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

version 3 (curated until May 28, 2011)

Carbohydrate metabolism in the Toxoplasma gondii apicoplast: localization of three glycolytic isoenzymes, the single pyruvate dehydrogenase complex, and a plastid phosphate translocator.

Fleige, T., Fischer, K., Ferguson, D. J., Gross, U., Bohne, W. (2007 Jun, Eukaryot Cell)

Many apicomplexan parasites, such as Toxoplasma gondii and Plasmodium species, possess a nonphotosynthetic plastid, referred to as the apicoplast, which is essential for the parasites' viability and displays characteristics similar to those of nongreen plastids in plants. In this study, we localized several key enzymes of the carbohydrate metabolism of T. gondii to either the apicoplast or the cytosol by engineering parasites which express epitope-tagged fusion proteins. The cytosol contains a complete set of enzymes for glycolysis, which should enable the parasite to metabolize imported glucose into pyruvate. All the glycolytic enzymes, from phosphofructokinase up to pyruvate kinase, are present in the T. gondii genome, as duplicates and isoforms of triose phosphate isomerase, phosphoglycerate kinase, and pyruvate kinase were found to localize to the apicoplast. The mRNA expression levels of all genes with glycolytic products were compared between tachyzoites and bradyzoites; however, a strict bradyzoite-specific expression pattern was observed only for enolase I. The T. gondii genome encodes a single pyruvate dehydrogenase complex, which was located in the apicoplast and absent in the mitochondrion, as shown by targeting of epitope-tagged fusion proteins and by immunolocalization of the native pyruvate dehydrogenase complex. The exchange of metabolites between the cytosol and the apicoplast is likely to be mediated by a phosphate translocator which was localized to the apicoplast. Based on these localization studies, a model is proposed that explains the supply of the apicoplast with ATP and the reduction power, as well as the exchange of metabolites between the cytosol and the apicoplast.

PubMed: 17449654, full text

Localisation information

TGME49_065450 (Hexokinase, HK) hexokinase

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_083780 (GPI) glucose-6-phosphate isomerase

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_026960 (Phosphofructokinase II, PFKII) phosphofructokinase, putative

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_036040 (Aldolase I, aldolase, aldolase-1) fructose-1,6-bisphosphate aldolase

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_025930 (TPI I) triosephosphate isomerase, putative

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_033500 (TPI II) triosephosphate isomerase, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TPI II, PGK II, and PK II are targeted to the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: Apicoplast during intracellular tachyzoite

TGME49_089690 (GAPDH I) glyceraldehyde-3-phosphate dehydrogenase

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_118230 (PGK I) phosphoglycerate kinase, putative

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: C terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: Cytosol during intracellular tachyzoite

TGME49_022020 (PGK II) phosphoglycerate kinase, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TPI II, PGK II, and PK II are targeted to the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: Apicoplast during intracellular tachyzoite

TGME49_097060 (PGM II) phosphoglycerate mutase 1, putative

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_068850 (ENO2) enolase 2

Experimental localisation: cytosol during intracellular tachyzoite, nucleus during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: Cytosol and nucleus during intracellular tachyzoite

TGME49_068860 (ENO1) enolase 1

Experimental localisation: cytosol during intracellular tachyzoite, nucleus during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: Cytosol and nucleus during intracellular tachyzoite

TGME49_056760 (PK I, pyruvate kinase-1, PK1) pyruvate kinase, putative

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "A complete set of glycolytic enzymes is targeted to the cytosol."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: cytosol during intracellular tachyzoite

TGME49_099070 (PK II, PyKII) pyruvate kinase, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TPI II, PGK II, and PK II are targeted to the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: Apicoplast during intracellular tachyzoite

TGME49_045670 (PDH E1-alpha, PDHE1a) pyruvate dehydrogenase, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All four PDH subunits are localized inside the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: Blast from DQ457185.1, annotation matches
  • Localisation record: apicoplast during intracellular tachyzoite

TGME49_006610 (PDH E2, PDHE2) biotin requiring domain-containing protein / 2-oxo acid dehydrogenases acyltransferase catalytic domain-containing protein

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All four PDH subunits are localized inside the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag, polyclonal antibody directly to protein
  • Strain: RH
  • Gene model mapping comments: Blast from primers in supplementary material
  • Localisation record: apicoplast during intracellular tachyzoite

TGME49_072290 (PDH E1-beta, PDHE1b) pyruvate dehydrogenase E1 beta subunit, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All four PDH subunits are localized inside the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag, polyclonal antibody directly to protein
  • Strain: RH
  • Gene model mapping comments: Blast from DQ457186.1, annotation matches
  • Localisation record: apicoplast during intracellular tachyzoite

TGME49_105980 (PDH E3 I) dihydrolipoyl dehydrogenase protein, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All four PDH subunits are localized inside the apicoplast."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: Blast from transcript sequence in supplementary S3
  • Localisation record: apicoplast during intracellular tachyzoite

TGME49_006470 (PDH E3 II) dihydrolipoyl dehydrogenase, putative

Experimental localisation: mitochondrion during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The mitochondrial localization of dihydrolipoyl-dehydrogenase II/E3 II was confirmed by colocalization using the mitochondrial marker S9-GFP"
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: Blast from transcript sequence in supplementary S3
  • Localisation record: mitochondria during intracellular tachyzoite

TGME49_064080 (ACP) acyl carrier protein

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Plastid localization was confirmed by colocalization with an ACP-YFP fusion protein."
  • Microscopy type: Light
  • Microscopy method: YFP tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: apicoplast during intracellular tachyzoite

TGME49_098990 (FNR) ferredoxin NADP+ oxidoreductase, putative

Experimental localisation: apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The plastid localization was confirmed by colocalization with an FNR-RFP fusion protein."
  • Microscopy type: Light
  • Microscopy method: RFP tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: apicoplast during intracellular tachyzoite

TGME49_061070 (PT, APT1, APT) hypothetical protein

Experimental localisation: apicoplast during intracellular tachyzoite, reticular staining outside apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Plastid localization of the TgPT"
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: taken directly from publication
  • Localisation record: apicoplast and reticular staining outside apicoplast during intracellular tachyzoite
  • Comment: Possibly apicoplast envelope? T. gondii only contains 1 PT, unlike plasmodium species, which contain 2 – one for inner apicoplast membrane and another probably for outer membrane