perilipins

Perilipins are a family of lipid droplet–associated proteins that regulate lipid storage and mobilization in eukaryotic cells. In mammals, the perilipin family contains PLIN1 through PLIN5, with tissue‑specific expression patterns that tailor droplet dynamics to cellular energy needs.

PLIN1 (perilipin A) is abundant in adipocytes. In the basal state it coats the droplet and protects stored triglycerides from lipases. Hormonal stimulation activates protein kinase A, leading to phosphorylation of PLIN1, recruitment of hormone‑sensitive lipase and activation of adipose triglyceride lipase via CGI‑58, and enhanced lipolysis. Other perilipins have distinct roles: PLIN2 (adipophilin) is widely expressed and associates with droplets in many cell types; PLIN3 (tip47) participates in droplet formation and trafficking; PLIN4 (S3‑12) has broader but less well defined function; PLIN5 (OXPAT/MLDP) is enriched in oxidative tissues and linked to coupling lipid stores to mitochondrial oxidation.

Perilipins are regulated at the transcriptional level by nuclear receptors such as PPARs and SREBPs, and at the post‑translational level by phosphorylation, ubiquitination, and possibly other signals. Interactions with lipases and co‑factors—such as hormone‑sensitive lipase, CGI‑58/ABHD5, and ATGL—coordinate lipolysis and lipid turnover. Dysregulation of perilipin expression or function has been associated with metabolic disorders, including obesity, insulin resistance, non‑alcoholic fatty liver disease, and cardiometabolic risk.