ApiLoc - A database of published protein sub-cellular localisation in Apicomplexa

version 3 (curated until May 28, 2011)

Mitochondrial translation in absence of local tRNA aminoacylation and methionyl tRNA Met formylation in Apicomplexa.

Pino, P., Aeby, E., Foth, B. J., Sheiner, L., Soldati, T., Schneider, A., Soldati-Favre, D. (2010 May, Mol Microbiol)

Apicomplexans possess three translationally active compartments: the cytosol, a single tubular mitochondrion, and a vestigial plastid organelle called apicoplast. Mitochondrion and apicoplast are of bacterial evolutionary origin and therefore depend on a bacterial-like translation machinery. The minimal mitochondrial genome contains only three ORFs, and in Toxoplasma gondii the absence of mitochondrial tRNA genes is compensated for by the import of cytosolic eukaryotic tRNAs. Although all compartments require a complete set of charged tRNAs, the apicomplexan nuclear genomes do not hold sufficient aminoacyl-tRNA synthetase (aaRSs) genes to be targeted individually to each compartment. This study reveals that aaRSs are either cytosolic, apicoplastic or shared between the two compartments by dual targeting but are absent from the mitochondrion. Consequently, tRNAs are very likely imported in their aminoacylated form. Furthermore, the unexpected absence of tRNA(Met) formyltransferase and peptide deformylase implies that the requirement for a specialized formylmethionyl-tRNA(Met) for translation initiation is bypassed in the mitochondrion of Apicomplexa.

PubMed: 20374492, full text

Localisation information

TGME49_088360 (TrpRS2) tryptophanyl-tRNA synthetase, putative

Experimental localisation: apicoplast during tachyzoite, not cytosol during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgTrpRS2-Ty localized to the apicoplast whereas TgTrpRS1-Ty was cytosolic but, unexpectedly, both proteins were absent from the mitochondrion (Fig. 2A)."
  • Microscopy type:
  • Microscopy method: Ty tag
  • Strain:
  • Gene model mapping comments: taken directly from publication, gene model inconsistent?, blast from ADC80549
  • Localisation record: apicoplast and not cytosol and not mitochondrion during tachyzoite

TGME49_054110 (TrpRS1) tryptophanyl-tRNA synthetase, putative

Experimental localisation: cytosol during tachyzoite, not apicoplast during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgTrpRS2-Ty localized to the apicoplast whereas TgTrpRS1-Ty was cytosolic but, unexpectedly, both proteins were absent from the mitochondrion (Fig. 2A)."
  • Microscopy type:
  • Microscopy method: Ty tag
  • Strain:
  • Gene model mapping comments: Blast from EF463012, gene model inconsistent?
  • Localisation record: cytosol and not apicoplast and not mitochondrion during tachyzoite

TGME49_017460 (GlnRS) glutaminyl-tRNA synthetase, putative

Experimental localisation: cytosol during tachyzoite, not apicoplast during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "GlnRS-Ty and ProRS-Ty appear to be cytosolic."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: blast from ADC80544, gene model inconsistent?
  • Localisation record: cytosol and not apicoplast and not mitochondrion during tachyzoite

TGME49_099810 (CysRS) cysteinyl-tRNA synthetase, putative

Experimental localisation: apicoplast during tachyzoite, cytosol during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Although we have not assessed the localization of each of these gene products experimentally, we anticipate that, as for CysRS, expression of AspRS, AsnRS and ProRS genes leads to dual targeting of the enzymes between the cytosol and the apicoplast. The mechanism by which such dual targeting is achieved is not understood; however, in the case of CysRS, our data indicate that the full protein under the control of its own promoter is required (Fig. 3)."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: Gene model inconsistent?, blast from ADC80543
  • Localisation record: apicoplast and cytosol and not mitochondrion during tachyzoite

TGME49_019850 (ProRS) prolyl-tRNA synthetase, putative

Experimental localisation: cytosol during tachyzoite, not apicoplast during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "GlnRS-Ty and ProRS-Ty appear to be cytosolic."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: blast from ADC80545, gene model inconsistent?
  • Localisation record: cytosol and not apicoplast and not mitochondrion during tachyzoite

TGME49_066730 (LeuRS2) leucyl-tRNA synthetase, putative

Experimental localisation: apicoplast during tachyzoite, not cytosol during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgLeuRS1 and TgSerRS1 lack a targeting signal and are expected to be cytosolic, whereas TgLeuRS2 and TgSerRS2 possess an N-terminal bipartite extension and were shown by epitope tagging (TgLeuRS2-Ty, TgSerRS2-Ty) to localize exclusively to the apicoplast (Fig. 2A)."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: apicoplast and not cytosol and not mitochondrion during tachyzoite

TGME49_071730 (SerRS2) seryl-tRNA synthetase, putative

Experimental localisation: apicoplast during tachyzoite, not cytosol during tachyzoite, not mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgLeuRS1 and TgSerRS1 lack a targeting signal and are expected to be cytosolic, whereas TgLeuRS2 and TgSerRS2 possess an N-terminal bipartite extension and were shown by epitope tagging (TgLeuRS2-Ty, TgSerRS2-Ty) to localize exclusively to the apicoplast (Fig. 2A)."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication, gene model inconsistent? Publication says
  • Localisation record: apicoplast and not cytosol and not mitochondrion during tachyzoite

TGME49_023940 (GAP45) hypothetical protein

Experimental localisation: inner membrane complex during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Anti-GAP45 stains the pellicle and anti-TgHSP70 stains the mitochondrion."
  • Microscopy type: Light
  • Microscopy method: antibody
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: pellicle during tachyzoite

TGME49_073760 (HSP70) heat shock protein 70, putative

Experimental localisation: mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Anti-GAP45 stains the pellicle and anti-TgHSP70 stains the mitochondrion."
  • Microscopy type: Light
  • Microscopy method: antibody
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: mitochondrion during tachyzoite

TGME49_098990 (FNR) ferredoxin NADP+ oxidoreductase, putative

Experimental localisation: apicoplast during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Parasites were transfected with the known apicoplast marker FNR-DsRed for colocalization with the apicoplast. "
  • Microscopy type: Light
  • Microscopy method: DsRed tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: apicoplast during tachyzoite