Intramolecular backfolding of the carboxyl-terminal end of MxA protein is a prerequisite for its oligomerization

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Updated: Oct 18, 2026

Characterization of Multi-subunit Protein Complexes of Human MxA Using Non-denaturing Polyacrylamide Gel-electrophoresis
08:55

Characterization of Multi-subunit Protein Complexes of Human MxA Using Non-denaturing Polyacrylamide Gel-electrophoresis

Published on: October 28, 2016

C Di Paolo1, H P Hefti, M Meli

  • 1Institute of Medical Virology, University of Zürich, CH-8028 Zürich, Switzerland.

The Journal of Biological Chemistry
|November 5, 1999
PubMed

Insights

Human MxA protein, crucial for antiviral defense, forms oligomers via its carboxyl-terminal domains. These domains, including amphipathic helices, mediate interactions essential for MxA

Area of Science:

  • Virology
  • Molecular Biology
  • Immunology

Background:

  • Mx proteins are large GTPases integral to the type I interferon response against viruses.
  • Human MxA protein inhibits RNA virus replication and self-assembles into oligomeric structures.

Purpose of the Study:

  • To identify domains within the carboxyl-terminal moiety of MxA responsible for its oligomerization.
  • To elucidate the mechanism of MxA oligomerization and its functional implications.

Main Methods:

  • Mammalian two-hybrid system to study protein-protein interactions.
  • Interaction-dependent nuclear translocation assay to map functional domains.
  • Co-expression of wild-type MxA with mutant fragments to assess dominant-negative effects.

Main Results:

  • Three domains in the carboxyl-terminal region of MxA were identified as critical for oligomerization.
  • An intramolecular interaction involving the LZ1 amphipathic helix is a prerequisite for intermolecular complex formation.
  • The carboxyl-terminal region, including LZ1 and LZ2 helices, can exert a dominant-negative effect, suggesting competitive binding.

Conclusions:

  • MxA oligomerization is a complex process involving specific intramolecular and intermolecular interactions within its carboxyl-terminal region.
  • The carboxyl-terminal region's ability to interfere with MxA function suggests a role in regulating interactions with cellular or viral targets.

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