ATG5 is a member of the ATG family that regulates autophagy, the evolutionary conserved homeostatic response to a diverse variety of self- and foreign-originating cellular stresses. ATG5 is ubiquitously expressed in cells and found co-localized with cytoplasmic non-muscle actin under normal resting conditions, but upon the triggering of apoptosis, ATG5 expression dramatically ramps up, and ATG5 directly conjugates with other related ATG family proteins to form autophagosomes.
