Structural and biochemical studies have revealed that procaspases form dimers prior to
proteolytic activation. How the two procaspases interact in the dimer is unclear. To study the
mechanisms of dimer-dependent caspase activation we used a heterodimeric system so that
two caspase molecules can be specifically brought together. Surprisingly, only one caspase
partner in the dimer needs to be enzymatically active for caspase processing and activation
to occur. Caspase activation is inefficient in the dimer in the absence of intramolecular …