Micronemal transport of Plasmodium ookinete chitinases to the electron-dense area of the apical complex for extracellular secretion.
Langer, R. C., Hayward, R. E., Tsuboi, T., Tachibana, M., Torii, M., Vinetz, J. M. (2000 Nov, Infect Immun)
Plasmodium ookinetes secrete chitinases to penetrate the acellular, chitin-containing peritrophic matrix of the mosquito midgut en route to invasion of the epithelium. Chitinases are potentially targets that can be used to block malaria transmission. We demonstrate here that chitinases of Plasmodium falciparum and P. gallinaceum are concentrated at the apical end of ookinetes. The chitinase PgCHT1 of P. gallinaceum is present within ookinete micronemes and subsequently becomes localized in the electron-dense area of the apical complex. These observations suggest a pathway by which ookinetes secrete proteins extracellularly.
PFL2510w (CHT1) chitinase
zygote remnant during ookinete retort
- Species: Plasmodium falciparum
- Quote inferring localisation: "Confocal immunofluorescence microscopy of immature P.falciparum ookinetes stained simultaneously with mouse anti-P. falciparum chitinase (PfCHT1) MAb 1C3 (green) and rabbit polyclonal antiserum to a recombinant P.falciparum zygote-ookinete surface antigen (Pfs25-Pfs28) fusion protein (8) (red). The surface of the parasite is delineated by rhodamine staining of surface proteins Pfs25 and Pfs28. Staining with MAb 1C3 demonstrates the granular appearance of PfCHT1, which is most concentrated in the zygote remnant but also appears to be present anteriorly as well, reaching near the apical end."
- Microscopy type: Light
- Microscopy method: Monoclonal antibody directly to protein
- Strain: 3D7
- Gene model mapping comments: Blast from AF172445
- Localisation record: strong zygote remnant during ookinete retort
- Comment: blasting the nucleotide sequence of AF172445 doesn't appear to work, but the protein sequence matches perfectly
AF064079.1 (CHT1) gi|7530423|gb|AF064079.1| Plasmodium gallinaceum endochitinase precursor, mRNA, complete cds
microneme during mature ookinete
- Species: Plasmodium gallinaceum
- Quote inferring localisation: "Longitudinal section of a maturing ookinete in which PgCHT1 is associated with micronemes (mn) at the apical third of the parasite (arrow)."
- Microscopy type: Light
- Microscopy method: polyclonal antibody directly to protein
- Gene model mapping comments: AF064079.1 taken directly from publication
- Localisation record: microneme during mature ookinete
- Comment: strain information not available online
- Comment: genbank not available, but sequence is available from http://www.pnas.org/content/96/24/14061.full