Characterization of the Plasmodium falciparum homologue of Vps16, a member of the Vps-2 C tethering complex.

The organelles of the apical complex (rhoptries, micronemes and dense granules) are critical for erythrocyte invasion by the malaria parasite Plasmodium falciparum. Though they have essential roles in the parasite lifecycle, the mechanisms behind their biogenesis are still poorly defined. The Class C Vps proteins Vps11, 16, 18 and 33 constitute the core of the CORVET and HOPS complexes implicated in vesicle tethering and fusion in the eukaryotic endolysosomal system. Work in the model apicomplexan Toxoplasma gondii has revealed that TgVps11 is essential for the generation of the apical complex. P. falciparum possesses all the four subunits of the Vps-C complex but their function is currently unknown. We here present an initial characterization of the P. falciparum orthologue of Vps16, a member of the Vps-C complex. Our structural predictions suggest that the structure of PfVps16 is similar to its other eukaryotic counterparts and that the binding region responsible for its interaction with PfVps33 is conserved. We next show that PfVps16 is expressed throughout the asexual erythrocytic cycle and that it is potentially associated with the rhoptries in schizont stage parasites. Finally, we present our unsuccessful attempts at studying its function using knock sideways.