Question

Explain how the enzyme AMPK responds to low cellular energy and regulates any one of its target metabolic pathways

Answer 1

Under conditions of low energy, AMPK phosphorylates specific enzymes and growth control nodes to increase ATP generation and decrease ATP consumption.This energy switch controls cell growth and several other cellular processes, including lipid and glucose metabolism and autophagy.

As a cellular energy sensor responding to low ATP levels, AMPK activation positively regulates signaling pathways that replenish cellular ATP supplies, including fatty acid oxidation and autophagy. AMPK negatively regulates ATP-consuming biosynthetic processes including gluconeogenesis, lipid and protein synthesis. AMPK accomplishes this through direct phosphorylation of a number of enzymes directly involved in these processes as well as through transcriptional control of metabolism by phosphorylating transcription factors, co-activators, and co-repressors.

Due to its role as a central regulator of both lipid and glucose metabolism, AMPK is considered to be a potential therapeutic target for the treatment of type II diabetes mellitus, obesity, and cancer. AMPK has also been implicated in a number of species as a critical modulator of aging through its interactions with mTOR and sirtuins.