PfRH1 is localized in the rhoptry in free merozoites by using superresolution microscopy. Co-immunofluorescence staining was carried out in the late schizont stage T994 parasites by using mAbs against PfRH1 (EBD, MD and RVIII), AMA1 and EBA175. The co-staining combinations include PfRH1 mAbs against EBD (a, green) with either MD (left panel, red) or RVIII (right panel, red). Two micronemal proteins AMA1 (b, green) or EBA175 (c, green) was co-stained with either MD (left panel, red) or RVIII (right panel, red). Dapi (blue) is used as nuclear stain. Individual staining and merged images are shown for each of the mAbs. In the merged images, areas of overlap between the red and the green signals are shown in yellow. Scale bars = 1μm. To investigate whether the different fragments of PfRH1 are involved in the early junction formation, invading merozoites were arrested using Cytochalasin D (Cyto D) followed by airyscan super-resolution microscopy (Figure 3). This showed that in junction arrested merozoites MD was still completely co-localized with EBD (top panel in Figure 3a) while this was not the case for RVIII and EBD (bottom panel in Figure
3a) indication potential functional differences between the fragments at this step of invasion. Interestingly, MD but not RVIII completely co-localized with AMA1 (b) in the junction, suggesting that EBD and MD may form complex with AMA1 at this stage. However, neither MD nor RVIII co-localized with EBA175, another
micronemes protein that has been suggested to be involved in junction formation (c).
Gunalan K, Gao X, Yap SSL, Lai SK, Ravasio A, Ganesan S, Li HY, Preiser PR. A processing product of the Plasmodium falciparum reticulocyte binding protein RH1 shows a close association with AMA1 during junction formation. Cell Microbiol. 2020 May 25:e13232.
Other associated proteins
|PF3D7_0402300||reticulocyte binding protein homologue 1 normocyte binding protein 1|
|PF3D7_0731500||erythrocyte binding antigen-175|