Hierarchical activation of compartmentalized pools of AMPK depends on severity of nutrient or energy stress

Cell Res. 2019 Jun;29(6):460-473. doi: 10.1038/s41422-019-0163-6. Epub 2019 Apr 4.

Abstract

AMPK, a master regulator of metabolic homeostasis, is activated by both AMP-dependent and AMP-independent mechanisms. The conditions under which these different mechanisms operate, and their biological implications are unclear. Here, we show that, depending on the degree of elevation of cellular AMP, distinct compartmentalized pools of AMPK are activated, phosphorylating different sets of targets. Low glucose activates AMPK exclusively through the AMP-independent, AXIN-based pathway in lysosomes to phosphorylate targets such as ACC1 and SREBP1c, exerting early anti-anabolic and pro-catabolic roles. Moderate increases in AMP expand this to activate cytosolic AMPK also in an AXIN-dependent manner. In contrast, high concentrations of AMP, arising from severe nutrient stress, activate all pools of AMPK independently of AXIN. Surprisingly, mitochondrion-localized AMPK is activated to phosphorylate ACC2 and mitochondrial fission factor (MFF) only during severe nutrient stress. Our findings reveal a spatiotemporal basis for hierarchical activation of different pools of AMPK during differing degrees of stress severity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / biosynthesis
  • AMP-Activated Protein Kinases / metabolism*
  • Animals
  • CRISPR-Cas Systems
  • Cells, Cultured
  • Energy Metabolism*
  • HEK293 Cells
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Microscopy, Fluorescence
  • Nutrients / metabolism*
  • Phosphorylation

Substances

  • AMP-Activated Protein Kinases