title: Biophysical analysis of binding of WW domains of the YAP2 transcriptional regulator to PPXY motifs within WBP1 and WBP2 adaptors.
abstract: The YAP2 transcriptional regulator mediates a plethora of cellular functions, including the newly discovered Hippo tumor suppressor pathway, by virtue of its ability to recognize WBP1 and WBP2 signaling adaptors among a wide variety of other ligands. Herein, using isothermal titration calorimery and circular dichroism in combination with molecular modeling and molecular dynamics, we provide evidence that the WW1 and WW2 domains of YAP2 recognize various PPXY motifs within WBP1 and WBP2 in a highly promiscuous and subtle manner. Thus, although both WW domains strictly require the integrity of the consensus PPXY sequence, nonconsensus residues within and flanking this motif are not critical for high-affinity binding, implying that they most likely play a role in stabilizing the polyproline type II helical conformation of the PPXY ligands. Of particular interest is the observation that both WW domains bind to a PPXYXG motif with highest affinity, implicating a preference for a nonbulky and flexible glycine one residue to the C-terminal side of the consensus tyrosine. Importantly, a large set of residues within both WW domains and the PPXY motifs appear to undergo rapid fluctuations on a nanosecond time scale, suggesting that WW-ligand interactions are highly dynamic and that such conformational entropy may be an integral part of the reversible and temporal nature of cellular signaling cascades. Collectively, our study sheds light on the molecular determinants of a key WW-ligand interaction pertinent to cellular functions in health and disease.
authors: Department of Biochemistry and Molecular Biology and USylvester Braman Family Breast Cancer Institute, Leonard Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.
authors: Caleb B
authors: CB
authors: McDonald
authors: Samantha K N
authors: SK
authors: McIntosh
authors: David C
authors: DC
authors: Mikles
authors: Vikas
authors: V
authors: Bhat
authors: Brian J
authors: BJ
authors: Deegan
authors: Kenneth L
authors: KL
authors: Seldeen
authors: Ali M
authors: AM
authors: Saeed
authors: Laura
authors: L
authors: Buffa
authors: Marius
authors: M
authors: Sudol
authors: Zafar
authors: Z
authors: Nawaz
authors: Amjad
authors: A
authors: Farooq
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism; D020816:Amino Acid Motifs; D002151:Calorimetry; D018360:Crystallography, X-Ray; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013816:Thermodynamics; D015534:Trans-Activators; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D015534:Trans-Activators; D014157:Transcription Factors; C106907:WBP1 protein, human; C106908:WBP2 protein, human; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human