FIG. 4.

Repression of autophagy/mitophagy is necessary for beige fat maintenance. Upon β-adrenergic stimulation, beige fat is recruited into white adipose tissue through a process that does not require autophagy. Upon removal of the β-adrenergic stimulation, beige fat converts back to white fat through the autophagic/mitophagic clearance of mitochondria. Adenylate cyclase (AC)/cAMP/PKA represses autophagy to maintain beige fat upon β-adrenergic stimulation. In brown fat, some studies showed that the same cAMP/PKA pathway can repress autophagy during β-adrenergic stimulation. ? represents an inhibition that is not yet confirmed. Color images are available online.