Autophagy-related protein (ATG)

Autophagy-related proteins represent a large and conserved family of molecules essential for autophagy, a lysosome-dependent cellular process responsible for the degradation and recycling of intracellular components. These proteins are involved in a tightly regulated sequence spanning autophagosome induction (initiated by complexes containing ULK1/ULK2, Atg13, FIP200, Atg101), vesicle nucleation (Beclin-1 complex, PI3K/Vps34, Atg14, VPS15), expansion (Atg8/LC3 lipidation system, Atg12–Atg5–Atg16L1 complex), and eventual vesicle closure and fusion with lysosomes. Various subgroups and molecular classes ensure that autophagy adapts to environmental stimuli (nutrient deprivation, oxidative stress) and maintains cellular homeostasis. Mutations or dysregulation of individual ATG proteins are implicated in diverse diseases, making specific ATG proteins attractive therapeutic targets. However, “autophagy-related proteins” as a collective is less precise than naming a specific ATG protein, and refers to the broader set of conserved molecules with roles in autophagy regulation, membrane dynamics, cargo recognition, and trafficking.

Other names

ATG proteinsAutophagy proteinsMacroautophagy proteinsBeclin-1 (ATG6)ULK1LC3 (ATG8)Atg4Atg12Atg16L1

Induction of autophagy via inhibition of mTOR/activation of ULK1 complex; Inhibition of autophagy via lysosomal pH modulation (chloroquine class); Modulation of Beclin 1-Bcl-2 protein-protein interactions to regulate autophagosome formation; Ubiquitin-like conjugation for membrane expansion (Atg8/LC3 lipidation, Atg12-Atg5 system).