Beginning on page 603, Mancini et al. describe studies on the localization and substrate specificity of the protease caspase-2, which has a key role in apoptosis. The results show that caspase-2 localizes to the Golgi complex, where it cleaves the protein golgin-160 at a unique site, suggesting that the Golgi complex, like mitochondria, may be involved in transducing apoptotic signals.
Earlier studies demonstrated that caspase-2 is found in the cytoplasm and nucleus, but the specific localization and downstream substrates of this protease were unknown. Using indirect immunofluorescence microscopy, the authors localized endogenous caspase-2 to both the Golgi apparatus and nucleus in several cell types. The protease cleaves the Golgi-specific protein golgin-160 early in apoptosis, and inhibiting golgin-160 cleavage delays disintegration of the Golgi complex during apoptosis. The authors suggest that the Golgi apparatus, by virtue of its central location...
