Mitochondrial Import Pathways to the Inner Membrane

Mitochondrial import pathways move nuclear-encoded precursor proteins to the inner membrane in several steps. Two main translocons, TIM22 and TIM23, handle much of this sorting. A third translocase, OXA, helps insert some proteins into the membrane after they have moved partway through the system.

Translocation across the inner membrane is driven by the electrochemical potential of the proton gradient across the inner membrane.

Negative charges towards the matrix side of the inner membrane unfold the precursor and pull the positively charged presequence in.

Two distinct translocases, TIM23 and TIM22, facilitate the transport...