Regulation of PTP1B via glutathionylation of the active site cysteine 215
Regulation of PTP1B via glutathionylation of the active site cysteine 215
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DOI：
10.1021/bi990240v
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发表时间：
1999-05-18
期刊：
影响因子：
2.9
通讯作者：
Chock, PB
中科院分区：
文献类型：
--
作者：
Barrett, WC;DeGnore, JP;Chock, PB
蛋白酪氨酸磷酸酶的可逆调控是处理信号转导和调节细胞周期的重要机制。最近的报道表明，活性位点半胱氨酸残基Cys215可被可逆氧化为半胱氨酸亚磺酸衍生物（Denu and Tanner, 1998; Lee et al., 1998）。我们提出了另一种对蛋白酪氨酸磷酸酶1B （PTP1B, EC 3.1.3.48）体内调节有影响的修饰：将Cys215的谷胱甘肽化为混合蛋白二硫化物。用二胺和还原型谷胱甘肽或仅用谷胱甘肽二硫化物（GSSG）处理PTP1B，可以通过质谱检测到半胱氨酸残基被氧化成与谷胱甘肽混合的二硫化物。通过添加二硫代苏糖醇（可能是通过减少半胱氨酸二硫化物）来恢复活性。此外，失活的PTP1B被谷胱甘肽特异性去硫酶硫转移酶（glutaredoxin）酶促地重新激活，表明该磷酸酶的失活形式是谷胱甘肽基混合二硫。半胱氨酸亚砜衍生物很容易氧化为不可逆的亚砜和磺酸形式，如果不转化为更稳定和可逆的终产物，如谷胱甘肽基衍生物，则会阻碍调节效率。半胱氨酸亚砜衍生物的谷胱甘肽化将阻止酶进一步氧化为不可逆形式，并构成有效的调节机制。
The reversible regulation of protein tyrosine phosphatase is an important mechanism in processing signal transduction and regulating cell cycle. Recent reports have shown that the active site cysteine residue, Cys215, can be reversibly oxidized to a cysteine sulfenic derivative (Denu and Tanner, 1998; Lee et al., 1998). We propose an additional modification that has implications for the in vivo regulation of protein tyrosine phosphatase 1B (PTP1B, EC 3.1.3.48): the glutathionylation of Cys215 to a mixed protein disulfide. Treatment of PTP1B with diamide and reduced glutathione or with only glutathione disulfide (GSSG) results in a modification detected by mass spectrometry in which the cysteine residues are oxidized to mixed disulfides with glutathione. The activity is recovered by the addition of dithiothreitol, presumably by reducing the cysteine disulfides. In addition, inactivated PTP1B is reactivated enzymatically by the glutathione-specific dethiolase enzyme thioltransferase (glutaredoxin), indicating that the inactivated form of the phosphatase is a glutathionyl mixed disulfide. The cysteine sulfenic derivative can easily oxidize to its irreversible sulfinic and sulfonic forms and hinder the regulatory efficiency if it is not converted to a more stable and reversible end product such as a glutathionyl derivative. Glutathionylation of the cysteine sulfenic derivative will prevent the enzyme from further oxidation to its irreversible forms, and constitutes an efficient regulatory mechanism.