Computational properties of mitochondria in T cell activation and fate

In this article, we review how mitochondrial Ca(2+) transport (mitochondrial Ca(2+) uptake and Na(+)/Ca(2+) exchange) is involved in T cell biology, including activation and differentiation through shaping cellular Ca(2+) signals. Based on recent observations, we propose that the Ca(2+) crosstalk between mitochondria, endoplasmic reticulum and cytoplasm may form a proportional–integral–derivative (PID) controller. This PID mechanism (which is well known in engineering) could be responsible for computing cellular decisions. In addition, we point out the importance of analogue and digital signal processing in T cell life and implication of mitochondrial Ca(2+) transport in this process.