A divalent metal ion binding site in the kinase insert domain of the alpha-platelet-derived growth factor receptor regulates its association with SH2 domains

A novel divalent metal ion binding site present in the alpha-platelet-derived growth factor receptor (alpha-PDGFR) kinase insert (KI) domain regulates the binding of the recombinant alpha-PDGFR KI domain with the p85 N-SH2 domain. Presence of Ca2+ ions enhances this binding. In the presence of insulin, maturation is delayed upon injecting this domain into Xenopus oocytes and this reveals the compatibility of the three-dimensional structure of the KI domain with biological activity.