Photograph by Avi Blizovsky · CC BY-SA 3.0

Irwin Rose helped discover ubiquitin-mediated protein degradation, the process by which cells tag damaged or unneeded proteins for destruction and recycling — a mechanism now understood to be central to nearly everything cells do, from regulating division to correcting errors. He shared the 2004 Nobel Prize in Chemistry with Aaron Ciechanover and Avram Hershko for the discovery.