ATP-Sensitive Potassium Channel (Mitochondrial) (mitoKATP)

The mitochondrial ATP-sensitive potassium channel (mitoKATP) is a potassium-selective ion channel located in the inner mitochondrial membrane. It acts as a metabolic sensor, coupling the energetic state of the cell to mitochondrial function by regulating potassium flux in response to intracellular levels of ATP and ADP. It is composed of MITOK (pore-forming) and MITOSUR (regulatory) subunits. The channel opens or closes depending on the cellular ATP/ADP ratio, with high ATP inhibiting and low ATP/high ADP activating the channel. Physiologically, it regulates mitochondrial volume, maintains membrane potential, and provides cytoprotection. Dysfunction is implicated in various diseases involving metabolic stress or ischemic injury. It is pharmacologically modulated by openers like diazoxide and pinacidil, and inhibitors like sulfonylureas.

Openers (e.g., diazoxide, pinacidil) activate the mitoKATP channel, increasing K+ influx into the mitochondria. Inhibitors (e.g., sulfonylureas like glibenclamide) block the channel, preventing K+ influx.