Atg13, an integral part of the ULK1 kinase complex in vertebrates, is crucial for autophagy. Autophagy is an intracellular degradation process involved in recycling cytoplasmic components and removing organelles, protein aggregates, or pathogens [2]. The ULK1 complex, containing Ser/Thr kinase ULK1 and accessory proteins including Atg13, plays a key role in autophagy initiation, sensing nutritional status signals, recruiting downstream ATG proteins, and governing autophagosome formation [3].

Atg13-mediated ULK complex positively regulated autophagy and inflammation in lung epithelial cells upon PM2.5 treatment. PM2.5-downregulated ALKBH5 protein expression promoted m6A modification of Atg13 mRNA, and knockout of ALKBH5 in mice further accelerated ULK complex-regulated autophagy, inflammation, and pulmonary fibrosis, highlighting its role in PM2.5-induced pulmonary fibrosis [1]. Atg13-deficient mice die in utero, with embryos showing growth retardation and myocardial growth defects. In cultured fibroblasts, Atg13 deficiency blocks autophagosome formation at an upstream step, and deletion of Atg13 enhances sensitivity to TNF-α-induced apoptosis [4].

In conclusion, Atg13 is essential for autophagy, with its deficiency having severe impacts on embryonic development and cardiac growth. Its role in regulating autophagy-mediated inflammation in PM2.5-induced pulmonary fibrosis shows its significance in disease-related research. Studies using Atg13 knockout mouse models have provided valuable insights into its biological functions and its implications in specific disease conditions.