Strategic Research Centre for Molecular and Medical Research and Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, 3125 Victoria, Australia.
Mental Health Research Institute of Victoria, Parkville, 3052 Victoria, Australia.
J Biol Chem. 2010 Aug 27;285(35):27111-27121. doi: 10.1074/jbc.M110.154468. Epub 2010 Jun 21.
The copper-transporting P-type ATPases (Cu-ATPases), ATP7A and ATP7B, are essential for the regulation of intracellular copper homeostasis. In this report we describe new roles for glutathione (GSH) and glutaredoxin1 (GRX1) in Cu homeostasis through their regulation of Cu-ATPase activity. GRX1 is a thiol oxidoreductase that catalyzes the reversible reduction of GSH-mixed disulfides to their respective sulfhydryls (deglutathionylation). Here, we demonstrated that glutathionylation of the Cu-ATPases and their interaction with GRX1 were affected by alterations in Cu levels. The data support our hypothesis that the Cu-ATPases serve as substrates for Cu-dependent GRX1-mediated deglutathionylation. This in turn liberates the Cu-ATPase cysteinyl thiol groups for Cu binding and transport. GSH depletion experiments led to reversible inhibition of the Cu-ATPases that correlated with effects on intracellular Cu levels and GRX1 activity. Finally, knockdown of GRX1 expression resulted in an increase in intracellular Cu accumulation. Together, these data directly implicate GSH and GRX1 with important new roles in redox regulation of the Cu-ATPases, through modulation of Cu binding by the Cu-ATPase cysteine motifs.
铜转运 P 型 ATP 酶（Cu-ATPases）ATP7A 和 ATP7B 对于调节细胞内铜稳态至关重要。在本报告中，我们通过调节 Cu-ATPase 活性描述了谷胱甘肽（GSH）和谷氧还蛋白 1（GRX1）在铜稳态中的新作用。GRX1 是一种硫醇氧化还原酶，可催化 GSH-混合二硫化物可逆还原为其各自的巯基（去谷胱甘肽化）。在这里，我们证明了 Cu-ATPases 的谷胱甘肽化及其与 GRX1 的相互作用受 Cu 水平变化的影响。这些数据支持我们的假设，即 Cu-ATPases 可作为 Cu 依赖性 GRX1 介导的去谷胱甘肽化的底物。这反过来又释放了 Cu-ATPase 半胱氨酸巯基，用于 Cu 结合和运输。GSH 耗竭实验导致 Cu-ATPases 可逆抑制，这与细胞内 Cu 水平和 GRX1 活性的影响相关。最后，GRX1 表达的敲低导致细胞内 Cu 积累增加。总之，这些数据直接表明 GSH 和 GRX1 通过调节 Cu-ATPase 半胱氨酸基序的 Cu 结合，在 Cu-ATPase 的氧化还原调节中具有重要的新作用。
