Department of Pharmacology, Physiology and Toxicology, JCE School of Medicine at Marshall University, Huntington, West Virginia 25755; Institute of Biomedical Engineering, Yanshan University, Qinhuangdao 066004, China.
Department of Medicine, University of Toledo College of Medicine, Toledo, Ohio 43614.
J Biol Chem. 2013 Nov 22;288(47):34249-34258. doi: 10.1074/jbc.M113.461020. Epub 2013 Oct 11.
Cardiotonic steroids (such as ouabain) signaling through Na/K-ATPase regulate sodium reabsorption in the renal proximal tubule. We report here that reactive oxygen species are required to initiate ouabain-stimulated Na/K-ATPase·c-Src signaling. Pretreatment with the antioxidant N-acetyl-L-cysteine prevented ouabain-stimulated Na/K-ATPase·c-Src signaling, protein carbonylation, redistribution of Na/K-ATPase and sodium/proton exchanger isoform 3, and inhibition of active transepithelial (22)Na(+) transport. Disruption of the Na/K-ATPase·c-Src signaling complex attenuated ouabain-stimulated protein carbonylation. Ouabain-stimulated protein carbonylation is reversed after removal of ouabain, and this reversibility is largely independent of de novo protein synthesis and degradation by either the lysosome or the proteasome pathways. Furthermore, ouabain stimulated direct carbonylation of two amino acid residues in the actuator domain of the Na/K-ATPase α1 subunit. Taken together, the data indicate that carbonylation modification of the Na/K-ATPase α1 subunit is involved in a feed-forward mechanism of regulation of ouabain-mediated renal proximal tubule Na/K-ATPase signal transduction and subsequent sodium transport.
强心甾体（如哇巴因）通过 Na/K-ATP 酶信号转导调节肾近端小管中的钠重吸收。我们在此报告，活性氧是启动哇巴因刺激的 Na/K-ATP 酶·c-Src 信号转导所必需的。抗氧化剂 N-乙酰-L-半胱氨酸预处理可防止哇巴因刺激的 Na/K-ATP 酶·c-Src 信号转导、蛋白羰基化、Na/K-ATP 酶和钠/质子交换体 3 同工型的重分布以及主动跨上皮（22）Na（+）转运的抑制。破坏 Na/K-ATP 酶·c-Src 信号转导复合物可减弱哇巴因刺激的蛋白羰基化。哇巴因刺激的蛋白羰基化在哇巴因去除后可逆转，这种逆转在很大程度上独立于溶酶体或蛋白酶体途径的从头蛋白质合成和降解。此外，哇巴因刺激 Na/K-ATP 酶α1 亚基的激活结构域中两个氨基酸残基的直接羰基化。总之，这些数据表明，Na/K-ATP 酶α1 亚基的羰基化修饰参与了哇巴因介导的肾近端小管 Na/K-ATP 酶信号转导和随后的钠转运的正反馈调节机制。
