Proteins are the building blocks of all living things. A vast amount research takes place on how these proteins are made and what they do, from enzymes that carry out chemical reactions to messengers that transmit signals between cells. In 2004, Aaron Ciechanover, Avram Hershko, and Irwin Rose won the Nobel Prize in Chemistry for a different but just as important process of protein machinery: how organisms break down proteins when they are finished doing their job.