A Conserved Region in the EBL Proteins Is Implicated in Microneme Targeting of the Malaria Parasite Plasmodium falciparum

• Published in: The Journal of biological chemistry Vol. 281; no. 42; pp. 31995 - 32003
• Main Authors: Treeck, Moritz, Struck, Nicole S., Haase, Silvia, Langer, Christine, Herrmann, Susann, Healer, Julie, Cowman, Alan F., Gilberger, Tim W.
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 20.10.2006
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M606717200

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.