9.B.19 The Plasmodium Early Transcribed Ring Stage Membrane Protein (ETRAMP) Family

The early transcribed membrane proteins (ETRAMPs) are a family of small, highly charged transmembrane proteins unique to malaria parasites. Some members of the ETRAMP family have been localized to the parasitophorous vacuole membrane that separates the intracellular parasite from the host cell and thus presumably have a role in host-parasite interactions. Although it has been shown that two ETRAMPs are critical for rodent malaria parasite liver-stage development, the importance of most ETRAMPs during the parasite life cycle remains unknown. MacKellar et al. 2011 identified nine ETRAMPs in the genome of the rodent malaria parasite Plasmodium yoelii, and elucidate their conservation in other malaria parasites. etramp expression profiles are diverse throughout the parasite life cycle. Protein expression occurs in blood and liver stages with differences in both their timing of expression and their subcellular localizations. Gene targeting studies of each of the nine uncharacterized ETRAMPs showed that two are refractory to deletion and thus may be essential for blood-stage replication. Seven ETRAMSs are not essential for any life cycle stage. Systematic characterization of the members of the ETRAMP family revealed the diversity of the family members at the interface between host and parasite throughout the developmental cycle of the malaria parasite.