We thank members of the Pelkmans and Klemm laboratories for discussions. We further thank J. Michael Peters, A. Merdes and M. Polymenidou for reagents and acknowledge the assistance and support of the Center for Microscopy and Image Analysis, University of Zurich for performing FRAP experiments. EMBO and HFSP LTF supported A.K.R. J.-X.C was supported by an MDC-NYU PhD exchange program fellowship. L.P. is supported by the Swiss National Science Foundation and the University of Zurich.

Reviewer information

Nature thanks A. Gladfelter, A. Hyman and the other anonymous reviewer(s) for their contribution to the peer review of this work.