Fig. 2

Pinocytosis is partially dependent on clathrin and dynamin in HUVECs. a Effects of the clathrin inhibitor Pitstop-2 on FITC-dextran uptake. Cells were pretreated with either Pitstop-2 (20 µM) or vehicle for 30 min and then subjected to the FITC-dextran uptake assay. Upper, Representative images (scale bar: 20 µm); lower, quantified data. b Effects of clathrin heavy chain (CHC) knockdown on FITC-dextran uptake. Cells were transfected with either scrambled or CHC–siRNA. Left upper, Representative images; left lower, quantified data of FITC-dextran uptake; right upper, representative blots of CHC protein; right lower, quantified data of protein expression levels. c Effects of the expression of monomeric red fluorescent protein (mRFP)-tagged dominant negative dynamin-2 (K44A) mutant (dn-Dyn2) on FITC-dextran uptake. Cells were transfected with either mRFP-tagged wild type dynamin2 (wt-Dyn2) or dn-Dyn2, and 24 h later subjected to FITC-dextran uptake. Upper, Representative images of cells. Nuclei were stained with DAPI (blue). Lower, Quantified data of FITC-dextran uptake. n = 50–60 cells were analyzed in each group. Data are presented as the median and IQR in a, b, lower left and c, and as the mean ± SEM in b, lower right. Asterisks indicate statistical significance between the indicated groups: *p < 0.05, **p < 0.01, ***p < 0.001