CIECHANOVER, AARON J. (1947– ), Israeli biochemist and Nobel laureate. Ciechanover obtained his medical degree in 1973 from Hadassah and the Hebrew University School of Medicine. Following military service as a physician in the Israeli Defense Forces (1973–76), including the Yom Kippur War, he obtained his Ph.D. in biochemistry from the Faculty of Medicine at the Technion in Haifa in 1981. During this period, along with his mentor, Prof. Avram *Hershko, he discovered the ubiquitin proteolytic system, which is now known to be involved in regulating a broad array of biological processes in health and disease. He continued his training at MIT and the Whitehead Institute in Cambridge, Mass. (1981–84). After returning to Israel, he joined the Faculty of Medicine at the Technion, becoming distinguished professor. He was director of the Rappaport Family Institute for Research in the Medical Sciences at the Technion from 1993 to 2000. Ciechanover holds the Janet and David Polak Chair in Life Sciences in the Faculty of Medicine at the Technion and has received numerous awards for his groundbreaking and far-reaching work in cancer research and the life sciences. These include the Albert and Mary Lasker Award for basic medical research in 2000, the EMET Prize in 2002, and the Israel Prize in biology in 2003.
Among Ciechanover's most significant contributions are major studies of ubiquitin, a protein that marks other proteins for destruction. Programmed, ubiquitin-mediated destruction of proteins has emerged as a critically important post-translational modification that plays major roles in regulating a broad array of basic cellular processes such as division, differentiation, signal transduction, trafficking, and quality control. A drug based on the general discovery of the ubiquitin system is used for the treatment of multiple myeloma. Ciechanover shared the 2004 Nobel Prize in chemistry with Avram *Hershko and Irwin *Rose for the discovery of the ubiquitin system.