Figure 7
Live-cell images showing that Rab21 localises to motile macropinosomes, which form after the deactivation of PA-Rac1.
(a) RAW264 cells were co-transfected with pTriEx/mCherry-PA-Rac1 and pGFP-Rab21. The blue rectangular area in the cell was repeatedly irradiated using a blue laser for 12.2 min. The top left panel shows a merged image of the phase-contrast, mCherry and GFP fluorescence signals obtained before the photoactivation of PA-Rac1, confirming the expression of mCherry-PA-Rac1 and GFP-Rab21. The other panels show selected time-lapse phase-contrast (upper) and GFP-Rab21 images (lower; green). Time 0 indicates the initiation of photoactivation. The bars indicate 5 μm. (b) The recruitment of Rab21 to macropinosomes after PA-Rac1 deactivation in the same cell as shown in Fig. 7a. The top left panel shows a merged image of the phase-contrast, mCherry and GFP signals obtained when the irradiation was stopped (equivalent to time 12.2 min in Fig. 7a). The broken line rectangle indicates the previously irradiated area shown in Fig. 7a. The other panels show selected time-lapse phase-contrast (upper) and GFP-Rab21 images (lower; green), captured at the indicated times. Time 0 indicates the time when the photoactivation was stopped. The bar indicates 5 μm.
