TIMM22 is an essential core component of the TIM22 protein insertion complex, a complex that mediates the import and insertion of multi-pass transmembrane proteins into the mitochondrial inner membrane. In the TIM22 complex, it constitutes the voltage-activated, signal-gated hydrophilic high-conductance channel. It forms a twin-pore translocase that uses the membrane potential as an external driving force in 2 voltage-dependent steps.