FAM134B improves preadipocytes differentiation by enhancing mitophagy

Family with Sequence Similarity 134, Member B (FAM134B) is a protein that known to be necessary for the long-term survival of nociceptive and autonomic ganglion neurons. Recent work has exhibited 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 adipocyte differentiation. Here, we found that adipocyte-specific FAM134B overexpression mice are obese and have increased white adipose tissue (WAT) mass. Serum tests showed that they developed high glucose level and severe insulin resistance. In addition, they also exhibited enhanced autophagy and reduced mitochondria amount, suggesting the function of FAM134B to promote autophagy in adipocytes. Overexpression of FAM134B in 3 T3-L1 preadipocytes promoted autophagy and differentiation, while the effect could be inhibited after treatment with autophagyinhibitors, 3-methyladenine (3-MA). Overexpressioncells also showed an early reduction of mitochondria number, while its autophagy flux level increased fast from differentiation day 2. These findings indicate that FAM134B improves adipocytes differentiation through enhancing mitophagy.