How Can Organellar Protein N-terminal Sequences Be Dual Targeting Signals? In silico Analysis and Mutagenesis Approach

Pujol, Claire; Maréchal-Drouard, Laurence; Duchêne, Anne‐Marie

doi:10.1016/j.jmb.2007.03.015

Cited by 64 publications

(73 citation statements)

References 42 publications

(74 reference statements)

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“…This may be a possibility since the current model for chloroplast import predicts that transit peptides are recognized initially by Toc34 and interact subsequently with Toc159 (Becker et al 2004b;Soll and Schleiff 2004). Perhaps the acidic CrToc34 domain influences the composition of C. reinhardtii transit peptides to resemble vascular plant mitochondrial transit peptides, which are generally shorter (Zhang and Glaser 2002) and more enriched in arginine residues within their N termini (Pujol et al 2007).…”

Section: Resultsmentioning

confidence: 99%

“…These negatively charged regions on an essential chloroplast import receptor are likely reciprocated by extra positive charges on inbound transit peptides, particularly given that Toc34 is proposed to form the initial contact with the transit peptide (Becker et al 2004b). Since mitochondrial-targeting epitopes are also enriched in arginine residues (Pujol et al 2007), C. reinhardtii chloroplast transit peptides might appear more similar to mitochondrial-targeting peptides when screened by neural network predictors. How C. reinhardtii distinguishes between chloroplast and mitochondrial proteins is unknown, although a C. reinhardtii-specific transit peptide predictor may assist in answering this question.…”

Section: Resultsmentioning

confidence: 99%

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The Chloroplast Protein Translocation Complexes ofChlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae

2008

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The recently completed genome of Chlamydomonas reinhardtii was surveyed for components of the chloroplast protein translocation complexes. Putative components were identified using reciprocal BlastP searches with the protein sequences of Arabidopsis thaliana as queries. As a comparison, we also surveyed the new genomes of the bryophyte Physcomitrella patens, two prasinophyte green algae (Ostreococcus lucimarinus and Ostreococcus tauri), the red alga Cyanidioschizon merolae, and several cyanobacteria. Overall, we found that the components of the import pathway are remarkably well conserved, particularly among the Viridiplantae lineages. Specifically, C. reinhardtii contained almost all the components found in A. thaliana, with two exceptions. Missing from C. reinhardtii are the C-terminal ferredoxin-NADPH-reductase (FNR) binding domain of Tic62 and a full-length, TPR-bearing Toc64. Further, the N-terminal domain of C. reinhardtii Toc34 is highly acidic, whereas the analogous region in C. reinhardtii Toc159 is not. This reversal of the vascular plant model may explain the similarity of C. reinhardtii chloroplast transit peptides to mitochondrial-targeting peptides. Other findings from our genome survey include the absence of Tic22 in both Ostreococcus genomes; the presence of only one Toc75 homolog in C. merolae; and, finally, a distinctive propensity for gene duplication in P. patens.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The Chloroplast Protein Translocation Complexes ofChlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae

2008

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“…A few N-terminal sequences have been shown to allow targeting to both mitochondria and chloroplasts. These sequences are called dual or ambiguous targeting sequences, and prediction programs are usually inefficient to determine the precise localization of proteins with such an extension (11).…”

Section: Resultsmentioning

confidence: 99%

“…In most cases, targeting sequences are specific to one organelle or the other, and dual targeting is rare. Approximately 40 examples of dual-targeted proteins of the thousands of organellar-imported proteins have been identified in A. thaliana, but half of these proteins correspond to aaRSs (11). Eighteen of 24 identified A. thaliana organellar aaRSs are shared between mitochondria and chloroplasts (8,18).…”

Section: Glnrs Mito Nd-glursmentioning

confidence: 99%

Dual-targeted tRNA-dependent amidotransferase ensures both mitochondrial and chloroplastic Gln-tRNA ^Gln synthesis in plants

