Journal: bioRxiv
Article Title: PITPβ promotes COPI vesicle fission through lipid transfer and membrane contact formation
doi: 10.1101/2024.05.27.596058
Figure Lengend Snippet: Quantitative data are shown as mean ± s.e.m, with the number of independent experiments indicated. Statistics was performed using the two-tailed student t -test: **** p<0.0001, ** p<0.01, ns p>0.05. A , Colocalization of PITPβ with ER marker (Sec61β) and Golgi marker (giantin) as assessed by confocal microscopy using Airyscan, PITPβ (blue), Sec61β (green), giantin (red). A representative image is shown in upper left panel, bar=10 μm. An inset is shown in upper right panel with arrow heads highlighting PITPβ colocalizing with both Sec61β and Giantin. A reconstruction of the region highlighted by the arrow heads in the inset is shown in lower left panel. Line scan along the dotted line in the inset is shown in the lower right panel. B , The effect of siRNA against PITPβ on the colocalization of an ER marker (Sec61β) and a Golgi marker (giantin) as assessed by confocal microscopy using Airyscan. Quantitation is shown on right, n=6. Representative images are shown on left, bar=10 µm. Arrow heads highlight areas of colocalization. C , Airyscan confocal microscopy examining the effect of siRNA against PITPβ on the colocalization of an ER marker (Sec61β) and a TGN marker (TGN46). Representative images are shown on left, bar=10 µm. Arrow heads highlight areas of colocalization. Quantitation is shown on right, n=4. D , EM tomography analysis of COPI buds at the Golgi showing close proximity to ER membrane. A representative tomographic image slice is shown in upper left panel with arrow heads pointing to COPI buds, bar=200 nm. 3D reconstruction of the Golgi, COPI buds, and ER elements is shown in lower left panel. Quantitation is shown on right, comparing distance between COPI buds and ER membranes versus distance between Golgi cisternal margins and ER membranes, n=3. E , Proximity ligation assay examining the effect of siRNA against PITPβ on the proximity between calnexin and giantin, n=5. F , Proximity ligation assay assessing the effect of PITPβ depletion on the colocalization of calnexin and ζ-COP, n=5. G , Proximity ligation assay examining the effect of siRNA against PITPβ on the proximity between calnexin and TGN46, n=4.
Article Snippet: VAP-A (104447) and VAP-B (104448) in pEGFP-C1 and mEmerald-tagged Sec61β in pEGFP-C1 (90992) were obtained from Addgene.
Techniques: Two Tailed Test, Marker, Confocal Microscopy, Quantitation Assay, Tomography, Membrane, Proximity Ligation Assay