Full-Spectral Multiplexing of Bioluminescence Resonance Energy Transfer in Three TRPV Channels.

Multiplexed bioluminescence resonance energy transfer (BRET) assays were developed to monitor the activation of several functional transient receptor potential (TRP) channels in live cells and in real time. We probed both TRPV1 intramolecular rearrangements and its interaction with Calmodulin (CaM) under activation by chemical agonists and temperature. Our BRET study also confirmed that: (1) capsaicin and heat promoted distinct transitions, independently coupled to channel gating, and that (2) TRPV1 and Ca-bound CaM but not Ca-free CaM were preassociated in resting live cells, while capsaicin activation induced both the formation of more TRPV1/CaM complexes and conformational changes.