A conserved region in the EBL proteins is implicated in microneme targeting of the malaria parasite Plasmodium falciparum.
The proliferation of the malaria parasite Plasmodium falciparum within the human host is dependent upon invasion of erythrocytes. This process is accomplished by the merozoite, a highly specialized form of the parasite. Secretory organelles including micronemes and rhoptries play a pivotal role in the invasion process by storing and releasing parasite proteins. The mechanism of protein sorting to these compartments is unclear. Using a transgenic approach we show that trafficking of the most abundant micronemal proteins (members of the EBL-family: EBA-175, EBA-140/BAEBL, and EBA-181/JSEBL) is independent of their cytoplasmic and transmembrane domains, respectively. To identify the minimal sequence requirements for microneme trafficking, we generated parasites expressing EBA-GFP chimeric proteins and analyzed their distribution within the infected erythrocyte. This revealed that: (i) a conserved cysteine-rich region in the ectodomain is necessary for protein trafficking to the micronemes and (ii) correct sorting is dependent on accurate timing of expression.
Treeck
Moritz
M
Bernhard Nocht Institute for Tropical Medicine, Malaria II, 20359 Hamburg, Germany.
Struck
Nicole S
NS
Haase
Silvia
S
Langer
Christine
C
Herrmann
Susann
S
Healer
Julie
J
Cowman
Alan F
AF
Gilberger
Tim W
TW
D000818:Animals; D000953:Antigens, Protozoan / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D017124:Conserved Sequence; D003593:Cytoplasm / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence; D010963:Plasmodium falciparum / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection
D000953:Antigens, Protozoan; D002352:Carrier Proteins; C474029:EBA-181 protein, Plasmodium falciparum; C438380:EBA140 protein, Plasmodium falciparum; D008565:Membrane Proteins; D015800:Protozoan Proteins; C065668:erythrocyte-binding antigen 175, Plasmodium