Lights out: deactivation of the phototransduction cascade.

The phototransduction G-protein-coupled signaling cascade is an extremely rapid response to photons of light. Equally important to activation of signaling is switching the signal off. A variety of strategies, ranging from the action of kinases and phosphatases, to feedback regulation by substrates and small molecules, ensures efficient inactivation. Here, we focus on phototransduction in Drosophila as a paradigm for the study of deactivation in a complex G-protein-coupled signaling pathway in vivo.