TTC17 is required for the polarized arrangement of Golgi cisternae and posttranslational modifications. (A–C) Control HeLa cells (A) and cells depleted of CCDC157 (B) or TTC17 (C) were incubated in the presence or absence (DMSO) of 500 ng/ml nocodazole for 2 h, and analyzed by immunofluorescence microscopy with anti-TGN46 and anti-GM130 antibodies. Depolymerization of the microtubule cytoskeleton was monitored with an anti–α-tubulin antibody. Nuclei were stained with DAPI. Scale bars, 10 µm. Insets from A, B, and C, show Golgi stack dispersion after nocodazole treatment. Intensity profile graphs of TGN46 and GM130 colocalization derived along the lines indicated in the confocal micrograph inserts. (D) Pearson’s correlation coefficient of colocalization between TGN46 and GM130 from confocal micrographs acquired for control cells, and cells depleted of CCDC157 or TTC17 after nocodazole treatment (n = 24; two-tailed Student’s t test for comparison to control condition siCtr; ***, P < 0.001; ns, statistically nonsignificant). (E) Total cell lysates of control HeLa cells and cells depleted of TTC17 or CCDC157 were analyzed by immunoblotting with anti-LAMP2 and anti–α-tubulin antibodies. Results are representative of three independent experiments.