Biological cells process numerous types of information, for optimal control of their life cycles or to adapt to their environment, and recruit for this purpose signaling proteins. The best known among the latter are the G-proteins, involved in numerous diseases and related to many targets of drugs. G-proteins are closely related to motor proteins: G-proteins get switched on and off through the binding of GTP and its hydrolysis to GDP; motor proteins generate mechanical force through binding of ATP and its hydrolysis to ADP. A recent publication reports a 19,463 atom computer simulation using NAMD that reveals a "power stroke" in G-proteins likewise found in motor proteins. The stroke switches on and off G-proteins' ability to interact with other signaling proteins, with a power stroke that transforms the protein from an ordered into a disordered conformation.