Previous studies have suggested that phosphorylation of translation elongation factor 1A (eEF1A) can alter its function, and large-scale phospho-proteomic analyses in Saccharomyces cerevisiae have identified 14 eEF1A residues phosphorylated under various conditions. Here, a series of eEF1A mutations at these proposed sites were created and the effects on eEF1A activity were analyzed. The eEF1A-S53D and eEF1A-T430D phosphomimetic mutant strains were inviable, while corresponding alanine mutants survived but displayed defects in growth and protein synthesis. The activity of an eEF1A-S289D mutant was significantly reduced in the absence of the guanine nucleotide exchange factor eEF1Bα and could be restored by an exchange-deficient form of the protein, suggesting that eEF1Bα promotes eEF1A activity by a mechanism other than nucleotide exchange. Our data show that several of the phosphorylation sites identified by high-throughput analysis are critical for eEF1A function.

中文翻译：

---

突变分析揭示了真核延伸因子 1A 中潜在的磷酸化位点，这对其活性很重要

以前的研究表明，翻译延伸因子 1A (eEF1A) 的磷酸化可以改变其功能，并在酿酒酵母中进行大规模的磷酸化蛋白质组学分析已经确定了在各种条件下磷酸化的 14 个 eEF1A 残基。在这里，在这些提议的位点创建了一系列 eEF1A 突变，并分析了对 eEF1A 活性的影响。eEF1A-S53D 和 eEF1A-T430D 拟磷突变株是不可行的，而相应的丙氨酸突变株存活下来，但在生长和蛋白质合成方面表现出缺陷。在没有鸟嘌呤核苷酸交换因子 eEF1Bα 的情况下，eEF1A-S289D 突变体的活性显着降低，并且可以通过蛋白质的交换缺陷形式恢复，这表明 eEF1Bα 通过核苷酸交换以外的机制促进 eEF1A 活性。我们的数据表明，通过高通量分析确定的几个磷酸化位点对 eEF1A 功能至关重要。