Mattè Alessandro, Federti Enrica, Tibaldi Elena, Di Paolo Maria Luisa, Bisello Giovanni, Bertoldi Mariarita, Carpentieri Andrea, Pucci Pietro, Iatchencko Iana, Wilson Anand B, Riccardi Veronica, Siciliano Angela, Turrini Francesco, Kim Dae Won, Choi Soo Young, Brunati Anna Maria, De Franceschi Lucia
Department of Medicine, University of Verona and AOUI Verona, 37134 Verona, Italy.
Department of Molecular Medicine, University of Padua, 35128 Padua, Italy.
Antioxidants (Basel). 2021 Feb 1;10(2):206. doi: 10.3390/antiox10020206.
Peroxiredoxin-2 (Prx2) is the third most abundant cytoplasmic protein in red blood cells. Prx2 belongs to a well-known family of antioxidants, the peroxiredoxins (Prxs), that are widely expressed in mammalian cells. Prx2 is a typical, homodimeric, 2-Cys Prx that uses two cysteine residues to accomplish the task of detoxifying a vast range of organic peroxides, HO, and peroxynitrite. Although progress has been made on functional characterization of Prx2, much still remains to be investigated on Prx2 post-translational changes. Here, we first show that Prx2 is Tyrosine (Tyr) phosphorylated by Syk in red cells exposed to oxidation induced by diamide. We identified Tyr-193 in both recombinant Prx2 and native Prx2 from red cells as a specific target of Syk. Bioinformatic analysis suggests that phosphorylation of Tyr-193 allows Prx2 conformational change that is more favorable for its peroxidase activity. Indeed, Syk-induced Tyr phosphorylation of Prx2 enhances in vitro Prx2 activity, but also contributes to Prx2 translocation to the membrane of red cells exposed to diamide. The biologic importance of Tyr-193 phospho-Prx2 is further supported by data on red cells from a mouse model of humanized sickle cell disease (SCD). SCD is globally distributed, hereditary red cell disorder, characterized by severe red cell oxidation due to the pathologic sickle hemoglobin. SCD red cells show Tyr-phosphorylated Prx2 bound to the membrane and increased Prx2 activity when compared to healthy erythrocytes. Collectively, our data highlight the novel link between redox related signaling and Prx2 function in normal and diseased red cells.
过氧化物酶体增殖物激活受体2（Prx2）是红细胞中含量第三丰富的细胞质蛋白。Prx2属于一个著名的抗氧化剂家族——过氧化物酶体增殖物激活受体（Prxs），在哺乳动物细胞中广泛表达。Prx2是一种典型的同源二聚体2-半胱氨酸Prx，它利用两个半胱氨酸残基来完成对多种有机过氧化物、羟基自由基和过氧亚硝酸盐的解毒任务。尽管在Prx2的功能表征方面已经取得了进展，但关于Prx2翻译后变化仍有许多有待研究的地方。在这里，我们首先表明，在暴露于二酰胺诱导的氧化作用的红细胞中，Prx2被Syk酪氨酸（Tyr）磷酸化。我们确定重组Prx2和红细胞中的天然Prx2中的Tyr-193是Syk的特异性靶点。生物信息学分析表明，Tyr-193的磷酸化使Prx2的构象发生变化，这更有利于其过氧化物酶活性。事实上，Syk诱导的Prx2的Tyr磷酸化增强了体外Prx2的活性，但也有助于Prx2转位到暴露于二酰胺的红细胞膜上。人源化镰状细胞病（SCD）小鼠模型红细胞的数据进一步支持了Tyr-193磷酸化Prx2的生物学重要性。SCD是一种全球分布的遗传性红细胞疾病，其特征是由于病理性镰状血红蛋白导致严重的红细胞氧化。与健康红细胞相比，SCD红细胞显示Tyr磷酸化的Prx2与膜结合且Prx2活性增加。总的来说，我们的数据突出了正常和患病红细胞中氧化还原相关信号与Prx2功能之间的新联系。
