Fig. 4

Mutation of EXO70A1 displayed decreased both delivery rate of PM localized CESA6 and internalization of FM4-64. (A, B) Delivery rate of tdTomato-CESA6 to the PM is significantly reduced in exo70a1-1 cells. (A) Single-frame images displaying the tdTomato-CESA6 before, 5 s and 5 min after photobleaching. FRAP assays were performed in the WT and exo70a1-1. Yellow boxes mark the photobleached areas. Scale bar = 5 μm. (B) Quantifications of the delivery rate of tdTomato-CESA6 by FRAP assays descripted in (A). The delivery rate of tdTomato-CESA6 was calculated from the total number of new successfully delivered CESA6 during the initial 5 min of recovery divided by the measured area and time. n = 13 ROIs from 13 cells of WT, n = 17 ROIs from 17 cells of exo70a1-1. Error bars represent SD. The Student’s t-test was performed, p < 0.0001. (C, D) The exo70a1-1 exhibit defects in endocytosis of FM4-64. (C) Single-frame images displaying the intracellular FM4-64 puncta distribution after FM4-64 treatment 20 min, Scale bar = 5 μm. (D) Quantifications of the intracellular FM4-64 puncta density were analyzed. Error bars represent SD. The Student’s t-test was performed, p < 0.05. The epidermal cells of 3-day-old etiolated hypocotyls were observed. Images of (A) were captured with SDCM, Images of (C) were captured with LSCM (LEICA TCS SP8).