The role of the N-terminal domain of chloroplast targeting peptides in organellar protein import and miss-sorting

Bhushan, Shashi; Kuhn, Claus; Berglund, Anna-Karin; Roth, Christian; Glaser, Elzbieta

doi:10.1016/j.febslet.2006.06.018

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Volume 580, Issue 16 , Pages 3966-3972, 10 July 2006

The role of the N-terminal domain of chloroplast targeting peptides in organellar protein import and miss-sorting

Edited by Ulf-Ingo Flügge

Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden

Received 9 May 2006; received in revised form 8 June 2006; accepted 9 June 2006. published online 19 June 2006.

Abstract

We have analysed 385 mitochondrial and 567 chloroplastic signal sequences of proteins found in the organellar proteomes of Arabidopsis thaliana. Despite overall similarities, the first 16 residues of transit peptides differ remarkably. To test the hypothesis that the N-terminally truncated transit peptides would redirect chloroplastic precursor proteins to mitochondria, we studied import of the N-terminal deletion mutants of ELIP, PetC and Lhcb2.1. The results show that the deletion mutants were neither imported into chloroplasts nor miss-targeted to mitochondria in vitro and in vivo, showing that the entire transit peptide is necessary for correct targeting as well as miss-sorting.

Keywords: Chloroplast, Mitochondria, Targeting peptide, Protein import, Miss-sorting