Fig 1: SORLA dimers are located within endosomes. (A) Schematic representation showing SORLA proteins with C-terminal FLAG-tag (SORLA-FLAG) or GFP-tag (SORLA-GFP). A red PLA signal will be formed when the two antibody-bound SORLA constructs get into close contact representing dimerization. (B) Representative immunofluorescence images of HEK293 cells transfected with SORLA-FLAG and SORLA-GFP and immunostained for FLAG and GFP. Bar graph in the Right panel illustrates quantifications of colocalization between FLAG and GFP signals using Mander’s (n = 13 from two independent experiments). (C–E) Representative immunofluorescence images after PLA (red) of HEK293 cells transfected with SORLA-FLAG and SORLA-GFP (green) treated with GFP (C), FLAG (D) or both antibodies (E). Bar graph in the Right panel illustrates quantifications of colocalization between GFP (green) and PLA (red) signals using Mander’s (n = 36 from two independent experiments). (F) Representative immunofluorescence images after PLA (purple) of HEK293 cells transfected with SORLA-FLAG and SORLA-GFP (green) counterstained with VPS35 (white). Bar graph in the Right panel illustrates quantifications of colocalization between PLA (purple) and VPS35 (white) signals using Mander’s (n = 23). (Scale bars, 5 µm.) Error bars indicate SEM.