Nobel for translator of cell messages.

An array of chemicals orchestrates activities between and within cells. This week, a pair of molecular pharmacologists won a Nobel prize for their work identifying the family of agents responsible for relaying into cells the commands of hormones, drugs, and other external chemical messengers.

A 1971 Nobel prize honored the man who demonstrated that hormones work by carrying explicit commands to the outside of target cells. But before a cell can execute such a directive, something in the cell's barrier membrane must first convert that external command into the language of the "second messengers." These communicators are charged with relaying signals within the cell.

Martin Rodbell, retired from the National Institute of Environmental Health Sciences in Research Triangle Park, N.C., and Alfred G. Gilman at the University of Texas Southwestern Medical Center at Dallas share this year's Nobel Prize in Physiology or Medicine for identifying G proteins, which translate and integrate external signals for the cell's second messengers.

Fourteen years ago, Rodbell discovered that cellular communications relied on the presence of a molecule known as GTP (guanosine triphosphate). Seven years later, Gilman, then at the University of Virginia School of Medicine in Charlottesville, showed that GTP was located on the inner surface of cell membranes -- bound to things that he termed G proteins.

Rodbell went on to study G proteins and how they interpret the cacophony of ambient signals for healthy functioning. (Faulty G proteins have recently been linked to disease, including cancer.) In his most recent work, Gilman has been teasing out the shape and function of G proteins and their targets.

National Institutes of Health Deputy Director Ruth L. Kirschstein says both men "made significant findings [on] how cells perceive and react in a coordinated way to the thousands of messages that bombard them. This Nobel prize underscores how important such basic studies are to understanding normal cell function and the diseases that result when cell processes go awry."