Yeast mitochondrial and cytoplasmic valyl-tRNA synthetases

Felter, S.; Diatewa, Martin; Schneider, Claude; Stahl, A

doi:10.1016/0006-291x(81)91173-6

Cited by 13 publications

(7 citation statements)

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“…Because ValRS cannot discriminate the tRNA Val isoacceptors in the cytoplasm from those in mitochondria (10), the retarded precursor molecules can efficiently aminoacylate the cytosolic tRNA Val species and sustain the growth of the knockout strain on a FOA plate. In contrast, the cytoplasmic enzyme, even when highly expressed, could not move across the mitochondrial membranes and thus could not rescue the growth phenotype of the knockout on a YPG plate ( Figure 2B).…”

Section: Strategy For Studying Differential Localization Of the Vas1mentioning

confidence: 99%

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Mitochondrial Form of a tRNA Synthetase Can Be Made Bifunctional by Manipulating Its Leader Peptide

et al. 2003

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Previous studies showed that yeast VAS1 encodes both the cytoplasmic and mitochondrial forms of valyl-tRNA synthetase (ValRS), using alternative transcription and translation. The ValRS isoforms have identical polypeptide sequences, except for a 46-amino acid leader peptide that functions as a mitochondrial targeting signal. Although the two forms of the enzyme exhibit indistinguishable tRNA specificities in vitro, they cannot substitute for each other in vivo because of their different localizations. Here we show that the 46-residue leader sequence can be divided into two nonoverlapping peptides, each of which retains the ability to target the enzyme into mitochondria. The engineered proteins (with truncated leader sequences) are dual-targeted, rescuing both the cytoplasmic and mitochondrial defects of a vas1 knockout strain. Thus, in addition to alternative splicing and alternative translation initiation as mechanisms by which a single gene can encode cytoplasmic and mitochondrial activities, the inherent characteristics of a single polypeptide may enable it to be distributed simultaneously between two cellular compartments. This mechanism may explain how certain other single genes in Saccharomyces cerevisiae provide dual functions.

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Section: Strategy For Studying Differential Localization Of the Vas1mentioning

confidence: 99%

“…The transit peptide is subsequently cleaved off upon import into the matrix of mitochondria. In vitro studies confirmed that two ValRS isoforms exhibit similar chromatographic properties and identical tRNA specificities (10). However, because the two isozymes are targeted to distinct compartments, they cannot substitute for each other in vivo (9).…”

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confidence: 94%

Mitochondrial Form of a tRNA Synthetase Can Be Made Bifunctional by Manipulating Its Leader Peptide

et al. 2003

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“…In order to act as a suppressor, the mt-tRNA VAL needs to be charged with an amino acid by a tRNA synthetase. Nothing is known about K. lactis tRNA synthetases but, in the closely related yeast Saccharomyces cerevisiae, both the cytoplasmic and the mitochondrial isoforms of valyl-tRNA synthetases are encoded by the same nuclear gene; the two enzymes do not discriminate in vitro the cytoplasmic tRNA VAL from the mitochondrial one and also show identical K m values for the tRNA VAL from Escherichia coli (Felter et al, 1981;Chatton et al, 1988). One could hypothesize that a similar situation also exists in K. lactis, and that the cytoplasmic valyl-tRNA synthetase can also charge the mt-tRNA VAL Although misacylation with an amino acid different from valine cannot be excluded, the K. lactis mt-tRNA VAL shows conserved structural characteristics common to known prokaryotic and eukaryotic valyl transfer RNAs (Saks et al, 1994;Horowitz et al, 1999) and therefore it is expected to be correctly charged by valyl-tRNA synthetases.…”

Section: Fig 5 the Presence Of The Mt-trnamentioning

confidence: 99%

Suppression of a nuclear frameshift mutation by a mitochondrial tRNA in the yeast Kluyveromyces lactis^‡

