Membrane association induces a conformational change in the Ebola virus matrix protein

Abstract

contributed equally to this workThe matrix protein VP40 from Ebola virus is targeted to the plasma membrane, where it is thought to induce assembly and budding of virions through its association with the lipid bilayer. Ebola virus VP40 is expressed as a monomeric molecule in solution, consisting of two loosely associated domains. Here we show that a C-terminal truncation of seven residues destabilizes the monomeric closed conformation and induces spontaneous hexamerization in solution, as indicated by chemical cross-linking and electron microscopy. Three-dimensional reconstruction of electron microscopy images shows ring-like structures consisting of the N-terminal domain along with evidence for¯exibly attached C-terminal domains. In vitro destabilization of the monomer by urea treatment results in similar hexameric molecules in solution.In addition, we demonstrate that membrane association of wild-type VP40 also induces the conformational switch from monomeric to hexameric molecules that may form the building blocks for initiation of virus assembly and budding. Such a conformational change induced by bilayer targeting may be a common feature of many viral matrix proteins and its potential inhibition may result in new anti-viral therapies.

Crystal structure of the Borna disease virus matrix protein (BDV-M) reveals ssRNA binding properties

“…As postulated for other M-proteins (20,29), the basic face of the BDV-M tetramer, interspersed with surface exposed aliphatic and aromatic residues, could facilitate membrane targeting and/or binding, consistent with membrane binding capabilities of the BDV-M tetramer (16). VP40 membrane binding is affected by the C-terminal domains in the hexameric state (9,33) in an as-yet-unknown manner.…”

“…M-proteins of several negative-strand RNA viruses (NSVs) are also involved in the regulation of virus replication and transcription and in the transport of ribonucleoprotein (RNP) complexes (9)(10)(11)(12)(13). BDV-M, the M-protein of BDV, is the smallest M-protein (16.2 kDa) among all NSVs.…”

Analysis of Ebola virus and VLP release using an immunocapture assay

“…The crystal structure of EBOV VP40 shows that the protein consists of two domains both folding into similar ␤-sandwich structures connected by a flexible linker region that allows the two domains to rotate into different conformations (Dessen et al, 2000). Conformational changes in monomeric VP40 are thought to play an important role in mediating coordinated oligomerization and membrane localization of the protein, a process that is critical in the formation of filamentous VLP structure Scianimanico et al, 2000). VP40 also contains three potential viral late domains that seem to play a role in viral egress for some retroviruses, rhabdoviruses, and filoviruses (Freed, 2002;Licata et al, 2003), although these motifs are not entirely conserved in Marburg virus strains.…”

Surface features of a Mononegavirales matrix protein indicate sites of membrane interaction

“…A number of matrix-like proteins are known to bind membranes or lipid vesicles in vitro, most likely through a combination of hydrophobic and electrostatic interactions (12)(13)(14). Expression of certain Ms in eukaryotic cells in the absence of other viral proteins can induce formation of virus-like particles (VLPs).…”