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Discrete spatio-temporal regulation of tyrosine phosphorylation directs influenza A virus M1 protein towards its

Angeles Mecate-Zambrano1,2, Swathi Sukumar1,2, Guiscard Seebohm3

  • 1Institute of Virology Muenster, University of Muenster, Muenster, Germany.

Plos Pathogens
|September 1, 2020
PubMed

Insights

Influenza A virus matrix protein 1 (M1) phosphorylation at Y132 is crucial for viral replication. This modification regulates M1 function, impacting viral assembly, stability, and pathogenicity in mice.

Area of Science:

  • Virology
  • Structural Biology
  • Molecular Biology

Background:

  • Small RNA viruses, like influenza A, rely on multifunctional proteins due to limited coding capacity.
  • The influenza A matrix protein 1 (M1) is a key regulator of viral replication, but its posttranslational modifications are not fully understood.
  • Posttranslational modifications, particularly phosphorylation, are increasingly implicated in the regulation of M1 functions.

Purpose of the Study:

  • To investigate the role of M1 tyrosine phosphorylation in influenza A virus replication during genuine infection.
  • To elucidate the mechanisms by which M1 phosphorylation regulates viral assembly, stability, and pathogenicity.

Main Methods:

  • Utilized recombinant influenza A viruses expressing M1 phosphomutants (Y132A, Y10F).
  • Employed mass spectrometry to characterize M1 phosphorylation dynamics.
  • Conducted molecular dynamics simulations to predict structural changes.
  • Assessed viral replication, lipid raft localization, M1-HA interaction, M1-RNA binding affinity, and viral particle morphology and pathogenicity in mice.

Main Results:

  • M1 Y132A mutation significantly decreased viral replication compared to wild-type and M1 Y10F.
  • Y132 phosphorylation was detected in M1 within virions, likely mediated by Janus kinases late in infection.
  • M1 Y132A exhibited impaired lipid raft localization due to reduced interaction with hemagglutinin (HA), leading to decreased progeny stability and filamentous particle formation.
  • Reduced M1-RNA binding affinity in Y132A mutants resulted in inefficient genome incorporation and non-infectious virions, diminishing pathogenicity in mice.

Conclusions:

  • M1 tyrosine phosphorylation, specifically at Y132, is essential for efficient influenza A virus replication and pathogenicity.
  • Phosphorylation regulates M1's interaction with viral components (HA, RNA) and influences viral assembly and stability.
  • Targeting M1 posttranslational modifications presents a potential antiviral intervention strategy.

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