Zinquin identifies subcellular compartmentalization of zinc in cortical neurons. Relation to the trafficking of zinc and the mitochondrial compartment

Zinquin (Zn 2+ selective fluorophore), when used to visualize intracellular Zn 2+, typically shows brightly fluorescent perinuclear endosome-like structures, presumably identifying Zn 2+ containing organelles. In this study, zinquin identified numerous and widespread sites of Zn 2+ compartmentalization in primary cultures of embryonic rat cortical neurons. Nuclear fluorescence, however, was absent. We labeled neuronal mitochondria with MitoTracker Green in the presence of zinquin and show that the fluorescent patterns of MitoTracker Green and zinquin were distinct and clearly different in both the perinuclear region and in processes. The mitochondrial compartment was much larger than the sum of the areas of zinquin fluorescence, as indicated by the small amount (