A) Diagram of the RUSH system. The Halo-tagged cargo is retained in the ER by the binding of the Streptavidin binding peptide (SBP) to Streptavidin (StrepA), which is fused to the ER retention signal, KDEL. The cargo is synchronously released upon the addition of biotin, which outcompetes SBP for binding to Streptavidin.B) Diagram of the tagged cargo constructs used in this study. C) Steady state expression of UAS-SBP-Halo-Cadherin99c (magenta) under the control of traffic jam-Gal4, showing its localization to the apical microvilli. Phalloidin staining of F-actin (green) labels the apical microvilli in the follicle cells and the oocyte. Scale bar 10 µm. D) Steady state expression of UAS-SBP-SNAP-Ndg (magenta) under the control of traffic jam-Gal4, showing its localization to the basement membrane. Actin is shown in green. Scale bar 10 µm. E) En face view of SBP-SNAP-Ndg in the basement membrane. Scale bar 10 µm. F) Time course of SBP-Halo-Cadherin99C trafficking in fixed samples. G) 25 min after release from the ER, Cad99c (green) localizes to subapical puncta that are labeled by Rab11 (magenta). Scale bar 10 µm. In all figures with a cross-section of the follicle cells, apical is toward the top of the image and basal toward the bottom.
How are specific cargos targeted to apical & basolateral domains within #EpithelialCells? This study uses a novel #vesicle tracking software "MSP-tracker" to show that the secretory pathway in #Drosophila follicle cells is unexpectedly spatially organized @plosbiology.org 🧪 plos.io/3EfJsBp