Highlights d Specific compounds against P. falciparum Plasmepsin IX and X were identified d PMIX and PMX are modulators of parasite proteins for egress, invasion, and development d Anti-PMIX and anti-PMX compounds inhibit liver, blood, and mosquito stages of Plasmodium d One compound, WM382, can clear mouse models of P. berghei and P. falciparum parasites

Summary Deregulation of the G1/G0 phase of the cell cycle can lead to cancer. During G1, most cells commit alternatively to DNA replication and division, or to cell cycle exit and differentiation. The anaphase-promoting complex or cyclosome (APC/C) activated by Cdh1 coordinately eliminates positive cell cycle regulators and also inhibitors of differentiation, coupling cell cycle exit and differentiation. Misregulation of Cdh1 thus has the potential to promote both cell cycle re-entry and either perturbed differentiation or dedifferentiation. Additionally, APC/CCdh1 is required to maintain genomic stability. As a result, loss of Cdh1 can contribute to tumorigenesis in the form of proliferation of poorly differentiated and genetically unstable cells.

Blood-stage replication of the human malaria parasite Plasmodium falciparum occurs via schizogony, wherein daughter parasites are formed by a specialized cytokinesis known as segmentation. Here we identify a parasite protein, which we name P. falciparum Merozoite Organizing Protein (PfMOP), as essential for cytokinesis of blood-stage parasites. We show that, following PfMOP knockdown, parasites undergo incomplete segmentation resulting in a residual agglomerate of partially divided cells. While organelles develop normally, the structural scaffold of daughter parasites, the inner membrane complex (IMC), fails to form in this agglomerate causing flawed segmentation. In PfMOP-deficient gametocytes, the IMC formation defect causes maturation arrest with aberrant morphology and death. Our results provide insight into the mechanisms of replication and maturation of malaria parasites.