Core principles of autophagy initiation mechanisms

Autophagy is a conserved intracellular degradation system essential for maintaining cellular homeostasis and adapting to a variety of environmental or metabolic cues. Different types of autophagy are induced in response to various physiological signals through distinct mechanisms. In this Review, we highlight recent advances in understanding the molecular mechanisms that induce autophagic degradation of cytoplasmic material in bulk upon nutrient or energy deprivation, and those that trigger the selective autophagic removal of specific cellular components for their quality or quantity control. We discuss mechanistic principles shared across different types of autophagy, such as phase-separation-mediated assembly and activation of related factors, and the coordination between cargo recognition and membrane biogenesis, delineating how diverse mechanisms converge on core principles to ensure context-specific control of autophagy initiation.