Wide range antiviral activity of MxA protein

Abstract

Mx proteins are interferon-induced GTPases belonging to the dynamin superfamily of large GTPases.A unique property of Mx GTPases is their antiviral activity against a wide range of RNA viruses, including bunya-and orthomyxoviruses. The human MxA GTPase accumulates in the cytoplasm of interferon-treated cells, partly associating with the endoplasmic reticulum. In the cases of Thogoto and La Cross viruses, MxA appears to detect viral infection by sensing nucleocapsid-like structures. Indeed, MxA interacts directly with the viral nucleocapsid protein of these viruses. As a consequence, these viral components are trapped and sorted to locations where they become unavailable for the generation of new virus particles. In both cases, the GTP-binding and carboxy-terminal effector functions of MxA are required for target recognition. Moreover, human MxA possesses many biophysical properties of traditional dynamin and may act to inhibit viral replication through alterations in membrane organization or viral trafficking. This hypothesis still needs to be demonstrated.