Sawada, M., Sun, W., Hayes, P., Leskov, K., Boothman, D. A. & Matsuyama, S. Ku70 suppresses the apoptotic translocation of Bax to mitochondria. Nature Cell Biol. 5, 320–329 (2003).

Sawada, M., Hayes, P. & Matsuyama, S. Cytoprotective membrane-permeable peptides designed from the Bax-binding domain of Ku70. Nature Cell Biol. 5, 352–357 (2003).

We are retracting these papers because they contain a significant number of digital image manipulations in the published figures. An investigation by the Blood Center of Wisconsin, with advice from the US Office of Research Integrity, has implicated only the first author, Dr. Motoshi Sawada, in this deception. The investigation further concluded that Dr. Sawada's intent was to improve the appearance of the figures, rather than to fabricate results that did not exist. This retraction supercedes the previous corrigendum dealing with the first of these papers (Nature Cell Biol. 6, 373–374; 2004). Although original data exist that support the conclusions drawn from each figure, we believe that the number of figures affected by the digital manipulations made by Dr. Sawada means that the appropriate response is to retract these papers at this time.

On behalf of all of the other authors, we wish to state that we have collectively confirmed the reproducibility of the findings reported in these articles. Specifically, these studies have confirmed that: first, Ku70 binds and inhibits Bax activation; second, the Bax binding domain of Ku70 localizes to amino acids 578-583; and third, the penta-peptide derived from the Bax-binding domain of Ku70 is cell permeable and is able to inhibit Bax-induced cell death.

Furthermore, all materials (plasmids, peptides and cells) described in the original papers exist, and we are always ready to send these materials to researchers on request — as we have done over the past four years.

As the conclusions drawn within each of the affected articles have been confirmed to be reproducible, this retraction should not affect the validity of numerous articles published by other groups relating to the subject matter of the two retracted papers.

We apologize to the readers and researchers for any problems caused by the retraction of these papers.