Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Controlling self-assembly of microtubule spools via kinesin motor density.

ABSTRACT: Active self-assembly, in which non-thermal energy is consumed by the system to put together building blocks, allows the creation of non-equilibrium structures and active materials. Microtubule spools assembled in gliding assays are one example of such non-equilibrium structures, capable of storing bending energies on the order of 10(5) kT. Although these structures arise spontaneously in experiments, the origin of microtubule spooling has long been debated. Here, using a stepwise kinesin gradient, we demonstrate that spool assembly can be controlled by the surface density of kinesin motors, showing that pinning of microtubules due to dead motors plays a dominant role in spool initiation.

SUBMITTER: Lam AT

PROVIDER: S-EPMC4198420 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Controlling self-assembly of microtubule spools via kinesin motor density.

Lam A T AT Curschellas C C Krovvidi D D Hess H H

Soft matter 20141101 43

Active self-assembly, in which non-thermal energy is consumed by the system to put together building blocks, allows the creation of non-equilibrium structures and active materials. Microtubule spools assembled in gliding assays are one example of such non-equilibrium structures, capable of storing bending energies on the order of 10(5) kT. Although these structures arise spontaneously in experiments, the origin of microtubule spooling has long been debated. Here, using a stepwise kinesin gradien ...[more]

PMID: 25269076

Similar Datasets

Kinesin motor density and dynamics in gliding microtubule motility.

Project description:Kinesin motors and their associated filaments, microtubules, are essential to many biological processes. The motor and filament system can be reconstituted in vitro with the surface-adhered motors transporting the filaments along the surface. In this format, the system has been used to study active self-assembly and to power microdevices or perform analyte detection. However, fundamental properties of the system, such as the spacing of the kinesin motors bound to the microtubule and the dynamics of binding, remain poorly understood. We show that Fluorescence Interference Contrast (FLIC) microscopy can illuminate the exact height of the microtubule, which for a sufficiently low surface density of kinesin, reveals the locations of the bound motors. We examine the spacing of the kinesin motors on the microtubules at various kinesin surface densities and compare the results with theory. FLIC reveals that the system is highly dynamic, with kinesin binding and unbinding along the length of the microtubule as it is transported along the surface.

| S-EPMC6510761 | biostudies-literature

The axonal transport motor kinesin-2 navigates microtubule obstacles via protofilament switching.

Project description:Axonal transport involves kinesin motors trafficking cargo along microtubules that are rich in microtubule-associated proteins (MAPs). Much attention has focused on the behavior of kinesin-1 in the presence of MAPs, which has overshadowed understanding the contribution of other kinesins such as kinesin-2 in axonal transport. We have previously shown that, unlike kinesin-1, kinesin-2 in vitro motility is insensitive to the neuronal MAP Tau. However, the mechanism by which kinesin-2 efficiently navigates Tau on the microtubule surface is unknown. We hypothesized that mammalian kinesin-2 side-steps to adjacent protofilaments to maneuver around MAPs. To test this, we used single-molecule imaging to track the characteristic run length and protofilament switching behavior of kinesin-1 and kinesin-2 motors in the absence and presence of 2 different microtubule obstacles. Under all conditions tested, kinesin-2 switched protofilaments more frequently than kinesin-1. Using computational modeling that recapitulates run length and switching frequencies in the presence of varying roadblock densities, we conclude that kinesin-2 switches protofilaments to navigate around microtubule obstacles. Elucidating the kinesin-2 mechanism of navigation on the crowded microtubule surface provides a refined view of its contribution in facilitating axonal transport.

| S-EPMC5687255 | biostudies-literature

Kinesin-binding protein remodels the kinesin motor to prevent microtubule binding.

Project description: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.

| S-EPMC8604404 | biostudies-literature

A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast.

Project description:Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end-directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end-directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.

| S-EPMC5706992 | biostudies-literature

Electro-detachment of kinesin motor domain from microtubule in silico.

Project description:Kinesin is a motor protein essential in cellular functions, such as intracellular transport and cell-division, as well as for enabling nanoscopic transport in bio-nanotechnology. Therefore, for effective control of function for nanotechnological applications, it is important to be able to modify the function of kinesin. To circumvent the limitations of chemical modifications, here we identify another potential approach for kinesin control: the use of electric forces. Using full-atom molecular dynamics simulations (247,358 atoms, total time ∼ 4.4 μs), we demonstrate, for the first time, that the kinesin-1 motor domain can be detached from a microtubule by an intense electric field within the nanosecond timescale. We show that this effect is field-direction dependent and field-strength dependent. A detailed analysis of the electric forces and the work carried out by electric field acting on the microtubule-kinesin system shows that it is the combined action of the electric field pulling on the β-tubulin C-terminus and the electric-field-induced torque on the kinesin dipole moment that causes kinesin detachment from the microtubule. It is shown, for the first time in a mechanistic manner, that an electric field can dramatically affect molecular interactions in a heterologous functional protein assembly. Our results contribute to understanding of electromagnetic field-biomatter interactions on a molecular level, with potential biomedical and bio-nanotechnological applications for harnessing control of protein nanomotors.

| S-EPMC9939557 | biostudies-literature

Visualisation of a kinesin-13 motor on microtubule end mimics.

