Figure 3.

Architecture of β_Rat-actin networks. (A) (i) β_Rat and (ii) F-actin solutions form (iii) networks when mixed. Some holoenzymes are identified (blue circles). Boxes (45 nm) show image averages of the dominant subpopulations (top: holoenzymes (n = 21; 25.8 ± 0.8 nm); bottom: proteolyzed hubs (n = 15; 18.0 ± 0.3 nm)). (iii) Multiple (six) F-actin filaments joined by one holoenzyme (center; large blue circle). Junctions with two or three filaments formed by single holoenzymes (blue circles) are common. The box (45 nm) shows the image average of junction-localized β_Rat (n = 30; 24.0 ± 2.6 nm). (B) (i–iii) β_Rat-actin networks. Junctions have one (blue circles) or two (green circles) holoenzymes.