Actin cable distribution and dynamics arising from cross-linking, motor pulling, and filament turnover.
Bottom Line: Our simulations reproduce the particular actin cable structures in myoVΔ cells and predict the effect of increased myosin V pulling.Increasing cross-linking parameters generates thicker actin cables.It also leads to antiparallel and parallel phases with straight or curved cables, consistent with observations of cells overexpressing α-actinin.
Affiliation: Department of Physics, Lehigh University, Bethlehem, PA 18015.Show MeSH
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Mentions: Prior experiments show that deletion of both copies of myosin V, Myo51p and Myo52p, leads to short, curved, and misoriented cables in interphase fission yeast cells (Lo Presti et al., 2012; Figure 3A). By eliminating the simulated myosin V pulling, actin filaments converge into thicker and less straight bundles near the cell tips that do not span the entire cell, in agreement with experimental observations (Figure 3B and Supplemental Video S1). Simulations predict that excessive myosin V pulling unbundles the cables (Figure 3B): as the number of myosin V per unit length along the filament, ρmyo, increases from 0 to 10/μm, the percentage of bundled actin filaments decreases from 75 to 58% (Figure 3C). Increase in ρmyo also leads to a more uniform distribution of filaments across the cell (Figure 3D and Supplemental Figure S3D). Enhanced myosin pulling affects the number of filaments in the largest linked cable, increases the total number of cables, and straightens them (Supplemental Figure S3, A–C). This highlights the critical role of motors in actin cable organization.
Affiliation: Department of Physics, Lehigh University, Bethlehem, PA 18015.