GRAF2 and WDR44 are involved in the specific export of neosynthesized E-cadherin, MMP14, and CFTR ΔF508. (A) Export efficiency of E-cadherin–RFP, HA–α_2B-AR–RFP, and GFP-GPI in HeLa cells and of MMP14-GFP in HT 1080 cells upon cotransfection of GFP or RFP-tagged proteins, as appropriate. n = 3–8. (B) Confocal images of HeLa cells 8 h after transfection. E-cadherin was found in many Rab8a- and GRAF2-positive puncta (arrowheads) or was often associated with GRAF2-positive tubules. (C) Export efficiency of E-cadherin–GFP, HA–α_2B-AR–GFP, and GFP-GPI in shRNA-expressing HeLa cells and of MMP14-GFP in shRNA-expressing HT 1080 cells. n = 4–14. (D) Confocal stacks of transfected HeLa cells. In shGRAF2- and shWDR44a-expressing cells, E-cadherin–RFP was trapped in an intracellular compartment. (E) Confocal images of transfected HT 1080 cells 8 h after transfection showing colocalization of MMP14-GFP with RFP-Rab8a and GRAF2-RFP in intracellular tubules. (F) Confocal stacks of transfected HT 1080 cells. In shGRAF2a- and shWDR44a-expressing cells, MMP14-GFP was trapped in an intracellular compartment. (G) Export efficiency of MMP14-GFP in shRNA-expressing HT 1080 cells without or with RFP-WDR44_res or RFP–WDR44_res ΔPro. n = 5–7. (H) Confocal images of transfected HeLa cells. GFP-CFTR and GFP–CFTR ΔF508 colocalized with RFP-Rab8a and myc-WDR44 tubules. myc-WDR44 was detected with α-myc staining. (I) Export efficiency of GFP-Extope CFTR and GFP-Extope CFTR ΔF508 in transfected 293T cells. n = 3–9. (J) Export efficiency of GFP–Extope CFTR or GFP–Extope CFTR ΔF508 in 293T cells cotransfected with the indicated shRNAs and RFP, GRAF2_res-RFP, RFP-WDR44_res, or RFP–WDR44_res ΔPro. n = 3–10. (A, C, G, I, and J) Data are means ± SEM; *, P < 0.05; **, P < 0.01; ***, P < 0.001; and ****, P < 0.0001. The dashed line represents the export efficiency under control conditions. (B, D–F, and H) Insets show magnifications of the boxed areas. Scale bars: 10 µm; scale bars of insets: 2 µm.