In vitro biosynthesis and membrane translocation of the serine rich protein of Plasmodium falciparum

The serine-rich protein (SERP) of Plasmodium falciparum is found within the parasitophorous vacuole. Exons 1 and 2 of the SERP gene were combined to a continuous open reading frame and expressed in a cell free translation/translocation system to study translocation of the protein across membranes. The protein was found to be translocated co-translationally across canine pancreatic microsomes. This process required the presence of the signal recognition particle, and it was accompanied by cleavage of a signal peptide. We conclude that the authentic SERP is exported from the parasite cell via the endoplasmic reticulum.