A three-helix homo-oligomerization domain containing BH3 and BH1 is responsible for the apoptotic activity of Bax

Nicholas M. George, Jacquelynn J D Evans, Xu Luo

Research output: Contribution to journalArticle

98 Citations (Scopus)

Abstract

Homo-oligomerization of Bax (or Bak) has been hypothesized to be responsible for cell death through the mitochondria-dependent apoptosis pathway. However, partly due to a lack of structural information on the Bax homo-oligomerization and apoptosis inducing domain(s), this hypothesis has remained difficult to test. In this study, we identified a three-helix unit, comprised of the BH3 (helix 2) and BH1 domains (helix 4 and helix 5), as the homo-oligomerization domain of Bax. When targeted to mitochondria, this minimum oligomerization unit induced apoptosis in Bax-/-Bak-/- mouse embryonic fibroblasts (DKO). Strikingly, the central helix of Bax (helix 5), when replacing the corresponding helix (helix 5) of Bcl-xL, an anti-apoptotic Bcl-2 family protein structurally homologous to Bax, converted Bcl-xL into a Bax-like molecule capable of forming oligomers and causing apoptosis in the DKO cells. Finally, a series of systematic mutagenesis analyses revealed that homo-oligomerization is both necessary and sufficient for the apoptotic activity of Bax. These results suggest that active Bax causes mitochondrial damage through homo-oligomers of a three-helix functional unit.

Original languageEnglish (US)
Pages (from-to)1937-1948
Number of pages12
JournalGenes and Development
Volume21
Issue number15
DOIs
StatePublished - Aug 1 2007

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Apoptosis
Mitochondria
Hominidae
Mutagenesis
Cell Death
Fibroblasts
Proteins

Keywords

  • Apoptotic activity
  • BH3
  • Bax
  • Bcl-2 family
  • Homo-oligomerization

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

Cite this

A three-helix homo-oligomerization domain containing BH3 and BH1 is responsible for the apoptotic activity of Bax. / George, Nicholas M.; Evans, Jacquelynn J D; Luo, Xu.

In: Genes and Development, Vol. 21, No. 15, 01.08.2007, p. 1937-1948.

Research output: Contribution to journalArticle

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