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Daniel R Peet, Nigel J Burroughs, Robert A Cross
Kinesin-1 is a nanoscale molecular motor that walks towards the fast-growing (plus) ends of microtubules, hauling molecular cargo to specific reaction sites in cells. Kinesin-driven transport is central to the self-organization of eukaryotic cells and shows great promise as a tool for nano-engineering1 . Recent work hints that kinesin may also play a role in modulating the stability of its microtubule track, both in vitro2,3 and in vivo4 , but the results are conflicting5-7 and the mechanisms are unclear. Here, we report a new dimension to the kinesin-microtubule interaction, whereby strong-binding state (adenosine triphosphate (ATP)-bound and apo) kinesin-1 motor domains inhibit the shrinkage of guanosine diphosphate (GDP) microtubules by up to two orders of magnitude and expand their lattice spacing by ~1...
March 12, 2018: Nature Nanotechnology
Frédéric Adam, Alexandre Kauskot, Mathieu Kurowska, Nicolas Goudin, Isabelle Munoz, Jean-Claude Bordet, Jian-Dong Huang, Marijke Bryckaert, Alain Fischer, Delphine Borgel, Geneviève de Saint Basile, Olivier D Christophe, Gaël Ménasché
OBJECTIVE: Platelet secretion is crucial for many physiological platelet responses. Even though several regulators of the fusion machinery for secretory granule exocytosis have been identified in platelets, the underlying mechanisms are not yet fully characterized. APPROACH AND RESULTS: By studying a mouse model (cKO [conditional knockout]Kif5b ) lacking Kif5b (kinesin-1 heavy chain) in its megakaryocytes and platelets, we evidenced unstable hemostasis characterized by an increase of blood loss associated to a marked tendency to rebleed in a tail-clip assay and thrombus instability in an in vivo thrombosis model...
March 8, 2018: Arteriosclerosis, Thrombosis, and Vascular Biology
You Kure Wu, Hiroki Umeshima, Junko Kurisu, Mineko Kengaku
Nuclear migration of newly born neurons is essential for cortex formation in the brain. The nucleus is translocated by actin and microtubules, yet the actual force generated by the interplay of these cytoskeletons remains elusive. High-resolution time-lapse observation of migrating murine cerebellar granule cells revealed that the nucleus actively rotates along the direction of its translocation, independently of centrosome motion. Pharmacological and molecular perturbation indicated that spin torque is primarily generated by microtubule motors through the LINC complex in the absence of actomyosin contractility...
March 8, 2018: Development
Melanie Laura Duncan, Jacquelyn Horsington, Preethi Eldi, Zahrah Al Rumaih, Gunasegaran Karupiah, Timothy P Newsome
Ectromelia virus (ECTV) is an orthopoxvirus and the causative agent of mousepox. Like other poxviruses such as variola virus (agent of smallpox), monkeypox virus and vaccinia virus (the live vaccine for smallpox), ECTV promotes actin-nucleation at the surface of infected cells during virus release. Homologs of the viral protein A36 mediate this function through phosphorylation of one or two tyrosine residues that ultimately recruit the cellular Arp2/3 actin-nucleating complex. A36 also functions in the intracellular trafficking of virus mediated by kinesin-1...
March 5, 2018: Viruses
I A Kuznetsov, A V Kuznetsov
We develop a mathematical model that enables us to investigate possible mechanisms by which two primary markers of Alzheimer's disease (AD), extracellular amyloid plaques and intracellular tangles, may be related. Our model investigates the possibility that the decay of anterograde axonal transport of amyloid precursor protein (APP), caused by toxic tau aggregates, leads to decreased APP transport towards the synapse and APP accumulation in the soma. The developed model thus couples three processes: (i) slow axonal transport of tau, (ii) tau misfolding and agglomeration, which we simulated by using the Finke-Watzky model and (iii) fast axonal transport of APP...
February 2018: Proceedings. Mathematical, Physical, and Engineering Sciences
Rossina Novas, Magdalena Cardenas-Rodriguez, Paola Lepanto, Matías Fabregat, Magela Rodao, María Inés Fariello, Mauricio Ramos, Camila Davison, Gabriela Casanova, Lucía Alfaya, Federico Lecumberry, Gualberto González-Sapienza, Florencia Irigoín, Jose L Badano
Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinal degeneration, obesity, polydactyly, renal disease and mental retardation. CCDC28B is a BBS-associated protein that we have previously shown plays a role in cilia length regulation whereby its depletion results in shortened cilia both in cells and Danio rerio (zebrafish). At least part of that role is achieved by its interaction with the mTORC2 component SIN1, but the mechanistic details of this interaction and/or additional functions that CCDC28B might play in the context of cilia remain poorly understood...
