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

version 3 (curated until May 28, 2011)

Host cell egress and invasion induce marked relocations of glycolytic enzymes in Toxoplasma gondii tachyzoites.

Pomel, S., Luk, F. C., Beckers, C. J. (2008 Oct, PLoS Pathog)

Apicomplexan parasites are dependent on an F-actin and myosin-based motility system for their invasion into and escape from animal host cells, as well as for their general motility. In Toxoplasma gondii and Plasmodium species, the actin filaments and myosin motor required for this process are located in a narrow space between the parasite plasma membrane and the underlying inner membrane complex, a set of flattened cisternae that covers most the cytoplasmic face of the plasma membrane. Here we show that the energy required for Toxoplasma motility is derived mostly, if not entirely, from glycolysis and lactic acid production. We also demonstrate that the glycolytic enzymes of Toxoplasma tachyzoites undergo a striking relocation from the parasites' cytoplasm to their pellicles upon Toxoplasma egress from host cells. Specifically, it appears that the glycolytic enzymes are translocated to the cytoplasmic face of the inner membrane complex as well as to the space between the plasma membrane and inner membrane complex. The glycolytic enzymes remain pellicle-associated during extended incubations of parasites in the extracellular milieu and do not revert to a cytoplasmic location until well after parasites have completed invasion of new host cells. Translocation of glycolytic enzymes to and from the Toxoplasma pellicle appears to occur in response to changes in extracellular [K(+)] experienced during egress and invasion, a signal that requires changes of [Ca(2+)](c) in the parasite during egress. Enzyme translocation is, however, not dependent on either F-actin or intact microtubules. Our observations indicate that Toxoplasma gondii is capable of relocating its main source of energy between its cytoplasm and pellicle in response to exit from or entry into host cells. We propose that this ability allows Toxoplasma to optimize ATP delivery to those cellular processes that are most critical for survival outside host cells and those required for growth and replication of intracellular parasites.

PubMed: 18949028, full text

Localisation information

TGME49_065450 (Hexokinase, HK) hexokinase

Experimental localisation: cytosol during intracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All three enzymes are found throughout the cytoplasm of intracellular Toxoplasma and associated with the pellicles of extracellular parasites."
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: Cytosol during intracellular tachyzoite

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

Experimental localisation: cytoplasm during intracellular tachyzoite after 0.5-4 hours, cytoplasmic face of inner membrane complex during extracellular tachyzoite, cytoplasmic face of inner membrane complex during intracellular tachyzoite until 0.5-4 hours, nowhere except cytoplasmic face of inner membrane complex during extracellular tachyzoite, nowhere except cytoplasmic face of inner membrane complex during intracellular tachyzoite until 0.5-4 hours, not inner membrane complex during immature daughter tachyzoites
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "When we used our affinity-purified antibodies to Toxoplasma aldolase-1 to localize this enzyme in intracellular parasites, we found it to be distributed throughout the parasites' cytoplasm (Figure 3A and Figure 4), irrespective of the fixation conditions used. In extracellular parasites, on the other hand, the protein localized to the parasite periphery (Figure 3A, C) where it overlapped with IMC1, a membrane skeleton protein of the Toxoplasma IMC"
  • Microscopy type: Light
  • Microscopy method: c terminal myc tag, antibody directly to protein
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: throughout cytoplasm during intracellular tachyzoite after 0.5-4 hours, cytoplasmic face of IMC and nowhere except cytoplasmic face of IMC during extracellular tachyzoite and intracellular tachyzoite until 0.5-4 hours, not IMC during immature daughter tachyzoites
  • Comment: Some coloc with IMC1 during extracellular

