Genomic deletion of the SNX-BAR binding site abrogates retrograde transport of endogenous as well as reexpressed CI-MPR. (A) CRISPR-Cas9 was used to introduce a 6-aa deletion of the WLM SNX-BAR binding motif into the endogenous CI-MPR locus of a HeLa cell line. The immunofluorescence shows the colocalization between endogenous CI-MPR and the TGN marker TGN46. (B) 3D reconstruction of the CI-MPR and TGN46 staining in a HeLa cell and in a cell carrying the SNX-BAR–binding site deletion. The colocalization between CI-MPR and TGN46 was quantified over three independent experiments. (C) Reexpression of WT and WLM-AAA CI-MPR in a CI-MPR–KO HeLa cell line. The transfected cells were stained for CI-MPR and endogenous TGN46, and colocalization was quantified over three independent experiments. Bars, 10 µm. Error bars indicate SD. *, P < 0.05 compared with control conditions in a t test.