Fluorogenic Probes for Functional Imaging of Endoplasmic Reticulum-Resident Proteins: from Molecular Engineering to Biomedical Applications

Endoplasmic reticulum-resident proteins (ERPs) are crucial for maintaining cellular homeostasis and are tightly associated with the onset and progression of various diseases. The emergence of fluorogenic probes responsive to ERPs has enabled scientists to in situ monitor the spatial distribution and function status of target ERPs in real-time, which is very helpful for elucidating ERP-related pathological mechanisms and developing innovative therapeutics. Over the past decade, a range of fluorogenic probes for sensing and imaging ERPs, including ion channels, oxidases, hydrolases, and transferases, have been devised. This review systematically summarizes the recent advances in molecular engineering and biomedical applications of ERP fluorogenic probes. Engineering strategies for constructing ERP-activatable probes, along with their structural features, recognition fragments, and sensing performances, are discussed. Meanwhile, biomedical applications of these probes in biomarker analysis, disease treatment, multimodal imaging, and drug discovery are also highlighted. Finally, a forward-looking perspective on the future directions and underlying challenges is explored. The insights and knowledge presented here will spur further innovation and technological breakthroughs in developing multifunctional ERP probes, advancing disease diagnosis, ER biology, and drug discovery.