To live or to die? This crucial question eloquently reflects the dual role of Ca2+ in living organisms--survival factor or ruthless killer. It has long been known that Ca2+ signals govern a host of vital cell functions and so are necessary for cell survival. However, more recently it has become clear that cellular Ca2+ overload, or perturbation of intracellular Ca2+ compartmentalization, can cause cytotoxicity and trigger either apoptotic or necrotic cell death.