Nat. Immunol. 8, 772–779 (2007); published online 17 June 2007; corrected after print 19 October 2007

In the version of this article initially published, the distance values reported in Tables 1 and 2 are incorrect. The correct values are provided in the revised tables. Accordingly, line 6 on p 774 should read “7.3 nm”; line 11 on p 774 should read “a 12% decrease”; line 12 on p 777 should read “7.0 nm”; and lines 17–20 on p 777 should read “We calculated the C-terminal intermolecular distance in the endosome to be less 5.4 nm. Given the fact that the donor and acceptor fluorophores are buried inside the fluorescent proteins, their minimal distance is approximately 5.0 nm. Thus, these measurements indicate that the TLR9 TIR domains were brought in close proximity after the binding of CpG DNA ligand to the TLR9 ectodomains (Table 2).” The error has been corrected in the HTML and PDF versions of the article.