February 14, 2018: Scientific Reports
Joseph M Muretta, Babu J N Reddy, Guido Scarabelli, Alex F Thompson, Shashank Jariwala, Jennifer Major, Monica Venere, Jeremy N Rich, Belinda Willard, David D Thomas, Jason Stumpff, Barry J Grant, Steven P Gross, Steven S Rosenfeld
Numerous posttranslational modifications have been described in kinesins, but their consequences on motor mechanics are largely unknown. We investigated one of these-acetylation of lysine 146 in Eg5-by creating an acetylation mimetic lysine to glutamine substitution (K146Q). Lysine 146 is located in the α2 helix of the motor domain, where it makes an ionic bond with aspartate 91 on the neighboring α1 helix. Molecular dynamics simulations predict that disrupting this bond enhances catalytic site-neck linker coupling...
February 5, 2018: Proceedings of the National Academy of Sciences of the United States of America
Qingzhou Feng, Keith J Mickolajczyk, Geng-Yuan Chen, William O Hancock
Kinesin-based cargo transport in cells frequently involves the coordinated activity of multiple motors, including kinesins from different families that move at different speeds. However, compared to the progress at the single-molecule level, mechanisms by which multiple kinesins coordinate their activity during cargo transport are poorly understood. To understand these multimotor coordination mechanisms, defined pairs of kinesin-1 and kinesin-2 motors were assembled on DNA scaffolds and their motility examined in vitro...
January 23, 2018: Biophysical Journal
Lu Zhou, Minoas Evangelinos, Valentin Wernet, Antonia F Eckert, Yuji Ishitsuka, Reinhard Fischer, G Ulrich Nienhaus, Norio Takeshita
Polarized growth of filamentous fungi requires continuous transport of biomolecules to the hyphal tip. To this end, construction materials are packaged in vesicles and transported by motor proteins along microtubules and actin filaments. We have studied these processes with quantitative superresolution localization microscopy of live Aspergillus nidulans cells expressing the photoconvertible protein mEosFPthermo fused to the chitin synthase ChsB. ChsB is mainly located at the Spitzenkörper near the hyphal tip and produces chitin, a key component of the cell wall...
January 2018: Science Advances
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No abstract text is available yet for this article.
February 1, 2018: Molecular Biology of the Cell
Michael Bugiel, Aniruddha Mitra, Salvatore Girardo, Stefan Diez, Erik Schäffer
Three-dimensional (3D) nanometer tracking of single biomolecules provides important information about their biological function. However, existing microscopy approaches often have only limited spatial or temporal precision and do not allow the application of defined loads. Here, we developed and applied a high-precision 3D-optical-tweezers force clamp to track in vitro the 3D motion of single kinesin-1 motor proteins along microtubules. To provide the motors with unimpeded access to the whole microtubule lattice, we mounted the microtubules on topographic surface features generated by UV-nanoimprint lithography...
January 30, 2018: Nano Letters
Betsy B McIntosh, Serapion Pyrpassopoulos, Erika L F Holzbaur, E Michael Ostap
Microtubule and actin filament molecular motors such as kinesin-1 and myosin-Ic (Myo1c) transport and remodel membrane-bound vesicles; however, it is unclear how they coordinate to accomplish these tasks. We introduced kinesin-1- and Myo1c-bound giant unilamellar vesicles (GUVs) into a micropatterned in vitro cytoskeletal matrix modeled after the subcellular architecture where vesicular sorting and membrane remodeling are observed. This array was composed of sparse microtubules intersecting regions dense with actin filaments, and revealed that Myo1c-dependent tethering of GUVs enabled kinesin-1-driven membrane deformation and tubulation...
January 9, 2018: Current Biology: CB
Wonseok Hwang, Changbong Hyeon
An efficient molecular motor would deliver cargos to the target site at a high speed and in a punctual manner while consuming a minimal amount of energy. According to a recently formulated thermodynamic principle, referred to as the thermodynamic uncertainty relation, the travel distance of a motor and its variance are, however, constrained by the free energy being consumed. Here we use the principle underlying the uncertainty relation to quantify the transport efficiency of molecular motors for varying ATP concentration ([ATP]) and applied load (f)...
