A megadalton protein (Pc2500) is present during the intraerythrocytic development of P. chabaudi

Red cells infected with Plasmodium chabaudi display a megadalton protein, named Pc2500, synthesized during the early trophozoite stage with an apparent molecular mass of 2500 kDa. When infected red cells at the young trophozoite stage metabolically labeled with [35S] methionine are treated with Triton X-100, the megadalton protein remains in the insoluble fraction. At this stage, Pc2500 was found to be phosphorylated when infected red cells were incubated with [32P] orthophosphate. In late trophozoite stage, the Pc2500 is solubilized in Triton X-100 and is unphosphorylated. Infected cells, were subjected to nitrogen cavitation. Analysis of isolated erythrocyte membranes and parasites using electron microscopy and marker enzymes demonstrated the purity of these fractions. In the phosphorylated from, Pc2500 was shown to be mostly associated with the parasite whereas, at the late trophozoite stage, it was found to have migrated to the host cell membrane.