Defining the Determinants for Dual Targeting of Amino Acyl-tRNA Synthetases to Mitochondria and Chloroplasts

Berglund, Anders; Pujol, Claire; Duchêne, Anne‐Marie; Glaser, Elzbieta

doi:10.1016/j.jmb.2009.08.072

Cited by 45 publications

(38 citation statements)

References 56 publications

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“…Structurally, most mTPs are predicted to form an amphiphilic α‐helix, which has been shown to play an important role in mitochondrial import , while cTPs appear to be unstructured in most studies . Nevertheless, some cTPs have been reported to form helical structures in a membrane mimetic environment .…”

Section: Introductionmentioning

confidence: 99%

NMR investigations of the dual targeting peptide of Thr‐tRNA synthetase and its interaction with the mitochondrial Tom20 receptor in Arabidopsis thaliana

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et al. 2012

The FEBS Journal

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Most mitochondrial proteins are synthesized in the cytosol as precursor proteins containing an N-terminal targeting peptide and are imported into mitochondria through the import machineries, the translocase of the outer mitochondrial membrane (TOM) and the translocase of the inner mito-chondrial membrane (TIM). The N-terminal targeting peptide of precursor proteins destined for the mitochondrial matrix is recognized by the Tom20 receptor and plays an important role in the import process. Protein import is usually organelle specific, but several plant proteins are dually targeted into mitochondria and chloroplasts using an ambiguous dual targeting pep-tide. We present NMR studies of the dual targeting peptide of Thr-tRNA synthetase and its interaction with Tom20 in Arabidopsis thaliana. Our findings show that the targeting peptide is mostly unstructured in buffer, with a propensity to form a-helical structure in one region, S6-F27, and a very weak b-strand propensity for Q34-Q38. The a-helical structured region has an amphiphilic character and a uvvuu motif, both of which have previously been shown to be important for mitochondrial import. Using NMR we have mapped out two regions in the peptide that are important for Tom20 recognition: one of them, F9-V28, overlaps with the amphiphilic region, and the other comprises residues L30-Q39. Our results show that the targeting peptide may interact with Tom20 in several ways. Furthermore, our results indicate a weak, dynamic interaction. The results provide for the first time molecular details on the interaction of the Tom20 receptor with a dual targeting peptide. Database The backbone chemical shift assignments for ThrRS-dTP(2-60) have been deposited with the Biological Magnetic Resonance Bank (BMRB) under the accession code 18248 Structured digital abstract ThrRS-dTP and Tom20-4 bind by nuclear magnetic resonance (View interaction) Abbreviations aaRS, aminoacyl-tRNA synthetase; AOX, alternative oxidase; CLEANEX, clean chemical exchange; cTP, chloroplastic targeting peptide; dTP, dually targeting peptide; GST, glutathione S-transferase; HSQC, heteronuclear single-quantum coherence; mTP, mitochondrial targeting peptide; SSP, secondary structure propensity; ThrRS-dTP, threonyl tRNA synthetase dual targeting peptide; TIC, translocase of the inner envelope membrane of chloroplasts; TIM, translocase of the inner mitochondrial membrane; TOC, translocase of the outer envelope membrane of chloroplasts; TOM, translocase of the outer mitochondrial membrane.

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Section: Introductionmentioning

confidence: 99%

NMR investigations of the dual targeting peptide of Thr‐tRNA synthetase and its interaction with the mitochondrial Tom20 receptor in Arabidopsis thaliana

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Unnerståle

et al. 2012

The FEBS Journal

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“…Examples of this have been previously reported to occur naturally, in Arabidopsis acyl-activating enzymes which display an identical arrangement of targeting signals except the mitochondrial signal is replaced with a chloroplast signal [56], and an artificially created protein containing the chloroplast targeting signal of Small subunit unit of rubisco (SSU) attached to both RFP and GFP followed by a PTS1 signal, could in fact target to both chloroplasts and peroxisomes in vivo [57]. This suggests that both signals can be recognized in the cell environment, even though the N-terminal signal would emerge from the ribosome before the C-terminal this differs slightly from previous work performed on the targeting signals of dual targeted proteins [58,59]. However these studies were focused on dual targeting between mitochondria and chloroplasts, where the targeting signals are both located at the N-terminus.…”

