Eukaryotic Translation Elongation Factor 1 Epsilon 1 (EEF1e1)

EEF1e1 encodes a multifunctional protein that localizes both in the cytoplasm and in the nucleus. In the cytoplasm, the encoded protein is an auxiliary component of the macromolecular aminoacyl-tRNA synthase complex. However, its mouse homolog has been shown to translocate to the nucleus in response to DNA damage and plays a positive role in ATM/ATR-mediated p53 activation. Alternative splicing results in multiple transcript variants.ATM activity was dependent on the level of p18, suggesting that p18 is required for activation of ATM. RT-PCR showed that p18 expression was low in several different human cancer cell lines and tissues. These results, as well as findings in p18 mutant mice, suggested that p18 is a haploinsufficient tumor suppressor and a key factor for ATM/ATR-mediated p53 activation.