Ubiquitin-like protein MNSFβ covalently binds to cytosolic 10-formyltetrahydrofolate dehydrogenase and regulates thymocyte function
Ubiquitin-like protein MNSFβ covalently binds to cytosolic 10-formyltetrahydrofolate dehydrogenase and regulates thymocyte function
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DOI：
10.1016/j.bbrc.2015.07.083
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发表时间：
2015-09-04
影响因子：
3.1
通讯作者：
Notsu, Kaori
中科院分区：
文献类型：
--
作者：
Nakamura, Morihiko;Watanabe, Natsuko;Notsu, Kaori
MNSF β是泛素样家族的一个广泛表达的成员，参与各种生物学功能。之前的研究表明，MNSF β与各种靶蛋白共价结合，包括促凋亡蛋白Bcl-G。在这项研究中，我们纯化了一个115 kDa的MNSF β加合物从鼠肝裂解物上的DEAE和抗MNSF β IgG偶联琼脂糖凝胶在ATP的存在下，通过连续色谱。MALDI-TOF MS指纹图谱显示，该MNSF β加合物由8.5 kDa MNSF β和10-甲酰四氢叶酸脱氢酶（FDH）组成，FDH是一种丰富的叶酸代谢酶。有趣的是，MNSF β优选结合胞质而不是线粒体FDH。MNSF β加合物的指纹分析表明，MNSF β与细胞溶质FDH结合，C-末端Gly 74和Lys 72之间存在连接。115 kDa MNSF β/FDH复合物在所检查的任何组织中均不表达，表明这种加合物形成并非普遍存在。我们发现，MNSF β/FDH复合物的形成诱导地塞米松在胸腺细胞。MNSF β和FDH的双敲低强烈减少地塞米松诱导的细胞凋亡。总之，MNSF β/FDH复合物的形成可能正调节胸腺细胞的凋亡。(C)2015爱思唯尔公司All rights reserved.
MNSF beta is a ubiquitously expressed member of the ubiquitin-like family that has been involved in various biological functions. Previous studies have demonstrated that MNSF beta covalently binds to various target proteins including Bcl-G, a proapoptotic protein. In this study, we purified a 115 kDa MNSF beta adduct from murine liver lysates by sequential chromatography on DEAE and anti-MNSF beta IgG-conjugated Sepharose in the presence of ATP. MALDI-TOF MS fingerprinting revealed that this MNSF beta adduct consists of an 8.5 kDa MNSF beta and 10-formyltetrahydrofolate dehydrogenase (FDH), an abundant enzyme of folate metabolism. Interestingly, MNSF beta preferably binds to cytosolic but not mitochondrial FDH. Fingerprinting analysis of the MNSF beta adduct demonstrate that MNSF beta conjugates to cytosolic FDH with a linkage between the C-terminal Gly74 and Lys72. The 115 kDa MNSF beta/FDH complex was not expressed in any of the tissues examined, indicating that this adduct formation is not ubiquitous. We found that MNSF beta/FDH complex formation was induced by dexamethasone in thymocytes. Double knockdown of MNSF beta and FDH strongly reduced dexamethasone-induced apoptosis. Collectively, MNSF beta/FDH complex formation may positively regulate apoptosis in thymocytes. (C) 2015 Elsevier Inc. All rights reserved.