Skip to main content
. 2020 Nov 5;8:590192. doi: 10.3389/fcell.2020.590192

FIGURE 2.

FIGURE 2

Promotion of autophagy through nutrient or energy restriction. Caloric restriction (CR) suppresses insulin, IGF1, and leptin, each of which suppress autophagy via activation of mTOR following binding to their cognate receptor. Induction of ghrelin by CR promotes activation of AMPK to promote autophagy. Dietary energy modulation by CR limits availability of key nutrient regulators of autophagy including amino acids and glucose. In CR, AMPK signaling is induced in response to reduced ATP and/or glucose concentrations. ATG5-ATG12 complex activity is regulated by the availability of acetyl-coA and the activity of deacetylases. In CR, reduced acetyl-coA limits protein acetylation by reducing substrate availability for acetyltransferases. CR induced increase in NAD + levels promote the activity of sirtuins. Key: Black lines reflect regulation at basal states; Black arrows reflect activation, while black T bars reflect inhibition. Red arrows reflect changes in hormone/metabolite availability induced by fasting which may modulate autophagy.