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

version 3 (curated until May 28, 2011)

Apicomplexan rhomboids have a potential role in microneme protein cleavage during host cell invasion.

Dowse, T. J., Pascall, J. C., Brown, K. D., Soldati, D. (2005 Jun, Int J Parasitol)

Apicomplexan parasites secrete transmembrane (TM) adhesive proteins as part of the process leading to host cell attachment and invasion. These microneme proteins are cleaved in their TM domains by an unidentified protease termed microneme protein protease 1 (MPP1). The cleavage site sequence (IA downward arrowGG), mapped in the Toxoplasma gondii microneme proteins TgMIC2 and TgMIC6, is conserved in microneme proteins of other apicomplexans including Plasmodium species. We report here the characterisation of novel T. gondii proteins belonging to the rhomboid family of intramembrane-cleaving serine proteases. T. gondii possesses six genes encoding rhomboid-like proteins. Four are localised along the secretory pathway and therefore constitute possible candidates for MPP1 activity. Toxoplasma rhomboids TgROM1, TgROM2 and TgROM5 cleave the TM domain of Drosophila Spitz, an established substrate for rhomboids from several species, demonstrating that they are active proteases. In addition, TgROM2 cleaves chimeric proteins that contain the TM domains of TgMIC2 and TgMIC12.

PubMed: 15913633, full text

Localisation information

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

Experimental localisation: inner membrane complex during 20 hours after tachyzoite infection
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "To provide a marker for cell division, Toxoplasma was stably transfected with IMC1CFP, a marker for the inner membrane complex (IMC)21."
  • Microscopy type: Light
  • Microscopy method: CFP tag
  • Strain: RH
  • Gene model mapping comments: inferred from another publication
  • Localisation record: inner membrane complex during 20h after tachyzoite infection

TGME49_000290 (ROM1) rhomboid family domain-containing protein

Experimental localisation: microneme during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "(A) Predominantly micronemal localisation of TgROM1; anti-myc (a-myc) in green, and anti-MIC4 (a-MIC4, micronemal marker) in red"
  • Microscopy type: Light
  • Microscopy method: N-terminal myc tag
  • Strain: RH hxgprt-
  • Gene model mapping comments: inferred from another publication
  • Localisation record: microneme during tachyzoite

TGME49_008030 (MIC4, MIC 4) microneme protein MIC4

Experimental localisation: microneme during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "(A) Predominantly micronemal localisation of TgROM1; anti-myc (a-myc) in green, and anti-MIC4 (a-MIC4, micronemal marker) in red"
  • Microscopy type: Light
  • Microscopy method: polyclonal antibody directly to protein
  • Strain: RH hxgprt-
  • Gene model mapping comments: inferred from another publication
  • Localisation record: microneme during tachyzoite

TGME49_063290 (ROM2) rhomboid-like protease TgROM2

Experimental localisation: golgi apparatus during tachyzoite, not microneme during tachyzoite
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "Golgi-localisation of TgROM2; a-myc in green or red (upper and lower panel, respectively), a-MIC4 in red and the cis-Golgi marker GRASP-YFP in green."
  • Microscopy type: Light
  • Microscopy method: N-terminal myc tag
  • Strain: RH hxgprt-
  • Gene model mapping comments: inferred from another publication
  • Localisation record: golgi and not microneme during tachyzoite

TGME49_068590 (ROM4) rhomboid-like protease 4

Experimental localisation: parasite plasma membrane during tachyzoite, cytoplasmic structure during after tachyzoite division, residual body during after tachyzoite division
  • Species: Toxoplasma gondii
  • Quote inferring localisation: "(D) Peripheral localisation of TgROM5 at the plasma membrane and in undefined intracellular structures and residual bodies sometimes produced after parasite division; a-myc in green, a-MIC4 or a-GAP45 in red."
  • Microscopy type: Light
  • Microscopy method: N-terminal myc tag
  • Strain: RH hxgprt-
  • Gene model mapping comments: inferred from another publication
  • Localisation record: plasma membrane during tachyzoite, sometimes cytoplasmic structures and residual bodies during after tachyzoite division