Progress in Protein Translocation across Mitochondrial Membrane.

ABSTRACT

About 98% of the 1 000 or so mitochondrial proteins are encoded in the nucleus and synthesized on cytosolic ribosomes as precursors, which are then imported into mitochondria. In the present article the import machinery and pathway of mitochondrial proteins located in the matrix or inner membrane are described. Apocytochrome c, precursor of cytochrome c does not possess a cleavable N-terminal presequence and no proteinaceous component responsible for its import has ever been identified. A quite unique translocation pathway of apocytochrome c is also reviewed.