Quantitative model and physical mechanisms of iRBC membrane curling during egress of malaria parasites

Egress of malaria merozoites from infected red blood cells (iRBC) is a critical step in the parasite’s life cycle. The egress is accompanied by the formation of a pore in the erythrocyte membrane, followed by an outward curling of the membrane around the pore, resulting in a complete eversion of the erythrocyte membrane, pushing the parasites away. Despite the well-documented steps of the egress, the detailed mechanism and source of energy for such a spectacular eversion of iRBC remains largely unknown. In this paper, we consider a biophysical model based on the energetics of the egress process that includes both viscous dissipation and energy consumption for the formation of the rim around the pore in iRBC. We show that viscosity does not play a significant role in iRBC eversion and we hypothesize that this process is controlled by lateral lipid diffusion. The model is supported by quantitative estimates and is in good agreement with known experimental data.