Fig. 6

PI3K-C2β is required for the formation of pinosome-associated actin patches. a–c Super-resolution microscopic images of HUVECs transfected with the expression vectors of mRFP-CLC (red) and the F-actin-binding peptide mEmerald-Lifeact (green), and either of scrambled (a), PI3K-C2α (b) or -C2β (c) siRNAs. Cells were then subjected to Alexa Fluor 647-dextran (0.5 mg/ml) uptake. Nuclei were stained with DAPI (blue). The region outlined by the dotted-box is shown at higher magnification (upper, dextran/Lifeact; lower,  CLC/Lifeact) on the right panels. White arrowheads denote clathrin-coated, dextran-containing pinosomes that are associated with actin patches, whereas yellow arrows denote clathrin-non-coated, dextran-containing pinosomes that are associated or not with actin patches. d Average number of dextran⁺-vesicles per cell was quantified from images. e and f Co-localization of  Lifeact and CLC (e) and dextran and Lifeact (f). The co-localization indices (Pearson’s correlation coefficient) are shown. Data are presented as the median and IQR in d–f. Asterisks indicate statistical significance between the indicated groups: *p < 0.05, **p  < 0.01, ***p < 0.001; ns not significant