Project description:An expanding collection of proteins localises to microtubule ends to regulate cytoskeletal dynamics and architecture by unknown molecular mechanisms. Electron microscopy is invaluable for studying microtubule structure, but because microtubule ends are heterogeneous, their structures are difficult to determine. We therefore investigated whether tubulin oligomers induced by the drug dolastatin could mimic microtubule ends. The microtubule end-dependent ATPase of kinesin-13 motors is coupled to microtubule depolymerisation. Significantly, kinesin-13 motor ATPase activity is stimulated by dolastatin-tubulin oligomers, suggesting, first, that these oligomers share properties with microtubule ends and, second, that the physical presence of an end is less important than terminal tubulin flexibility for microtubule end recognition by the kinesin-13 motor. Using electron microscopy, we visualised the kinesin-13 motor-dolastatin-tubulin oligomer interaction in nucleotide states mimicking steps in the ATPase cycle. This enabled us to detect conformational changes that the motor undergoes during depolymerisation. Our data suggest that such tubulin oligomers can be used to examine other microtubule end-binding proteins.

| S-EPMC2396873 | biostudies-literature

Microtubule Minus-End Binding Protein CAMSAP2 and Kinesin-14 Motor KIFC3 Control Dendritic Microtubule Organization.

Project description:Neuronal dendrites are characterized by an anti-parallel microtubule organization. The mixed oriented microtubules promote dendrite development and facilitate polarized cargo trafficking; however, the mechanism that regulates dendritic microtubule organization is still unclear. Here, we found that the kinesin-14 motor KIFC3 is important for organizing dendritic microtubules and to control dendrite development. The kinesin-14 motor proteins (Drosophila melanogaster Ncd, Saccharomyces cerevisiae Kar3, Saccharomyces pombe Pkl1, and Xenopus laevis XCTK2) are characterized by a C-terminal motor domain and are well described to organize the spindle microtubule during mitosis using an additional microtubule binding site in the N terminus [1-4]. In mammals, there are three kinesin-14 members, KIFC1, KIFC2, and KIFC3. It was recently shown that KIFC1 is important for organizing axonal microtubules in neurons, a process that depends on the two microtubule-interacting domains [5]. Unlike KIFC1, KIFC2 and KIFC3 lack the N-terminal microtubule binding domain and only have one microtubule-interacting domain, the motor domain [6, 7]. Thus, in order to regulate microtubule-microtubule crosslinking or sliding, KIFC2 and KIFC3 need to interact with additional microtubule binding proteins to connect two microtubules. We found that KIFC3 has a dendrite-specific distribution and interacts with microtubule minus-end binding protein CAMSAP2. Depletion of KIFC3 or CAMSAP2 results in increased microtubule dynamics during dendritic development. We propose a model in which CAMSAP2 anchors KIFC3 at microtubule minus ends and immobilizes microtubule arrays in dendrites.

| S-EPMC7063570 | biostudies-literature

Rapid microtubule self-assembly kinetics.

Project description:Microtubule assembly is vital for many fundamental cellular processes. Current models for microtubule assembly kinetics assume that the subunit dissociation rate from a microtubule tip is independent of free subunit concentration. Total-Internal-Reflection-Fluorescence (TIRF) microscopy experiments and data from a laser tweezers assay that measures in vitro microtubule assembly with nanometer resolution, provides evidence that the subunit dissociation rate from a microtubule tip increases as the free subunit concentration increases. These data are consistent with a two-dimensional model for microtubule assembly, and are explained by a shift in microtubule tip structure from a relatively blunt shape at low free concentrations to relatively tapered at high free concentrations. We find that because both the association and the dissociation rates increase at higher free subunit concentrations, the kinetics of microtubule assembly are an order-of-magnitude higher than currently estimated in the literature.

| S-EPMC3171214 | biostudies-literature

Motility and microtubule depolymerization mechanisms of the Kinesin-8 motor, KIF19A.

Project description:The kinesin-8 motor, KIF19A, accumulates at cilia tips and controls cilium length. Defective KIF19A leads to hydrocephalus and female infertility because of abnormally elongated cilia. Uniquely among kinesins, KIF19A possesses the dual functions of motility along ciliary microtubules and depolymerization of microtubules. To elucidate the molecular mechanisms of these functions we solved the crystal structure of its motor domain and determined its cryo-electron microscopy structure complexed with a microtubule. The features of KIF19A that enable its dual function are clustered on its microtubule-binding side. Unexpectedly, a destabilized switch II coordinates with a destabilized L8 to enable KIF19A to adjust to both straight and curved microtubule protofilaments. The basic clusters of L2 and L12 tether the microtubule. The long L2 with a characteristic acidic-hydrophobic-basic sequence effectively stabilizes the curved conformation of microtubule ends. Hence, KIF19A utilizes multiple strategies to accomplish the dual functions of motility and microtubule depolymerization by ATP hydrolysis.

| S-EPMC5045296 | biostudies-literature

Kinesin-5, a mitotic microtubule-associated motor protein, modulates neuronal migration.

Project description:Kinesin-5 (also called Eg5 or kif11) is a homotetrameric motor protein that functions by modulating microtubule (MT)-MT interactions. In the case of mitosis, kinesin-5 slows the rate of separation of the half-spindles. In the case of the axon, kinesin-5 limits the frequency of transport of short MTs, and also limits the rate of axonal growth. Here we show that experimental inhibition of kinesin-5 in cultured migratory neurons results in a faster but more randomly moving neuron with a shorter leading process. As is the case with axons of stationary neurons, short MT transport frequency is notably enhanced in the leading process of the migratory neuron when kinesin-5 is inhibited. Conversely, overexpression of kinesin-5, both in culture and in developing cerebral cortex, causes migration to slow and even cease. Regions of anti-parallel MT organization behind the centrosome were shown to be especially rich in kinesin-5, implicating these regions as potential sites where kinesin-5 forces may be especially relevant. We posit that kinesin-5 acts as a "brake" on MT-MT interactions that modulates the advance of the entire MT apparatus. In so doing, kinesin-5 regulates the rate and directionality of neuronal migration and possibly the cessation of migration when the neuron reaches its destination.

| S-EPMC3084678 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data