Fig. 1.

Targets for apoptosis detection. During apoptosis, initiator caspases are activated, via either cell death receptor-mediated or mitochondrial signalling. These initiator caspases, in turn, trigger the activation of effector caspases, such as caspase-3. The activation of caspase-3 results in the typical characteristics of apoptosis, such as DNA fragmentation, substrate cleavage of cytoplasmic proteins and cell membrane alterations. These apoptotic characteristics and the activation of caspase-3 offer targets for molecular imaging of apoptosis