Bni5-mediated localization of Myo1 at the division site before cytokinesis facilitates retrograde actin cable flow. (A) Diagram of Myo1-facilitated retrograde flow of actin cables before cytokinesis. See details in the text. (B) Time-lapse analysis of retrograde actin cable flow in bni5Δ and myo1 mutants. Montages showing dynamics of GFP-xACT–labeled actin cables were created from selected frames of a time-lapse series taken with 1-s intervals. Arrowheads indicate the distal ends of elongating actin cables. The myo1Δ strain (YEF10170) was grown on a 5-FOA to eliminate the MYO1 cover plasmid prior to imaging. Strains used: YEF10201 (GFP-xACT), YEF10173 (bni5Δ GFP-xACT), YEF10170 (myo1Δ GFP-xACT), and YEF11489 (myo1-mTD1Δ GFP-xACT). (C) Quantification of actin cable flow rate from the time-lapse data shown in B. Gray circles, blue bars, and black bars represent individual data points, mean values, and SD, respectively. P values were determined using a two-sided Mann–Whitney U test.