Martin Rodbell

Martin Rodbell (1925-1998), American biochemist and Nobel Prize winner, born in Baltimore, Maryland. For his contributions to how cells communicate with each other, Rodbell shared the 1994 Nobel Prize in physiology or medicine with American pharmacologist Alfred Gilman.

Rodbell received a Ph.D. degree from the University of Washington in 1954 and worked for the National Institutes of Health (NIH), where he carried out much of his pioneering research, from 1970 to 1985. Rodbell served as scientific director of the National Institute of Environmental Health Sciences from 1985 to 1989. He remains a scientist emeritus in the Laboratory of Cellular and Molecular Pharmacology there.

Well before the 1960s cell biologists knew that certain hormones and other cellular molecules produced by glands, nerves, and other tissues play a role in communication between cells. They knew that these molecules somehow affect the cell membrane so that changes occur inside the cell. What was not understood was just how this information is passed from the outside to the inside of the cell through the cell membrane. Rodbell's contribution in the late 1960s and early 1970s lay in discovering how external signals change to internal signals, triggering actions inside the cell.

Rodbell came to understand that three different entities are involved when a cell acts upon a chemical signal from outside. First, receptors in the cell membrane “bind,” or attach, to specific cellular molecules from other cells that come into contact with the cell's surface. Each receptor can bind to only one type of cellular molecule. This is called discrimination, and the receptor is called the discriminator. When the binding occurs, a second chemical reaction, or signal, occurs within the cell membrane, causing the cell to perform some sort of action (in the case of nerve cells, for instance, to pass signals from the sensory organs to the brain). This second action is called amplification, and the protein responsible for it is called an amplifier.

Rodbell's insight was that a third action somehow has to link the discriminator and the amplifier. He discovered that the cellular molecule guanosine triphosphate (GTP) activates a kind of chemical switchboard, called a transducer, that converts the message between the discriminator and the amplifier.

Building upon Rodbell's original research, Gilman of the University of Virginia discovered the specific protein that bound the GTP found by Rodbell. Gilman called it the G-protein.