Understanding how var2csa uORF signals for cellular localization in Plasmodium falciparum

Pregnancy-associated malaria (PAM) caused by the protozoan parasite Plasmodium falciparum results from placental sequestration of iRBCS expressing a unique PfEMP1 that adhere to chondroitin sulfate A (CSA) and therefore named VAR2CSA. Among the var gene family, var2csa is the only gene that contains an upstream open reading frame (uORF) which was shown to be involved in the translation regulation of the downstream VAR2CSA. We previously found that the peptide encoded by the uORF signals for cellular localization of the downstream protein to the ER. To better understand the mechanisms by which the uORF signals for cellular localization we performed functional deletion analysis, using a uORF-GFP ectopic expression plasmid and identified an 8 aa sequence essential for its cellular localization. Preliminary Co-IP experiments of parasites overexpressing uORF-myc plasmid followed by mass spectrometry indicate that the uORF peptide interacts with many proteins which participate in the cellular trafficking machinery. We currently expand our study to investigate the role of RNA binding proteins in regulation of transcript containing uORFs.