Investigating Membrane Binding Properties of Marburg and Ebola Virus Matrix Protein‐ VP40

The Marburg virus (MARV) and Ebola virus (EBOV) are from the family Filoviridae that cause severe hemorrhagic fever with high mortality rates in humans. These are filamentous lipid‐enveloped viruses that extract their lipid coat during replication from the host cell they infect. VP40 is the matrix protein of these viruses and it alone can mediate the budding of the nascent viral particles through the interaction with the inner leaflet of the host cell's plasma membrane. It has been shown that virus like particles (VLPs) generated from EBOV or MARV VP40 expressing cells are nearly indistinguishable from live virus. Even though a significant amount of information on membrane association is available for EBOV VP40 almost nothing is known about MARV VP40 membrane interactions. Objective: To understand the lipid binding properties of MARV VP40 protein. Methods: liposome sedimentation assay and liposome flotation assay. Results: we are able to confirm that MARV VP40 membrane interaction is driven through electrostatic interaction as it preferentially associates with anionic phospholipids such as Phosphatidyl Serine (PS) and Phosphatidyl inositol phosphate (PIP) derivatives. PS and PIP showed an additive effect on MARV VP40 association with membranes. MARV VP40 membrane association with liposomes containing PS was enhanced by Cholesterol. Conclusions MARV VP40 uses electrostatic interactions to associate with plasma membrane and behave as a negative charge sensor. Data also suggests that membrane curvature may influence on MARV VP40 association with membranes. Financial Support: NIH AI081077