Adipocyte differentiation‐related protein reduces lipid droplet association of adipose triglyceride lipase and slows triacylglycerol turnover

Despite the ubiquity of neutral lipid storage droplets and their importance in obesity, very little is known about how their synthesis and turnover are controlled. A major candidate for regulating these processes is adipocyte differentiation‐related protein (ADRP; also known as adipophilin). To determine the mechanism through which ADRP affects lipid storage, we stably expressed the protein in HEK 293 cells. ADRP was targeted to the surface of lipid droplets in 293 cells and increased triacylglycerol (TAG) mass under both unsupplemented and oleate‐supplemented conditions. At least part of the increased mass resulted from a 2‐fold decrease in the rate of TAG hydrolysis in ADRP‐expressing cells. Furthermore, ADRP expression induced a significant decrease in association of adipose triglyceride lipase (ATGL) with lipid droplets. Reduced lipid droplet association of ATGL and/or other lipases may explain the decrease in TAG turnover observed in ADRP‐expressing cells. This work was supported by a National Institutes of Health (NIH) Ruth L. Kirschstein National Research Service Award (1 F32 GM074453‐01, to L. L. L.), and NIH grant GM47897 (to D. A. B.).