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Active remodelling of the TIM23 complex during translocation of preproteins into mitochondria
Author(s) -
PopovČeleketić Dušan,
Mapa Koyeli,
Neupert Walter,
Mokranjac Dejana
Publication year - 2008
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2008.79
Subject(s) - translocase , biology , translocase of the inner membrane , translocase of the outer membrane , microbiology and biotechnology , inner membrane , mitochondrion , inner mitochondrial membrane , intermembrane space , atp–adp translocase , chromosomal translocation , protein targeting , biochemistry , bacterial outer membrane , mitochondrial membrane transport protein , membrane protein , membrane , escherichia coli , gene
The TIM23 ( t ranslocase of the mitochondrial i nner m embrane) complex mediates translocation of preproteins across and their insertion into the mitochondrial inner membrane. How the translocase mediates sorting of preproteins into the two different subcompartments is poorly understood. In particular, it is not clear whether association of two operationally defined parts of the translocase, the membrane‐integrated part and the import motor, depends on the activity state of the translocase. We established conditions to in vivo trap the TIM23 complex in different translocation modes. Membrane‐integrated part of the complex and import motor were always found in one complex irrespective of whether an arrested preprotein was present or not. Instead, we detected different conformations of the complex in response to the presence and, importantly, the type of preprotein being translocated. Two non‐essential subunits of the complex, Tim21 and Pam17, modulate its activity in an antagonistic manner. Our data demonstrate that the TIM23 complex acts as a single structural and functional entity that is actively remodelled to sort preproteins into different mitochondrial subcompartments.