Pujol

Bailly

Kern

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Aminoacyl-tRNAs are generally formed by direct attachment of an amino acid to tRNAs by aminoacyl-tRNA synthetases, but Gln-tRNA is an exception to this rule. Gln-tRNA Gln is formed by this direct pathway in the eukaryotic cytosol and in protists or fungi mitochondria but is formed by an indirect transamidation pathway in most of bacteria, archaea, and chloroplasts. We show here that the formation of Gln-tRNA Gln is also achieved by the indirect pathway in plant mitochondria. The mitochondrial-encoded tRNA Gln , which is the only tRNA Gln present in mitochondria, is first charged with glutamate by a nondiscriminating GluRS, then is converted into Gln-tRNA Gln by a tRNA-dependent amidotransferase (AdT). The three subunits GatA, GatB, and GatC are imported into mitochondria and assemble into a functional GatCAB AdT. Moreover, the mitochondrial pathway of Gln-tRNA Gln formation is shared with chloroplasts as both the GluRS, and the three AdT subunits are dual-imported into mitochondria and chloroplasts.amidation ͉ aminoacylation ͉ GatCAB ͉ glutamyl-tRNA synthetase ͉ protein trafficking

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“…On the other hand, MultiLoc/TargetLoc program predicted a dual localization to both the chloroplast and mitochondrion with a probability of 97%. In addition, the transit peptide (MAASNFLLQLPLRSFTVINVA-SASSS) is rich in Ser residues, deficient of Glu, and has features typical for ambiguous targeting signals (Pujol et al, 2007;Mitschke et al, 2009).…”

Section: Primary Structure and Mitochondrial Prediction Of Pssrxmentioning

confidence: 99%

The Dual-Targeted Plant Sulfiredoxin Retroreduces the Sulfinic Form of Atypical Mitochondrial Peroxiredoxin

et al. 2010

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Sulfiredoxin (Srx) couples the energy of ATP hydrolysis to the energetically unfavorable process of reducing the inactive sulfinic form of 2-cysteine peroxiredoxins (Prxs) to regenerate its active form. In plants, Srx as well as typical 2-cysteine Prx have been considered as enzymes with exclusive chloroplast localization. This work explores the subcellular localization of Srx in pea (Pisum sativum) and Arabidopsis (Arabidopsis thaliana). Immunocytochemistry, analysis of protein extracts from isolated intact organelles, and cell-free posttranslational import assays demonstrated that plant Srx also localizes to the mitochondrion in addition to plastids. The dual localization was in line with the prediction of a signal peptide for dual targeting. Activity tests and microcalorimetric data proved the interaction between Srx and its mitochondrial targets Prx IIF and thioredoxin. Srx catalyzed the retroreduction of the inactive sulfinic form of atypical Prx IIF using thioredoxin as reducing agent. Arabidopsis Srx also reduced overoxidized human Prx V. These results suggest that plant Srx could play a crucial role in the regulation of Prx IIF activity by controlling the regeneration of its overoxidized form in mitochondria, which are sites of efficient reactive oxygen species production in plants.

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How Can Organellar Protein N-terminal Sequences Be Dual Targeting Signals? In silico Analysis and Mutagenesis Approach

Cited by 64 publications

References 42 publications

The Chloroplast Protein Translocation Complexes ofChlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae

The Chloroplast Protein Translocation Complexes ofChlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae

Dual-targeted tRNA-dependent amidotransferase ensures both mitochondrial and chloroplastic Gln-tRNA ^Gln synthesis in plants

The Dual-Targeted Plant Sulfiredoxin Retroreduces the Sulfinic Form of Atypical Mitochondrial Peroxiredoxin

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How Can Organellar Protein N-terminal Sequences Be Dual Targeting Signals? In silico Analysis and Mutagenesis Approach

Cited by 64 publications

References 42 publications

The Chloroplast Protein Translocation Complexes ofChlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae

The Chloroplast Protein Translocation Complexes ofChlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae

Dual-targeted tRNA-dependent amidotransferase ensures both mitochondrial and chloroplastic Gln-tRNA Gln synthesis in plants

The Dual-Targeted Plant Sulfiredoxin Retroreduces the Sulfinic Form of Atypical Mitochondrial Peroxiredoxin

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Dual-targeted tRNA-dependent amidotransferase ensures both mitochondrial and chloroplastic Gln-tRNA ^Gln synthesis in plants