Molecular architecture of the active mitochondrial protein gate

Takuya Shiota, Kenichiro Imai, Jian Qiu, Victoria L Hewitt, Kher Shing Tan, Hsin-Hui Shen, Noriyuki Sakiyama, Yoshinori Fukasawa, Sikander Hayat, Megumi Kamiya, Arne Elofsson, Kentaro Tomii, Paul Horton, Nils Wiedemann, Nikolaus Pfanner, Trevor J Lithgow, Toshiya Endo

Research output: Contribution to journalArticleResearchpeer-review

146 Citations (Scopus)


Mitochondria fulfill central functions in cellular energetics, metabolism, and signaling. The outer membrane translocator complex (the TOM complex) imports most mitochondrial proteins, but its architecture is unknown. Using a cross-linking approach, we mapped the active translocator down to single amino acid residues, revealing different transport paths for preproteins through the Tom40 channel. An N-terminal segment of Tom40 passes from the cytosol through the channel to recruit chaperones from the intermembrane space that guide the transfer of hydrophobic preproteins. The translocator contains three Tom40 beta-barrel channels sandwiched between a central alpha-helical Tom22 receptor cluster and external regulatory Tom proteins. The preprotein-translocating trimeric complex exchanges with a dimeric isoform to assemble new TOM complexes. Dynamic coupling of alpha-helical receptors, beta-barrel channels, and chaperones generates a versatile machinery that transports about 1000 different proteins.
Original languageEnglish
Pages (from-to)1544 - 1548
Number of pages5
Issue number6255
Publication statusPublished - 2015

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