Uncovering the protein translocon at the chloroplast inner envelope membrane

Shingo Kikuchi, Jocelyn Bédard, Minako Hirano, Yoshino Hirabayashi, Maya Oishi, Midori Imai, Mai Takase, Toru Ide, Masato Nakai

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153 Citations (Scopus)

Abstract

Chloroplasts require protein translocons at the outer and inner envelope membranes, termed TOC and TIC, respectively, to import thousands of cytoplasmically synthesized preproteins. However, the molecular identity of the TIC translocon remains controversial. Tic20 forms a 1-megadalton complex at the inner membrane and directly interacts with translocating preproteins. We purified the 1-megadalton complex from Arabidopsis, comprising Tic20 and three other essential components, one of which is encoded by the enigmatic open reading frame ycf1 in the chloroplast genome. All four components, together with well-known TOC components, were found stoichiometrically associated with different translocating preproteins. When reconstituted into planar lipid bilayers, the purified complex formed a preprotein-sensitive channel. Thus, this complex constitutes a general TIC translocon.

Original languageEnglish
Pages (from-to)571-574
Number of pages4
JournalScience
Volume339
Issue number6119
DOIs
Publication statusPublished - Feb 1 2013
Externally publishedYes

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ASJC Scopus subject areas

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Cite this

Kikuchi, S., Bédard, J., Hirano, M., Hirabayashi, Y., Oishi, M., Imai, M., Takase, M., Ide, T., & Nakai, M. (2013). Uncovering the protein translocon at the chloroplast inner envelope membrane. Science, 339(6119), 571-574. https://doi.org/10.1126/science.1229262