Plin1, encoding perilipin-1, is a member of the PAT protein family related to lipid droplet surface proteins. It coats lipid droplets in adipocytes, playing a vital role in droplet formation, triglyceride storage, and lipolysis. Phosphorylation of PLIN1 is crucial in adipose tissue lipolysis and fat storage in adipocytes. It is also involved in pathways like AMPK, Wnt, and PPAR signaling which are related to fat proliferation and differentiation [2].

In genetic studies, PLIN1 haploinsufficiency, rather than causing lipodystrophy as previously thought, leads to a favorable metabolic profile. Individuals with PLIN1 protein-truncating variants (PTVs) have increased high-density lipoprotein cholesterol, reduced triglycerides, waist-to-hip ratio, and systolic blood pressure, and a reduced risk of myocardial infarction and hypertension [1]. Also, in chicken preadipocytes, knockout of PLIN1 decreased differentiation ability and early apoptotic activity while increasing proliferation ability, and had differential effects on lipolysis under basal and hormone-stimulated conditions [3].

In conclusion, Plin1 is essential for lipid metabolism in adipocytes, regulating processes like lipolysis and fat storage. Studies with gene knockout models, especially in chicken preadipocytes, have provided insights into its role in cell proliferation, apoptosis, and differentiation. Additionally, understanding Plin1 haploinsufficiency has implications for cardiovascular disease prevention as it seems to confer a beneficial metabolic profile [1,3].