Analysis Of The Dynamics And Trafficking Of MGPBs To Membranes In Pathogen Infected Cells
SIVALINGAM G. 1, LEGEWIE L. 1, NORA S. 1, DEGRANDI D. 1, PFEFFER K. 1
1 Institute of Medical Microbiology and Hospital Hygiene, Düsseldorf, Germany
Murine Guanylate-binding proteins (mGBPs) belong to the superfamily of dynamin-like proteins featuring an important role in the cell-autonomous immunity against intracellular pathogens. For example, mGBP2 and mGBP7 are essential effector proteins in the control of Toxoplasma gondii (T. gondii) replication. T. gondii is an apicomplexan parasite, which replicates within the parasitophorous vacuole (PV) in the host cell. MGBPs are induced by Interferon-γ (IFN-γ) and accumulate at the PV membrane (PVM) of T. gondii leading to its disruption or permeabilization. Eventually, the plasma membrane of T. gondii is targeted as well. However, the molecular processes behind these observations are yet to be understood. To this aim, we make use of the giant unilamellar vesicles (GUVs) technology in order to investigate the interactions of mGBPs with membranes of different compositions and to unravel the mode and consequences of mGBP-lipid binding. Additionally, the role and function of Interferon-stimulated gene product 15 (ISG15) in T. gondii infection is in the focus of our studies, as it also plays an essential role in the host response against pathogenic stimuli. ISG15 is a member of the Ubiquitin-like protein family and targets proteins in a three-step enzymatic process called ISGylation. We aim at understanding the role of post-translational ISGylation on the outcome of T. gondii infection.