G0S2 (G0/G1 switch 2) is a small 103-amino acid protein that functions primarily as a negative regulator of lipolysis. Its best-characterized mechanism involves direct inhibition of adipose triglyceride lipase (ATGL), the rate-limiting enzyme for triglyceride hydrolysis in lipid droplets 1. G0S2 accomplishes this through direct protein-protein interaction with ATGL, preventing fatty acid mobilization from adipose tissue 2. This inhibitory function is critical for maintaining the balance between lipid storage and mobilization, with G0S2 exhibiting cyclical expression patterns between adipose tissue and liver that regulate tissue-specific fatty acid flux and whole-body energy homeostasis 2. Beyond lipolysis regulation, emerging evidence indicates G0S2 involvement in inflammatory responses. G0S2 is upregulated in moderate-high disease activity rheumatoid arthritis, where it appears as part of a proinflammatory gene signature in peripheral blood mononuclear cells 3. Additionally, G0S2 serves as a diagnostic biomarker for abdominal aortic aneurysm (AUC = 0.861-0.911) and correlates with immune cell infiltration including neutrophils, macrophages, and regulatory T cells 4. Recently, G0S2 was identified as subject to placenta-specific genomic imprinting with polymorphic expression patterns 5. G0S2 has also been identified as a diagnostic gene in diabetic nephropathy pathogenesis 6. These findings establish G0S2 as a multifunctional regulator of metabolic and immune processes with potential clinical significance in metabolic and inflammatory diseases.