Li Tianxia, Liu Jingnan, Smith Wanli W
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States of America.
PLoS One. 2014 Dec 29;9(12):e115233. doi: 10.1371/journal.pone.0115233. eCollection 2014.
Recent studies have suggested that synphilin-1, a cytoplasmic protein, is involved in energy homeostasis. Overexpression of synphilin-1 in neurons results in hyperphagia and obesity in animal models. However, the mechanism by which synphilin-1 alters energy homeostasis is unknown. Here, we used cell models and biochemical approaches to investigate the cellular functions of synphilin-1 that may affect energy balance. Synphilin-1 was pulled down by ATP-agarose beads, and the addition of ATP and ADP reduced this binding, indicating that synphilin-1 bound ADP and ATP. Synphilin-1 also bound GMP, GDP, and GTP but with a lower affinity than it bound ATP. In contrast, synphilin-1 did not bind with CTP. Overexpression of synphilin-1 in HEK293T cells significantly increased cellular ATP levels. Genetic alteration to abolish predicted ATP binding motifs of synphilin-1 or knockdown of synphilin-1 by siRNA reduced cellular ATP levels. Together, these data demonstrate that synphilin-1 binds and regulates the cellular energy molecule, ATP. These findings provide a molecular basis for understanding the actions of synphilin-1 in energy homeostasis.
最近的研究表明，细胞质蛋白α-突触核蛋白-1参与能量稳态调节。在动物模型中，神经元中α-突触核蛋白-1的过表达会导致食欲亢进和肥胖。然而，α-突触核蛋白-1改变能量稳态的机制尚不清楚。在这里，我们使用细胞模型和生化方法来研究α-突触核蛋白-1可能影响能量平衡的细胞功能。α-突触核蛋白-1被ATP琼脂糖珠拉下，添加ATP和ADP会减少这种结合，表明α-突触核蛋白-1与ADP和ATP结合。α-突触核蛋白-1也与GMP、GDP和GTP结合，但亲和力低于与ATP的结合。相比之下，α-突触核蛋白-1不与CTP结合。在HEK293T细胞中过表达α-突触核蛋白-1显著提高了细胞ATP水平。通过基因改造消除α-突触核蛋白-1预测的ATP结合基序或通过siRNA敲低α-突触核蛋白-1会降低细胞ATP水平。总之，这些数据表明α-突触核蛋白-1结合并调节细胞能量分子ATP。这些发现为理解α-突触核蛋白-1在能量稳态中的作用提供了分子基础。
