The interaction network of phosphotyrosine recognition domains

Residues cycling between a phosphorylated and a non-phosphorylated form play a key role in the modulation of signal transduction. Over the past few years we have designed and implemented a strategy to describe the network of interactions linking phosphorylated peptides to their binding domains. Here we report the substrate specificity characterization of SH2 domain family. We have cloned and expressed all the 120 human SH2 domains; for 73 of them we have been able to identify their recognition specificity by incubating the proteins with a glass chip containing approximately 6000 phospho-peptides covering most of the human phosphotyrosine-proteome. The sequences of peptides selectively bound by SH2 domains were used to infer the interaction network mediated by this phosphotyrosine recognition module. The coverage of interactions previously described in the literature and the results of our pull-down experiments have demonstrated that our approach provides a significant and trustworthy shortcut for the detection of molecular interactions involved in tyrosine phosphorylation networks.