Roles of Tom70 in import of presequence-containing mitochondrial proteins

Hayashi Yamamoto, Kenji Fukui, Hisashi Takahashi, Shingo Kitamura, Takuya Shiota, Kayoko Terao, Mayumi Uchida, Masatoshi Esaki, Shuh Ichi Nishikawa, Tohru Yoshihisa, Koji Yamano, Toshiya Endo

Research output: Contribution to journalArticleResearchpeer-review

62 Citations (Scopus)


Mitochondrial protein traffic requires precise recognition of the mitochondrial targeting signals by the import receptors on the mitochondrial surface including a general import receptor Tom20 and a receptor for presequence-less proteins, Tom70. Here we took a proteome-wide approach of mitochondrial protein import in vitro to find a set of presequence-containing precursor proteins for recognition by Tom70. The presequences of the Tom70-dependent precursor proteins were recognized by Tom20, whereas their mature parts exhibited Tom70-dependent import when attached to the presequence of Tom70-independent precursor proteins. The mature parts of the Tom70-dependent precursor proteins have the propensity to aggregate, and the presence of the receptor domain of Tom70 prevents their aggregate formation. Therefore Tom70 plays the role of a docking site for not only cytosolic chaperones but also aggregate-prone substrates to maintain their solubility for efficient transfer to downstream components of the mitochondrial import machineries.

Original languageEnglish
Pages (from-to)31635-31646
Number of pages12
JournalThe Journal of Biological Chemistry
Issue number46
Publication statusPublished - 2009
Externally publishedYes

Cite this