Nat. Med.; doi:10.1038/nm.4070; corrected online 22 April 2016

In Figure 2a of the version of this article initially published online, one phenyl ring was inadvertently deleted from the chemical structure of compound SR2211. One affiliation of H.-W.C. (Veterans Affairs Northern California Health Care System–Mather, Mather, California, USA) was also inadvertently omitted. These errors have been corrected for the print, PDF and HTML versions of this article.