Flower-containing vesicles are polarized earlier to the IS than to CGs and localize around endocytic CGs. (A) Time-lapse maximal-intensity projections of a Flower-deficient CTL transfected with Flower-pHluorin (green) and syb2-mRFP (red) and conjugated to a target cell in the presence of anti-RFP405 antibody in the medium. The arrows point to the endocytic CGs (magenta). Bar, 10 µm. (B) Real-time dynamics of Flower-containing vesicles and CGs in CTL monitored by TIRFM. Flower-deficient CTLs were transfected with Flower-pHluorin (green) and syb2-mRFP (red). Bar, 5 µm. (C) Quantitative analysis from panel B of the number of vesicles arriving at the IS over time. Data are given as mean ± SEM.