Aaron Ciechanover is an Israeli biochemist who shared the 2004 Nobel Prize in Chemistry with Avram Hershko and Irwin Rose for their joint discovery of the mechanism by which the cells of most living organisms cull unwanted proteins.
Professor Chehanovo's main academic contribution is the discovery of the ubiquitin-mediated protein degradation system. In the late 1970s and early ’80s, Ciechanover, Hershko, and Rose worked together at the Fox Chase Cancer Center in Philadelphia, where much of their prizewinning research was done. The process that they discovered involves a series of carefully orchestrated steps by which cells degrade, or destroy, the proteins that no longer serve any useful purpose. They also demonstrated that ubiquitin-mediated protein degradation helps control a number of other critical biochemical processes, including cell division, the repair of defects in DNA, and gene transcription, the process in which genes use their coded instructions to manufacture a protein. Diseases such as cystic fibrosis result when the protein-degradation system does not work normally, and researchers hoped to use the findings to develop drugs against such illnesses.