PfEMP1 trafficking and surface exposure on KAHRP mutant cell lines. (A) Immunofluorescence assay on 3D7-K119- and 3D7-K(re)-infected erythrocytes with anti-ATS antibody detecting PfEMP1 and anti-MAHRP, a Maurer clefts marker. The first panel in each row shows a phase-contrast image, the second panel is nuclear DNA stained with DAPI, the third panel is the reaction with the anti-ATS antibody for PfEMP1 detection, the fourth panel is the reaction with anti-MAHRP antibody, and the fifth panel illustrates an overlay of the previous 4 panels with colocalization shown in yellow. (B) Western blot analysis of trypsin treated (+) or untreated (-) intact erythrocytes infected with all mutant cell lines. The anti-ATS antibody detects cleaved PfEMP1 in case of presence of PfEMP1 on the surface in trypsin-treated samples (arrowhead). The full-length PfEMP1 runs at the same molecular weight as cross-reactive uRBC proteins.