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

version 3 (curated until May 28, 2011)

Dual targeting of antioxidant and metabolic enzymes to the mitochondrion and the apicoplast of Toxoplasma gondii.

Pino, P., Foth, B. J., Kwok, L. Y., Sheiner, L., Schepers, R., Soldati, T., Soldati-Favre, D. (2007 Aug 31, PLoS Pathog)

Toxoplasma gondii is an aerobic protozoan parasite that possesses mitochondrial antioxidant enzymes to safely dispose of oxygen radicals generated by cellular respiration and metabolism. As with most Apicomplexans, it also harbors a chloroplast-like organelle, the apicoplast, which hosts various biosynthetic pathways and requires antioxidant protection. Most apicoplast-resident proteins are encoded in the nuclear genome and are targeted to the organelle via a bipartite N-terminal targeting sequence. We show here that two antioxidant enzymes-a superoxide dismutase (TgSOD2) and a thioredoxin-dependent peroxidase (TgTPX1/2)-and an aconitase are dually targeted to both the apicoplast and the mitochondrion of T. gondii. In the case of TgSOD2, our results indicate that a single gene product is bimodally targeted due to an inconspicuous variation within the putative signal peptide of the organellar protein, which significantly alters its subcellular localization. Dual organellar targeting of proteins might occur frequently in Apicomplexans to serve important biological functions such as antioxidant protection and carbon metabolism.

PubMed: 17784785, full text

Localisation information

PFF1130c (SOD2) superoxide dismutase

Experimental localisation: apicoplast during ring, apicoplast during trophozoite, apicoplast during schizont, not mitochondrion during ring, not mitochondrion during trophozoite, not mitochondrion during schizont
  • Species: Plasmodium falciparum
  • Quote inferring localisation: "PfSOD2 Is Targeted to the Apicoplast in the Intra-Erythrocytic Stages of P. falciparum"
  • Microscopy type: Light
  • Microscopy method: GFP tag, Ty tag
  • Strain: 3D7
  • Gene model mapping comments: Blast from AAT11554, annotation doesn't match
  • Localisation record: apicoplast and not mitochondria during blood stages

TGME49_116330 (SOD2, SODB2) iron-containing superoxide dismutase

Experimental localisation: apicoplast during tachyzoite, mitochondrion during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "TgSOD2 Contains an Unusual Bipartite N-Terminal Signal and Is Targeted to both Mitochondrion and Apicoplast"
  • Microscopy type: Light, EM
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: Blast from AY176062, annotation matches
  • Localisation record: apicoplast and mitochondria during tachyzoite
  • Comment: bimodal dual targeting
  • Comment: not usually expressed during tachyzoite stages, but when expressed using a constitutive promoter it localises to mitochondria and apicoplast

TGME49_116190 (SOD3, SODB3) superoxide dismutase, putative

Experimental localisation: mitochondrion during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Table 1."
  • Microscopy type: Light, EM
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: blast from AY254045, annotation matches, gene model inconsistent
  • Localisation record: mitochondria during intracellular tachyzoite
  • Comment: not expressed during tachyzoite, but constitutive promoters get around this, so localisations are still done in tachyzoite

TGME49_030410 (PRX3, Prx3) peroxiredoxin 3

Experimental localisation: mitochondrion during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Table 1."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: blast from AY251021, annotation matches
  • Localisation record: mitochondria during intracellular tachyzoite

TGME49_066120 (TPX1/1, TPX1/2) glutathione/thioredoxin peroxidase, putative

Experimental localisation: apicoplast during intracellular tachyzoite, mitochondrion during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Table 1."
  • Microscopy type: Light
  • Microscopy method: Ty tag
  • Strain: RH
  • Gene model mapping comments: blast from AY633702
  • Localisation record: apicoplast and mitochondria during intracellular tachyzoite
  • Comment: gene model TGME49_066120 should be 3 different gene models, so not recorded

TGME49_026730 (ACN/IRP, Aconitase (ACN)) aconitate hydratase, putative

Experimental localisation: mitochondrion during intracellular tachyzoite, apicoplast during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Colocalisation reveals bimodal targeting of SPTP(ACN)GFP-Ty fusion protein to the parasite mitochondrion and apicoplast."
  • Microscopy type: Light
  • Microscopy method: GFP tag, Ty tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: mitochondria and apicoplast during intracellular tachyzoite

TGME49_057680 (MLC1) myosin light chain TgMLC1

Experimental localisation: periphery of parasite during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The periphery of T. gondii parasites is labeled in red with anti-MLC1 "
  • Microscopy type: Light
  • Microscopy method: polyclonal antibody directly to protein
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: periphery of parasite during intracellular tachyzoite