Fig. 4.

Colocalization of VE-PTP with VE-cadherin in aorta and vena cava. a–a’ Confocal microscopic images of aorta (a) and vena cava (a’) showing partial colocalization (white) of the largest VE-PTP particles (> 1.4-µm diameter, red) with VE-cadherin (green) at the downstream tip of endothelial cells (arrows). Blood flow left to right. Scale bar: 10 µm. b–b’ Dot plots for aorta (b) and vena cava (b’) comparing percent of the largest VE-PTP particles (> 1.4 µm) colocalized with VE-cadherin (% of VE-PTP, left dot plots) and percent of VE-cadherin colocalized with VE-PTP (% of VE-cadherin, right dot plots). The percent of VE-PTP colocalized with VE-cadherin was significantly greater (asterisks) than VE-cadherin colocalized with VE-PTP, as expected for colocalization limited to focal regions of plasma membrane. *P < 0.05 by one-way ANOVA followed by Tukey’s multiple comparison test. Mean ± SEM, n = 12 images from 6 mice/group. c Plots of van Steensel’s peak cross-correlation coefficient (CCF) (ImageJ/Fiji > JACoP plugin) in an aorta and vena cava showing positive pixel shift values at maximal colocalization, indicating that the VE-PTP image was shifted to the right (toward the downstream plasma membrane) at peak CCF. This feature is evidence that large VE-PTP particles at the cell tip in (a, a’) were composed to two parts, non-colocalized red pixels in the cytoplasm and colocalized white pixels in the plasma membrane. d Heterogeneity of pixel shift values for 12 image pairs having peak CCF values with a right shift averaging +5.3 pixels (0.66 µm) in aorta and +8.7 pixels (1.07 µm) in vena cava. Y-axes show CCF values scaled in micrometers (left) and pixels (right). *P < 0.05 by Student’s t test. Mean ± SEM, n = 12 images from 6 mice/group