(1925–98), American biochemist and Nobel laureate, known for his discovery of natural signal transducers known as G-proteins and demonstration of their function in fundamental processes in cells of all living organisms.

Born in Baltimore, Md., Rodbell was educated there at Johns Hopkins University and at the University of Washington in Seattle, Wash., where he earned his Ph.D. in 1954. His career was spent largely at the National Institutes of Health (1956–85) in Bethesda, Md. From 1985 until his retirement in 1994 he served as the head of the laboratory of signal transduction at the National Institute of Environmental Health Sciences in Durham, N.C.

In the 1960s Rodbell’s research was focused on the study of cell communication to determine how cells respond with a specific action to a specific signal received from outside. At that time it was known that hormones and neurotransmitters participate in carrying messages from one cell to another. His contribution was to the elucidation of the biochemical reactions that make possible the actual transduction (transfer) of messages from the cell’s membrane to its interior. Rodbell discovered the proteins involved in the process, which became known as G-proteins because they became activated when bound to guanosine triphosphate (GTP), a derivate of base guanine in the makeup of AMINO ACIDS, (q.v.). In active form G-proteins trigger the formation of a second messenger, for example, the cyclic adenosine monophosphate (the cyclic AMP), a nucleotide component of nucleic acids (see ADENOSINE TRIPHOSPHATE; ATP), which is of fundamental importance in cell metabolism. Rodbell’s discovery was followed up by the American pharmacologist Alfred G. Gilman, who isolated the first G-protein and described its activities when studying cellular communication in mutated (genetically altered) leukemia cells in the early 1970s. The various G-proteins, of which more than 20 were later identified, are important links in cholera, cancer, diabetes, and other diseases.

Rodbell and Gilman shared the 1994 Nobel Prize in physiology or medicine for their discovery of “G-proteins and the role of these proteins in signal transduction in cells.”

See also CELL,; HORMONE,; PROTEIN,.