Section: Discussionmentioning

confidence: 88%

The dual targeting ability of type II NAD(P)H dehydrogenases arose early in land plant evolution

et al. 2013

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BackgroundType II NAD(PH) dehydrogenases are located on the inner mitochondrial membrane of plants, fungi, protists and some primitive animals. However, recent observations have been made which identify several Arabidopsis type II dehydrogenases as dual targeted proteins. Targeting either mitochondria and peroxisomes or mitochondria and chloroplasts.ResultsMembers of the ND protein family were identified in various plant species. Phylogenetic analyses and subcellular targeting predictions were carried out for all proteins. All ND proteins from three model plant species Arabidopsis, rice and Physcomitrella were cloned as N- and C-terminal GFP fusions and subcellular localisations were determined. Dual targeting of plant type II dehydrogenases was observed to have evolved early in plant evolution and to be widespread throughout different plant species. In all three species tested dual targeting to both mitochondria and peroxisomes was found for at least one NDA and NDB type protein. In addition two NDB type proteins from Physcomitrella were also found to target chloroplasts. The dual targeting of NDC type proteins was found to have evolved later in plant evolution.ConclusionsThe functions of type II dehydrogenases within plant cells will have to be re-evaluated in light of this newly identified subcellular targeting information.

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“…The ambiguous presequence generates a single protein isoform with a targeting peptide recognized by the import apparatus of both mitochondria and chloroplasts. Although this configuration can be organized in domains determining targeting specificity to an individual organelle, the signals responsible for organellar targeting most frequently overlap (Berglund et al, 2009a). Hence, ambiguous presequences cannot be completely distinguished from organelle-specific targeting peptides and they have an intermediate amino acid composition using the same organellar import pathways as the organelle-specific proteins.…”

Section: Expression and Protein Targeting Of Arabidopsis Lon Genesmentioning

confidence: 99%

Evolution and significance of the Lon gene family in Arabidopsis organelle biogenesis and energy metabolism

et al. 2014

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Lon is the first identified ATP-dependent protease highly conserved across all kingdoms. Model plant species Arabidopsis thaliana has a small Lon gene family of four members. Although these genes share common structural features, they have distinct properties in terms of gene expression profile, subcellular targeting and substrate recognition motifs. This supports the notion that their functions under different environmental conditions are not necessarily redundant. This article intends to unravel the biological role of Lon proteases in energy metabolism and plant growth through an evolutionary perspective. Given that plants are sessile organisms exposed to diverse environmental conditions and plant organelles are semi-autonomous, it is tempting to suggest that Lon genes in Arabidopsis are paralogs. Adaptive evolution through repetitive gene duplication events of a single archaic gene led to Lon genes with complementing sets of subfunctions providing to the organism rapid adaptability for canonical development under different environmental conditions. Lon1 function is adequately characterized being involved in mitochondrial biogenesis, modulating carbon metabolism, oxidative phosphorylation and energy supply, all prerequisites for seed germination and seedling establishment. Lon is not a stand-alone proteolytic machine in plant organelles. Lon in association with other nuclear-encoded ATP-dependent proteases builds up an elegant nevertheless, tight interconnected circuit. This circuitry channels properly and accurately, proteostasis and protein quality control among the distinct subcellular compartments namely mitochondria, chloroplasts, and peroxisomes.

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Defining the Determinants for Dual Targeting of Amino Acyl-tRNA Synthetases to Mitochondria and Chloroplasts

Cited by 45 publications

References 56 publications

NMR investigations of the dual targeting peptide of Thr‐tRNA synthetase and its interaction with the mitochondrial Tom20 receptor in Arabidopsis thaliana

NMR investigations of the dual targeting peptide of Thr‐tRNA synthetase and its interaction with the mitochondrial Tom20 receptor in Arabidopsis thaliana

The dual targeting ability of type II NAD(P)H dehydrogenases arose early in land plant evolution

Evolution and significance of the Lon gene family in Arabidopsis organelle biogenesis and energy metabolism

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