P Preiser1; A X Gao1; K Gunalan12; S L Yap1;
1 Division of Molecular Genetics & Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore; 2 Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, United States
DiscussionInvasion of the host red blood cell by the merozoite is a complex process involving a range of parasite ligand - host receptor interactions. The reticulocyte binding like protein homologues (RH) of Plasmodium falciparum play a critical role in host cell recognition and parasite signaling events during invasion. Along with all other RH proteins PfRH1 is extensively and sequentially processed during maturation and merozoite release. We have generated a panel of monoclonal antibodies against different regions of PfRH1 to investigate the fate of the different processing fragments during merozoite maturation and invasion. Using a combination of Immunofluorescents assays (IFA), Proximity Ligation Assays (PLA)and Fluorescence Resonance Energy Transfer (FRET) by acceptor bleaching we are able to establish protein co-localization data at the low nanometer scale. We obtain clear evidence that the different PfRH1 processing products interact with different parasite proteins during invasion. In particular we can demonstrate that a specific part of PfRH1 interact with AMA1 but note EBA175 in the junction of invading merozoites. Interestingly, we can obtain no evidence that EBA175 and AMA1 co-localize at any time in merozoites or during the invasion process. Taken together our data provides first clues on the biological role of RH protein processing during invasion.