Table 1:

Summary of energy sensors in mammalian cells.

Sensor	Activator	Target genes	Effect	Reference
AMPK	ADP: ATP Ca2+ flux	Phosphorylates multiple metabolic genes	Inhibits anabolism, promotes catabolism, autophagy and mitophagy	[40, 41]
mTOR	Amino acids Growth factors	Phosphorylates S6 kinases (S6Ks), 4EBP1/2 and Akt	Inhibits autophagy, promotes cell growth and anabolism.	[42, 43]
SIRTs	NAD+: NADH	Deacetylates multiple transcription factors and co-factors	Inhibits anabolism and inflammation, promotes insulin secretion, influences hypothalamus/pituitary axis	[44, 45]
PGC-1α	Exercise, fasting, cold exposure, Ca2+	PPARs, ERRα, FoxO1, NRF1	Promotes gluconeogenesis, fatty acid oxidation and angiogenesis; Regulates circadian clock	[46, 47]
PASK	Glucose	Phosphorylates Pdx-1, eEF1A1, S6 and glycogen synthase (Gsy)	Promotes insulin secretion, glycogen synthesis, protein translation and lipid accumulation	[48, 49]
HBP	Glucose	O-GIcNAc modification of Sp1, PGC-1β, and NRF1	Decreases mitochondrial function and oxidative phosphorylation; Increases leptin production	[50–52]
PPARs	Fatty acids and fatty acid derivatives	Fatty acid oxidation and autophagy related genes	Induces fatty acid oxidation, autophagic lipid degradation and lipophagy.	[53, 54]
FXR	Bile acids	Hal, Prodh, Cps1, Ass1, Glul	Suppresses gluconeogenesis and autophagy; Promotes cholesterol metabolism	[55–57]
UPR	Unfolded proteins	IRE1, eIF2, PERK, ATF6	Regulates protein folding, ER biogenesis, autophagy, innate immunity and glucose metabolism	[58, 59]