Core Insights - The article discusses the role of Adipogenin (Adig) in lipid metabolism, highlighting its interaction with seipin to form a dodecameric complex that promotes lipid droplet development [2][3][11]. Molecular Function - Adig is a microprotein composed of 80 amino acids, highly expressed in adipose tissue and fatty liver, and is linked to leptin levels in the blood, indicating its significance in energy metabolism [2]. - The study published in Science reveals that Adig interacts with seipin to form a stable complex, which is crucial for lipid droplet formation and expansion [3][11]. Structural Insights - The seipin-Adig complex provides a structural platform for lipid droplet formation, with Adig modulating the conformation of seipin to regulate lipid storage capacity, resulting in fewer but larger lipid droplets [7][10]. - Cryo-electron microscopy analysis identified two oligomeric forms: a seipin eleven-mer and a seipin-Adig twelve-mer, with resolutions of approximately 3.2 Å and 3.0 Å, respectively [8]. Physiological Impact - The presence of the seipin-Adig complex alters triglyceride flow in the endoplasmic reticulum, leading to the formation of larger lipid droplets [10]. - In mouse models, overexpression of Adig in adipocytes promotes lipid droplet enlargement and adipose tissue expansion, while its absence reduces the number of seipin complexes and impairs triglyceride accumulation in brown adipose tissue [10][11]. Conclusion - The research establishes Adig as a key auxiliary factor that regulates seipin's function and lipid storage in adipose tissue, providing new potential intervention targets for diseases related to lipid metabolism disorders [11].