AMPK is one of the more important regulatory components in our metabolic machinery, activated by lower energy intake - such as calorie restriction - and diminishing with age. As such, AMPK signaling changes are prime target for investigation. From EurekAlert!: "when cells are kept hungry in a culture dish, a watchdog enzyme called AMPK jumps into action and attaches a chemical phosphate group to a target protein named raptor. As a result, raptor, whose job is to cradle a growth-promoting protein called mTOR, is disabled, inactivating mTOR and halting cell division. Cells then safely switch into energy conservation mode until plentiful times return. ... Simply the most rudimentary information that any cell needs is to know whether there is food around - that's what AMPK senses. If there is not, you need to turn off factors that make cells grow." mTOR is another party of interest for calorie restriction research - is there a good way to achieve the beneficial health and longevity benefits of calorie restriction by directly manipulating the controls our biochemistry?