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

version 3 (curated until May 28, 2011)

A novel Cryptosporidium parvum antigen, CP2, preferentially associates with membranous structures.

O'Hara, S. P., Yu, J. R., Lin, J. J. (2004 Mar, Parasitol Res)

The present study addresses the cloning and characterization of a Cryptosporidium parvum antigen, CP2. Sequencing of cDNA and genomic clones revealed a novel gene capable of coding a message of 2,136 nucleotides flanked by 28 and 140 nucleotides of the 5'- and 3'-noncoding regions, respectively. The deduced amino acid sequence suggests that CP2 is a secreted and/or membrane protein. Immunofluorescence microscopy detected CP2 enrichment in sporozoites that subsequently appeared to encase type I meronts in infected HCT-8 cells. Immunogold electron microscopy revealed that CP2 consistently localized to membranous structures throughout development. In addition, progression from macrogametocyte to sporulated oocyst revealed CP2 initially at the periphery of amylopectin-like granules, in the cytoplasm and discrete vesicles, the parasitophorous vacuole, on the surface of sporozoites, and finally on the parasitophorous vacuole membrane (PVM). The observed expression pattern suggests that CP2 may be involved in the invasion process and/or PVM integrity.

PubMed: 14727189, full text

Localisation information

cgd6_5410 (CP2) signal peptide plus thr stretch, charged repeats, likely mucin

Experimental localisation: periphery of amylopectin-like granules during early macrogametocyte, cytoplasm proximal to amylopectin-like granules during early macrogametocyte, peripheral during immature oocyst, between pellicle and parasitophorous vacuole membrane during immature oocyst, parasitophorous vacuole membrane during fully sporulated oocyst, plasma membrane during fully sporulated oocyst, oocyst wall during fully sporulated oocyst
  • Species: Cryptosporidium parvum
  • Quote inferring localisation: "A mature type I meront is shown in Fig. 10B. Again, few gold particles associate with the PVM in regions where the membrane is visible (arrows). Surprisingly, no gold particles were observed in the merozoites. Figure 11A–D illustrates the progression from an early macrogametocyte to a sporulated oocyst. Initially, gold particles are found in the amylopectin-like granules of an early macrogametocyte (Fig. 11A). Figure 11B shows that most electron-dense wall-forming bodies (arrowheads) are negative. Instead, the gold particles heavily decorate the periphery of amylopectin-like vesicles (arrows) and the cytoplasm proximal to these vesicles. An immature oocyst is shown in Fig. 11C. Again, the periphery of amylopectin-like granules and cytoplasm are labeled. Of note in this image is the localization of gold particle clusters at the periphery of the parasite subjacent to the parasitophorous vacuole (arrows) and between the parasite pellicle and PVM (arrowheads). An infection site harboring a fully sporulated oocyst is shown in Fig. 11D. Gold particles decorate the PVM and sporozoite membrane and the oocyst wall (Fig. 11E). Thus, CP2 was found, to some degree, on the PVM of all developmental stages examined."
  • Microscopy type: EM
  • Microscopy method: polyclonal antibody to whole protein
  • Strain: Iowa
  • Gene model mapping comments: inferred from another publication
  • Localisation record: Periphery of amylopectin-like granules and cytoplasm proximal to amylopectin-like granules during early macrogametocyte, periphery of parasite subjacent to the parasitophorous vacuole during immature oocyst, between pellicle and parasitophorous vacuole membrane during immature oocyst, PVM and membrane and oocyst wall during fully sporulated oocyst

cgd6_5410 (CP2) signal peptide plus thr stretch, charged repeats, likely mucin

Experimental localisation: sporozoite, not residual body during empty oocyst, trophozoite, surrounding during mature type i meront
  • Species: Cryptosporidium parvum
  • Quote inferring localisation: "Immunogold electron microscopy revealed that CP2 consistently localized to membranous structures throughout development."
  • Microscopy type: Light
  • Microscopy method: polyclonal antibody to whole protein
  • Strain: Iowa
  • Gene model mapping comments: blast from AY471868, annotation doesn't match
  • Localisation record: during sporozoite, not residual body during empty oocyst, varied during trophozoite, surrounding during mature type I meront,