Oxidative stress-responsive intracellular regulation specific for the angiostatic form of human tryptophanyl-tRNA synthetase.
Oxidative stress-responsive intracellular regulation specific for the angiostatic form of human tryptophanyl-tRNA synthetase.
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DOI：
10.1021/bi048313k
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发表时间：
2005-01
期刊：
影响因子：
2.9
通讯作者：
K. Wakasugi;Tomomi Nakano;I. Morishima
中科院分区：
文献类型：
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作者：
K. Wakasugi;Tomomi Nakano;I. Morishima
色氨酸-tRNA合成酶（TrpRS）在人细胞中以两种形式存在，即，一种主要形式代表全长蛋白质，另一种截短形式（miniTrpRS）由于其前mRNA的选择性剪接而缺失了NH（2）末端延伸。Mini TrpRS可以作为血管生成抑制因子，而全长TrpRS是无活性的。我们在此表明，氧化形式的人甘油醛-3-磷酸脱氢酶（GapDH）与全长和迷你TrpRS相互作用，并特异性刺激迷你，但不是全长，TrpRS的氨酰化潜力。相反，还原的GapDH不与TrpRS结合，并且不影响其氨酰化活性。诱变实验表明，GapDH的NH（2）-末端Rossmann折叠区对于其与miniTrpRS以及tRNA的相互作用以及调节其氨酰化潜力是至关重要的，并表明单体GapDH可以结合miniTrpRS并刺激其氨酰化活性。这些结果表明，血管生成抑制的人迷你，而不是全长，TrpRS可能发挥重要作用，在细胞内调节蛋白质合成的氧化应激条件下。
Tryptophanyl-tRNA synthetase (TrpRS) exists in two forms in human cells, i.e., a major form which represents the full-length protein and a truncated form (mini TrpRS) in which an NH(2)-terminal extension is deleted because of alternative splicing of its pre-mRNA. Mini TrpRS can act as an angiostatic factor, while full-length TrpRS is inactive. We herein show that an oxidized form of human glyceraldehyde-3-phosphate dehydrogenase (GapDH) interacts with both full-length and mini TrpRSs and specifically stimulates the aminoacylation potential of mini, but not full-length, TrpRS. In contrast, reduced GapDH did not bind to TrpRSs and did not influence their aminoacylation activity. Mutagenesis experiments clarified that the NH(2)-terminal Rossmann fold region of GapDH is crucial for its interaction with mini TrpRS as well as tRNA and for the regulation of its aminoacylation potential and suggested that monomeric GapDH can bind to mini TrpRS and stimulate its aminoacylation activity. These results suggest that the angiostatic human mini, but not the full-length, TrpRS may play an important role in the intracellular regulation of protein synthesis under conditions of oxidative stress.