Time-course of synthesis, transport and incorporation of a protein identified in purified membranes of host erythrocytes infected with a knob-forming strain of Plasmodium falciparum.

Membranes from host erythrocytes infected with a knob-positive strain of Plasmodium falciparum were purified by free-flow electrophoresis or gradient centrifugation. In these membranes the main parasite-derived protein was a 92000 Da protein which was not present after infection of erythrocytes with the corresponding knob-negative strain. The protein is synthesized between 9-21 h after merozoite invasion and then synthesis ceases. At least 6 h elapses between the start of synthesis and the appearance of the protein in the erythrocyte membrane. No precursor proteins for the 92000 Da protein were found. Since the purified erythrocyte membranes were free from contamination with whole parasites or parasite membranes, the 92000 Da protein is clearly present in the host erythrocyte membrane.