Signal recognition initiates reorganization of the presequence translocase during protein import

• DOI: 10.1038/emboj.2013.23
• Publication Date: 2013-02-12T15:05:34Z
• Authors: Oleksandr Lytovch...; Jonathan Melin; Christian Schulz; Markus Kilisch; Dana P Hutu; Peter Rehling
• Keywords: Models, Molecular; 0303 health sciences; Binding Sites; Saccharomyces cerevisiae Proteins; Membrane Proteins; Membrane Transport Proteins; Saccharomyces cerevisiae; Protein Sorting Signals; Mitochondrial Membrane Transport Proteins; Protein Structure, Secondary; Substrate Specificity; Protein Transport; 03 medical and health sciences; Mitochondrial Precursor Protein Import Complex Proteins; Protein Interaction Domains and Motifs; Carrier Proteins; Protein Binding

The mitochondrial presequence translocase interacts with presequence-containing precursors at the intermembrane space (IMS) side of the inner membrane to mediate their translocation into the matrix. Little is known as too how these matrix-targeting signals activate the translocase in order to initiate precursor transport. Therefore, we analysed how signal recognition by the presequence translocase initiates reorganization among Tim-proteins during import. Our analyses revealed that the presequence receptor Tim50 interacts with Tim21 in a signal-sensitive manner in a process that involves the IMS-domain of the Tim23 channel. The signal-driven release of Tim21 from Tim50 promotes recruitment of Pam17 and thus triggers formation of the motor-associated form of the TIM23 complex required for matrix transport.