Plasmodium falciparum: Co-dependent expression and co-localization of the PfCCp multi-adhesion domain proteins.

In Plasmodium falciparum, a family of six secreted proteins having a conserved architecture of multiple adhesive domains was recently identified by genome annotation. Three of the proteins, termed PfCCp1, PfCCp2, and PfCCp3 due to a common LCCL domain, are expressed inside the gametocyte parasitophorous vacuole and released during gamete emergence, where they relocate extracellularly surrounding exflagellation complexes. In this study we show that the three PfCCp proteins are co-expressed at the gametocyte surface. Abrogation of PfCCp3 in gene disruptant parasites leads to the loss of PfCCp1 and PfCCp2 protein but not transcript, indicating a co-dependent protein expression. In view of these data we propose that the three PfCCp proteins interact during gametocytogenesis by formation of a protein complex.