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YRKL sequence of influenza virus M1 functions as the L domain motif and interacts with VPS28 and Cdc42

Eric Ka-Wai Hui1, Subrata Barman, Dominic Ho-Ping Tang

  • 1Department of Microbiology, Immunology and Molecular Genetics, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, David Geffen School of Medicine, UCLA, Los Angeles, 90095, USA.

Journal of Virology
|February 14, 2006
PubMed

Insights

The YRKL sequence in influenza A virus matrix protein (M1) acts as an L domain, crucial for virus budding. This motif interacts with VPS28 and Cdc42, essential for efficient influenza virus production and replication.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • Influenza A virus matrix protein (M1) C-terminal helix 6 (H6) is implicated in virus budding.
  • The YRKL sequence within M1 H6 has been previously linked to this budding process.

Purpose of the Study:

  • To identify the specific L domain motif of influenza virus.
  • To elucidate the role of the YRKL sequence in virus budding and replication.
  • To investigate the interaction of M1 with cellular factors involved in virus release.

Main Methods:

  • Site-directed mutagenesis to create M1 protein variants with altered YRKL sequences.
  • Assays to assess virus budding and release efficiency.
  • Coimmunoprecipitation and Western blotting to detect protein interactions.
  • Small interfering RNA (siRNA) mediated depletion of VPS28 and Cdc42.
  • Expression of dominant-negative and constitutively active Cdc42 mutants.

Main Results:

  • The YRKL sequence was confirmed as the influenza virus L domain motif, functioning independently of its nuclear localization signal (NLS) activity.
  • Mutations in YRKL disrupted virus release, reduced virus titer, and altered virus morphology.
  • VPS28 (ESCRT-I component) and Cdc42 (Rho GTPase) directly interacted with the M1 protein through the YRKL motif.
  • Depletion of VPS28 or Cdc42, or inhibition of Cdc42 activity, significantly reduced viral production.

Conclusions:

  • The YRKL motif is the essential L domain for influenza A virus budding and release.
  • VPS28 and Cdc42 are key cellular factors interacting with M1 via the YRKL motif, mediating viral replication.
  • Targeting the M1-VPS28-Cdc42 interaction presents a potential strategy for antiviral therapies against influenza.

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