Mitochondrial calcium in command of juggling myriads of cellular functions

The puzzling traits related to the evolutionary aspect of mitochondria, still positions the mitochondrion at the center of the research. The theory of endosymbiosis popularized by Lynn Margulis in 1967 gained prominence wherein the mitochondrion is believed to have emerged as a prokaryote and later integrated into the eukaryotic system. This semi-autonomous organelle has bagged two responsible but perilous cellular functions: a) energy metabolism, and b) calcium buffering, though both are interdependent. While most of the mitochondrial functions are saliently regulated by calcium ions, the calcium buffering role of mitochondria decides the cellular fate. Though calcium overload in few mitochondria makes them dysfunctional at the early stage of cellular stress, this doesn't lead to sudden cell death due to critical checkpoints like mitophagy, mitochondrial fusion, etc. Thus, mitochondrion juggles with multiple crucial cellular functions with its calcium buffering skill.