Nat. Cell Biol. 13, 1282–1288 (2011); published online 2 November 2011; corrected after print 29 April 2015

Corrected after print 14 May 2015

In the version of this Review originally published reference 34 should have appeared in the caption of Fig. 3: 'The actin-binding protein WASP has been discovered in the nucleus and modulates transcription independently or with the ARP2/3 complex34,97.' This has been corrected in the online versions of the Review.