Essential core component of the TIM22 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 and signal-gated channel. Forms a twin-pore translocase that uses the membrane potential as external driving force in 2 voltage-dependent steps (By similarity). Component of the TIM22 complex, whose core is composed of TIMM22, associated with peripheral protein FXC1/TIMM10B and the 70 kDa heterohexamer. In most cases, the 70 kDa complex is composed of TIMM9 and TIMM10 (TIMM10A or TIMM10B). A small fraction of the 70 kDa complex is composed of TIMM8 (TIMM8A/DDP1 or TIMM8B/DDP2) and TIMM13. The TIM22 complex also contains AGK and TIMM29. Interacts directly with TIMM9, TIMM10A and FXC1/TIMM10B. Interacts (when oxidized) with TIMM29; interaction is direct. Disulfide bonds promote efficient assembly of the TIM22 complex. Belongs to the Tim17/Tim22/Tim23 family.