Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington; Department of Genome Sciences, University of Washington, Seattle, Washington.
University of Massachusetts, Worcester, Massachusetts.
Mol Cell Proteomics. 2020 Jul;19(7):1104-1119. doi: 10.1074/mcp.RA120.001946. Epub 2020 Mar 31.
Stimulating brown adipose tissue (BAT) activity represents a promising therapy for overcoming metabolic diseases. mTORC2 is important for regulating BAT metabolism, but its downstream targets have not been fully characterized. In this study, we apply proteomics and phosphoproteomics to investigate the downstream effectors of mTORC2 in brown adipocytes. We compare wild-type controls to isogenic cells with an induced knockout of the mTORC2 subunit RICTOR () by stimulating each with insulin for a 30-min time course. In cells, we identify decreases to the abundance of glycolytic and lipogenesis enzymes, and increases to mitochondrial proteins as well as a set of proteins known to increase upon interferon stimulation. We also observe significant differences to basal phosphorylation because of chronic RICTOR loss including decreased phosphorylation of the lipid droplet protein perilipin-1 in cells, suggesting that RICTOR could be involved with regulating basal lipolysis or droplet dynamics. Finally, we observe mild dampening of acute insulin signaling response in cells, and a subset of AKT substrates exhibiting statistically significant dependence on RICTOR.
刺激棕色脂肪组织（BAT）的活性代表了克服代谢疾病的一种有前途的治疗方法。mTORC2 对于调节 BAT 代谢很重要，但它的下游靶点尚未完全确定。在这项研究中，我们应用蛋白质组学和磷酸蛋白质组学来研究棕色脂肪细胞中 mTORC2 的下游效应物。我们将野生型对照与诱导敲除 mTORC2 亚基 RICTOR 的同基因细胞（）进行比较，通过用胰岛素刺激每种细胞 30 分钟的时间过程。在 细胞中，我们发现糖酵解和脂肪酸生成酶的丰度降低，线粒体蛋白增加，以及一组已知在干扰素刺激时增加的蛋白质。我们还观察到由于慢性 RICTOR 缺失导致的基础磷酸化的显著差异，包括 细胞中脂滴蛋白 perilipin-1 的磷酸化减少，这表明 RICTOR 可能参与调节基础脂肪分解或液滴动力学。最后，我们观察到 细胞中急性胰岛素信号反应的轻微减弱，以及一组 AKT 底物表现出对 RICTOR 的统计学上显著的依赖性。
