A widely applicable, high-throughput TR-FRET assay for the measurement of kinase autophosphorylation: VEGFR-2 as a prototype.

Homogeneous time-resolved fluorescence resonance energy transfer (TR-FRET) assays represent a highly sensitive and robust high-throughput screening (HTS) method for the quantification of kinase activity. Traditional TR-FRET kinase assays detect the phosphorylation of an exogenous substrate. The authors describe the development and optimization of a TR-FRET technique that measures the autophosphorylation of vascular endothelial growth factor receptor 2 (VEGFR-2) kinase and extend its applicability to a variety of other kinases. The VEGFR-2 assay demonstrated dose-dependent inhibition by compounds known to modulate the catalytic activity of this receptor. In addition, kinetic analysis of a previously characterized VEGFR-2 inhibitor was performed using the method, and results were consistent with those obtained using a different assay format. Because of the known involvement of VEGFR-2 in angiogenesis, this assay should facilitate HTS for antiangiogenic agents. In addition, this general technique should have utility for the screening for inhibitors of kinases as potential therapeutic agents for many other disease indications.