An Arabidopsis Mutant Defective in the Plastid General Protein Import Apparatus

• DOI: 10.1126/science.282.5386.100
• Publication Date: 2002-07-27T09:43:20Z
• Authors: Paul Jarvis; Lih-Jen Chen; Hsou-min Li; Charles A. Peto; Christian Fankhauser; Joanne Chory
• Keywords: Chlorophyll; 0301 basic medicine; Chloroplasts; Arabidopsis Proteins; Molecular Sequence Data; Arabidopsis; Membrane Proteins; Biological Transport; Intracellular Membranes; Plants, Genetically Modified; Plant Leaves; 03 medical and health sciences; Phenotype; Gene Expression Regulation, Plant; Mutation; Amino Acid Sequence; Sequence Alignment; Plant Proteins

Elaborate mechanisms have evolved for the translocation of nucleus-encoded proteins across the plastid envelope membrane. Although putative components of the import apparatus have been identified biochemically, their role in import remains to be proven in vivo. An Arabidopsis mutant lacking a new component of the import machinery [translocon at the outer envelope membrane of chloroplasts (Toc33), a 33-kilodalton protein] has been isolated. The functional similarity of Toc33 to another translocon component (Toc34) implies that multiple different translocon complexes are present in plastids. Processes that are mediated by Toc33 operate during the early stages of plastid and leaf development. The data demonstrate the in vivo role of a translocon component in plastid protein import.