Retraction to: Cell Death and Differentiation (2006) 13, 1554–1563; doi:10.1038/sj.cdd.4401839

It has come to our attention that multiple bands in Figure 1e and lanes in Figure 3a have been inappropriately duplicated. The authors are unable to provide the original source files that were used to generate these data and they have all agreed to retract this article. The conclusions of the paper have been confirmed by subsequent papers.