We thank F. Lammertyn and all colleagues of the Functional Proteomics group at VIB and Ecophysiology–Biochemistry–Toxicology, Centre for Proteome Analysis and Mass Spectrometry (EBT-CEPROMA) at Antwerp University for technical assistance; M. I. Puga and J. Paz-Ares for providing the prey cDNA library for Y2H screens; V. Storme for help with statistical analysis; J. Van Leene and M. Karimi for discussions; and M. De Cock for help in preparing the manuscript. This work was supported by the Research Foundation–Flanders (predoctoral fellowship to L.P.), the Agency for Innovation by Science and Technology in Flanders (‘Generisch Basisonderzoek aan de Universiteiten’, and predoctoral fellowships to S.T. and J.G.), the Special Research Fund of Ghent University (postdoctoral fellowship to W.G.), the National Institutes of Health (to J.L.) and the Spanish Ministerio de Ciencia y Tecnología and the Comunidad de Madrid (to R.S.).

Author Contributions L.P., G.F.B., J.G., S.T., W.G., A.C.P., J.M.C., R.V.B., J.S., E.G, G.G.-C. and J.A.L. performed experiments and analysed the results. L.P., W.G., E.W., J.A.L., G.D.J., R.S. and A.G. planned experiments and analyses. L.P., D.I., J.A.L., R.S. and A.G. wrote the manuscript. All authors commented on the results and the manuscript.