Publisher Correction: The SERK3 elongated allele defines a role for BIR ectodomains in brassinosteroid signalling.
In the version of this Letter originally published, there were errors in the x axis labels of Figs 1, 2 and 4: in Fig. 1b, the label Col-0 should not have been included on the axis; in Fig. 2b BIR should have read BIR2, and DN221 should have read D122N; in Fig. 4f, pSEK3 should have read pSERK3. These figures have now been amended in all versions of the Letter.