You may not be familiar with the protein AMPK, but if you exercise regularly, like to drink red wine, take certain diabetes medications or practice caloric restriction in hopes of extending your life, AMPK is very important to you. AMPK is a master switch that controls a number of key cellular mechanisms, and all the activities listed above stimulate AMPK signals.Recently, Dr. Reuben Shaw’s lab at the Salk Institute for Biological Studies, with assistance from Dr. Malene Hansen’s lab at Sanford-Burnham, published a paper in the journal Science showing how AMPK triggers a process called autophagy, which recycles damaged parts when cells are low on energy. Problems with AMPK and autophagy are associated with type 2 diabetes, cancer, Alzheimer’s and other age-related diseases.
In a nutshell, AMPK senses low cellular energy and activates the protein ULK1, which initiates autophagy. The components are then recycled for cellular use. This is an ancient mechanism, as graduate student Sara Gelino in the Hansen lab showed that these proteins similarly regulate autophagy in the worm C. elegans.
“These observations are significant as they suggest a novel mechanism by which the nutrient status of the animal is directly coupled to autophagy, a link that is ultimately crucial for cell survival,” says Dr. Hansen. “These findings also add new insights into the possible mechanism by which the well-known AMPK activator Metformin functions to have beneficial effects on health, primarily as a diabetes drug.”