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The matrix (M) protein of Newcastle disease virus binds to human bax through its BH3 domain

Aidin Molouki1, Yi-Te Hsu, Fatemeh Jahanshiri

  • 1Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor DE, Malaysia.

Virology Journal
|August 4, 2011
PubMed

Insights

Newcastle disease virus (NDV) proteins, particularly the matrix protein (AF2240-M), contain BH3-like domains that induce cancer cell death. This interaction with Bax protein is crucial for NDV-mediated apoptosis.

Area of Science:

  • Virology
  • Molecular Biology
  • Cancer Research

Background:

  • Newcastle disease virus (NDV) exhibits oncolytic properties, but its mechanisms of cancer cell killing are not fully understood.
  • Viral proteins can interact with host Bcl-2 family proteins, influencing viral pathogenicity and cell death.
  • NDV strains, like the Malaysian AF2240, possess proteins with potential Bcl-2 homology (BH) domains.

Purpose of the Study:

  • To investigate the role of Bcl-2 homology-like domains in NDV proteins in inducing cancer cell apoptosis.
  • To identify specific NDV proteins and their domains responsible for cytotoxicity.
  • To elucidate the interaction between NDV proteins and host Bcl-2 family members.

Main Methods:

  • Sequence alignment of NDV AF2240 proteins (M, L, F) with human Bcl-2 family members to identify BH3-like and BH1-like domains.
  • Cloning and transfection of AF2240-M and AF2240-F genes into HeLa cells.
  • Flow cytometry analysis of apoptosis in cells expressing wild-type and mutated NDV constructs.
  • Co-immunoprecipitation assays to assess protein-protein interactions between NDV proteins and Bcl-2 family members.
  • Quantitative reverse transcription PCR (qRT-PCR) to measure endogenous Bax and Bcl-2 mRNA levels.

Main Results:

  • NDV matrix (AF2240-M) and fusion (AF2240-F) proteins contain BH3-like regions; AF2240-M and AF2240-F share BH1-like domains with Mcl-1.
  • Expression of AF2240-M and AF2240-F in HeLa cells induced cell death.
  • Deletion of the BH3-like region in AF2240-M significantly reduced apoptosis, while the N-terminal domain retained cell death-promoting activity.
  • AF2240-M promoted Bax redistribution to mitochondria and directly interacted with Bax via its BH3-domain.
  • AF2240-F did not interact with tested Bcl-2 family proteins, though Bcl-XL partially inhibited its cytotoxic effect.
  • NDV infection did not alter endogenous Bax and Bcl-2 mRNA levels or their ratio.

Conclusions:

  • The BH3-like domain of NDV AF2240-M protein is critical for inducing apoptosis in cancer cells.
  • NDV AF2240-M directly interacts with Bax, leading to its mitochondrial redistribution and subsequent cell death.
  • These findings provide insights into the molecular mechanisms of NDV-induced apoptosis, highlighting viral protein interactions with the host apoptotic machinery.

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