Simultaneous Zn2+ tracking in multiple organelles using super-resolution morphology-correlated organelle identification in living cells

Zn 2+ plays important roles in metabolism and signaling regulation. Subcellular Zn 2+ compartmentalization is essential for organelle functions and cell biology, but there is currently no method to determine Zn 2+ signaling relationships among more than two different organelles with one probe. Here, we report simultaneous Zn 2+ tracking in multiple organelles (Zn-STIMO), a method that uses structured illumination microscopy (SIM) and a single Zn 2+ 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 2+ fluorescent probe, NapBu-BPEA, by regulating the lipophilicity of naphthalimide-derived Zn 2+ 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 2+ enhancement. Therefore, direct organelle identification supported by SIM imaging makes Zn-STIMO a reliable method to determine labile Zn 2+ 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. Subcellular Zn 2+ compartmentalisation is essential for cell biology. Here the authors make a turn-on fluorescent Zn 2+ probe that localises to multiple organelles, and correlate its location using organelle morphology derived from structured illumination microscopy.