Methionine Sulfoxide Reductase B1 (MsrB1) Recovers TRPM6 Channel Activity during Oxidative Stress
Methionine Sulfoxide Reductase B1 (MsrB1) Recovers TRPM6 Channel Activity during Oxidative Stress
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DOI：
10.1074/jbc.m110.103655
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发表时间：
2010-08-20
影响因子：
4.8
通讯作者：
Hoenderop, Joost G. J.
中科院分区：
文献类型：
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作者：
Cao, Gang;Lee, Kyu Pil;Hoenderop, Joost G. J.
Mg2+是许多细胞过程的必需离子，包括蛋白质合成、核酸稳定性和许多酶促反应。哺乳动物体内Mg2+的平衡取决于肠道吸收、肾脏排泄和与骨骼交换之间的平衡。瞬时受体电位美拉他汀6型（TRPM6）是一种上皮Mg2+通道，在肾和肠细胞的管腔膜中大量表达。它是上皮Mg2+转运的看门人。值得注意的是，TRPM6结合了Mg2+可渗透通道和α激酶结构域。在这里，通过Ras募集系统，我们确定了蛋氨酸亚砜还原酶B1 （MsrB1）是TRPM6 α激酶结构域的一个相互作用蛋白。重要的是，MsrB1和TRPM6都存在于肾Mg2+转运远曲小管中。在常压条件下，MsrB1对TRPM6通道活性没有影响。然而，过氧化氢（H2O2）降低了TRPM6通道的活性。MsrB1与TRPM6共表达可减弱H2O2的抑制作用（TRPM6为对照组的67 +/- 5%；TRPM6 + MsrB1为对照组的81 +/- 5%）。细胞表面生物素化实验表明，H2O2处理不影响质膜上TRPM6的表达。接下来，TRPM6中Met（1755）突变为Ala，降低H2O2对TRPM6通道活性的抑制作用（TRPM6 M1755A：对照的84 +/- 10%），从而模仿MsrB1的作用。因此，这些数据表明MsrB1通过减少Met（1755）的氧化来恢复TRPM6通道活性，从而可以在氧化应激期间作为TRPM6的调节剂发挥作用。
Mg2+ is an essential ion for many cellular processes, including protein synthesis, nucleic acid stability, and numerous enzymatic reactions. Mg2+ homeostasis in mammals depends on the equilibrium between intestinal absorption, renal excretion, and exchange with bone. The transient receptor potential melastatin type 6 (TRPM6) is an epithelial Mg2+ channel, which is abundantly expressed in the luminal membrane of the renal and intestinal cells. It functions as the gatekeeper of transepithelial Mg2+ transport. Remarkably, TRPM6 combines a Mg2+-permeable channel with an alpha-kinase domain. Here, by the Ras recruitment system, we identified methionine sulfoxide reductase B1 (MsrB1) as an interacting protein of the TRPM6 alpha-kinase domain. Importantly, MsrB1 and TRPM6 are both present in the renal Mg2+-transporting distal convoluted tubules. MsrB1 has no effect on TRPM6 channel activity in the normoxic conditions. However, hydrogen peroxide (H2O2) decreased TRPM6 channel activity. Co-expression of MsrB1 with TRPM6 attenuated the inhibitory effect of H2O2 (TRPM6, 67 +/- 5% of control; TRPM6 + MsrB1, 81 +/- 5% of control). Cell surface biotinylation assays showed that H2O2 treatment does not affect the expression of TRPM6 at the plasma membrane. Next, mutation of Met(1755) to Ala in TRPM6 reduced the inhibitory effect of H2O2 on TRPM6 channel activity (TRPM6 M1755A: 84 +/- 10% of control), thereby mimicking the action of MsrB1. Thus, these data suggest that MsrB1 recovers TRPM6 channel activity by reducing the oxidation of Met(1755) and could, thereby, function as a modulator of TRPM6 during oxidative stress.