Comparing Guiding Track Requirements for Myosin- and Kinesin-Powered Molecular Shuttles

Abstract

The design of nanoscale transport systems utilizing motor proteins as engines has advanced rapidly. Here, actin/myosin- and microtubule/kinesin-based molecular shuttles are compared with respect to their requirements for track designs. To this end, the trajectory persistence length of actin filaments gliding on myosin-coated surfaces has been experimentally determined to be equal to 8.8 +/- 2 microm. This measurement complements an earlier determination of the trajectory persistence length of microtubules gliding on kinesin-coated surfaces and enables a comparison of the accessible track designs for kinesin and myosin motor-powered systems. Despite the 200-fold smaller stiffness of actin filaments compared to that of microtubules, the dimensions of myosin tracks for actin filaments have to be quite similar to the dimensions of kinesin tracks for microtubules (radii larger than 200 nm and widths smaller than 0.9 microm compared to 600 nm and 19 microm). The difference in gliding speed is shown to require additional consideration in the design of track modules.

Self-Organization of Motor-Propelled Cytoskeletal Filaments at Topographically Defined Borders

“…A Monte-Carlo simulation approach was developed on basis of previous work [25, 26] and implemented in Matlab (Mathworks, Natick, MA). In the modelling, different geometries for a motility supporting area, delimited by walls like those surrounding the tracks in Figure 1, could be simulated from an ellipse and two second degree polynomials (Figure 2).…”

“…The motility of actin filaments on micro- and nanopatterned surfaces may be simulated by Monte-Carlo approaches [25, 26] where the winding filament paths on open areas are characterized by a persistence length (the length along a polymer/path over which the “memory” of a tangent angle of the polymer/path is maintained. For example, the higher flexural rigidity of the polymer the longer the persistence length.)…”

Determination of the persistence length of actin filaments on microcontact printed myosin patterns

“…diagnostic, or biocomputation devices, the persistence length of cytoskeleton filaments should be precisely known and, if possibly, controlled. [30] The values of the persistence length of actin filaments reported in the literature [31][32][33] are between 5 and 17 μm, with the latest measurements [34,35] reporting the value of ~ 8.75 μm. While the average value of 4.67 μm, as calculated here from the motility on narrowly confined spaces, is consistent with the other reports, it is nevertheless placed at the lower end of the spectrum.…”

Engineering Applications of Biomolecular Motors

“…Thermal fluctuations of the advancing tip of the cytoskeletal filament cause the deviations from a straight path, and, as a result, the trajectory can be described by a persistence length (63,64). In principle, the trajectory persistence length should be equal to the filament persistence length (65), but the length dependency of the microtubule persistence length (66) reduces the trajectory persistence length to the persistence length of the tip segment of the gliding microtubule (63,67,68). Using the statistical description of the shuttle movement, one can accurately predict average shuttle behavior in Monte Carlo simulations that include the effect of physical barriers (69) and external forces (70).…”