After this article [1] was published, concerns were raised about Figures 4, 5 and 7.

Specifically:

• The TAP-1 panel in Figure 4A appears similar to the LMP-7 panel in Figure 4C.
• There appear to be vertical discontinuities between lanes M and 1 and between lanes 1 and 2 suggestive of splicing in Figure 4B. In addition, lanes 1 and 2 appear similar.
• Lanes 1–5 of the Actin panel in Figure 5A appear similar to lanes 2–6 of the β-Actin panel in Figure 7A, with altered exposure.

The authors did not respond to requests for comment on the above concerns. In the absence of the original blots, gels and data underlying the published figures, and in light of the concerns affecting multiple figures which cast doubt on the reliability of the results, the PLOS ONE Editors retract this article.

All authors either did not respond directly or could not be reached.