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

version 3 (curated until May 28, 2011)

Functional analysis of key nuclear trafficking components reveals an atypical Ran network required for parasite pathogenesis.

Frankel, M. B., Knoll, L. J. (2008 Oct, Mol Microbiol)

Protozoan parasites represent major public health challenges. Many aspects of their cell biology are distinct from their animal hosts, providing potential therapeutic targets. Toxoplasma gondii is a protozoan parasite that contains a divergent regulator of chromosome condensation 1 (TgRCC1) that is required for virulence and efficient nuclear trafficking. RCC1 proteins function as a guanine exchange factor for Ras-related nuclear protein (Ran), an abundant GTPase responsible for the majority of nucleocytoplasmic transport. Here we show that while there are dramatic differences from well-conserved RCC1 proteins, TgRCC1 associates with chromatin, interacts with Ran and complements a mammalian temperature-sensitive RCC1 mutant cell line. During the investigation of TgRCC1, we observed several unprecedented phenotypes for TgRan, despite a high level of sequence conservation. The cellular distribution of TgRan is found throughout the parasite cell, whereas Ran in late branching eukaryotes is predominantly nuclear. Additionally, T. gondii tolerates at least low-level expression of dominant lethal Ran mutants. Wild type parasites expressing dominant negative TgRan grew similarly to wild type in standard tissue culture conditions, but were attenuated in serum-starved host cells and mice. These growth characteristics paralleled the TgRCC1 mutant and highlight the importance of the nuclear transport pathway for virulence of eukaryotic pathogens.

PubMed: 18761691, full text

Localisation information

TGME49_048340 (Ran) GTP-binding nuclear protein RAN/TC4, putative

Experimental localisation: nucleus during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "In wild type parasites, TgRan was distributed throughout the cell, in both the nuclear and cytoplasmic compartments (Fig.οΎ 4A)."
  • Microscopy type: fixed light
  • Microscopy method: C terminal FLAG tag
  • Strain: Pru HXGPRT-
  • Gene model mapping comments: Taken directly from publication, annotation matches
  • Localisation record: nucleus during extracellular tachyzoite

TGME49_088380 (Hsp90) heat shock protein 90

Experimental localisation: cytosol during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "We co-stained with either 4',6'-diamidino-2-phenylindole or T. gondii histone H2B (Dalmasso et al., 2006) to indicate the nucleus, and heat-shock protein 90 (Hsp90) as a cytosolic marker (Echeverria et al., 2005)."
  • Microscopy type: fixed light
  • Microscopy method: antibody
  • Strain: Pru HXGPRT-
  • Gene model mapping comments: inferred from another publication
  • Localisation record: cytosol during extracellular tachyzoite

TGME49_009910 (H2Bv1, h2b) histone H2B variant 1

Experimental localisation: nucleus during extracellular tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "We co-stained with either 4',6'-diamidino-2-phenylindole or T. gondii histone H2B (Dalmasso et al., 2006) to indicate the nucleus, and heat-shock protein 90 (Hsp90) as a cytosolic marker (Echeverria et al., 2005)."
  • Microscopy type: fixed light
  • Microscopy method: antibody
  • Strain: Pru HXGPRT-
  • Gene model mapping comments: inferred from another publication
  • Localisation record: nucleus during extracellular tachyzoite