Bax mitochondrial relocation is linked to its phosphorylation and its interaction with Bcl-xL

Abstract

The heterologous expression of Bax, and other Bcl-2 family members, in the yeast Saccharomyces cerevisiae, has proved to be a valuable reporter system to investigate the molecular mechanisms underlying their interaction with mitochondria. By combining the co-expression of Bax and Bcl-xL mutants with analyzes of their localization and interaction in mitochondria and post-mitochondrial supernatants, we showed that the ability of Bax and Bcl-xL to interact is dependent both on Bax phosphorylation – mimicked by a substitution S184D – and by Bax and Bcl-xL localization. This, and previous data, provide the molecular basis for a model of dynamic equilibrium for Bax localization and activation, regulated both by phosphorylation and Bcl-xL.

Keywords

• Bax
• Bcl-xL
• mitochondria
• phosphorylation
• cytochrome c release
• apoptosis
• yeast (S. cerevisiae)