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Updated: May 28, 2026

Examining BCL-2 Family Function with Large Unilamellar Vesicles
08:35

Examining BCL-2 Family Function with Large Unilamellar Vesicles

Published on: October 5, 2012

The vaccinia virus-encoded Bcl-2 homologues do not act as direct Bax inhibitors

Antonio Postigo1, Michael Way

  • 1Cancer Research UK London Research Institute, London, United Kingdom.

Journal of Virology
|October 21, 2011
PubMed

Insights

Vaccinia virus F1 protein inhibits apoptosis by targeting Bak. Contrary to reports, N1 protein does not interact with Bax or block cell death, suggesting F1 orthologs are the primary apoptosis inhibitors.

Area of Science:

  • Virology
  • Molecular Biology
  • Cellular Biology

Background:

  • Viruses, including poxviruses, encode inhibitors to block apoptosis by binding proapoptotic Bcl-2 proteins Bak and Bax.
  • Vaccinia virus (VACV) has F1 protein, a Bcl-2-like protein that sequesters Bak, and N1 protein, a virulence factor suggested to interact with Bax.

Purpose of the Study:

  • To investigate if VACV inhibits Bak/Bax-dependent apoptosis through the combined action of F1 and N1 proteins.
  • To clarify the role of N1 protein in apoptosis and its interaction with Bax.

Main Methods:

  • Comparative analysis of apoptosis inhibition in VACV wild-type (WR) and mutant viruses (ΔN1L, ΔF1L, ΔN1L/F1L).
  • Assessment of Bax activation and apoptosis levels during infection.
  • In vitro experiments to evaluate N1 protein's effect on cell death and Bax interaction.

Main Results:

  • VACV WR and ΔN1L viruses equally inhibited drug- and infection-induced apoptosis.
  • ΔF1L and ΔN1L/F1L viruses showed similar levels of Bax activation and apoptosis.
  • N1 protein did not inhibit drug- or Bax-induced cell death outside of infection and did not interact with Bax.
  • Other conserved VACV Bcl-2 homologs (A46, A52, B14, C1, C6, C16/B22, K7, N2) did not associate with Bax or inhibit cell death.

Conclusions:

  • N1 protein is not an antiapoptotic factor and does not interact with Bax.
  • VACV F1 orthologs are the sole orthopoxvirus Bcl-2 homologs that directly inhibit the Bak/Bax apoptotic checkpoint.

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