PfPK2 regulates microneme release. B .PfPK2 loxP parasites were treated with DMSO or RAP. Subsequently, schizonts were treated with E64 to prevent egress and IFA was performed to detect AMA1 and MSP1. DAPI was used to stain the nucleus, DIC provides the brightfield image of the parasite. AMA1 localizes to microneme in schizonts stage (DMSO, upper panel) but during egress it comes to the merozoite surface in a significant number of parasites (DMSO, lower panel). In RAP-treated parasite while some parasites exhibited AMA1 on the surface (RAP, upper panel) in a significant number of parasites it was retained in the micronemes in most parasites (RAP, lower panel),which was confirmed by counting parasites (Right panel) with AMA1 staining on the surface (mean±SEM,n=3, *p<0.05, paired t-test). C. The presence of AMA1 at the Tight Junction in DMSO or RAP-treated PfPK2-loxP parasites was determined by performing IFA for AMA1 and RON2. In the case of DMSO-treated parasites ,AMA1 localized proximal to RON2 whereas it was either not detected or it was significantly reduced in RAP-treated parasites. Right panel, parasites exhibiting abnormal or no AMA1 staining were quantitated (SEM±SE,n=3, ANOVA, ***P<0.001).

Rawat RS, Gupta A, Antil N, Bhatnagar S, Singh M, Rawat A, Prasad TSK, Sharma P. Protein kinase PfPK2 mediated signalling is critical for host erythrocyte invasion by malaria parasite. PLoS Pathog. 2023 19(11):e1011770. PMID: 37988347