Fig. 2: Macropinocytosis is associated with tissue crowding and low levels of tension.
From: Apical size reduction by macropinocytosis alleviates tissue crowding
a Image of Xenopus stained with phalloidin (white) at ST34 (left) and ST42 (right, asterisk highlight actin ruffles). Scale bar 10 μm. b Quantification of cell density (blue; right axis) and macropinocytotic events (MP, red; left axis) at ST34 and ST42 (n = 3 exp. and 15 embryos per stage for cell density, p-value = 3.43e-10; 4 exp. and 6 embryos for macropinocytotic events at ST34 and 5 exp. and 16 embryos at ST42, p-value = 0.0282). c Quantification of cell density (blue; right axis) and macropinocytotic events (red; left axis) in embryo treated or not with Roscovitine for 24 h (n = 4 exp. and 18 control embryos and 21 Roscovitine-treated embryos for MP events, p-value = 0.0019; 3 exp. and 29 control embryos and 28 Roscovitine-treated embryos for goblet cell density, p-value = 0.0045). d Representation of the generation of 3D organoids or 2D explant plated onto fibronectin coated coverslip. Adapted from61,62. e Representative images of the surface of 2D explant (left) or 3D organoids (right) expressing Lifeact-FP. Scale bar 30 μm. f Quantification of cell density (blue; right axis) and macropinocytosis (red; left axis) in 2D explants or 3D organoids (n = 6 experiments with 22 explants and 23 organoids; MP p-value = 2.00e-06 and density p-value = 5.97e-07). g Image of actin ruffles (asterisk) in the epithelium of an embryo expressing Lifeact-FP before (up) and after (down) treatment with GsMTx4. Scale bar 30 μm. h Quantification of the fold difference in macropinocytosis level between 1 h before and 1 h after treatment with DMSO (mock treatment, n = 9 embryo), GsMTx4 (n = 5 embryo; p-value = 2.03e-06), NaDeoxy (n = 5 embryo; p-value = 0.0012), Mβ Cyclodextrin (n = 11 embryo; p-value = 0.0260), or Yoda1 (n = 5 embryo; p-value 3.00e-05). All tests are two-sided unpaired t-tests. Source data are provided as a Source Data file.
