Figure 10.

Model for the participation of ESCRT-III in phagocytosis. (0 min) Attachment to human erythrocytes to trophozoites involves plasma membrane proteins including Gal/GalNAc lectin, TMK96 and EhADH. In particular, EhADH possesses a Bro1 domain in the cytoplasmic tail that recruits EhVps32 upon binding of erythrocytes to trophozoites. In this first phase of contact, it is also possible to observe EhVps20 in close contact with the plasma membrane. (2–10 min) The union of erythrocytes triggers signaling mechanisms that modulate actin cytoskeleton that together with other proteins remodels and produces the phagocytic cup. During this stage, EhADH-EhVps32 complex and EhVps20 independently recruit the other ESCRT-III molecules to the phagocytic cup and surround the nascent phagosome forming hetero-polymers that will finally lead to the scission and internalization of the phagosome. (30–90 min) After longer times, huge phagosomes with different number of erythrocytes inside them appear as a product of the fusion of several phagosomes. In such phagosomes, the formation of ILVs is triggered by the action of ESCRT-III polymers and the proteins are present either surrounding the phagosome, or inside them in close contact with the internalized erythrocytes. After 60 min of phagocytosis, EhVps2 and EhVps24 consistently migrated to the nucleus. E, erythrocyte.