Fig. 3: VgrG4 colocalizes with the ER.

VgrG4 localisation within the cells was analysed by confocal microscopy of A549 mCherryER cells (ER in red). Cells were infected with YeVgrG4 for 90 min, or Kp52145 for 3 h, or left uninfected (n.i.) VgrG4 was stained with VSV-G or FLAG (in green) (a). b Immunoblot analysis of VgrG4-tagged with VSV-G, Calnexin (ER marker) and Tom20 (mitochondria marker) in fractionated lysates of A549 cells infected with YeVgrG4 for 90 min or left uninfected (n.i.). c Confocal microscopy of A549 mCherryER cells infected with Y. enterocolitica encoding N- and C-terminal truncated forms of VgrG4 tagged with VSV-G for 90 min. To determine the tethering protein associating with VgrG4, A549 mCherryER cells were transfected with siRNAs for VAPB or MFN2 and infected with YeVgrG4 for 90 min (d). e Confocal microscopy of A549 cells transfected with the MFN2-YFP plasmid (MFN2 in green) and infected with YeVgrG4 for 90 min. VgrG4 was stained with VSV-G. f Immunoblot analysis of VSV-G (VgrG4) and GFP (MFN2) levels in immunoprecipitates of A549. 24 h after transfection with a MFN2-YFP plasmid, cells were infected with YeVgrG4 for 90 min. Lysates were immunoprecipitated using anti-GFP antibody, and membranes were first probed with antibody against VSV-G and subsequently with antibody against GFP. Pre-immune mouse IgG served as negative control. All images and immunoblots are representative of three independent experiments.