Analysis of EphA4 receptor tyrosine kinase substrate specificity using peptide-based arrays.

Eph receptor tyrosine kinases regulate many important biological processes. In the present study, we explored the substrate specificity of the EphA4 receptor tyrosine kinase using peptide arrays. We define a consensus substrate motif for EphA4 and go on to identify and test a number of potential EphA4 substrates and map their putative site(s) of phosphorylation. Cotransfection studies validate two of the predicted substrates: Nck2 and Dok1. Our findings identify several potential EphA4 substrates and demonstrate the general utility of using peptide arrays to rapidly identify and map protein kinase phosphorylation sites.