Carrier and channel properties of the mitochondrial transporters: physiology and pathology?

The mitochondrial metabolite transporters form a protein superfamily that is known to switch from its specific carrier mechanism to a channel/pore mode. The altered carrier function probably has pathophysiological significance. Thus, the permeability transition appears to be due to the switch of the adenine nucleotide translocator to a channel/pore mode. Similarly, when there exist abnormally high fatty-acid levels, mitochondrial carriers appear to mediate the fatty-acid uncoupling. It has been proposed that carriers facilitate the translocation of the fatty acid anion, although the possibility exists that the underlying mechanism is the conversion to the pore mode.