Supplementary Figure 8: Stac protein colocalises with Rab7 and Rab39.

(a–e) Confocal images from fixed and immunostained (a–c) and living (d,e) embryos expressing mCherry-StacA (magenta in merge) and an endogenously tagged Rab protein (YRab; green in merge). Each panel shows a single focal plane. Whereas YRab1 (a) signals do not overlap with mCherry-StacA signals, YRab7 (b and d) and YRab39 (c and e) show a significant degree of colocalisation with mCherry-StacA. Red asterisks above Stac vesicles in the close-up views (insets) indicate colocalisation. Note that although the fixed samples provide higher spatial resolution, the distribution of YRab7 (compare b to d) and YRab39 (compare c to e) appears more fragmented in the fixed samples compared to the living samples. Images are representative of at least 10 embryos per genotype. (f) Quantification of colocalisation between YRab proteins and mCherry-StacA in immunostained samples. The central track region of three independent FC pairs for each genotype was segmented manually. The degree of colocalisation is expressed by the ranked Kendall’s tau-b (KTB) correlation coefficient, determined in combination with Costes threshold determination. KTB values between 0 and 1 indicate colocalisation, whereas values between 0 and −1 indicate no colocalisation between the compared signals. For each condition a horizontal line indicates the KTB mean value and a vertical line indicates the standard deviation. N = 3 embryos per condition. Statistics source data are provided in Supplementary Table 3.