PLST-1 is essential for effective coalescence of nascent NMY-2 filaments into mature contractile foci. (A) Cortical views of control and plst-1 zygotes coexpressing GFP::Utrophin, NMY-2::mCherry, and HIS-58::mCherry before, during, and after polarization. Bar, 5 µm. (B) Time-lapse montage of the formation and the subsequent disassembly of an NMY-2 focus during polarity establishment in control and plst-1 zygotes. Bar, 5 µm. (C) Histogram showing distribution of mature NMY-2 foci area in control (n = 10, n = 236) and plst-1 (n = 10, n = 239) zygotes. (D) Histogram showing distribution of initial cortical area coalescing into NMY-2 foci in control (n = 14, n = 120) and plst-1 (n = 11, n = 110) zygotes. (E) Histogram showing distribution of NMY-2 foci lifetime in control (n = 9, n = 858) and plst-1 (n = 9, n = 1156) zygotes.