Interaction of ZPR1 with translation elongation factor-1 alpha in proliferating cells

The zinc finger protein ZPR1 is present in the cytoplasm of quiescent mamma lian cells and translocates to the nucleus upon treatment with mitogens, in cluding epidermal growth factor (EGF). Homologues of ZPR1 were identified i n yeast and mammals. These ZPR1 proteins bind to eukaryotic translation elo ngation factor-1 alpha (eEF-1 alpha). Studies of mammalian cells demonstrat ed that EGF treatment induces the interaction of ZPR1 with eEF-1 alpha and the redistribution of both proteins to the nucleus. In the yeast Saccharomy ces cerevisiae, genetic analysis demonstrated that ZPR1 is an essential gen e. Deletion analysis demonstrated that the NH2-terminal region of ZPR1 is r equired for normal growth and that the COOH-terminal region was essential f or viability in S. cerevisiae. The yeast ZPR1 protein redistributes from th e cytoplasm to the nucleus in response to nutrient stimulation. Disruption of the binding of ZPR1 to eEF-1 alpha by mutational analysis resulted in an accumulation of cells in the G2/M phase of cell cycle and defective growth . Reconstitution of the ZPR1 interaction with eEF-1 alpha restored normal g rowth. We conclude that ZPR1 is essential for cell viability and that its i nteraction with eEF-1 alpha contributes to normal cellular proliferation.