Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA.
Int J Mol Sci. 2020 Jun 18;21(12):4352. doi: 10.3390/ijms21124352.
A role for the cytoplasmic protein synphilin-1 in regulating energy balance has been demonstrated recently. Expression of synphilin-1 increases ATP levels in cultured cells. However, the mechanism by which synphilin-1 alters cellular energy status is unknown. Here, we used cell models and biochemical approaches to investigate the cellular functions of synphilin-1 on the AMP-activated protein kinase (AMPK) signaling pathway, which may affect energy balance. Overexpression of synphilin-1 increased AMPK phosphorylation (activation). Moreover, synphilin-1 interacted with AMPK by co-immunoprecipitation and GST (glutathione S-transferase) pull-down assays. Knockdown of synphilin-1 reduced AMPK phosphorylation. Overexpression of synphilin-1 also altered AMPK downstream signaling, i.e., a decrease in acetyl CoA carboxylase (ACC) phosphorylation, and an increase in p70S6K phosphorylation. Treatment of compound C (an AMPK inhibitor) reduced synphilin-1 binding with AMPK. In addition, compound C diminished synphilin-1-induced AMPK phosphorylation, and the increase in cellular ATP (adenosine triphosphate) levels. Our results demonstrated that synphilin-1 couples with AMPK, and they exert mutual effects on each other to regulate cellular energy status. These findings not only identify novel cellular actions of synphilin-1, but also provide new insights into the roles of synphilin-1 in regulating energy currency, ATP.
最近，研究表明细胞质蛋白 synphilin-1 在调节能量平衡中发挥作用。synphilin-1 的表达增加了培养细胞中的 ATP 水平。然而，synphilin-1 改变细胞能量状态的机制尚不清楚。在这里，我们使用细胞模型和生化方法研究了 synphilin-1 在 AMP 激活蛋白激酶（AMPK）信号通路中的细胞功能，该通路可能影响能量平衡。synphilin-1 的过表达增加了 AMPK 的磷酸化（激活）。此外，通过免疫共沉淀和 GST（谷胱甘肽 S-转移酶）下拉实验证实 synphilin-1 与 AMPK 相互作用。synphilin-1 的敲低降低了 AMPK 的磷酸化。synphilin-1 的过表达还改变了 AMPK 的下游信号通路，即乙酰辅酶 A 羧化酶（ACC）磷酸化减少，p70S6K 磷酸化增加。用化合物 C（AMPK 抑制剂）处理减少了 synphilin-1 与 AMPK 的结合。此外，化合物 C 降低了 synphilin-1 诱导的 AMPK 磷酸化以及细胞内 ATP（三磷酸腺苷）水平的增加。我们的研究结果表明，synphilin-1 与 AMPK 偶联，并相互作用调节细胞能量状态。这些发现不仅确定了 synphilin-1 的新的细胞作用，而且为 synphilin-1 在调节能量货币 ATP 中的作用提供了新的见解。
