A transducer is a protein that converts chemical information from a hormone that binds to its receptor into a language that the biochemical machinery within a cell can understand and act upon. Transducers normally act as liaisons between receptors that have bound to a particular hormone and the effector proteins that actually generate the final cellular responses. They are frequently arranged in a series of steps, a cascade, which allows amplification of the original hormonal signal by recruitment of cellular energy stores. Typical transducers include enzymes like protein kinases that incorporate phosphate groups into cellular proteins, thereby changing the charge, shape, position and/or functionality of the proteins targeted. They also include small molecules, such as cyclic AMP or diacyl glyceride, that act as secondary messengers within cells by binding to proteins and altering their activities.