AMPK CA(R)Sts a new light on amino acid sensing.

AMP-activated protein kinase (AMPK) is recognized as a critical regulator of cellular energy metabolism impacted by AMP/ATP and ADP/ATP ratios, or glucose- and fatty acid-derived metabolites. However, its ability to sense alterations in amino acid levels is poorly understood. Recent work by Yuan et al (2021) identifies a novel mechanism of AMPK regulation responsive to changes in availability of the sulfur-containing amino acid cysteine.