Effects of knockdown of ER–Golgi MCS components on PI4P turnover and BiFC visualization of the VAP-A–OSBP complex. (A) PI4P staining in control (Cont), VAP-A/B, CERT/OSBP, and Sac1 knockdown HeLa cells. (B) HeLa cells stably coexpressing Vn-OSBP and Vc-VAP-A were treated with or without 2 µg/ml 25-HC for 2.5 h. The coexpression of Vn-OSBP and Vc-VAP-A was visualized with an anti-GFP antibody. Scale bars, 10 µm.