Cytoplasmic activation-induced cytidine deaminase (AID) exists in stoichiometric complex with translation elongation factor 1α (eEF1A)
Cytoplasmic activation-induced cytidine deaminase (AID) exists in stoichiometric complex with translation elongation factor 1α (eEF1A)
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DOI：
10.1073/pnas.1106729108
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发表时间：
2011-11-08
影响因子：
11.1
通讯作者：
Neuberger, Michael S.
中科院分区：
文献类型：
--
作者：
Haesler, Julien;Rada, Cristina;Neuberger, Michael S.
激活诱导胞苷脱氨酶 (AID) 是一种 B 淋巴细胞特异性 DNA 脱氨酶，作用于 Ig 基因座以触发抗体基因多样化。然而，大多数 AID 保留在细胞质中，并且其核丰度受到仔细调节，因为 AID 的脱靶作用会导致癌症。胞质 AID 复合物的性质以及调节其从细胞质释放并输入细胞核的机制仍然未知。在这里，我们证明 DT40 B 细胞中的胞质 AID 是 11S 复合物的一部分，并且使用内源标记的 AID 蛋白来避免过度表达伪影，它以良好的化学计量与翻译延伸因子 1 α (eEF1A) 结合。 AID/eEF1A 相互作用在转染细胞中重现，并且取决于 eEF1A 的 C 末端结构域（不负责 GTP 或 tRNA 结合）。 eEF1A 相互作用被 AID 突变破坏，影响其胞质保留。这些结果表明，eEF1A 是 AID 的胞质保留因子，并扩展了 eEF1A 的多种兼职功能。
Activation-induced cytidine deaminase (AID) is a B lymphocyte-specific DNA deaminase that acts on the Ig loci to trigger antibody gene diversification. Most AID, however, is retained in the cytoplasm and its nuclear abundance is carefully regulated because off-target action of AID leads to cancer. The nature of the cytosolic AID complex and the mechanisms regulating its release from the cytoplasm and import into the nucleus remain unknown. Here, we show that cytosolic AID in DT40 B cells is part of an 11S complex and, using an endogenously tagged AID protein to avoid overexpression artifacts, that it is bound in good stoichiometry to the translation elongation factor 1 alpha (eEF1A). The AID/eEF1A interaction is recapitulated in transfected cells and depends on the C-terminal domain of eEF1A (which is not responsible for GTP or tRNA binding). The eEF1A interaction is destroyed by mutations in AID that affect its cytosolic retention. These results suggest that eEF1A is a cytosolic retention factor for AID and extend on the multiple moonlighting functions of eEF1A.