Calcium and mitochondria in the regulation of cell death

• The interaction between the different forms of cell death is complex and still a matter of debate.
• Mitochondria play a crucial role in several cell death modalities and in the cross-talk between them.
• The Ca2+ ion is critically involved in both the initiation and effectuation of various modes of cell death.

The calcium ion has long been known to play an important role in cell death regulation. Hence, necrotic cell death was early associated with intracellular Ca2+ overload, leading to mitochondrial permeability transition and functional collapse. Subsequent characterization of the signaling pathways in apoptosis revealed that Ca2+/calpain was critically involved in the processing of the mitochondrially localized, Apoptosis Inducing Factor. More recently, the calcium ion has been demonstrated to play important regulatory roles also in other cell death modalities, notably autophagic cell death and anoikis. In this review, we summarize current knowledge about the mechanisms involved in Ca2+ regulation of these various modes of cell death with a focus on the importance of the mitochondria.