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Filamentous influenza virus enters cells via macropinocytosis

Jeremy S Rossman1, George P Leser, Robert A Lamb

  • 1Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA.

Journal of Virology
|August 10, 2012
PubMed

Insights

Filamentous influenza viruses primarily enter host cells via macropinocytosis, a pathway distinct from spherical virions. This process involves fragmentation within endosomes, potentially enhancing viral and endosomal membrane fusion.

Area of Science:

  • Virology
  • Cell Biology
  • Infectious Diseases

Background:

  • Influenza virus exhibits pleomorphism, with both spherical and filamentous virions.
  • Spherical virions enter cells via clathrin-mediated endocytosis.
  • The entry mechanism for filamentous influenza virions remained largely undetermined.

Purpose of the Study:

  • To elucidate the entry pathway of filamentous influenza virus particles.
  • To investigate the role of macropinocytosis in influenza virus entry.
  • To understand the fate of filamentous virions post-entry.

Main Methods:

  • Confirmation of influenza virus utilizing macropinocytosis.
  • Observation of filamentous virion entry as intact filaments within macropinosomes.
  • Analysis of virion trafficking to the late-endosomal compartment and low pH-induced changes.

Main Results:

  • Filamentous influenza viruses predominantly use macropinocytosis for cell entry.
  • Virions are internalized as intact filaments and trafficked to acidic endosomes.
  • Low pH induces M2 ion channel conformational changes, leading to virion fragmentation.

Conclusions:

  • Macropinocytosis is the primary entry route for filamentous influenza virions.
  • Virion fragmentation within endosomes may facilitate viral-endosomal membrane fusion.
  • This study reveals a novel entry and uncoating mechanism for pleomorphic viruses.

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