Proteins are the building blocks of living things, and much scientific research has been dedicated to figuring out how cells produce their myriad proteins. Fewer researchers were interested in studying the opposite problem: how cells identify and break down unwanted proteins. Now a trio of scientists who did just that has been rewarded with the Nobel Prize in Chemistry for their seminal work in solving this mystery.

Aaron Ciechanover (center) and Avram Hershko (left) of the Israel Institute of Technology, together with Irwin Rose of the University of California at Irvine (right), received the honor for the discovery of ubiquitin-mediated protein degradation, according to the selection committee. Ubiquitin, itself a polypeptide protein, identifies protein molecules that are ready to be destroyed. Once singled out and tagged by ubiquitin, the labeled proteins are sent to the cell's proteasome, which chops them into small pieces. The collaborative work of this international group of researchers has given us an important close-up view of the regulatory processes taking place inside human cells and what happens when these processes don't work properly, notes Charles P. Casey of the University of Wisconsin-Madison and current president of the American Chemical Society,

Protein degradation guided by ubiquitin, which derives its name from the Latin word meaning everywhere, occurs throughout the body. The Nobel committee noted that the laureates' work in the 1980s paved the way to understanding other cell processes such as DNA repair and gene transcription. In addition, some diseases, including cystic fibrosis and cervical cancer, involve improper protein breakdown, so a better understanding of how the process should work could shed light on new treatment options.