Fig. 8. Model of the moving junction during Toxoplasma invasion.

The model shows the moving junction as the point of contact between the parasite and host membranes during invasion. The sieving of transmembrane proteins from the nascent vacuole is shown in which type I transmembrane proteins and multimeric protein complexes are filtered from the forming vacuole. Filtering of type I transmembrane proteins is dependent on cytoplasmic tails, which are anchored in the cortical cytoskeleton. In contrast, GPI-anchored, raft-associated (rafts shown in yellow), multipass transmembrane, and acylated proteins are not filtered and enter the vacuole. The inset depicts a speculative arrangement of moving junction components; AMA1 and RON2 are shown serving as anchors for the MJ in the parasite and host membranes, respectively. Soluble RONs (RON4, RON5, RON8) are tethered to the cytoplasmic face of the plasma membrane by RON2 where they are positioned to perform further anchoring to the host cytoskeleton or sieving of host transmembrane proteins.