Nat. Med. 12, 568–573 (2006); published online 30 April 2006; corrected after print 16 June 2006

In the version of this article initially published, Errfi1 was incorrectly referred to as Erffi1 in several instances, and in Figure 1h the middle panels of the immunoblot were labeled Egf instead of Hgf.

The errors have been corrected in the HTML and PDF versions of the article.