Nat. Biotechnol. 33, 543–548 (2015); published online 24 March 2015; corrected after print 14 December 2017

In the version of this article initially published, in the HTML only, in Online Methods “Cell culture and reagents,” in the last two sentences, “...supplied with 1 mM SCR7 inhibitor until analysis. At SCR7 concentrations of 60 mM and 10 mM....”, “mM,” in every case, should have been “μM.” The errors have been corrected in the HTML version of the article.