Essential component of the TIM17:23 complex, a complex that mediates the translocation of transit peptide-containing proteins across the mitochondrial inner membrane. Links the inner and outer membranes (By similarity). Homomultimer. Component of the TIM17:23 complex at least composed of TIM23, TIM17 and TIM50. The complex interacts with the TIM44 component of the PAM complex. Also part of the NADH-ubiquinone oxidoreductase complex I. Interacts with OEP163, TIM17-2, TIM21, TIM50 and MPPA2. Expressed in roots and young cotyledons. Detected in leaves and flowers. Peak of expression during cotyledon development. The C-terminal part (143-188) is required for insertion in the mitochondrial inner membrane. Belongs to the Tim17/Tim22/Tim23 family.