Fig. 3

atln-1 mutants show high level of ER retraction. a–c Kymographs of ER (GFP::SP12) dynamic events in PVD 3° branches in WT (a), atln-1 (b), and atln-1; ser-2P3::atln-1 (c) worms at L4 stage. Magenta, white and yellow arrows indicate ER growth, retraction, and static events, respectively. Scale bar, 5 μm and 10 s. d Quantification of ER growth and retraction frequency. Values are mean and error bars are SEM. At least 200 events from more than 30 worms are quantified. ns, not significant, **p < 0.01 (Newman-Keuls multiple comparison test). e, f Quantification of ER growth (e) and retraction (f) length. Values are mean and error bars are SEM. At least 200 events from more than 30 worms are quantified. ns, not significant; ***p < 0.001 (Newman-Keuls multiple comparison test). g–i Representative 3D-SIM images of ER (GFP::SP12) complex structure at the most proximal branch point of the PVD anterior dendrite in WT (g), atln-1 (h), and atln-1; ser-2P3::atln-1 (i) worms. j Quantification of ER complexity index of the most proximal branching point. Values are mean and error bars are SEM, n > 40. **p < 0.01; ***p < 0.001 (Newman-Keuls multiple comparison test). To calculate the complexity index, we drew a circle of 1.6 μm diameter (dashed circle) at the branching point and a line within the circle along the dendrite trunk (dashed line). Complexity index = mean GFP intensity in the circle/mean GFP intensity on the line. Scale bars, 1 μm. k Quantification of ER complexity index at posterior branch points. Values are mean and error bars are SEM. At least 100 branch points from more than 30 worms are quantified. *p < 0.05; ***p < 0.001 (Newman-Keuls multiple comparison test). l Scanning electron microscopy images from a serial EM pictures showing ER complex structure on a branch point in PVD of a WT worm. The magenta arrows indicate ER. The blue arrows indicate PVD 2° branches. Scale bar, 500 nm