Fig. 1: Constitutive macropinocytosis occurs in the apical surface of the Xenopus embryonic epidermis.
From: Apical size reduction by macropinocytosis alleviates tissue crowding
a Actin ruffles (arrowheads) in the epidermis of Xenopus embryo stained with phalloidin. Scale bar 20 μm. b Timelapse of a single ruffle event in the epidermis of Xenopus embryo expressing Lifeact-fluorescent protein (FP). Scale bar 10 μm. c SEM images of actin ruffles as circular (top) or dome-shaped (bottom). Scale bar 5 μm. d–f Quantification of actin ruffle duration (d), peak area (e), and percentage of apical area (f) (n = 3 exp. and 90 ruffles; center line = mean; error bars = SD). g Quantification of actin ruffle localization within the cell (n = 9 exp. and 361 ruffles; bar = mean; error bars = SD). h Time lapse image of the Lifeact-FP (cyan) showing macropinocytotic internalization of fluorescent dextran (red) from the media, h’ is a z projection of the dotted line. Scale bar 10 μm. i Time lapse image of the Lifeact-FP (cyan) showing internalization of apical membrane (red) during macropinocytosis, i’ is a z projection of the dotted area. Scale bar 10 μm. j Circular actin ruffle (cyan, Lifeact-FP) surrounded by an outer ring of activated myosin II (red; SF9 intrabody). The dotted arrow shows an example of linescan averaged in (k). Scale bar 10 μm. k Localization of Lifeact and activated myosin II at the peak of an actin ruffles (n = 2 exp. and 15 ruffles; point = mean; error bars = SD). l Quantification of macropinocytosis (MP) events in embryos treated with DMSO or Blebbistatin (n = 3 exp. and 6 embryos; two-sided paired t-test, p-value: 0.0116). Source data are provided as a Source Data file.
