Proximity Ligation Analysis (PLA) of protein-protein interactions between FGFR2 and FGF1. HeLa cells were stained with 126791 (1:1200) and FGF1 mouse monoclonal antibody (1:50). Signals were detected by 30 Detection Kit 613 (red), and nuclei were counterstained with DAPI (blue). Each red dot represents the detection of protein-protein interaction complex.