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. Author manuscript; available in PMC: 2012 Nov 18.
Published in final edited form as: J Mol Biol. 2011 Sep 17;414(1):44–61. doi: 10.1016/j.jmb.2011.09.017

Figure 6.

Figure 6

In vitro motility assay of mono-phosphorylated tarantula thick filaments. (a) Differential interference contrast micrograph of thick filaments. Long straight ~5 μm features resembling thick filaments are indicated by white arrows. (b) Rhodamine/Phalloidin fluorescently labeled ~1.6 μm long rabbit purified F-actin filaments (arrows, Supplementary Movies 1, 3) (c) Rhodamine/Phalloidin labeled ~1.9 μm long tarantula thin filaments (arrows, Supplementary Movies 2, 4). (d) Twelve sequential frames (30.3 ms each) from a movie of Rhodamine/Phalloidin labeled tarantula thin filaments sliding along a thick filament under activating conditions (Supplementary Movie 4). The frames show one thin filament (white) that starts sliding (frame 3, yellow arrow) along a thick filament. The thin filament moves at 11.7 μm/s along a ~5 μm straight path (depicted in green) for 8 frames, at which point it stops (frame 10, red arrow) (e) Average sliding speed of rabbit F-actin (left) or tarantula thin filaments (right) sliding over single tarantula thick filaments as measured on in vitro motility assay experiments. F-actin filaments slides at 3.55±1.29 μm/s (n=321) in the presence (red) or 5.35±2.05 μm/s (n=574) in the absence (green) of Ca2+. Tarantula thin filaments (right) move only in the presence of Ca2+ (red) at 9.78±1.92 μm/s (n=130).