PITPβ interacts with VAP-A and coatomer. Quantitative data are shown as mean ± SD, with the number of independent experiments indicated. Statistics was performed using the two-tailed Student’s t test: ****P < 0.0001, ***P < 0.001, **P < 0.01, ns (non-significant) P > 0.05. (A) Co-precipitation experiment assessing the association of GFP-tagged VAP isoforms with endogenous PITPβ in cells, n = 3. A representative result is shown on the left and quantitation is shown on the right. (B) Pulldown experiments using purified components to assess the effect of mutating FFAT motifs (F107A/F108A) in PITPβ on its direct interaction with VAP-A, n = 3. A representative result is shown on left and quantitation is shown on right. (C) COPI transport assay assessing the effect of mutating the FFAT motif in PITPβ. Quantitation of a representative experiment is shown on right, n = 5. Representative confocal images are shown on left, VSVG-KDELR (green) and giantin (magenta), bar = 10 µm. (D) Pulldown experiment using purified components to confirm a specific di-lysine sequence in full-length PITPβ is critical for its direct interaction with coatomer, n = 5. A representative result is shown on the left and quantitation of a representative experiment is shown on the right. (E) COPI transport assay assessing the effect of mutating dilysine sequences in PITPβ. Quantitation of a representative experiment is shown on right, n = 5. Representative confocal images are shown on left, VSVG-KDELR (green) and giantin (magenta), bar = 10 µm. Source data are available for this figure: SourceData F4.