Correction to: Nature Published online 26 August 2010

In the version of this article initially published, due to a cropping error that occurred upon rescanning and replacing the actin blot in Fig. 2a in response to a reviewer’s request, the actin lane for an additional lysate that had been run at the end of the gel, but that was not part of the figure, was inadvertently included. This was an editing error and does not affect any results or conclusions in the article. The actin panel in Fig. 2a has now been cropped to remove the additional lane and is shown as Fig. 1, below. The original article has not been corrected online

Fig. 1
figure 1

Corrected Fig. 2a.