2005/03/01 by Agnieszka Chacińska, Agnieszka Chacinska, Maria Lind +10 · 4 citations
Biochemistry, Genetics and Molecular Biology · #Biology #Cell biology #Chromosomal translocation #Gene #Genetics #Microtubule #Mitochondrial Function and Pathology #Mitochondrion #Motor protein #RNA Research and Splicing #RNA modifications and cancer #Tethering #Translocase
paper · pdf · doi:10.1016/j.cell.2005.01.011
openalex publication_date 2005/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The presequence translocase of the inner mitochondrial membrane (TIM23 complex) operates at a central junction of protein import. It accepts preproteins from the outer membrane TOM complex and directs them to inner membrane insertion or, in cooperation with the presequence translocase-associated motor (PAM), to the matrix. Little is known of how the TIM23 complex coordinates these tasks. We have identified Tim21 (YGR033c) that interacts with the TOM complex. Tim21 is specific for a TIM23 form that cooperates with TOM and promotes inner membrane insertion. Protein translocation into the matrix requires a switch to a Tim21-free, PAM bound presequence translocase. Tim17 is crucial for the switch by performing two separable functions: promotion of inner membrane insertion and binding of Pam18 to form the functional TIM-PAM complex. Thus, the presequence translocase is not a static complex but switches between TOM tethering and PAM binding in a reaction cycle involving Tim21 and Tim17.