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The induction of Egr-1 expression by v-Fps is via a protein kinase C-independent intracellular signal that is sequentially dependent upon HaRas and Raf-1.
- Source :
-
Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research [Cell Growth Differ] 1992 Oct; Vol. 3 (10), pp. 731-7. - Publication Year :
- 1992
-
Abstract
- Activating the protein-tyrosine kinase activity of v-Fps leads to the rapid transcriptional activation of the Egr-1 gene, which encodes a mitogen-responsive transcription factor. Activation of Egr-1 by v-Fps was insensitive to protein kinase C depletion, suggesting that a protein kinase C-independent signal activated by v-Fps leads to the induction of Egr-1. Expression of v-Fps in transient expression assays induced Egr-1 promoter activation. v-HaRas and v-Raf also activated the Egr-1 promoter. To characterize HaRas and Raf-1 involvement in v-Fps-induced Egr-1 expression, we used recently characterized dominant negative mutants of HaRas and Raf-1. v-Fps-induced Egr-1 promoter activation was inhibited by the dominant negative mutants of both HaRas and Raf-1. v-HaRas-induced Egr-1 promoter activation was blocked by the negative Raf-1 mutant; however, v-Raf-1-induced Egr-1 promoter activation was unaffected by the inhibitory HaRas mutant. These data suggest that v-Fps activates a protein kinase C-independent intracellular signaling pathway that is dependent on both HaRas and Raf-1, where Raf-1 functions downstream of HaRas.
- Subjects :
- Animals
Avian Sarcoma Viruses
Cell Line
Cell Line, Transformed
Cell Transformation, Viral
Early Growth Response Protein 1
Enzyme Activation
Fusion Proteins, gag-onc physiology
Gene Expression Regulation
Mutation
Promoter Regions, Genetic
Protein Kinase C physiology
Proto-Oncogene Proteins genetics
Proto-Oncogene Proteins c-raf
Rats
Recombinant Fusion Proteins biosynthesis
DNA-Binding Proteins biosynthesis
Immediate-Early Proteins
Oncogene Protein p21(ras) physiology
Protein-Tyrosine Kinases physiology
Proto-Oncogene Proteins physiology
Signal Transduction
Transcription Factors biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 1044-9523
- Volume :
- 3
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research
- Publication Type :
- Academic Journal
- Accession number :
- 1332742