Structure and functions of the Ebola virus matrix protein VP40

The matrix protein VP40 of the highly pathogenic Ebola virus (EBOV), a member of the filovirus family, is the most abundant protein in EBOV virions. During the viral life cycle it mediates assembly and budding from the host cell, and is responsible for the characteristic filamentous shape of EBOV particles. In addition to this classical function as a matrix protein, VP40 was also shown to have a regulatory function in viral transcription. To enable these distinct functions, VP40 can adopt different oligomeric states, in particular, dimers, hexamers and ring-like octameric RNA-binding structures. This review describes the properties and functions of the EBOV matrix protein VP40 and how these different conformations of VP40 contribute to its diverse functions.