Fig 1: Proximity ligation assay (PLA) was employed to confirm proximity of enriched proteins (A-C) integrin a1, (D and E) HLA-E and (F-H) plexin B2. (A) SK-BR-3 cells were pre-incubated with anti-B7-H4 to induce clustering showing proximal integrin a1; (B) prefixed cells showing no surface integrin a1. (C) No B7-H4 antibody negative control (background). (D) Cells pre-incubated with anti-B7-H4 showing co-localised HLA-E; (E) cells not pre-incubated with anti-B7-H4 showing disperse HLA-E. (F) Cells pre-incubated with B7-H4 showing plexin B2 not co-localising with B7-H4 on the cell surface. (G) Cells with anti-B7-H4 only (negative control). (H) Plexin B2 (red) co-localising (yellow) with B7-H4 (green) intracellularly following permeabilization. All images are bright field with red overlay, except E. Scale bars: 10 µm, unless otherwise indicated. Images are representative from 3 replicate experiments.