scholarly journals Kinesin-14 motors drive a right-handed helical motion of antiparallel microtubules around each other

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Aniruddha Mitra ◽  
Laura Meißner ◽  
Rojapriyadharshini Gandhimathi ◽  
Roman Renger ◽  
Felix Ruhnow ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Three Dimensional ◽  
Helical Motion ◽  
In Vitro Motility Assay ◽  
In Vitro Motility ◽  
Torque Generation ◽  
Free Microtubules ◽  
20 Nm

Abstract Within the mitotic spindle, kinesin motors cross-link and slide overlapping microtubules. Some of these motors exhibit off-axis power strokes, but their impact on motility and force generation in microtubule overlaps has not been investigated. Here, we develop and utilize a three-dimensional in vitro motility assay to explore kinesin-14, Ncd, driven sliding of cross-linked microtubules. We observe that free microtubules, sliding on suspended microtubules, not only rotate around their own axis but also move around the suspended microtubules with right-handed helical trajectories. Importantly, the associated torque is large enough to cause microtubule twisting and coiling. Further, our technique allows us to measure the in situ spatial extension of the motors between cross-linked microtubules to be about 20 nm. We argue that the capability of microtubule-crosslinking kinesins to cause helical motion of overlapping microtubules around each other allows for flexible filament organization, roadblock circumvention and torque generation in the mitotic spindle.

scholarly journals The kinesin-14, Ncd, drives a right-handed, helical motion of antiparallel microtubules around each other

2019 ◽  
Author(s):  
Aniruddha Mitra ◽  
Rojapriyadharshini Gandhimathi ◽  
Felix Ruhnow ◽  
Roman Renger ◽  
Stefan Diez
Keyword(s):  
Mitotic Spindle ◽  
Three Dimensional ◽  
Helical Motion ◽  
Flexible Filament ◽  
Torque Generation ◽  
Free Microtubules ◽  
20 Nm ◽  
The Impact

AbstractWithin the mitotic spindle, several kinesin motors crosslink and slide microtubules. While some of them (e.g. kinesin-5, kinesin-8 and kinesin-14) have been shown to exhibit sideways components in their step cycles, the impact of the resulting off-axis power strokes on motility and force generation in the spindle has not been investigated so far. Here, we develop and utilize a novel three-dimensional in vitro motility assay to explore the kinesin-14, Ncd, driven sliding of crosslinked, fluorescently-labeled microtubules. We find that free microtubules, sliding in an antiparallel orientation on microtubules suspended between nanofabricated ridges, not only rotate around their own axis but also move around the suspended microtubules with right-handed helical trajectories. In contrast, microtubules crosslinked in parallel orientation are static with neither longitudinal nor helical motion. Further, our technique allows us to measure the in situ spatial extension of the motors between the crosslinked microtubules to be about 20 nm. We argue that the capability of microtubule-crosslinking kinesins to cause helical motion of microtubules around each other allows for flexible filament organization, roadblock circumvention and torque generation in the mitotic spindle.

scholarly journals Troponin I and troponin T interact with troponin C to produce different Ca2+-dependent effects on actin–tropomyosin filament motility

1997 ◽  
Vol 327 (2) ◽  
pp. 335-340 ◽  
Author(s):  
Wu BING ◽  
D. C. Iain FRASER ◽  
B. Steven MARSTON
Keyword(s):  
Skeletal Muscle ◽  
Troponin I ◽  
Troponin T ◽  
Troponin C ◽  
Heavy Meromyosin ◽  
In Vitro Motility Assay ◽  
Velocity Increase ◽  
In Vitro Motility ◽  
20 Nm

