Fat-specific protein 27, a novel lipid droplet protein that enhances triglyceride storage.
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.
Puri
Vishwajeet
V
Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Konda
Silvana
S
Ranjit
Srijana
S
Aouadi
Myriam
M
Chawla
Anil
A
Chouinard
My
M
Chakladar
Abhijit
A
Czech
Michael P
MP
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D050156:Adipogenesis / Q000502:physiology*; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000378:metabolism; D052436:Adipose Tissue, White / Q000166:cytology / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins; D002522:Chlorocebus aethiops; D008066:Lipolysis / Q000502:physiology*; D008297:Male; D051379:Mice; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014280:Triglycerides / Q000378:metabolism*
D002352:Carrier Proteins; D000070778:Perilipin-1; D010750:Phosphoproteins; D011506:Proteins; D014280:Triglycerides; C525805:fat-specific protein 27, mouse