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Updated: Aug 20, 2026

An Improved Method to Isolate Mitochondrial Contact Sites
Published on: June 16, 2023
Mim1, a protein required for the assembly of the TOM complex of mitochondria
Thomas Waizenegger1, Simone Schmitt, Jelena Zivkovic
1Institut für Physiologische Chemie der Universität München, Butenandtstrasse 5, 81377 Munich, Germany.
Abstract:
The translocase of the outer mitochondrial membrane (TOM complex) is the general entry site for newly synthesized proteins into mitochondria. This complex is essential for the formation and maintenance of mitochondria. Here, we report on the role of the integral outer membrane protein, Mim1 (mitochondrial import), in the biogenesis of mitochondria. Depletion of Mim1 abrogates assembly of the TOM complex and results in accumulation of Tom40, the principal constituent of the TOM complex, as a low-molecular-mass species. Like all mitochondrial beta-barrel proteins, the precursor of Tom40 is inserted into the outer membrane by the TOB complex. Mim1 is likely to be required for a step after this TOB-complex-mediated insertion. Mim1 is a constituent of neither the TOM complex nor the TOB complex; rather, it seems to be a subunit of another, as yet unidentified, complex. We conclude that Mim1 has a vital and specific function in the assembly of the TOM complex.
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