Abstract
The mammalian ATF/CREB family of transcription factors comprises a large group of basic-region leucine zipper (bZIP) proteins whose members mediate diverse transcriptional regulatory functions. Here we report that expression of a specific mouse ATF gene, ATFx, is down-regulated in a variety of cells undergoing apoptosis following growth factor deprivation. When stably expressed in an interleukin 3 (IL-3)-dependent cell line, ATFx suppresses apoptosis resulting from cytokine deprivation. Conversely, a dominant-negative ATFx mutant induces apoptosis of cells cultured in the presence of growth factors. We also show that 24p3, a secreted lipocalin that induces apoptosis when added to hematopoietic cells, represses ATFx expression. However, constitutive expression of ATFx renders cells resistant to 24p3-mediated apoptosis. Collectively, our results indicate that ATFx is an anti-apoptotic factor, a novel role for an ATF protein.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Activating Transcription Factors
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Acute-Phase Proteins / metabolism
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Acute-Phase Proteins / pharmacology
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Animals
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Apoptosis*
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Carrier Proteins / genetics
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Carrier Proteins / physiology*
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Cell Cycle
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Cell Division
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Cell Line
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Cell Survival
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Cyclic AMP Response Element-Binding Protein
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DNA-Binding Proteins*
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Down-Regulation
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HeLa Cells
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Humans
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Interleukin-3 / pharmacology
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Leucine Zippers / genetics
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Leucine Zippers / physiology*
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Lipocalin-2
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Lipocalins
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Mice
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Oncogene Proteins / metabolism
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Oncogene Proteins / pharmacology
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Proto-Oncogene Proteins
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / physiology
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Transcription Factors / genetics
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Transcription Factors / physiology*
Substances
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ATF7 protein, human
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Activating Transcription Factors
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Acute-Phase Proteins
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Carrier Proteins
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Cyclic AMP Response Element-Binding Protein
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DNA-Binding Proteins
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Interleukin-3
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LCN2 protein, human
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Lipocalin-2
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Lipocalins
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Oncogene Proteins
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Proto-Oncogene Proteins
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Recombinant Fusion Proteins
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Transcription Factors
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Lcn2 protein, mouse