In the version of Supplementary Fig. 3c originally published with this Article, the authors mistakenly duplicated a blot from Supplementary Fig. 3b. The correct versions of these figures are shown below. In addition, two independent repeats of the experiments presented in Supplementary Figs. 3b and 3c, showing results consistent with those originally reported, have been deposited in Figshare (10.6084/m9.figshare.7545263).