CD63 requires EE–to–TGN retrograde trafficking to facilitate SG maturation. (A–F′) Spinning-disc confocal images of live L3 salivary gland cells expressing Sgs3-DsRed (red) in different RNAi backgrounds without (A–F) or with (A′–F′) coexpression of CD63-GFP (green). Dashed boxes mark regions magnified twofold in the insets.