Lumenal association of HTsol-GFP at Maurer’s clefts. (B) 0° projections of an rHT-GFP–loaded erythrocyte ghost infected with 3D7 P falciparum (top) or a mock-loaded erythrocyte ghost infected with transgenic parasite expressing HTsol-GFP (bottom). Empty arrowhead, cleft structure not labeled with intraerythrocytic rHT-GFP; solid arrowhead, GFP labeled cleft. rHT-GFP was found to be uniformly distributed in the infected erythrocyte cytoplasm as well as the food vacuole of parasite (presumably via cytostome-mediated uptake of host cytoplasm). (C) Cells in panel B fixed, permeabilized, and probed with antibodies to GFP (green) and resident cleft protein PfSBP1 (red). Arrows show clefts. (D) Immunoelectron microscopy of cells in panel B showing distribution of GFP associated with Maurer’s clefts (MC). Bar indicates 500 nm. When resealed ghosts were infected with parasites that biosynthetically expressed secretory HTsol-GFP, green fluorescence was quantitatively associated with the clefts .
Bhattacharjee S, van Ooij C, Balu B, Adams JH, Haldar K. Maurer's clefts of Plasmodium falciparum are secretory organelles that concentrate virulence protein reporters for delivery to the host erythrocyte. Blood. 2008 111:2418-26.