Protein kinase C (PKC) contributes to vascular dysfunction in various disease states including inflammation,infection,trauma and diabetes.The precise cellular mechanisms by which PKC alters vascular function have not been elucidated at the molecular level.The shortcoming of knowledge is due,in part,to the technical difficulties in dynamic and quantitative assessment of PKC kinase activities specific to subcellular locations.In this study,we examined PKC membrane translocation and associated activities by measuring fluorescence resonance energy transfer (FRET) in vascular endothelial cells transfected with a genetically encoded fluorescent reporter that was targeted to either the cell membrane or the cytosol.