: PMC4852512 DOI: 10.1242/dev.130070] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 02/18/2016] [Indexed: 12/26/2022]
Abstract
The spectrin cytoskeleton crosslinks actin to the membrane, and although it has been greatly studied in erythrocytes, much is unknown about its function in epithelia. We have studied the role of spectrins during epithelia morphogenesis using the Drosophila follicular epithelium (FE). As previously described, we show that α-Spectrin and β-Spectrin are essential to maintain a monolayered FE, but, contrary to previous work, spectrins are not required to control proliferation. Furthermore, spectrin mutant cells show differentiation and polarity defects only in the ectopic layers of stratified epithelia, similar to integrin mutants. Our results identify α-Spectrin and integrins as novel regulators of apical constriction-independent cell elongation, as α-Spectrin and integrin mutant cells fail to columnarize. Finally, we show that increasing and reducing the activity of the Rho1-Myosin II pathway enhances and decreases multilayering of α-Spectrin cells, respectively. Similarly, higher Myosin II activity enhances the integrin multilayering phenotype. This work identifies a primary role for α-Spectrin in controlling cell shape, perhaps by modulating actomyosin. In summary, we suggest that a functional spectrin-integrin complex is essential to balance adequate forces, in order to maintain a monolayered epithelium.
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Affiliation(s)
- Bing Fu Ng
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Gokul Kannan Selvaraj
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | | | - Inna Grosheva
- Centro Andaluz de Biología del Desarrollo CSIC-Univ. Pablo de Olavide, Sevilla 41013, Spain
| | - Ines Alvarez-Garcia
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | | | - Isabel M Palacios
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
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18
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Watt D, Dixit R, Cavalli V. JIP3 Activates Kinesin-1 Motility to Promote Axon Elongation. J Biol Chem 2015; 290:15512-15525. [PMID: 25944905 DOI: 10.1074/jbc.m115.651885] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Indexed: 11/06/2022] Open
Abstract
Kinesin-1 is a molecular motor responsible for cargo transport along microtubules and plays critical roles in polarized cells, such as neurons. Kinesin-1 can function as a dimer of two kinesin heavy chains (KHC), which harbor the motor domain, or as a tetramer in combination with two accessory light chains (KLC). To ensure proper cargo distribution, kinesin-1 activity is precisely regulated. Both KLC and KHC subunits bind cargoes or regulatory proteins to engage the motor for movement along microtubules. We previously showed that the scaffolding protein JIP3 interacts directly with KHC in addition to its interaction with KLC and positively regulates dimeric KHC motility. Here we determined the stoichiometry of JIP3-KHC complexes and observed approximately four JIP3 molecules binding per KHC dimer. We then determined whether JIP3 activates tetrameric kinesin-1 motility. Using an in vitro motility assay, we show that JIP3 binding to KLC engages kinesin-1 with microtubules and that JIP3 binding to KHC promotes kinesin-1 motility along microtubules. We tested the in vivo relevance of these findings using axon elongation as a model for kinesin-1-dependent cellular function. We demonstrate that JIP3 binding to KHC, but not KLC, is essential for axon elongation in hippocampal neurons as well as axon regeneration in sensory neurons. These findings reveal that JIP3 regulation of kinesin-1 motility is critical for axon elongation and regeneration.
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Affiliation(s)
- Dana Watt
- Department of Anatomy and Neurobiology, School of Medicine, Washington University, St. Louis, Missouri 63110
| | - Ram Dixit
- Department of Biology, Washington University, St. Louis, Missouri 63110
| | - Valeria Cavalli
- Department of Anatomy and Neurobiology, School of Medicine, Washington University, St. Louis, Missouri 63110.
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19
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Burn KM, Shimada Y, Ayers K, Vemuganti S, Lu F, Hudson AM, Cooley L. Somatic insulin signaling regulates a germline starvation response in Drosophila egg chambers. Dev Biol 2015; 398:206-17. [PMID: 25481758 PMCID: PMC4340711 DOI: 10.1016/j.ydbio.2014.11.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 11/17/2014] [Accepted: 11/22/2014] [Indexed: 12/31/2022]
Abstract
Egg chambers from starved Drosophila females contain large aggregates of processing (P) bodies and cortically enriched microtubules. As this response to starvation is rapidly reversed upon re-feeding females or culturing egg chambers with exogenous bovine insulin, we examined the role of endogenous insulin signaling in mediating the starvation response. We found that systemic Drosophila insulin-like peptides (dILPs) activate the insulin pathway in follicle cells, which then regulate both microtubule and P body organization in the underlying germline cells. This organization is modulated by the motor proteins Dynein and Kinesin. Dynein activity is required for microtubule and P body organization during starvation, while Kinesin activity is required during nutrient-rich conditions. Blocking the ability of egg chambers to form P body aggregates in response to starvation correlated with reduced progeny survival. These data suggest a potential mechanism to maximize fecundity even during periods of poor nutrient availability, by mounting a protective response in immature egg chambers.
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Affiliation(s)
- K Mahala Burn
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States
| | - Yuko Shimada
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Seinou-tou D301, Tennoudai 1-1-1, Tsukuba,, Ibaraki 305-8572, Japan
| | - Kathleen Ayers
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States
| | - Soumya Vemuganti
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States
| | - Feiyue Lu
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States
| | - Andrew M Hudson
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States
| | - Lynn Cooley
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States; Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, United States; Department of Molecular, Cellular and Developmental Biology, Yale University, 260 Prospect Street, New Haven, CT 06510, United States.
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20
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Czaplinski K. Understanding mRNA trafficking: Are we there yet? Semin Cell Dev Biol 2014; 32:63-70. [DOI: 10.1016/j.semcdb.2014.04.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 04/17/2014] [Indexed: 10/25/2022]
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21
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Fu MM, Holzbaur ELF. Integrated regulation of motor-driven organelle transport by scaffolding proteins. Trends Cell Biol 2014; 24:564-74. [PMID: 24953741 DOI: 10.1016/j.tcb.2014.05.002] [Citation(s) in RCA: 205] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/06/2014] [Accepted: 05/08/2014] [Indexed: 12/25/2022]
Abstract
Intracellular trafficking pathways, including endocytosis, autophagy, and secretion, rely on directed organelle transport driven by the opposing microtubule motor proteins kinesin and dynein. Precise spatial and temporal targeting of vesicles and organelles requires the integrated regulation of these opposing motors, which are often bound simultaneously to the same cargo. Recent progress demonstrates that organelle-associated scaffolding proteins, including Milton/TRAKs (trafficking kinesin-binding protein), JIP1, JIP3 (JNK-interacting proteins), huntingtin, and Hook1, interact with molecular motors to coordinate activity and sustain unidirectional transport. Scaffolding proteins also bind to upstream regulatory proteins, including kinases and GTPases, to modulate transport in the cell. This integration of regulatory control with motor activity allows for cargo-specific changes in the transport or targeting of organelles in response to cues from the complex cellular environment.
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Affiliation(s)
- Meng-meng Fu
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Erika L F Holzbaur
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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22
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Williams LS, Ganguly S, Loiseau P, Ng BF, Palacios IM. The auto-inhibitory domain and ATP-independent microtubulebinding region of Kinesin heavy chain are major functional domains for transport in the Drosophila germline. J Cell Sci 2014. [DOI: 10.1242/jcs.147793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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