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Actin cable distribution and dynamics arising from cross-linking, motor pulling, and filament turnover.

Tang H, Laporte D, Vavylonis D - Mol. Biol. Cell (2014)

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.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Lehigh University, Bethlehem, PA 18015.

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Clustering of For3p and increase in cross-linking strength promote actin cable formation in simulations. (A) Steady-state configurations under different cluster densities and cross-linking interaction range rcrslnk with 72 formin nucleation sites per cell tip partitioned in the indicated number of clusters. High For3p clustering (cluster number, 4) and large rcrslnk show fewer and thicker actin cables. (B) Number of actin filaments in largest linked cable increases with increasing rcrslnk and cluster density. (C) Bundled actin filament percentage increases with increasing rcrslnk and cluster density. (D) Cable number as a function of rcrslnk and cluster density. (E) Bundled percentage landscape as function of cluster density and rcrslnk corresponding to C. In B–D, error bars are SEM from five runs.
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Figure 7: Clustering of For3p and increase in cross-linking strength promote actin cable formation in simulations. (A) Steady-state configurations under different cluster densities and cross-linking interaction range rcrslnk with 72 formin nucleation sites per cell tip partitioned in the indicated number of clusters. High For3p clustering (cluster number, 4) and large rcrslnk show fewer and thicker actin cables. (B) Number of actin filaments in largest linked cable increases with increasing rcrslnk and cluster density. (C) Bundled actin filament percentage increases with increasing rcrslnk and cluster density. (D) Cable number as a function of rcrslnk and cluster density. (E) Bundled percentage landscape as function of cluster density and rcrslnk corresponding to C. In B–D, error bars are SEM from five runs.

Mentions: For3p generates cables from tip cortical sites containing ∼10 For3p dimers/site (Martin and Chang, 2006). This For3p clustering may help the generation of actin bundles and control of their thickness. It is also possible that For3p clustering is not required for cable formation, since filaments growing from For3p at distant tip sites can form bundles by cross-linking in the cytoplasm. We examined how actin cable distribution depends on the degree of clustering of For3p at cell tips and cross-linking among filaments. In Figure 7 we vary the number of cortical tip sites and distribute a fixed number of filament nuclei randomly among these sites. The cortical cluster sites are randomly distributed on the semispherical cell tip. Formins within the same cortical site are distributed randomly over a small area around the center of the site. We also study the interplay with cross-linking by varying the effective cross-linking range parameter rcrslnk.


Actin cable distribution and dynamics arising from cross-linking, motor pulling, and filament turnover.

Tang H, Laporte D, Vavylonis D - Mol. Biol. Cell (2014)

Clustering of For3p and increase in cross-linking strength promote actin cable formation in simulations. (A) Steady-state configurations under different cluster densities and cross-linking interaction range rcrslnk with 72 formin nucleation sites per cell tip partitioned in the indicated number of clusters. High For3p clustering (cluster number, 4) and large rcrslnk show fewer and thicker actin cables. (B) Number of actin filaments in largest linked cable increases with increasing rcrslnk and cluster density. (C) Bundled actin filament percentage increases with increasing rcrslnk and cluster density. (D) Cable number as a function of rcrslnk and cluster density. (E) Bundled percentage landscape as function of cluster density and rcrslnk corresponding to C. In B–D, error bars are SEM from five runs.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 7: Clustering of For3p and increase in cross-linking strength promote actin cable formation in simulations. (A) Steady-state configurations under different cluster densities and cross-linking interaction range rcrslnk with 72 formin nucleation sites per cell tip partitioned in the indicated number of clusters. High For3p clustering (cluster number, 4) and large rcrslnk show fewer and thicker actin cables. (B) Number of actin filaments in largest linked cable increases with increasing rcrslnk and cluster density. (C) Bundled actin filament percentage increases with increasing rcrslnk and cluster density. (D) Cable number as a function of rcrslnk and cluster density. (E) Bundled percentage landscape as function of cluster density and rcrslnk corresponding to C. In B–D, error bars are SEM from five runs.
Mentions: For3p generates cables from tip cortical sites containing ∼10 For3p dimers/site (Martin and Chang, 2006). This For3p clustering may help the generation of actin bundles and control of their thickness. It is also possible that For3p clustering is not required for cable formation, since filaments growing from For3p at distant tip sites can form bundles by cross-linking in the cytoplasm. We examined how actin cable distribution depends on the degree of clustering of For3p at cell tips and cross-linking among filaments. In Figure 7 we vary the number of cortical tip sites and distribute a fixed number of filament nuclei randomly among these sites. The cortical cluster sites are randomly distributed on the semispherical cell tip. Formins within the same cortical site are distributed randomly over a small area around the center of the site. We also study the interplay with cross-linking by varying the effective cross-linking range parameter rcrslnk.

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.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Lehigh University, Bethlehem, PA 18015.

Show MeSH
Related in: MedlinePlus