Differential oxidation of protein-tyrosine phosphatases
Differential oxidation of protein-tyrosine phosphatases
复制标题
DOI：
10.1074/jbc.m412424200
复制
发表时间：
2005-03-18
影响因子：
4.8
通讯作者：
den Hertog, J
中科院分区：
文献类型：
--
作者：
Groen, A;Lemeer, S;den Hertog, J
氧化正在成为蛋白质酪氨酸磷酸酶（PTP）的重要调节机制。在这里，我们报告 PTP 被差异氧化，并为潜在机制提供了证据。通过使用识别 PTP (oxPTP) 中氧化催化位点半胱氨酸的抗体进行免疫探针评估，近膜 RPTP α-D1 具有催化活性，但不易氧化。相比之下，膜远端 RPTP α-D2 是一种较差的 PTP，很容易被氧化。 PTP 免疫探针和质谱分析中氧化催化位点半胱氨酸表明，Tyr(P) 环和 WPD 环中两个残基的突变逆转了 RPTP α-D1 和 RPTP α-D2 的催化活性，也逆转了氧化性，表明氧化性和催化活性是耦合的。然而，具有催化活性的 PTP1B 和 LAR-D1 很容易被氧化。氧化能力强烈依赖于pH，表明催化半胱氨酸的微环境具有重要作用。 PTP结构域的晶体结构表明，绝对保守的PTP环精氨酸的方向与PTP的氧化性相关，并且一致地，RPTP α-D1与RPTP α-D1具有相似的构象，不易被氧化。总之，PTP 在生理 pH 和 H2O2 浓度下被差异氧化，PTP 环精氨酸是氧化敏感性的重要决定因素。
Oxidation is emerging as an important regulatory mechanism of protein-tyrosine phosphatases (PTPs). Here we report that PTPs are differentially oxidized, and we provide evidence for the underlying mechanism. The membrane-proximal RPTP alpha-D1 was catalytically active but not readily oxidized as assessed by immunoprobing with an antibody that recognized oxidized catalytic site cysteines in PTPs (oxPTPs). In contrast, the membrane-distal RPTP alpha-D2, a poor PTP, was readily oxidized. Oxidized catalytic site cysteines in PTP immunoprobing and mass spectrometry demonstrated that mutation of two residues in the Tyr(P) loop and the WPD loop that reverse catalytic activity of RPTP alpha-D1 and RPTP alpha-D2 also reversed oxidizability, suggesting that oxidizability and catalytic activity are coupled. However, catalytically active PTP1B and LAR-D1 were readily oxidized. Oxidizability was strongly dependent on pH, indicating that the microenvironment of the catalytic cysteine has an important role. Crystal structures of PTP domains demonstrated that the orientation of the absolutely conserved PTP loop arginine correlates with oxidizability of PTPs, and consistently, RPTP alpha-D1, with a similar conformation as RPTP alpha-D1, was not readily oxidized. In conclusion, PTPs are differentially oxidized at physiological pH and H2O2 concentrations, and the PTP loop arginine is an important determinant for susceptibility to oxidation.