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Measuring the Motile Properties of Single Dynein Molecules
Published in Keiko Hirose, Handbook of Dynein, 2019
Hideo Higuchi, Chikako Shingyoji
Intracellular transport along microtubules is driven by the molecular motors of the kinesin and cytoplasmic dynein families. Dyneins and kinesins can be attached to the same cargo, which results in a tug-of-war between the motors. The force generated by the motors in cells was measured using an optical trap of endosomes. The value of the stall force generated by dynein bound to Dictyostelium endosomes was calculated to be 1.1 pN [35]. Gross and his group reported that there was a higher stall force of approximately 2.6 pN in Drosophila embryos [33]. This suggests that previous data (∼1 pN) were underestimated because of the inclusion of premature detachments in the analysis [33]. In contrast to these results, Sims and Xie optically trapped a lipid droplet in human cells and calculated the stall force generated by single dynein molecules to be 3–5 pN [25]. The stall force of single dynein molecules in human cells was slightly smaller than 6–8 pN obtained in the in vitro assay using porcine dynein. The forces measured in the cell may be underestimated because detachment of dynein before stalling will be included in the data [33].
Molecular Motors
Published in Yubing Xie, The Nanobiotechnology Handbook, 2012
Timothy D. Riehlman, Zachary T. Olmsted, Janet L. Paluh
The complexity of how to sort and transport various cargos begins often with the decision of whether to functionalize the tail or stalk of a motor versus manipulating the microtubule to carry out the transport (Figure 4.4). In the latter, the microtubule will be driven on a bed of fixed kinesin motors that use the energy of ATP hydrolysis to transport the microtubule. The consideration here is how to attach desired cargos to the microtubule (Malcos and Hancock, 2011). It is important to design in features of high affinity and high specificity. The reversible bonds for attachment will have a specific lifetime and need to withstand forces due to Brownian motion, which require bond strengths between 1 pN and 1 nN. An example of how Brownian forces affect bonds was revealed by characterization of the noncovalent bond between biotin and streptavidin. This bond can withstand a force of 5 pN for 1 min, though it survives for only 100 ms when a 170 pN force is applied (Merkel et al., 1999). The size of cargo that can be applied in such devices varies, from nanometer to the microscale. In one example, Hiyama et al. (2010) demonstrated transport using liposomes as cargo that varied in size from 100 to 590 nm. Though fewer numbers of larger cargo were transported, the larger liposomes carried a greater total volume of cargo than that of the smaller liposomes combined. Kinesin easily transports supramolecular structures with a diameter of 20–50 nm, such as synaptic vesicles (Cai and Sheng, 2009). In principle a collective force generated by a fleet of kinesins is preferred (Erickson et al. 2011) and can work to transport small microchips up to 20 μm in length (Limberis and Stewart, 2000).
Classifications and typical examples of biomotors
Published in Peixuan Guo, Zhengyi Zhao, Biomotors: Linear, Rotation, and Revolution Motion Mechanisms, 2017
Linear motors were the first described motor proteins. Unlike the rotation mechanism of the previous class of motors, they advance unidirectionally along a cytoskeletal track. This category includes three main types of motors—myosin, kinesin, and dynein—each of which has a large number of subtypes. Like the majority of other motors, they depend on ATP to produce mechanical work. They are responsible for most of the movement in eukaryotic cells. Myosin, for example, plays a primary role in muscle contraction as well as a variety of other intracellular functions. Kinesin is involved in several activities including meiosis, mitosis, and intracellular transport of cellular cargo.
Markov modeling of run length and velocity for molecular motors
Published in Applicable Analysis, 2022
James L. Buchanan, Robert P. Gilbert
Intracellular cargo is moved along the cytoskeletal tracks by the molecular motors kinesin, dynein, and myosin. Asbury et al. [1], Muthukrishnan et al. [2], Elting et al. [3] and Shastry and Hancock [4] describe in vitro experiments in which the procession of molecular motors along microtubule tracks attached to glass plates is measured. The latter three articles give statistics on the length traversed until detachment.