Skip to main content
. 2006 Feb;17(2):895–906. doi: 10.1091/mbc.E05-06-0512

Figure 4.

Figure 4.

Ultrastructural examination of polymerized TgACT1 filaments compared with rabbit actin. (A) Filaments formed by TgACT1 were short, unbranched, and often appeared bent or broken (TgACT1 control). When polymerized TgACT1 filaments were mixed with 5 μM phalloidin on the grid, they were straight and had more distinct edges, indicating they were stabilized. TgACT1 filaments were observed to form pairs or small bundles when polymerized in the presence of JAS (1 μM; see bottom panel for enlargement). Rabbit actin formed long straight filaments with a characteristic helical spiral. Enlarged views (bottom panels) demonstrate the repeat striations, helical pattern, and ∼9-nm diameter of the filaments formed by TgACT1 and rabbit actin. After polymerization of 5 μM actins in F-buffer, 100,000 × g pellets were resuspended in 1× F-buffer, negatively stained with uranyl acetate, and examined by EM. (B) Histogram showing the distribution of filament lengths between control, phalloidin (5 μM) or JAS (1 μM) treated TgACT1 and rabbit muscle actin. TgACT1 filaments were more than 10-fold shorter than rabbit actin filaments formed under similar conditions. Treatment of TgACT1 with phalloidin or JAS increased the average size.