Expression and functional activity of the Na/Mg exchanger, TRPM7 and MagT1 are changed to regulate Mg homeostasis and transport in rumen epithelial cells.
Expression and functional activity of the Na/Mg exchanger, TRPM7 and MagT1 are changed to regulate Mg homeostasis and transport in rumen epithelial cells.
复制标题
Na/Mg 交换器、TRPM7 和 MagT1 的表达和功能活性发生变化，以调节瘤胃上皮细胞中镁的稳态和转运。
作者：
M. Schweigel;Martin Kolisek;Z. Nikolić;J. Kuzinski
本研究旨在揭示瘤胃上皮细胞（REC）中镁转运途径的分子特征，并探讨细胞外[Mg]变化对其表达和活性的影响。通过RT-PCR、Western blot、流式细胞术和免疫细胞化学等方法检测到TRPM 7、MagT 1和Na+/Mg ~（2+）交换蛋白（[Mg]e = 1.2 mM），MagT 1减少或增加在REC分别在低（0.12 mM）和高（5 mM）-Mg培养基中孵育24小时后，观察到Na+/Mg 2+交换剂（~ 30%; 20%）和Na+/Mg 2+交换剂（~ 25%; 40%）蛋白丰度。为了确定Mg转运能力，通过使用mag-fura 2测量[Mg 2 +]i变化。基础[Mg 2]i（0.43 +/- 0.03 mM）不受预孵育培养基[Mg]的影响。然而，与对照细胞相比，在低或高镁培养基中孵育的REC分别显示出显著降低（59%）和升高（57%）的镁挤出率。此外，它们的特征在于增加的流入能力（30-40%）。在低镁细胞中，后者主要来自于强TRPM 7相关的转运组分，而在高镁细胞中，丙咪嗪敏感的Na+/Mg 2+交换剂介导的转运组分引起这种效应。总之，TRPM 7，MagT 1和Na+/Mg 2+交换器被证明是REC中的主要镁转运蛋白，它们的表达和功能活性受细胞镁状态的影响。后者的反应允许适应上皮Mg吸收，并使REC能够维持生理[Mg 2 +]i，这是各种细胞功能的先决条件。
The present study was performed to show the molecular identity of functionally characterized Mg transport pathways in rumen epithelial cells (REC) and to investigate the effects of extracellular [Mg] changes on their expression and activity. By using RT- PCR, Western blot, flow cytometry and immunocytochemistry, TRPM7, MagT1 and a Na+/Mg2+ exchanger were found in REC. Compared with control conditions ([Mg]e = 1.2 mM), a decreased or increased MagT1 (-30%; 20%) and Na+/Mg2+ exchanger (-25%; 40%) protein abundance was observed after a 24-h incubation of REC in low (0.12 mM)- and high (5 mM)-Mg medium, respectively. To determine the Mg transport capacity, [Mg2+]i changes were measured by use of mag-fura 2. The basal [Mg2]i (0.43 +/- 0.03 mM) was not influenced by the [Mg] of the pre-incubation medium. However, compared to control cells, REC incubated in low- or high-Mg medium showed significantly reduced (59%) and elevated (57%) Mg extrusion rates, respectively. In addition, they were characterized by an increased influx capacity (30-40%). In low-Mg cells the latter results mainly from a strong TRPM7 related transport component whereas in high-Mg cells the imipramine-sensitive, the Na+/Mg2+ exchanger-mediated transport component causes this effect. In conclusion, TRPM7, MagT1 and a Na+/Mg2+ exchanger are shown to be the main Mg transport proteins in REC and their expression and functional activity is influenced by the cellular Mg status. The latter responses permit adaptation of epithelial Mg absorption and enable REC to maintain a physiological [Mg2+]i which is a prerequisite for various cell functions.
影响因子：
3.2
作者：
C. Schmitz;Francina Deason;A. Perraud
通讯作者：
C. Schmitz;Francina Deason;A. Perraud