When Small Molecules Are Like Real Estate: It’s All about Location, Location, Location

In this issue of Cell Chemical Biology , Park et al. (2018) demonstrate that targeting apoptazole, an Hsp70 inhibitor, to mitochondria induces apoptosis by a distinct mechanism of action different from unmodified apoptazole, which accumulates in the lysosome. These results highlight the power of subcellular localization in small-molecule selectivity.