The parasitophorous vacuole membrane of Toxoplasma gondii: A custom structural framing with smart interior plumbing for resource allocation.

In essence, the parasitophorous vacuole (PV) of Toxoplasma is a "Do-It-Yourself" renovation project led by the parasite after invasion of a guest house (the host cell) to install itself surreptitiously in a private and custom-built room, reinforced by drywall (the PV membrane). The function of the PV membrane (PVM) is to keep away the host security guards (immune response, lysosomes) from the parasite while allowing necessary and controlled access to host resources. Inside the PV, Toxoplasma relies on a crew of creative interior designers (the GRA proteins or GRA) to remodel and transform the space into an efficient living and breeding suite. Some GRA set up specialized delivery systems in the PVM (pores) to siphon off groceries (nutrients) from the host cytosol. Other GRA build a complex network of tubules that attach to the PVM (intravacuolar network) to trap large grocery stores (host organelles) inside the PV, ensuring the massive supply of selective food (lipids). In a parallel circuit, specific GRA recruit host proteins at the PVM that shape this membrane and mediate scission (host ESCRT) to engulf more host resources. In addition to this interior layout, Toxoplasma establishes a plumbing system made of PVM tubules that pervade the host cell, which maximizes the surface area for nutrient uptake, and lasso host organelles (lipid droplets, ER) from the surroundings. Finally, the PV acts as a magnet to attract and keep possession of some host organelles (mitochondria, the ER) by hijacking their molecular Velcro (Membrane Contact Sites), allowing the parasite to tap into the host power grid to fuel its own metabolic needs.