Fig. 5. The TAZ WW domain binds to a PPXY motif. (A) Blot overlay analysis verifies PPXY motif selection for the TAZ WW domain. GST or GST fusion proteins containing the WW domains of YAP and TAZ were analyzed by SDS–PAGE, transferred to membranes and probed using biotin-labeled peptides corresponding to the WW domain-binding motifs PPXY, PPLP, PPR and pS/T-P. In control experiments, the PPLP peptide bound strongly to the FBP11 WW domain, and the PPR peptide bound strongly to the FBP30 WW domains (data not shown). (B) The activation domains of many transcription factors contain a PPXY motif. DBD denotes the DNA-binding domain, AD the activation domain, and ID the autoinhibitory domain of PEBP2α.