Pf NSF is associated with coated vesicles and Maurer clefts. (A) Western blot analysis of uninfected RBCs and IRBCs showed that Pf NSF was an approximate 89-kDa Triton X-100-insoluble, SDS-soluble protein that was absent in uninfected RBCs. Immunoelectron microscopy showed Pf NSF associated with (B) chains of coated vesicles in the RBC cytosol, black arrowhead, (C) coated vesicles closely apposed to the RBC membrane, black arrowhead, (D-E) the Maurer clefts, white arrowhead, (D) a large, double membrane structure in the RBC cytosol, and (E) transitional areas between a Maurer cleft and the RBC membrane. Scale bar = 70 nm.