Multiple pathways for protein transport into or across the thylakoid membrane - PubMed (original) (raw)

Comparative Study

Multiple pathways for protein transport into or across the thylakoid membrane

K Cline et al. EMBO J. 1993 Nov.

Abstract

Many thylakoid proteins are cytosolically synthesized and have to cross the two chloroplast envelope membranes as well as the thylakoid membrane en route to their functional locations. In order to investigate the localization pathways of these proteins, we over-expressed precursor proteins in Escherichia coli and used them in competition studies. Competition was conducted for import into the chloroplast and for transport into or across isolated thylakoids. We also developed a novel in organello method whereby competition for thylakoid transport occurred within intact chloroplasts. Import of all precursors into chloroplasts was similarly inhibited by saturating concentrations of the precursor to the OE23 protein. In contrast, competition for thylakoid transport revealed three distinct precursor specificity groups. Lumen-resident proteins OE23 and OE17 constitute one group, lumenal proteins plastocyanin and OE33 a second, and the membrane protein LHCP a third. The specificity determined by competition correlates with previously determined protein-specific energy requirements for thylakoid transport. Taken together, these results suggest that thylakoid precursor proteins are imported into chloroplasts on a common import apparatus, whereupon they enter one of several precursor-specific thylakoid transport pathways.

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References

    1. Plant Physiol. 1984 Jul;75(3):675-8 - PubMed
    1. Nucleic Acids Res. 1991 Jan 11;19(1):184 - PubMed
    1. J Biol Chem. 1991 Feb 15;266(5):3335-42 - PubMed
    1. J Biol Chem. 1989 Aug 25;264(24):14225-32 - PubMed
    1. Plant Physiol. 1949 Jan;24(1):1-15 - PubMed

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