Fiori

Francisci

Falcone³

2002

Molecular Microbiology

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SummaryA fragment of mitochondrial DNA containing the Kluyveromyces lactis gene for valine-tRNA (tRNA VAL ) was isolated as a multicopy suppressor of a respiratory-deficient mutant of this yeast. The mutant produced a truncated Cox14p because of a + 1 frameshift mutation in COX14 , a nuclear gene encoding a protein imported into mitochondria which is necessary for respiration (Fiori et al. 2000 Yeast 16: 307-314). We report here that the mitochondrial tRNA VAL gene, when transformed into K. lactis cells, is transcribed outside mitochondria and suppresses the frameshift mutation in COX14 restoring the correct reading frame during translation of its mRNA. In fact, using histidine tagging, the existence of a suppressed Cox14p of normal length was demonstrated in mutants expressing the mt-tRNA VAL from the nucleus. Suppression could occur through a non-canonical four base pairing between the tRNA VAL and the mutated mRNA or through slippage of ribosomes during translation. This is a new case of informational suppression in that the suppression of a chromosomal mutation is not casused by a second mutation but to a mislocalization/expression of a mt-tRNA.

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“…e ability of mitochondria for protein biosynthesis is well established. They therefore contain a set of mitochondrial aminoacyl-tRNA synthetases that are also coded for by the nuclear genome but often differ in chromatographic mobility during the isolation procedure from their cytoplasmic counterparts, suggesting nonidentity (Chiu & Suyama, 1973;Schneller et al, 1976;Schneller et al, 1978;Diatewa & Stahl, 1980;Felter et al, 1981;.…”

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confidence: 99%

Evolutionary aspects of accuracy of phenylalanyl-tRNA synthetase. Accuracy of fungal and animal mitochondrial enzymes and their relationship to their cytoplasmic counterparts and a prokaryotic enzyme

Gabius¹,

Engelhardt²,

Fr³

et al. 1983

Biochemistry

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Phenylalanyl-tRNA synthetases from mitochondria of yeast and hen liver resemble their corresponding cytoplasmic counterparts. Whereas slight intraspecies differences at the amino acid binding site, reflecting variations in the structures of these distinct enzymes, are exploitable by phenylalanine analogues, no intraspecies difference can be noted for the strategies to achieve the high fidelity of protein synthesis. While the yeast mitochondrial enzyme follows the pathway of posttransfer proofreading, the hen liver mitochondrial enzyme uses a tRNA-dependent pretransfer proofreading in the case of the natural amino acids. The accuracy of mitochondrial phenylalanyl-tRNA synthetases appears to be even better than the accuracy of the corresponding cytoplasmic enzymes. Interspecies rather than intraspecies differences for the functional role of certain amino acid residues of the enzymes further indicate the close relationship of the intracellular heterotopic isoenzymes. By use of a highly sensitive immunospotting procedure, common antigenic determinants are detected only within the enzymes from the two intracellular compartments of the same organism. The results suggest the origin of the cytoplasm-mitochondrion isoenzyme pair by independent gene duplication of the ancestral nuclear gene. A similarity of mitochondrial enzymes to the phenylalanyl-tRNA synthetase from Escherichia coli is not observed.

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Yeast mitochondrial and cytoplasmic valyl-tRNA synthetases

Cited by 13 publications

References 14 publications

Mitochondrial Form of a tRNA Synthetase Can Be Made Bifunctional by Manipulating Its Leader Peptide

Mitochondrial Form of a tRNA Synthetase Can Be Made Bifunctional by Manipulating Its Leader Peptide

Suppression of a nuclear frameshift mutation by a mitochondrial tRNA in the yeast Kluyveromyces lactis^‡

Evolutionary aspects of accuracy of phenylalanyl-tRNA synthetase. Accuracy of fungal and animal mitochondrial enzymes and their relationship to their cytoplasmic counterparts and a prokaryotic enzyme

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Yeast mitochondrial and cytoplasmic valyl-tRNA synthetases

Cited by 13 publications

References 14 publications

Mitochondrial Form of a tRNA Synthetase Can Be Made Bifunctional by Manipulating Its Leader Peptide

Mitochondrial Form of a tRNA Synthetase Can Be Made Bifunctional by Manipulating Its Leader Peptide

Suppression of a nuclear frameshift mutation by a mitochondrial tRNA in the yeast Kluyveromyces lactis‡

Evolutionary aspects of accuracy of phenylalanyl-tRNA synthetase. Accuracy of fungal and animal mitochondrial enzymes and their relationship to their cytoplasmic counterparts and a prokaryotic enzyme

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Suppression of a nuclear frameshift mutation by a mitochondrial tRNA in the yeast Kluyveromyces lactis^‡