RESUMEN
WW domain is a well known protein module that mediates protein to protein interactions by binding to proline-containing ligands. Based on the ligand predilections, the WW domains have been classified into four major groups. Group II and III WW domains have been reported to bind the proline-leucine and proline-arginine motifs, respectively. In the present study, using surface plasmon resonance technique we have shown that these WW domains have almost indistinguishable ligand preferences and kinetic properties. Hence, we propose that Group II and III WW domains should be joined together as one group (Group II/III). Unlike Group I and IV WW domains, Group II/III WW domains can bind simple polyprolines as well as the proline-leucine and proline-arginine motifs, and they possess two Xaa-proline (where Xaa is any amino acid) binding grooves similar to SH3 domains. Our work assigns Group II and III WW domains to a larger family of polyproline-binding modules and proteins, which includes SH3 domains and profilin. Because polyprolines belong to the most frequently found peptide motifs in several genomes, our study implies the versatile importance of Group II/III WW domains in signaling.
Asunto(s)
Estructura Terciaria de Proteína , Proteínas/química , Secuencia de Aminoácidos , Animales , Sitios de Unión , Proteínas de Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Humanos , Técnicas In Vitro , Cinética , Ligandos , Modelos Moleculares , Datos de Secuencia Molecular , Peptidilprolil Isomerasa de Interacción con NIMA , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/genética , Isomerasa de Peptidilprolil/metabolismo , Prolina/química , Proteínas/genética , Proteínas/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Homología de Secuencia de Aminoácido , Transducción de Señal , Resonancia por Plasmón de SuperficieRESUMEN
WW domains are protein modules that bind proline-rich ligands. WW domain-ligand complexes are of importance as they have been implicated in several human diseases such as muscular dystrophy, cancer, hypertension, Alzheimer's, and Huntington's diseases. We report the results of a protein array aimed at mapping all the human WW domain protein-protein interactions. Our biochemical approach integrates parallel synthesis of peptides, protein expression, and high-throughput screening methodology combined with tools of bioinformatics. The results suggest that the majority of the bioinformatically predicted WW peptide ligands and most WW domains are functional, and that only about 10% of the measured domain-ligand interactions are positive. The analysis of the WW domain protein arrays also underscores the importance of the amino acid residues surrounding the WW ligand core motifs for specific binding to WW domains. In addition, the methodology presented here allows for the rapid elucidation of WW domain-ligand interactions with multiple applications including prediction of exact WW ligand binding sites, which can be applied to the mapping of other protein signaling domain families. Such information can be applied to the generation of protein interaction networks and identification of potential drug targets. To our knowledge, this report describes the first protein-protein interaction map of a domain in the human proteome.