Fig. 1
Lateral flexibility of tight junction strands. a Fluorescence confocal live imaging of tight junction strands formed between adjacent Rat1 cells expressing mCldn2-GFP. Sequential images show a putative single strand undergoing continuous lateral mobility over the course of minutes. Strands arching and sharp bends in arbitrary directions are indicated with arrowheads and arrows, respectively. Scale bar = 1 µm. b–f Freeze-fracture TEM of mCldn15 strands expressed in HEK293T cells showing the grooves from single strands on the E-face b and a larger interconnected tight junction strand network on the P-face c–f. d, e Representative views of strand arching (arrowheads) and discrete bending points (arrows). f Example of a branching point. Scale bars = 200 nm for b, c and 100 nm for d–f. g Histogram showing the distribution of mCld15 strand curvature quantified from freeze-fracture TEM as a function of the inverse radius of curvature, κ; n = 16 strands
