Both ATP and an energized inner membrane are required to import a purified precursor protein into mitochondria.
AUTOR(ES)
Eilers, M
RESUMO
We have investigated the energy requirement of mitochondrial protein import with a simplified system containing only isolated yeast mitochondria, energy sources and a purified precursor protein. This precursor was a fusion protein composed of 22 residues of the cytochrome oxidase subunit IV pre-sequence fused to mouse dihydrofolate reductase. Import of this protein required not only an energized inner membrane, but also ATP. ATP could be replaced by GTP, but not by CTP, TTP or non-hydrolyzable ATP analogs. Added ATP did not increase the membrane potential of respiring mitochondria; it supported import even if the proton-translocating mitochondrial ATPase and the entry of ATP into the matrix were blocked. We conclude that ATP exerts its effect on mitochondrial protein import outside the inner membrane.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=553504Documentos Relacionados
- Import of an incompletely folded precursor protein into isolated mitochondria requires an energized inner membrane, but no added ATP.
- Unfolding and refolding of a purified precursor protein during import into isolated mitochondria.
- A purified precursor polypeptide requires a cytosolic protein fraction for import into mitochondria.
- Point mutations destabilizing a precursor protein enhance its post-translational import into mitochondria.
- MPI1, an essential gene encoding a mitochondrial membrane protein, is possibly involved in protein import into yeast mitochondria.