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

version 3 (curated until May 28, 2011)

Apical surface expression of aspartic protease Plasmepsin 4, a potential transmission-blocking target of the plasmodium ookinete.

Li, F., Patra, K. P., Yowell, C. A., Dame, J. B., Chin, K., Vinetz, J. M. (2010 Mar 12, J Biol Chem)

To invade its definitive host, the mosquito, the malaria parasite must cross the midgut peritrophic matrix that is composed of chitin cross-linked by chitin-binding proteins and then develop into an oocyst on the midgut basal lamina. Previous evidence indicates that Plasmodium ookinete-secreted chitinase is important in midgut invasion. The mechanistic role of other ookinete-secreted enzymes in midgut invasion has not been previously examined. De novo mass spectrometry sequencing of a protein obtained by benzamidine affinity column of Plasmodium gallinaceum ookinete axenic culture supernatant demonstrated the presence of an ookinete-secreted plasmepsin, an aspartic protease previously only known to be present in the digestive vacuole of asexual stage malaria parasites. This plasmepsin, the ortholog of Plasmodium falciparum plasmepsin 4, was designated PgPM4. PgPM4 and PgCHT2 (the P. gallinaceum ortholog of P. falciparum chitinase PfCHT1) are both localized on the ookinete apical surface, and both are present in micronemes. Aspartic protease inhibitors (peptidomimetic and natural product), calpain inhibitors, and anti-PgPM4 monoclonal antibodies significantly reduced parasite infectivity for mosquitoes. These results suggest that plasmepsin 4, previously known only to function in the digestive vacuole of asexual blood stage Plasmodium, plays a role in how the ookinete interacts with the mosquito midgut interactions as it becomes an oocyst. These data are the first to delineate a role for an aspartic protease in mediating Plasmodium invasion of the mosquito and demonstrate the potential for plasmepsin 4 as a malaria transmission-blocking vaccine target.

PubMed: 20056606, full text

Localisation information

PCAS_103520 (PM4) Nothing has been found

Experimental localisation: ookinete apical surface, microneme, surface during zygote
  • Species: Plasmodium gallinaceum
  • Quote inferring localisation: "PgPM4 and PgCHT2 (the P. gallinaceum ortholog of P. falciparum chitinase PfCHT1) are both localized on the ookinete apical surface and are both present in micronemes."
  • Microscopy type: Light
  • Microscopy method: monoclonal antibody
  • Strain:
  • Gene model mapping comments: blast from PfPM4 mentioned in the paper as the orthologue (and this protein's namesake)
  • Localisation record: ookinete apical surface and microneme, unpolarised on surface during zygote

PCAS_103520 (PM4) Nothing has been found

Experimental localisation: microneme during ookinete
  • Species: Plasmodium gallinaceum
  • Quote inferring localisation: "Fig 6. Micronemal localization of PgPM4 in the P. gallinaceum ookinete by immunoelectron microscopy."
  • Microscopy type: EM
  • Microscopy method: monoclonal antibody
  • Strain:
  • Gene model mapping comments: PCAS_103520 taken directly from publication
  • Localisation record: microneme during ookinete

No assigned gene identifier (WARP, CHT2) Nothing has been found

Experimental localisation: ookinete apical surface, microneme
  • Species: Plasmodium gallinaceum
  • Quote inferring localisation: "PgPM4 and PgCHT2 (the P. gallinaceum ortholog of P. falciparum chitinase PfCHT1) are both localized on the ookinete apical surface and are both present in micronemes."
  • Microscopy type: Light
  • Microscopy method: antibody
  • Strain:
  • Gene model mapping comments: A common gene for all genes not assigned to a gene model taken directly from publication
  • Localisation record: ookinete apical surface and microneme