fp-2 siRNA blocks the rupture of erythrocyte membrane at the time of merozoite release. (A) Fluorescent microscopic images of incompletely ruptured schizonts in 3D7+His parasites 56 h after fp-2 siRNA treatment, showing the localization of GFP fluorescence immediately surrounding the daughter merozoites, parasite nuclei are stained with DAPI (blue). The incompletely ruptured schizonts showed the GFP fluorescence throughout the RBC and around the merozoites. (B) Immunofluorescence images of incompletely ruptured schizonts using PfEMP1 antibodies (red), parasite nuclei are stained with DAPI (blue). (C) Immunofluorescence images of incompletely ruptured schizonts using Band-3 antibodies (red), parasite nuclei are stained with DAPI (blue). Incompletely ruptured schizonts in fp-2 siRNA treated cultures showed presence of PfEMP-1 as well as Band-3 in the membrane surrounding them, thereby suggesting that the limiting membrane surrounding the merozoite clusters in fp-2 siRNA treated parasite is indeed the erythrocyte plasma membrane. Results of these experiments showed that falcipain-2 plays an important role in the rupture of erythrocyte membrane and release of merozoites.

Dasaradhi PV, Mohmmed A, Kumar A, Hossain MJ, Bhatnagar RK, Chauhan VS, Malhotra P. A role of falcipain-2, principal cysteine proteases of Plasmodium falciparum in merozoite egression. Biochem Biophys Res Commun. 2005 336(4):1062-8..