Fig. 5. The trafficking properties of PKD2L1. (A) Confocal images above the apical surface of the cell and in the xz plane show cilia devoid of PKD2L1 with either COOH-terminal EGFP (A) or triple-HA (B) epitope tags. EGFP epifluorescence (A) and double indirect anti-HA immunofluorescence (B) are shown in green; anti-acetylated -tubulin, red. (A^*,B^*) Confocal images at the level of the nucleus showing that all cells express pPKD2L1. Bars, 10 µm. (C) PKD2L1 does not acquire detectable Endo H resistance (left panel) and is not detectably biotinylated on the cell surface in either LLC-PK1 of CHO-K1 cells (middle panel). Truncation of the predicted COOH terminus of PKD2L1 does not result in trafficking to the cell surface as indicated by the absence of a biotinylated species (right panel). `Lysate' is the total cellular protein from the starting material before streptavidin pull down; `biotin' is the eluted material after streptavidin pull down. PKD2L1 was detected by anti-HA in immunoblots. CD4 was co-transfected with PKD2L1 as a positive control for live cell surface biotinylation and streptavidin immunoprecipitation and was detected with anti-CD4 monoclonal antibody 1F6.