Acetyl‐ed question in mitochondrial biology?

Lysine acetylation on numerous mitochondrial proteins, targeted by the sirtuin deacylase SIRT 3, has been proposed to play a major role in regulating diverse mitochondrial functions, particularly in the liver. A new study by Weinert, Choudhary, and colleagues, in this issue of The EMBO Journal, finds that the absolute levels of hepatic mitochondrial protein acetylation in wild‐type mice are extremely low and may be insufficient to exert regulatory effects.