Nat. Cell Biol. 17, 20–30 (2015); published online 1 December 2014; corrected after print 1 April 2015

In the version of this Article originally published, incorrect western blot scans were provided for the actin panels in Figure 4h,i. These panels have been corrected online and are shown above. All samples in 4i were collected and processed simultaneously, on the same or on parallel gels/blots.