Regulating G Protein Signaling

Cell biologists have long known that cells can damp down their responses to hormones, neurotransmitters, and other regulators, but exactly how this “desensitization” occurs has been unclear. Now a flurry of work from several labs is revealing how one major group of intracellular communication lines—those using G proteins to transmit signals to the cell interior—achieves this volume control. Researchers have identified a new family of proteins, known as the RGS proteins (for regulators of G protein signaling), that attenuate signaling through those pathways, apparently by binding to one of the three protein subunits that make up a complete G protein. The new findings could lead to a much better understanding of how G protein-signal pathways work—information that could have practical implications as up to 60% of all drugs exert their effects through these pathways.