Autophagy initiation pathway

The autophagy initiation pathway is a fundamental cellular process that governs the formation of the autophagosome, a double-membrane vesicle used to sequester and degrade damaged organelles and protein aggregates [1]. This pathway is primarily controlled by the ULK1 (Unc-51 like autophagy activating kinase 1) complex, which includes ULK1, ATG13, RB1CC1 (FIP200), and ATG101, and the Class III Phosphoinositide 3-kinase (PI3K) complex, consisting of VPS34, Beclin-1, VPS15, and ATG14L [2]. Under nutrient-rich conditions, the pathway is suppressed by the Mechanistic Target of Rapamycin Complex 1 (mTORC1), which phosphorylates and inactivates ULK1 [3]. Conversely, energy depletion activates AMPK, which promotes ULK1 activity to initiate phagophore formation [1]. Dysregulation of this pathway is a hallmark of various diseases; for instance, its impairment is linked to the accumulation of toxic proteins in neurodegenerative disorders like Alzheimer's and Parkinson's, while in cancer, it can be exploited by tumor cells to survive metabolic stress [4]. Therapeutic strategies include the use of mTOR inhibitors like Rapamycin to induce autophagy or specific inhibitors like SBI-0206965 (targeting ULK1) and SAR405 (targeting VPS34) to block the pathway in oncology settings [5, 6].

Other names

Macroautophagy initiationULK1-mediated autophagy initiationAutophagy induction pathwayPhagophore initiation

mTORC1 inhibition, AMPK activation, ULK1 kinase inhibition, VPS34 inhibition