PfPK9 expression and localization across the intraerythrocytic life cycle. Immunofluorescence using polyclonal anti-PfPK9 antibody reveals a punctuate staining at late ring stage during which PfPK9 (green) appears to colocalize with exported protein 1 (red) in several spots. In addition to parasitophorous membrane staining (using EXP-1 PF11_0224 as PVM marker), diffused cytoplasmic staining is observed during both early and late trophozoites. During the schizont stage, the expression pattern emerges to be like merozoite surface protein 1 PFI1475w (red), a plasma membrane protein.Philip N, Haystead TA. Characterization of a UBC13 kinase in Plasmodium falciparum. Proc Natl Acad Sci U S A. 2007 104:7845-7850.