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Interferon-induced mx proteins: dynamin-like GTPases with antiviral activity

Otto Haller1, Georg Kochs

  • 1Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany. Haller@ukl.uni-freiburg.de

Traffic (Copenhagen, Denmark)
|September 17, 2002
PubMed

Insights

Mx proteins, a type of interferon-induced GTPase, exhibit broad antiviral activity by trapping viral nucleocapsids. This mechanism prevents viral replication and particle generation, offering a defense against RNA viruses.

Area of Science:

  • Molecular biology
  • Virology
  • Immunology

Background:

  • Mx proteins are interferon-induced GTPases within the dynamin superfamily.
  • They are characterized by high molecular weight, self-assembly, low GTP affinity, and rapid GTP hydrolysis.
  • A key feature is their potent antiviral activity against various RNA viruses.

Purpose of the Study:

  • To elucidate the antiviral mechanism of human MxA GTPase against bunya- and orthomyxoviruses.
  • To understand how MxA interferes with viral replication and assembly processes.

Main Methods:

  • Cellular localization studies of human MxA in interferon-treated cells.
  • Analysis of MxA interaction with viral components (nucleocapsid proteins).
  • Investigation of GTP-binding and effector functions in antiviral activity.

Main Results:

  • Human MxA accumulates in the cytoplasm, partly associated with the endoplasmic reticulum.
  • MxA inhibits bunyavirus nucleocapsid transport to the Golgi.
  • MxA prevents orthomyxovirus nucleocapsid entry into the nucleus.
  • Both GTP-binding and effector functions of MxA are crucial for antiviral action.

Conclusions:

  • Mx GTPases detect viral infection by sensing nucleocapsid-like structures.
  • MxA traps viral nucleocapsids, preventing their use in new virus particle formation.
  • This mechanism effectively halts viral replication and assembly.

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