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Updated: May 17, 2026

Studying Protein Import into Chloroplasts Using Protoplasts
Published on: December 10, 2018
The gateway to chloroplast: re-defining the function of chloroplast receptor proteins
Wai-Ling Chang1, Jürgen Soll, Bettina Bölter
1Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Grosshadernerstrasse 2-4, D-82152 Planegg-Martinsried, Germany.
Abstract:
Chloroplast biogenesis often requires a tight orchestration between gene expression (both plastidial and nuclear) and translocation of ~3000 nuclear-encoded proteins into the organelle. Protein translocation is achieved via two multimeric import machineries at the outer (TOC) and inner (TIC) envelope of chloroplast, respectively. Three components constitute the core element of the TOC complex: a β-barrel protein translocation channel Toc75 and two receptor constituents, Toc159 and Toc34. A diverse set of distinct TOC complexes have recently been characterized and these diversified TOC complexes have evolved to coordinate the translocation of differentially expressed proteins. This review aims to describe the recent discoveries relating to the typical characteristics of these distinct TOC complexes, particularly the receptor constituents, which are the main contributors for TOC complex diversification.
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