We have developed an in vitro motility assay to make a detailed quantitative analysis of Ca2+ control of skeletal-muscle troponin-tropomyosin control of actin-filament movement over immobilized myosin. Ca2+ regulates both filament velocity and the fraction of filaments that are motile. We have demonstrated that the two effects are due to separate interactions of troponin C with troponin I and troponin T. When 64 nM of the complex actin-tropomyosin-troponin I-troponin C was added at pCa 5, more than 80% of filaments were moving and their velocity did not change. At pCa 9, more than 20% of the filaments were moving. When 20 nM of the complex actin-tropomyosin-troponin T+troponin I+troponin C was added at pCa 5, filament motility remained high, whereas velocity increased. The 30% increase in velocity observed when troponin T was present was also observed when heavy meromyosin fragment 1 labelled with N-ethylmaleimide (NEM S-1) was added after actin-tropomyosin filaments. The NEM S-1 effect was not additive with the troponin T-dependent velocity increase. The pattern of motile behaviour is characteristic of myosin on silicone-treated glass and different from the behaviour on nitrocellulose-coated glass.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

scholarly journals Cardioinotropic Effects in Subchronic Intoxication of Rats with Lead and/or Cadmium Oxide Nanoparticles

2021 ◽  
Vol 22 (7) ◽  
pp. 3466
Author(s):  
Svetlana V. Klinova ◽  
Boris A. Katsnelson ◽  
Ilzira A. Minigalieva ◽  
Oksana P. Gerzen ◽  
Alexander A. Balakin ◽  
...  
Keyword(s):  
Cadmium Oxide ◽  
Male Rats ◽  
Sliding Velocity ◽  
Muscle Type ◽  
In Vitro Motility Assay ◽  
Thin Filaments ◽  
In Vitro Motility ◽  
Toxic Impact ◽  
Cdo Nanoparticles

Subchronic intoxication was induced in outbred male rats by repeated intraperitoneal injections with lead oxide (PbO) and/or cadmium oxide (CdO) nanoparticles (NPs) 3 times a week during 6 weeks for the purpose of examining its effects on the contractile characteristics of isolated right ventricle trabeculae and papillary muscles in isometric and afterload contractions. Isolated and combined intoxication with these NPs was observed to reduce the mechanical work produced by both types of myocardial preparation. Using the in vitro motility assay, we showed that the sliding velocity of regulated thin filaments drops under both isolated and combined intoxication with CdO–NP and PbO–NP. These results correlate with a shift in the expression of myosin heavy chain (MHC) isoforms towards slowly cycling β–MHC. The type of CdO–NP + PbO–NP combined cardiotoxicity depends on the effect of the toxic impact, the extent of this effect, the ratio of toxicant doses, and the degree of stretching of cardiomyocytes and muscle type studied. Some indices of combined Pb–NP and CdO–NP cardiotoxicity and general toxicity (genotoxicity included) became fully or partly normalized if intoxication developed against background administration of a bioprotective complex.

Caged FEDA-ATP: a new tool in the measurement of ATP turnover during the in vitro motility assay

1995 ◽  
Vol 23 (3) ◽  
pp. 401S-401S ◽  
Author(s):  
Daren S. Jeffreys ◽  
Robert J. Eaton ◽  
Clive R. Bagshaw
Keyword(s):  
Motility Assay ◽  
In Vitro Motility Assay ◽  
In Vitro Motility ◽  
Atp Turnover

scholarly journals An automated in vitro motility assay for high-throughput studies of molecular motors

Lab on a Chip ◽  
2018 ◽  
Vol 18 (20) ◽  
pp. 3196-3206 ◽  
Author(s):  
Till Korten ◽  
Elena Tavkin ◽  
Lara Scharrel ◽  
Vandana Singh Kushwaha ◽  
Stefan Diez
Keyword(s):  
High Throughput ◽  
Molecular Motors ◽  
Lab On A Chip ◽  
Force Generation ◽  
Motility Assay ◽  
In Vitro Motility Assay ◽  
In Vitro Motility ◽  
Cargo Transport

Molecular motors, essential to force-generation and cargo transport within cells, are invaluable tools for powering nanobiotechnological lab-on-a-chip devices.

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