Crosstalk between apoptosis and autophagy signaling pathways

The fate of a cell is determined by multiple signaling pathways in response to a range of stimuli. Probably the most prominent cell death mechanism is apoptosis which can be triggered by both internal stresses, as well as extracellular stimuli, and is executed by two well-characterized pathways, the intrinsic and the extrinsic apoptosis pathways. Although autophagy can also lead to cell death under certain circumstances, its major function is as a cell survival process. Given that the life of a cell is at stake, it is not surprising that there is significant molecular crosstalk between these pathways. The nature of these interconnections is diverse and ranges from protein-protein interactions and post-translational modifications through to the degradation of molecular components by different proteins and organelles. In this chapter we review these mechanisms in detail.