Atg14 also known as ATG14L is a core component of the class III phosphatidylinositol 3-kinase (PI3KC3) complex I that directs phosphatidylinositol 3-phosphate production at the endoplasmic reticulum to initiate autophagosome nucleation. By coupling Beclin 1–VPS34 signaling to early autophagy membrane dynamics, Atg14 supports autophagosome biogenesis, selective autophagy, and cellular adaptation to nutrient and proteotoxic stress. Disruption of ATG14-dependent autophagy has been linked to altered proteostasis, mitochondrial quality control, and inflammatory signaling, processes frequently studied in cancer biology, neurodegeneration, and metabolic stress models.