Extended Data Fig. 7: Localisation and Morphometric analysis of coated vesicles and buds.

a. Quantitation of the colocalisation between fluorescent markers against COPII (Halo-Sec23A), ERGIC (ERGIC-53 antibody) and COPI (β-COP antibody). Green indicates colocalisation as a percentage of COPII structures, cyan indicates colocalisation as a percentage of ERGIC structures and purple indicates colocalisation as a percentage of COPI structures. Each black point represents the percentage colocalisation reported per image, where each image contains 1-2 cells. The white points represent the percentage colocalisation reported across all images n = 9. The dashed lines represent the median and interquartile range. b. Violin plot of the circularity of COPI and COPII-coated vesicles measured by fitting ellipses to axial projection of segmented vesicles. Grey dashed and dotted lines represent the median and interquartile range respectively. COPI median and IQR = 0.92, 0.86–0.95. COPII median and IQR = 0.95, 0.91–0.97. c. Examples of fitted spheres and ellipsoids for a segmented COPII vesicle (top), and bud (bottom). On the right panels, a slice from the segmented density has been cut out for clarity. Scale bar 10 nm. d. Violin plot of the estimated volume of COPI and COPII-coated vesicles. White and black circles indicate vesicles best fitted by a sphere and ellipsoid respectively. Grey dashed and dotted lines represent the median and interquartile range respectively. COPI median and IQR = 134,153 nm3, 105,256–198,030 nm3. COPII median and IQR = 180,760 nm3, 148,776–228,868 nm3. P = 0.0014. e. Violin plot of the estimated volume of COPI and COPII-coated buds. White and black circles indicate buds best fitted by a sphere and ellipsoid respectively. Grey dashed and dotted lines represent the median and interquartile range respectively. COPII median and IQR = 158,886 nm3, 106,711–214,387 nm3. COPI median and IQR = 141,587 nm3, 98,046–210,180 nm3. P = n.s. Source numerical data are available in source data.

Source data