Members of the perilipin family, such as PLIN4, coat intracellular lipid storage droplets The predicted 1,348-amino acid protein is homologous to the mouse plasma membrane-associated protein S3-12. RT-PCR ELISA detected ubiquitous expression of PLIN4, with highest expression in skeletal muscle, followed by heart and liver, and lowest expression in adult whole brain. Using immunofluorescence microscopy, Wolins et al. (2003) demonstrated that supplementation of mouse adipocytes with fatty acids resulted in a shift from diffuse S3-12 cytoplasmic expression to S3-12 coating of lipid droplets on the cell periphery. Over time, Plin1 coexpression was observed. Formation of S3-12-coated droplets required glucose and fatty acids that could be incorporated into triacylglycerol and was dependent on insulin.