Fig. 3

LAPTM4B-35 distributing on Cdc42-induced filopodia. A, A431 cells stably expressing LAPTM4B-35-mCherry were transiently transfected with constitutively active Cdc42^G12V-GFP and imaged by live total internal reflection fluorescence (TIRF) microscopy. Scale bar: 10 ?m. A magnified region of interest at different time points is visible on the right. Yellow arrows highlight LAPTM4B-35 positive filopodia. B, A431 cells stably expressing LAPTM4B-35-mCherry were transiently transfected with dominant negative Cdc42^T17N-GFP, and imaged by TIRF microscopy. Scale bar: 10 ?m. A region of interest at different time points is on the right. C, A431 cells stably expressing LAPTM4B-35-mCherry were transiently transfected with either constitutively active Cdc42^G12V-GFP or dominant negative Cdc42^T17N-GFP and imaged by TIRF microscopy. The distance of filopodia tip movement in 10 min was quantified. Each dot represents a single measurement, middle line represents mean, and whiskers represent interquartile range. D, Cells stably expressing Flag-tagged LAPTM4B-35 and LAPTM4B-24 were transfected with integrin beta1-mCherry to visualize cell protrusions, and cells were imaged by live TIRF microscopy. The distance of filopodia tip movement in 10 min was quantified. Data are from three independent experiments and >10 videos per condition. LAPTM4B-35: n = 196 filopodia; LAPTM4B-24: n = 151 filopodia; p = 8.8 × 10^?8. Each dot represents a single measurement, middle line represents mean, and whiskers represent interquartile range