Proposed scheme of interplay between Ca²⁺, ATP and V_m in the β-cell.

<p>The oxidation of glucose that enters the β-cell hyperpolarises the mitochondrial membrane (ΔΨ_m) thereby leading to the elevation of cytosolic ATP/ADP ratio, closing of K_ATP channels, depolarisation of the plasma membrane (V_m) and Ca²⁺ entry. Elevated cytosolic [Ca²⁺] triggers a number of ATP-dependent processes including insulin secretion and Ca²⁺ removal into the ER and extracellular medium. By entering mitochondria via MCU, Ca²⁺ potentiates oxidative metabolism to counter-balance ATP expenditure. Ca²⁺ exits mitochondria via NCLX.