Simultaneous Zn tracking in multiple organelles using super-resolution morphology-correlated organelle identification in living cells.

Zn plays important roles in metabolism and signaling regulation. Subcellular Zn compartmentalization is essential for organelle functions and cell biology, but there is currently no method to determine Zn signaling relationships among more than two different organelles with one probe. Here, we report simultaneous Zn tracking in multiple organelles (Zn-STIMO), a method that uses structured illumination microscopy (SIM) and a single Zn fluorescent probe, allowing super-resolution morphology-correlated organelle identification in living cells. To guarantee SIM imaging quality for organelle identification, we develop a new turn-on Zn fluorescent probe, NapBu-BPEA, by regulating the lipophilicity of naphthalimide-derived Zn probes to make it accumulate in multiple organelles except the nucleus. Zn-STIMO with this probe shows that CCCP-induced mitophagy in HeLa cells is associated with labile Zn enhancement. Therefore, direct organelle identification supported by SIM imaging makes Zn-STIMO a reliable method to determine labile Zn dynamics in various organelles with one probe. Finally, SIM imaging of pluripotent stem cell-derived organoids with NapBu-BPEA demonstrates the potential of super-resolution morphology-correlated organelle identification to track biospecies and events in specific organelles within organoids.