Fat-specific protein 27, a novel lipid droplet protein that enhances triglyceride storage
Graduate School of Biomedical Sciences; Program in Molecular Medicine
Medical Subject Headings
3T3 Cells; Adipocytes; Adipogenesis; Adipose Tissue, Brown; Adipose Tissue, White; Animals; COS Cells; Cercopithecus aethiops; Lipolysis; Male; Mice; Phosphoproteins; Proteins; RNA Interference; Triglycerides
Life Sciences | Medicine and Health Sciences
Fat-specific protein (FSP)27/Cidec is most highly expressed in white and brown adipose tissues and increases in abundance by over 50-fold during adipogenesis. However, its function in adipocytes has remained elusive since its discovery over 15 years ago. Here we demonstrate that FSP27/Cidec localizes to lipid droplets in cultured adipocytes and functions to promote lipid accumulation. Ectopically expressed FSP27-GFP surrounds lipid droplets in 3T3-L1 adipocytes and colocalizes with the known lipid droplet protein perilipin. Immunostaining of endogenous FSP27 in 3T3-L1 adipocytes also confirmed its presence on lipid droplets. FSP27-GFP expression also markedly increases lipid droplet size and enhances accumulation of total neutral lipids in 3T3-L1 preadipocytes as well as other cell types such as COS cells. Conversely, RNA interference-based FSP27/Cidec depletion in mature adipocytes significantly stimulates lipolysis and reduces the size of lipid droplets. These data reveal FSP27/Cidec as a novel adipocyte lipid droplet protein that negatively regulates lipolysis and promotes triglyceride accumulation.
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Citation: J Biol Chem. 2007 Nov 23;282(47):34213-8. Epub 2007 Sep 19. Link to article on publisher's site