|Grahn, Tan Hooi Min|
Submitted to: Biochemical and Biophysical Research Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2013
Publication Date: 3/8/2013
Citation: Grahn, T., Zhang, Y., Lee, M., Sommer, A.G., Mostoslavsky, G., Fried, S.K., Greenberg, A.S., Puri, V. 2013. FSP27 and PLIN1 interaction promotes the formation of large lipid droplets in human adipocytes. Biochemical and Biophysical Research Communications. 432(2):296-301. Interpretive Summary: Fat specific protein 27 (FSP27) and perilipin1 (PLIN1) are two proteins that coat the surface of stored fat in fat cells. We investigated whether these two proteins bind to each other and whether the presence of these two proteins on the surface of stored fat regulates the amount of fat storage. In these studies we demonstrated that these two proteins actually bind to each other. Importantly, when these two proteins bind together on the surface of stored fat in fat cells they increase the amount of fat stored. This research indicates that when FSP27 and plin1 bind to each other they prevent the fat, stored in fat cells, from being broken down.
Technical Abstract: Human adipocytes express high levels of two distinct lipid droplet proteins, fat specific protein 27 (FSP27; also called CIDEC), a member of the CIDE family, and perilipin1 (PLIN1), a member of the PAT family. Both proteins play a role in fat metabolism in adipocytes, but how they interact is not known. Our present study demonstrates that FSP27 and PLIN1 co-localize and interact in cultured human primary adipocytes. We also found that the C-terminal domain of FSP27, aa 120-220, interacts with PLIN1. Individual expression of exogenous FSP27 or PLIN1 increased triglyceride content and decreased glycerol release (a measure of lipolysis), but co-expression of both proteins did not further increase triglyceride content or decrease lipolysis in human adipocytes. However, the combination of PLIN1 and FSP27 increased the average size of lipid droplets or caused the formation of unilocular adipocytes. Our data suggest that FSP27 interacts with PLIN1 to regulate lipid droplet size in human adipocytes in a concerted manner.