FAM134B promotes adipogenesis by increasing vesicular activity in porcine and 3T3-L1 adipocytes.

Abstract

Family with sequence similarity 134, Member B (FAM134B), is a cis-Golgi transmembrane protein that is known to be necessary for the long-term survival of nociceptive and autonomic ganglion neurons. Recent work has shown that FAM134B plays a pivotal role in autophagy-mediated turnover of endoplasmic reticulum (ER) membranes, tumor inhibition and lipid homeostasis. In this study, we provide mechanistic links between FAM134B and ARF-related protein 1 (ARFRP1) and further show that FAM134B resides in the Golgi apparatus. Here, we found that FAM134B increased lipid accumulation in adipocytes. Transport vehicle number and ADP-ribosylation factor (ARF) family gene expression were also increased by FAM134B overexpression, suggesting that vesicular transport activity enhanced lipid accumulation. ARF-related protein 1 (ARFRP1) is a GTPase that promotes protein trafficking. We show that FAM134B regulates the expression of ARFRP1, and the knockdown of ARFRP1 abolishes enhancement on lipid accumulation caused by FAM134B. In addition, FAM134B upregulates the PAT family protein (PAT), which associates with the lipid droplets (LDs) surface and promotes lipolysis by recruiting adipocyte triglyceride lipase (ATGL). These findings indicate that FAM134B promotes lipid accumulation and adipogenic differentiation by increasing vesicle transport activity in the Golgi apparatus and inhibiting the lipolysis of LDs.