p97/VCP targetsToxoplasma gondiivacuoles for parasite restriction in interferon-stimulated human cells

Abstract

AbstractInfection with the parasiteToxoplasma gondiileads to production of interferon gamma (IFNγ) that stimulates cells to upregulate defence proteins targeting the parasite for cell intrinsic elimination or growth restriction. Various host defence mechanisms operate at the parasitophorous vacuole (PV) in different human cell types leading to PV disruption, acidification, or membrane envelopment. Ubiquitin and p62 are players in all human host control mechanisms ofToxoplasma, but other unifying proteins have not been identified. Here, we show that p97/valosin-containing protein (VCP), as well as its associated proteins ANKRD13A and UBXD1 controlToxoplasmainfection while recruited to the PV in IFNγ-stimulated endothelial cells. Convergent deposition of ANKRD13A, p97/VCP and UBXD1 onto the same vacuole is dependent on vacuolar ubiquitination and observed within 2h post-infection. ANKRD13A, p97/VCP and UBXD1 all drive the acidification mechanism of the vacuole, which is the IFNγ-dependent control pathway ofToxoplasmain endothelial cells. We assessed p97/VCP inToxoplasmacontrol in various human cells and demonstrate that p97/VCP is a universal IFNγ-dependent host restriction factor targeting theToxoplasmaPV in epithelial (HeLa) and endothelial cells (HUVEC), fibroblasts (HFF) and macrophages (THP1).