Correction to: Nature Cell Biology https://www.nature.com/articles/ncb3472, published online 1 March 2017.

In the version of Supplementary Fig. 3d initially published alongside this article, the image shown in the Basal; +1 day panel was an inadvertent duplicate of the Spinous; +1 day image above. Due to the age of the article, the Supplementary Information in the original article cannot be replaced directly; instead, the revised Supplementary Information accompanying this amendment serves to correct the article.