Identification of mitochondrial transport proteins

A large number of transport proteins are required for the translocation of molecules across the impermeable inner membrane of mitochondria to link the pathways of the cytosol with those of the mitochondrial matrix. The transport processes are key to our understanding of mitochondrial and cellular physiology, as well as human disease.

Figure Schematic representation of the role of transport in mitochondrial and cellular metabolism.

The molecular identity of the majority of transport proteins involved in mitochondrial and cellular metabolism has not been established. Amino acids must be imported into the mitochondrial matrix for protein synthesis, interconversions or deamination reactions, yet the vast majority of amino acid transporters have not been identified. For the synthesis of iron-sulphur clusters and haem, mitochondria need to import a source of sulphur and to export aminolevulinic acid. Transporters for crucial cofactors such as NAD, biotin, pantothenic acid and pyridoxal phosphate or their precursors and derivatives have not been identified either. The transporters of guanine nucleotides for the synthesis of DNA and RNA and antioxidants for protection against reactive oxygen species are also unknown. There are 53 different members of the mitochondrial carrier family encoded by the human genome, but more than half have no assigned function [1][2]. There are also other membrane protein families involved in transport in mitochondria, for example the mitochondrial pyruvate transporter [3][4] and mitochondrial ABC transporters [5][6].

One of the major aims of the group is to identify new transport proteins and to understand their role in physiology and disease.