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. 2013 Dec 1;24(23):3710–3720. doi: 10.1091/mbc.E13-07-0388

FIGURE 3:

FIGURE 3:

αE-catenin ABD reduces barbed-end elongation of filamentous actin. (A) Average barbed-end polymerization rates measured in the presence of 4 μM Mg-ATP-actin (5% Cy3 labeled) plus 4 μM human profilin 1. Copolymerization with either 2 μM GFP αE-catenin ABD or 2 μM αE-catenin ABD slows barbed-end elongation. The difference in single-actin-filament elongation rates in the presence of GFP αE-catenin ABD vs. dark αE-catenin ABD suggests that the GFP tag may interfere slightly with barbed-end elongation. Error bars, SD (n ≥ 30 actin filaments from ≥2 experiments). (B, C) Representative kymographs of single actin filaments elongating in the presence of 4 μM Mg-ATP-Actin (5% Cy3 labeled) and 4 μM human profilin I alone (B) or in the presence of 2 μM αE-catenin ABD (C). (D) Barbed-end growth rates with 2 μM GFP αE-catenin ABD and increasing concentrations of KCl. Note that the barbed-end elongation in actin filament bundles is insensitive to the change in buffer ionic strength. (E) Kymograph showing bundling-dependent delay in barbed-end filament elongation in the presence of 2 μM Mg-ATP-actin, 2 μM GFP αE-catenin ABD, and 150 mM KCl. Dashed white lines mark the growing barbed ends of each filament in the kymograph.