Figure 7. Metacaspase proteins in cell death and cell growth pathways.

Metacaspase proteins could play a key role in the balance between life and death at a cellular level. Here they are predicted as the initiator proteins inducing cell death through a z-VAD-fmk inhibitable effector protease. The wide range of metacaspase functions suggests this activation could occur through 1) protein relocalization, 2) remodelling, or 3) specific processing mediated by an arginine-specific proteolytic activity. A secondary pathway could occur via the activation of other (meta)caspase proteins (MCAx) leading to a functionally redundant pathway.