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

Gangwani L, Mikrut M, Galcheva-Gargova Z, Davis RJ - J. Cell Biol. (1998)

Bottom Line: The yeast ZPR1 protein redistributes from the cytoplasm to the nucleus in response to nutrient stimulation.Disruption of the binding of ZPR1 to eEF-1alpha 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-1alpha restored normal growth.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute and Program in Molecular Medicine, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

ABSTRACT
The zinc finger protein ZPR1 is present in the cytoplasm of quiescent mammalian cells and translocates to the nucleus upon treatment with mitogens, including epidermal growth factor (EGF). Homologues of ZPR1 were identified in yeast and mammals. These ZPR1 proteins bind to eukaryotic translation elongation factor-1alpha (eEF-1alpha). Studies of mammalian cells demonstrated that EGF treatment induces the interaction of ZPR1 with eEF-1alpha and the redistribution of both proteins to the nucleus. In the yeast Saccharomyces cerevisiae, genetic analysis demonstrated that ZPR1 is an essential gene. Deletion analysis demonstrated that the NH2-terminal region of ZPR1 is required for normal growth and that the COOH-terminal region was essential for viability in S. cerevisiae. The yeast ZPR1 protein redistributes from the cytoplasm to the nucleus in response to nutrient stimulation. Disruption of the binding of ZPR1 to eEF-1alpha 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-1alpha restored normal growth. We conclude that ZPR1 is essential for cell viability and that its interaction with eEF-1alpha contributes to normal cellular proliferation.

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Redistribution of  ZPR1 in the yeast S. cerevisiae. The haploid yeast strain  MY28 (Table III) examined  by fluorescence microscopy.  This yeast strain expresses  cZPR1–GFP in the absence  of wild-type cZPR1. The cells  were grown in synthetic medium with glucose (CONTROL) and starved in glucose-free medium for 12 h  (STARVED). Glucose (2%)  was added to the starved cells  and incubated for 2 h (GLUCOSE). The GFP (green)  and DAPI (blue) represents  ZPR1 and DNA, respectively. Bar, 10 μm.
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Figure 6: Redistribution of ZPR1 in the yeast S. cerevisiae. The haploid yeast strain MY28 (Table III) examined by fluorescence microscopy. This yeast strain expresses cZPR1–GFP in the absence of wild-type cZPR1. The cells were grown in synthetic medium with glucose (CONTROL) and starved in glucose-free medium for 12 h (STARVED). Glucose (2%) was added to the starved cells and incubated for 2 h (GLUCOSE). The GFP (green) and DAPI (blue) represents ZPR1 and DNA, respectively. Bar, 10 μm.

Mentions: To study the localization of cZPR1 in the yeast S. cerevisiae, a recombinant cZPR1–GFP fusion gene was constructed. The cZPR1–GFP gene complemented the loss of viability of yeast with the disrupted zpr1::LEU2 gene. These haploid yeast expressing the cZPR1–GFP fusion protein were examined by fluorescence microscopy. Control experiments demonstrated that GFP was sequestered in the vacuole of yeast expressing GFP alone (data not shown). Fig. 6 shows that the cZPR1–GFP fusion protein (green) was present mainly in the nucleus of S. cerevisiae (CONTROL). Starvation of the yeast in glucose-free medium caused the redistribution of cZPR1 from the nucleus to the cytoplasm (Fig. 6). Readdition of glucose to the starved cells induced the translocation of cZPR1 from the cytoplasm to the nucleus. The localization and redistribution of ZPR1 in response to nutrients in S. cerevisiae appears to be similar to that observed in starved and mitogen-treated mammalian cells. Therefore, it is possible that cZPR1 may function as a signaling molecule in S. cerevisiae that responds to proliferation signals.


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

Gangwani L, Mikrut M, Galcheva-Gargova Z, Davis RJ - J. Cell Biol. (1998)

Redistribution of  ZPR1 in the yeast S. cerevisiae. The haploid yeast strain  MY28 (Table III) examined  by fluorescence microscopy.  This yeast strain expresses  cZPR1–GFP in the absence  of wild-type cZPR1. The cells  were grown in synthetic medium with glucose (CONTROL) and starved in glucose-free medium for 12 h  (STARVED). Glucose (2%)  was added to the starved cells  and incubated for 2 h (GLUCOSE). The GFP (green)  and DAPI (blue) represents  ZPR1 and DNA, respectively. Bar, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132977&req=5

Figure 6: Redistribution of ZPR1 in the yeast S. cerevisiae. The haploid yeast strain MY28 (Table III) examined by fluorescence microscopy. This yeast strain expresses cZPR1–GFP in the absence of wild-type cZPR1. The cells were grown in synthetic medium with glucose (CONTROL) and starved in glucose-free medium for 12 h (STARVED). Glucose (2%) was added to the starved cells and incubated for 2 h (GLUCOSE). The GFP (green) and DAPI (blue) represents ZPR1 and DNA, respectively. Bar, 10 μm.
Mentions: To study the localization of cZPR1 in the yeast S. cerevisiae, a recombinant cZPR1–GFP fusion gene was constructed. The cZPR1–GFP gene complemented the loss of viability of yeast with the disrupted zpr1::LEU2 gene. These haploid yeast expressing the cZPR1–GFP fusion protein were examined by fluorescence microscopy. Control experiments demonstrated that GFP was sequestered in the vacuole of yeast expressing GFP alone (data not shown). Fig. 6 shows that the cZPR1–GFP fusion protein (green) was present mainly in the nucleus of S. cerevisiae (CONTROL). Starvation of the yeast in glucose-free medium caused the redistribution of cZPR1 from the nucleus to the cytoplasm (Fig. 6). Readdition of glucose to the starved cells induced the translocation of cZPR1 from the cytoplasm to the nucleus. The localization and redistribution of ZPR1 in response to nutrients in S. cerevisiae appears to be similar to that observed in starved and mitogen-treated mammalian cells. Therefore, it is possible that cZPR1 may function as a signaling molecule in S. cerevisiae that responds to proliferation signals.

Bottom Line: The yeast ZPR1 protein redistributes from the cytoplasm to the nucleus in response to nutrient stimulation.Disruption of the binding of ZPR1 to eEF-1alpha 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-1alpha restored normal growth.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute and Program in Molecular Medicine, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

ABSTRACT
The zinc finger protein ZPR1 is present in the cytoplasm of quiescent mammalian cells and translocates to the nucleus upon treatment with mitogens, including epidermal growth factor (EGF). Homologues of ZPR1 were identified in yeast and mammals. These ZPR1 proteins bind to eukaryotic translation elongation factor-1alpha (eEF-1alpha). Studies of mammalian cells demonstrated that EGF treatment induces the interaction of ZPR1 with eEF-1alpha and the redistribution of both proteins to the nucleus. In the yeast Saccharomyces cerevisiae, genetic analysis demonstrated that ZPR1 is an essential gene. Deletion analysis demonstrated that the NH2-terminal region of ZPR1 is required for normal growth and that the COOH-terminal region was essential for viability in S. cerevisiae. The yeast ZPR1 protein redistributes from the cytoplasm to the nucleus in response to nutrient stimulation. Disruption of the binding of ZPR1 to eEF-1alpha 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-1alpha restored normal growth. We conclude that ZPR1 is essential for cell viability and that its interaction with eEF-1alpha contributes to normal cellular proliferation.

Show MeSH
Related in: MedlinePlus