Reversible inactivation of the tumor suppressor PTEN by H2O2
Reversible inactivation of the tumor suppressor PTEN by H2O2
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DOI：
10.1074/jbc.m111899200
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发表时间：
2002-06-07
影响因子：
4.8
通讯作者：
Rhee, SG
中科院分区：
文献类型：
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作者：
Lee, SR;Yang, KS;Rhee, SG
肿瘤抑制因子PTEN通过去除磷酸肌醇的T-磷酸来调节细胞迁移、生长和存活。纯化的PTEN或细胞暴露于H2 O2导致PTEN以时间和H2 O2浓度依赖性方式失活。对各种半胱氨酸突变体的分析，包括胰蛋白酶肽的质谱分析，表明PTEN活性位点中的必需Cys（124）残基在H2 O2氧化过程中特异性地与Cys（71）形成二硫化物。细胞中H2 O2氧化的PTEN的还原似乎主要由硫氧还蛋白介导。因此，硫氧还蛋白是更有效的比谷氧还蛋白，谷胱甘肽，或14 kDa的硫氧还蛋白样蛋白在体外氧化的PTEN的还原。硫氧还蛋白与细胞裂解物中的PTEN共免疫沉淀;用2，4-二硝基-1-氯苯（硫氧还蛋白还原酶的抑制剂）孵育细胞延迟了氧化的PTEN的还原，而用丁硫氨酸磺酰亚胺（谷胱甘肽生物合成的抑制剂）孵育则没有。这些结果表明，H2 O2对PTEN的可逆失活可能对3 '-磷酸化磷酸肌醇的积累很重要，并且与某些病理条件相关的H2 O2的不受控制的产生可能通过抑制PTEN功能而有助于细胞增殖。
The tumor suppressor PTEN regulates cell migration, growth, and survival by removing the T-phosphate of phosphoinositides. Exposure of purified PTEN or of cells to H2O2 resulted in inactivation of PTEN in a time-and H2O2 concentration-dependent manner. Analysis of various cysteine mutants, including mass spectrometry of tryptic peptides, indicated that the essential Cys(124) residue in the active site of PTEN specifically forms a disulfide with Cys(71) during oxidation by H2O2. The reduction of H2O2-oxidized PTEN in cells appears to be mediated predominantly by thioredoxin. Thus, thioredoxin was more efficient than glutaredoxin, glutathione, or a 14-kDa thioredoxin-like protein with regard to the reduction of oxidized PTEN in vitro. Thioredoxin co-immunoprecipitated with PTEN from cell lysates; and incubation of cells with 2,4-dinitro-1-chlorobenzene (an inhibitor of thioredoxin reductase) delayed the reduction of oxidized PTEN, whereas incubation with buthioninesulfoximine (an inhibitor of glutathione biosynthesis) did not. These results suggest that the reversible inactivation of PTEN by H2O2 might be important for the accumulation of 3'-phosphorylated phosphoinositides and that the uncontrolled generation of H2O2 associated with certain pathological conditions might contribute to cell proliferation by inhibiting PTEN function.