aip1Δ cells show an increase in lat A–insensitive actin assembly. (A) Single frames from time-lapse imaging of Abp1-mRFP in sla2Δ aip1Δ cells treated with 400 µM lat A. Kymographs show the delayed disassembly of the actin tails, and an arrowhead shows a burst of actin assembly ∼300 s after treatment with lat A. The schematic highlights actin flux fiduciary marks in the presence of lat A. (B) Single frames from simultaneous two-color imaging of Abp1-mRFP and Sla1-GFP in aip1Δ cells treated with 200 µM lat A are shown at the indicated times relative to lat A treatment. Kymographs show the spatiotemporal dynamics of actin assembly events at endocytic sites at early, intermediate, or late time points after lat A addition. The kymographs are oriented so that the cell exterior is on the top and the cell interior is oriented downward. dfc, distance from cortex.