HERSHKO, AVRAM (1937–), Israeli biochemist and Nobel laureate. Hershko was born in Karcag, Hungary, and immigrated with his family to Israel in 1950. He gained his M.D. (1965) and Ph.D. (1969) from the Hadassah Medical School of the Hebrew University of Jerusalem, a period which included service as a physician in the Israel Defense Forces (1965–67). After a postdoctoral fellowship with Gordon Tomkins at the University of San Francisco (1969–72), he joined the faculty of the Haifa Technion, becoming professor in 1980 and subsequently distinguished professor in the Unit of Biochemistry in the Rappaport Faculty of Medicine of the Technion. His main research interests concern the mechanisms by which cell proteins are normally degraded and replaced by newly synthesized proteins, a formerly neglected field of study. Hershko and his colleagues showed that, contrary to previous ideas, cellular proteins are degraded by a highly selective proteolytic system. This system tags proteins for destruction by linkage to a protein called ubiquitin, which had previously been identified in many tissues, as the name suggests, but whose function was hitherto unknown. Subsequent work in Hershko's and many other laboratories has shown that the ubiquitin system has a vital role in controlling the survival of a wide range of proteins which regulate cell division and replacement and are involved in the repair of damaged dna. The medical importance of these observations has been established. Inherited abnormalities in the ubiquitin system result in a degenerative disease of the nervous system and other diseases including cancer. Acquired abnormalities of the system, possibly following certain viral infections, may also lead to cancer and disorders of the immune system. The full range of functions of the ubiquitin system in health and disease was still to be elucidated, as were the implications for designing anti-cancer drugs. Hershko was awarded the Nobel Prize in chemistry (2004) jointly with his former Ph.D. student Aaron *Ciechanover and their colleague Irwin *Rose. His many honors include the Weizmann Prize for Science (1987), the Israel Prize for biochemistry and medicine (1994), the Gairdner Award (1999), the Lasker Prize for basic medical research (2000), and the Wolf Prize for medicine (2001). Hershko was a passionate advocate of proper support for scientific education and research in Israel.
[Michael Denman (2nd ed.)]