Hunt, Timothy (1943-), a British biologist, won a share of the 2001 Nobel Prize in physiology or medicine for his discovery of proteins that help control the growth and multiplication of cells in living organisms. He shared the prize with Sir Paul Nurse, another British biologist; and Leland Harrison Hartwell, an American geneticist. The three scientists all conducted research on the cell cycle —that is, the way cells grow and divide.

Experimenting with sea urchins, which are animals related to starfish, Hunt discovered a protein that helps regulate the cell cycle. He called the protein cyclin, because the level of the protein varies over the course of the cell cycle. Hunt discovered that the cyclin protein is formed and broken down during each step of the cycle. He later found that the cycle of protein formation and breakdown helped control the timing of the steps in the cell cycle. Hunt discovered cyclins in a wide variety of living organisms.

Scientists believe that problems occurring in the cell cycle may play a role in the development of cancer. Cancer is a disease in which cells multiply wildly, destroy healthy tissue, and endanger life. Defects in the cell cycle may produce faulty cyclins or similar proteins and lead to cell changes that can cause cancer. Hunt's research has provided scientists with new possibilities for developing successful treatments for cancer.

Richard Timothy (known as Tim) Hunt was born in Neston, England, on Feb. 19, 1943. He studied at Cambridge University, receiving his Bachelor of Arts degree in 1964 and his Ph.D. degree in 1968. From 1968 to 1970, he conducted research at the Albert Einstein College of Medicine in New York City. Hunt held positions in the Department of Biochemistry at Cambridge University from 1971 to 1990. In 1991, he became principal scientist at the Imperial Cancer Research Fund (now called Cancer Research U.K., Clare Hall Laboratories) near London.