N-Terminal Acetylation of Cellular Proteins Creates Specific Degradation Signals

Abstract

To Degrade or Not to Degrade Regulating the turnover of proteins within the cell is of fundamental importance to almost every physiological process. Hwang et al. (p. 973 , published online 28 January; see the Perspective by Mogk and Bukau ) now find that acetylated N-terminal methionine (Met) is a degradation signal. This degron is recognized by Saccharomyces cerevisiae Doa10, a transmembrane E3 ubiquitin ligase that resides in the endoplasmic reticulum and inner nuclear membrane. The removal of N-terminal Met by Met-aminopeptidases generates N-terminal residues that are often N-terminally acetylated. Doa10 selectively binds to the resulting N-degrons, which may represent the most prevalent class of cellular protein degradation signals.