Perilipins, members of the PAT protein family (named after lipid droplet proteins Perilipin, Adipophilin, and TIP47) are found exclusively at the surface of lipid droplets in adipocytes and steroidogenic cells. They have been suggested to function as regulators of lipolysis and triacylglycerol storage within adipose tissue. Four distinct isoforms ranging from perilipin A (57 kDa) to perilipin D (26 kDa) have been identified and they share an identical amino terminal sequences, and contain