January 12, 2018: Journal of Physical Chemistry Letters
Amy Tsui-Chi Lam, Stanislav Tsitkov, Yifei Zhang, Henry Hess
Biological materials and systems often dynamically self-assemble and disassemble, forming temporary structures as needed and allowing for dynamic responses to stimuli and changing environmental conditions. However, this dynamic interplay of localized component recruitment and release has been difficult to achieve in artificial molecular-scale systems, which are usually designed to have long-lasting, stable bonds. Here, we report the experimental realization of a molecular-scale system that dynamically assembles and disassembles its building blocks while retaining functionality...
January 10, 2018: Nano Letters
Zhisong Wang
Many motor proteins achieve high efficiency for chemomechanical conversion, and single-molecule force-resisting experiments are a major tool to detect the chemomechanical coupling of efficient motors. Here, we introduce several quantitative relations that involve only parameters extracted from force-resisting experiments and offer new benchmarks beyond mere efficiency to judge the chemomechanical optimality or deficit of evolutionary remote motors on the same footing. The relations are verified by the experimental data from F1-ATPase, kinesin-1, myosin V and cytoplasmic dynein, which are representative members of four motor protein families...
January 3, 2018: Integrative Biology: Quantitative Biosciences From Nano to Macro
Jared P Bergman, Matthew J Bovyn, Florence F Doval, Abhimanyu Sharma, Manasa V Gudheti, Steven P Gross, Jun F Allard, Michael D Vershinin
The eukaryotic cell's microtubule cytoskeleton is a complex 3D filament network. Microtubules cross at a wide variety of separation distances and angles. Prior studies in vivo and in vitro suggest that cargo transport is affected by intersection geometry. However, geometric complexity is not yet widely appreciated as a regulatory factor in its own right, and mechanisms that underlie this mode of regulation are not well understood. We have used our recently reported 3D microtubule manipulation system to build filament crossings de novo in a purified in vitro environment and used them to assay kinesin-1-driven model cargo navigation...
January 2, 2018: Proceedings of the National Academy of Sciences of the United States of America
Thomas S Randall, Yan Y Yip, Daynea J Wallock-Richards, Karin Pfisterer, Anneri Sanger, Weronika Ficek, Roberto A Steiner, Andrew J Beavil, Maddy Parsons, Mark P Dodding
The microtubule motor kinesin-1 interacts via its cargo-binding domain with both microtubules and organelles, and hence plays an important role in controlling organelle transport and microtubule dynamics. In the absence of cargo, kinesin-1 is found in an autoinhibited conformation. The molecular basis of how cargo engagement affects the balance between kinesin-1's active and inactive conformations and roles in microtubule dynamics and organelle transport is not well understood. Here we describe the discovery of kinesore, a small molecule that in vitro inhibits kinesin-1 interactions with short linear peptide motifs found in organelle-specific cargo adaptors, yet activates kinesin-1's function of controlling microtubule dynamics in cells, demonstrating that these functions are mechanistically coupled...
December 26, 2017: Proceedings of the National Academy of Sciences of the United States of America
Felix Ruhnow, Linda Kloβ, Stefan Diez
Cytoskeletal motor proteins are essential to the function of a wide range of intracellular mechano-systems. The biophysical characterization of their movement along their filamentous tracks is therefore of large importance. Toward this end, single-molecule, in vitro stepping-motility assays are commonly used to determine motor velocity and run length. However, comparing results from such experiments has proved difficult due to influences from variations in the experimental conditions and the data analysis methods...
December 5, 2017: Biophysical Journal
Samata Chaudhuri, Till Korten, Slobodanka Korten, Gloria Milani, Tobia Lana, Geertruy Te Kronnie, Stefan Diez
Development of miniaturized devices for the rapid and sensitive detection of analyte is crucial for various applications across healthcare, pharmaceutical, environmental, and other industries. Here, we report on the detection of unlabeled analyte by using fluorescently labeled, antibody-conjugated microtubules in a kinesin-1 gliding motility assay. The detection principle is based on the formation of fluorescent supramolecular assemblies of microtubule bundles and spools in the presence of multivalent analytes...
January 10, 2018: Nano Letters
Roderick P Tas, Anaël Chazeau, Bas M C Cloin, Maaike L A Lambers, Casper C Hoogenraad, Lukas C Kapitein
Microtubules are essential for polarized transport in neurons, but how their organization guides motor proteins to axons or dendrites is unclear. Because different motors recognize distinct microtubule properties, we used optical nanoscopy to examine the relationship between microtubule orientations, stability, and modifications. Nanometric tracking of motors to super-resolve microtubules and determine their polarity revealed that in dendrites, stable and acetylated microtubules are mostly oriented minus-end out, while dynamic and tyrosinated microtubules are oriented oppositely...
December 20, 2017: Neuron
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