Endogenous mitochondrial K+ influx is matched by mitochondrial K+/H+ exchange to reduce swelling and induce matrix acidosis

Abstract

Mitochondria pump protons to create a transmembrane pH gradient (ΔpHm) that contributes to polarizing ΔΨm; proton reentry tends to depolarize ΔΨm. Electrophoretic influx of other cations, i.e., Na+, K+, and Ca2+, can also depolarize ΔΨm and must be removed by exchanging one ion for another (chemiosmosis). The importance of regulated Km+ influx in bioenergetics is unclear but Km+ influx can lead to rapid mitochondrial swelling so the added Km+ must be extruded, primarily in exchange for Hm+ entry (KHEm).