Monitoring interactions between receptor tyrosine kinases and their downstream effector proteins in living cells using bioluminescence resonance energy transfer

A limited number of whole-cell assays allow monitoring of recep-tor tyrosine kinase (RTK) activity in a signaling pathway-specific manner. We present the general use of the bioluminescence res-onance energy transfer (BRET) technology to quantitatively study the pharmacology and signaling properties of the receptor ty-rosine kinase (RTK) superfamily. RTK BRET-2 assays monitor, in living cells, the specific interaction between RTKs and their effec-tor proteins, which control the activation of specific downstream signaling pathways. A total of 22 BRET assays have been estab-lished for nine RTKs derived from four subfamilies [erythroblastic leukemia viral (v-erb-b) oncogene homolog (ErbB), platelet-derived growth factor (PDGF), neurotrophic tyrosine kinase recep-tor (TRK), vascular endothelial growth factor (VEGF)] monitoring the interactions with five effectors (Grb2, p85, Stat5a, Shc46