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Subneuronal Processing of Information by Solitary Waves and Stochastic Processes
Published in Sergey Edward Lyshevski, Nano and Molecular Electronics Handbook, 2018
Danko D. Georgiev, James F. Glazebrook
Located within dendrites and axonal projections, microtubules serve as tracks for the transportation of post-Golgi vesicles by microtubule bound motor proteins (such as kinesin and dynein). Microtubules, however, are not passive elements in the vesicle transport, and results of experiments have shown that the tubulin C–terminal tails modulate the kinesin function. The results of [96] have revealed the β–tubulin tail as interacting with the kinesin switch II domain, while the α–tubulin tail possibly interacts with kinesin α 7–helix in such a way that after the kinesin bound ATP is hydrolyzed, the kinesin takes a stroll along the microtubule surface. Native microtubules that possess tubulin tails cannot be decorated by ADP (adenosine diphosphate)–kinesin molecules because of the weak ADP–kinesin/tubulin tail binding, while subtilisin treated microtubules that lack tubulin tails bind stably ADP–kinesin, thus blocking the kinesin walk. From such an experiment, one may conclude that the tubulin tails catalyze the detachment of the kinesin–ADP complex from the microtubule surface, thus permitting the kinesin dimer to take a “step” along the microtubule protofilament.
Structure and Function of Cartilage
Published in Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi, Articular Cartilage, 2017
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi
Microtubules differ from actin and intermediate filaments in terms of both size and filament construction. Tubulin is a heterodimer composed of α/β monomers 55 kDa in size. It self-assembles into hollow 23 nm diameter “tubes” forming the microtubules, with an internal lumen diameter on the order of 15 nm. GTP binding is required for this assembly, and tubulin has GTPase activity, with GTP hydrolysis driving microtubule assembly. Microtubules also differ in their role in resisting force, acting to resist compression more than tension. The cilia and flagella (including the primary cilium) are composed of a microtubule arrangement described as 9 + 2, featuring an outer circle of nine microtubule doublets interconnected with dynein and with an inner arrangement of two microtubules. In addition to resisting compressive force, microtubules are also critically important in intracellular transport of organelles or vesicles through the actions of the dynein and kinesin motor proteins. The role of microtubules in intracellular transport is elegantly demonstrated in the assembly of the mitotic spindle, a structure that results in the intracellular movement and segregation of the replicated DNA into two daughter cells during mitosis.
Innovative and Advanced Motor Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Molecular machines convert chemical, electrical, or other forms of energy into mechanical work for unidirectional movement. As an important component among them, molecular motors refer to the motors in molecular scales. Although molecular motors may overlap with nanomotors in their size, molecular motors often refer to the motors with a single molecule. They are of great interest not only for their basic scientific richness, but also for the potential to revolutionize critical technologies. In fact, molecular motors exist in nature, for example, in the form of myosins. Myosins are motor proteins that play an important role in living organisms in the contraction of muscles and the transport of other molecules between cells [15.70].
Toxicity, metabolism, and mitigation strategies of acrylamide: a comprehensive review
Published in International Journal of Environmental Health Research, 2022
Leila Peivasteh-Roudsari, Marziyeh Karami, Raziyeh Barzegar-Bafrouei, Samane Samiee, Hadis Karami, Behrouz Tajdar-Oranj, Vahideh Mahdavi, Adel Mirza Alizadeh, Parisa Sadighara, Gea Oliveri Conti, Amin Mousavi Khaneghah
Characteristic ataxia, weight loss, the frailty of skeletal muscles, distal swelling, and degeneracy of axons in the central and peripheral nervous systems are general symptoms of neural destruction due to AA exposure to humans (Rifai and Saleh 2020). Severe central nervous system symptoms regarding acute and subacute exposure to a high dose of AA have been reported, including confusion, drowsiness, disorientation, memory loss, and hallucinations. Also, characteristic symptoms of peripheral polyneuropathy may appear concerning long-term exposure to AA, such as tingling of the fingers, numbness of lower limbs, decreased pinprick sensation, sensitivity to touching, lost vibration sense, and weakness or absence of tendon reflexes (Zamani et al. 2017). The interplay of AA with kinesin motor protein in neurons may impair the rapid anterograde transfer of nerve growth factors from the cell body to the periphery, resulting in nerve death. AA has an adverse impact on the absorption of neurotransmitters into a striatal synaptic vesicle, chiefly because of a probable interplay with sulfhydryl groups on particular proteins, which disrupts the presynaptic secretion of neurotransmitters (Kumar et al. 2018).
Filament-motor protein system under loading: instability and limit cycle oscillations
Published in Soft Materials, 2021
Amir Shee, Subhadip Ghosh, Debasish Chaudhuri
We have studied dynamics of a cytoskeletal filament in a motor protein (MP) assay under external loading. We used a mean field description along with linear stability analysis to determine various phase boundaries. Under constant loading, the system shows a transition from stable to unstable behavior. We have shown that the over-damped active system under harmonic loading displays an emergence of spontaneous oscillations via a supercritical Hopf bifurcation. In linear stability analysis, this appears as a boundary between a stable and unstable spiral phase. The non-linearities make the boundary between unstable spiral and linear instability irrelevant, with the system showing stable limit cycle oscillations in both of them. The increase in the critical number of MPs required at the onset of stable limit cycle oscillations with increase in the stiffness of elastic loading may be utilized by spreading cells for sensing the stiffness of extra-cellular matrix. Using a Fokker-Planck description, we analyzed the limitations of the mean field equations used. Finally, we performed numerical simulations involving stochastic dynamics of individual MPs and the filament. The resulting phase diagram shows good agreement with the mean field prediction. While the stochastic dynamics displays characteristic spread of trajectories, they reproduce the limit cycle behavior in an average sense. We obtained semi-quantitative agreement between the mean field prediction for time evolution with stochastic trajectories.
Proteomic analysis of whole-body responses in medaka (Oryzias latipes) exposed to benzalkonium chloride
Published in Journal of Environmental Science and Health, Part A, 2020
Young Sang Kwon, Jae-Woong Jung, Yeong Jin Kim, Chang-Beom Park, Jong Cheol Shon, Jong-Hwan Kim, June-Woo Park, Sang Gon Kim, Jong-Su Seo
Microtubule-associated protein (spot 3) was significantly upregulated in BAC-exposed medaka. Microtubule-associated proteins are involved in microtubule dynamics and are essential for mitotic spindle formation and mitosis progression. Furthermore, microtubule-associated proteins play an essential role in the early developmental stages of zebrafish.[60] Also, microtubule-associated proteins are involved in the regulation of the immune response signaling of microtubules that construct eukaryotic cells and the cytoskeleton.[61] Recent evidence suggests that classical microtubule-associated proteins also guide motor protein transport, interact with the actin cytoskeleton, and are involved in various neuronal signaling networks.[62]