CANCELLED

The mitochondrion requires different proteins to accomplish its crucial role within the cell. Mitochondrial proteins are mostly produced in the cytosol and must be translocated to the mitochondrial interior in order to fulfill their functions. The Translocase Outer Membrane complex is involved in the translocation of unfolded proteins delivered by cytosolic Hsp90 to the mitochondrion interior via Tom70. Despite a wealth of studies conducted on the relevance of Tom70/Hsp90 complex formation, there is a dearth of information regarding the exact molecular mode of Tom70-Hsp90 interaction. To help fill this void, we have employed a combined experimental strategy consisting of crosslinking/mass spectrometry to investigate binding of the C-terminal Hsp90 domain to the cytosolic domain of Tom70. This approach has identified a novel region of contact between C-Hsp90 and Tom70, a finding that is confirmed by probing the corresponding peptides derived from crosslinking experiments via isothermal titration calorimetry and mitochondrial import assays. Collectively, our findings provide significant insight on the mechanisms by which preproteins interact with Hsp90 and are translocated via Tom70 to the mitochondrion.