Autophagy is a cellular process that degrades cytoplasmic components through lysosomes, playing a critical role in nutrient preservation during starvation and maintaining cellular homeostasis. This study investigates the role of Atg7, an essential gene for autophagy in yeast, in mice. Conditional knockout mice lacking Atg7 were generated to examine autophagy function. Atg7 is essential for ATG conjugation systems, and its deficiency leads to impaired autophagosome formation and starvation-induced degradation of proteins and organelles. Atg7-deficient mice exhibit reduced body weight, early death, and accumulation of abnormal organelles and ubiquitinated proteins. These findings suggest that autophagy is crucial for the clearance of ubiquitin-positive aggregates and the maintenance of cellular homeostasis during starvation. In adult mice, Atg7 deficiency impairs autophagosome formation and the constitutive turnover of cytoplasmic components, leading to hepatomegaly and accumulation of abnormal organelles. The study highlights the importance of autophagy in cellular homeostasis and its role in the pathogenesis of various diseases.Autophagy is a cellular process that degrades cytoplasmic components through lysosomes, playing a critical role in nutrient preservation during starvation and maintaining cellular homeostasis. This study investigates the role of Atg7, an essential gene for autophagy in yeast, in mice. Conditional knockout mice lacking Atg7 were generated to examine autophagy function. Atg7 is essential for ATG conjugation systems, and its deficiency leads to impaired autophagosome formation and starvation-induced degradation of proteins and organelles. Atg7-deficient mice exhibit reduced body weight, early death, and accumulation of abnormal organelles and ubiquitinated proteins. These findings suggest that autophagy is crucial for the clearance of ubiquitin-positive aggregates and the maintenance of cellular homeostasis during starvation. In adult mice, Atg7 deficiency impairs autophagosome formation and the constitutive turnover of cytoplasmic components, leading to hepatomegaly and accumulation of abnormal organelles. The study highlights the importance of autophagy in cellular homeostasis and its role in the pathogenesis of various diseases.