Apocytochrome c requires the TOM complex for translocation across the mitochondrial outer membrane
AUTOR(ES)
Diekert, Kerstin
FONTE
Oxford University Press
RESUMO
The import of proteins into the mitochondrial intermembrane space differs in various aspects from the classical import pathway into the matrix. Apocytochrome c defines one of several pathways known to reach the intermembrane space, yet the components and pathways involved in outer membrane translocation are poorly defined. Here, we report the reconstitution of the apocytochrome c import reaction using proteoliposomes harbouring purified components. Import specifically requires the protease-resistant part of the TOM complex and is driven by interactions of the apoprotein with internal parts of the complex (involving Tom40) and the ‘trans-side receptor’ cytochrome c haem lyase. Despite the necessity of TOM complex function, the translocation pathway of apocytochrome c does not overlap with that of presequence-containing preproteins. We conclude that the TOM complex is a universal preprotein translocase that mediates membrane passage of apocytochrome c and other preproteins along distinct pathways. Apocytochrome c may provide a paradigm for the import of other small proteins into the intermembrane space such as factors used in apoptosis and protection from stress.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=125676Documentos Relacionados
- Translocation of proteins across the mitochondrial inner membrane, but not into the outer membrane, requires nucleoside triphosphates in the matrix.
- Uncoupling of transfer of the presequence and unfolding of the mature domain in precursor translocation across the mitochondrial outer membrane
- Translocation of a folded protein across the outer membrane in Escherichia coli.
- Two distinct mechanisms drive protein translocation across the mitochondrial outer membrane in the late step of the cytochrome b2 import pathway
- Reconstituted TOM Core Complex and Tim9/Tim10 Complex of Mitochondria Are Sufficient for Translocation of the ADP/ATP Carrier across Membranes