ACA is localized on dynamic vesicles that coalesce at the back of polarized cells. (A) Montage of fluorescent images showing maximum intensity projections of a randomly moving ACA-YFP/aca⁻ cell. Also see Video 1. (B) Montage of fluorescent images showing maximum intensity projections of a ACA-YFP/aca⁻ cell chemotaxing toward a micropipette filled with 1 μM cAMP. The asterisk depicts the position of the micropipette. Also see Video 1. (C) 3D reconstruction of z-stack slices showing accumulation of vesicles at the back of a migrating ACA-YFP/aca⁻ cell. Also see Video 2. Videos are available.