Schematic overview of fluorescence-based techniques for ER signaling dynamics. This figure offers a visual representation of the use of fluorescence-based approaches in studying the five principal estrogen receptor (ER) signaling pathways. Each pathway is outlined within a pink frame and features an array of techniques for exploring ER dynamics. Notable methods demonstrated include fluorescent protein tagging (FPt), fluorescence resonance energy transfer (FRET), bioluminescence resonance energy transfer (BRET), and proximity ligation assay (PLA). Additionally, the involvement of 17β-estradiol (E2) in these assays is highlighted.