GFP-P4M detects ectopic PtdIns4P synthesis in the ER driven by hepatitis C nonstructural protein 5A. COS-7 cells transfected with GFP-P4M, NS5A-mCherry, and mTq2-tagged PI4KA wild type (WT) or its catalytically inactive D1957A mutant. Colocalization between GFP-P4M and NS5A-mCherry (mCh) is depicted in the nMDP images. The box and whisker plot shows the nMDP values for 30 cells (boxes denote the interquartile range with lines at the median; whiskers denote the 10th and 90th percentiles). The p-value was generated by a Mann–Whitney U test. Bar, 10 µm.