Remodelling of the active presequence translocase drives motor-dependent mitochondrial protein translocation
2014 | journal article; research paper. A publication with affiliation to the University of Göttingen.
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- Authors
- Schulz, Christian ; Rehling, Peter
- Abstract
- Proteins with N-terminal targeting signals are transported across the inner mitochondrial membrane by the presequence translocase. To drive precursor translocation, the Hsp70-import motor associates with the protein-conducting channel of the TIM23 complex. It is unknown how the ATPase cycle of Hsp70 is regulated in the context of a translocating polypeptide chain. Here we establish an assay to monitor protein dynamics in the precursor-occupied presequence translocase and find that regulatory subunits of the import motor, such as the ATPase-stimulating J-protein Pam18, are recruited into the translocation intermediate. The presence of all Hsp70 co-chaperones at the import channel is not sufficient to promote matrix protein import, instead a recharging of the active translocase with Pam18 is required for motor activity. Thus, a replenishment cycle of co-chaperones at the TIM23 complex is an integral part of Hsp70's ATPase cycle at the channel exit site and essential to maintain motor-driven mitochondrial protein import.
- Issue Date
- 2014
- Journal
- Nature Communications
- ISSN
- 2041-1723
- Extent
- 1
- Language
- English