TGME49_031640 (IMC1, ALV1, IMC, NET1) membrane skeletal protein IMC1

Experimental localisation: inner membrane complex during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "When we used our affinity-purified antibodies to Toxoplasma aldolase-1 to localize this enzyme in intracellular parasites, we found it to be distributed throughout the parasites' cytoplasm (Figure 3A and Figure 4), irrespective of the fixation conditions used. In extracellular parasites, on the other hand, the protein localized to the parasite periphery (Figure 3A, C) where it overlapped with IMC1, a membrane skeleton protein of the Toxoplasma IMC"
  • Microscopy type: Light
  • Microscopy method: polyclonal antibody directly to protein
  • Strain:
  • Gene model mapping comments: inferred from another publication
  • Localisation record: IMC during extracellular tachyzoite

TGME49_089690 (GAPDH I) glyceraldehyde-3-phosphate dehydrogenase

Experimental localisation: cytosol during intracellular tachyzoite, inner membrane complex during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All three enzymes are found throughout the cytoplasm of intracellular Toxoplasma and associated with the pellicles of extracellular parasites."
  • Microscopy type: Light
  • Microscopy method: C terminal myc tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: Cytosol during intracellular tachyzoite, IMC during extracellular tachyzoite

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

Experimental localisation: cytoplasm during intracellular tachyzoite after 0.5-4 hours, nowhere except cytoplasmic face of inner membrane complex during extracellular tachyzoite, nowhere except cytoplasmic face of inner membrane complex during intracellular tachyzoite until 0.5-4 hours, not inner membrane complex during immature daughter tachyzoites
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "When we used our affinity-purified antibodies to Toxoplasma aldolase-1 to localize this enzyme in intracellular parasites, we found it to be distributed throughout the parasites' cytoplasm (Figure 3A and Figure 4), irrespective of the fixation conditions used. In extracellular parasites, on the other hand, the protein localized to the parasite periphery"
  • Microscopy type: Light, EM
  • Microscopy method: antibody directly to protein
  • Strain:
  • Gene model mapping comments: blast from AY150663
  • Localisation record: throughout cytoplasm during intracellular tachyzoite after 0.5-4 hours, nowhere except cytoplasmic face of IMC during extracellular tachyzoite and intracellular tachyzoite until 0.5-4 hours, not IMC during immature daughter tachyzoites
  • Comment: The Toxoplasma genome contains two potential aldolase-encoding sequences, but only one of these, aldolase-1, is expressed in Toxoplasma tachyzoites and the second appears to represent a pseudogene ([7], data not shown).
  • Comment: Some coloc with IMC1 during extracellular

TGME49_014320 (GT1) facilitative glucose transporter, putative

Experimental localisation: parasite plasma membrane during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "The glucose transporter GT1 is found in the plasma membrane of Toxoplasma gondii tachyzoites."
  • Microscopy type: Light
  • Microscopy method: C terminal myc tag
  • Strain:
  • Gene model mapping comments: Blast from primers in publication, annotation matches
  • Localisation record: throughout parasite plasma membrane during tachyzoite

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

Experimental localisation: cytosol during intracellular tachyzoite, inner membrane complex during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All three enzymes are found throughout the cytoplasm of intracellular Toxoplasma and associated with the pellicles of extracellular parasites."
  • Microscopy type: Light
  • Microscopy method: C terminal myc tag
  • Strain: RH
  • Gene model mapping comments: Blast from primers in publication, annotation matches
  • Localisation record: Cytosol during intracellular tachyzoite, IMC during extracellular tachyzoite

TGME49_032350 (lactate dehydrogenase-1, LDH1) lactate dehydrogenase

Experimental localisation: cytosol during intracellular tachyzoite, inner membrane complex during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "All three enzymes are found throughout the cytoplasm of intracellular Toxoplasma and associated with the pellicles of extracellular parasites."
  • Microscopy type: Light
  • Microscopy method: C terminal myc tag
  • Strain: RH
  • Gene model mapping comments: Blast from primers in publication, annotation matches
  • Localisation record: Cytosol during intracellular tachyzoite, IMC during extracellular tachyzoite