Distinct mechanisms of activation of Stat1 and Stat3 by platelet-derived growth factor receptor in a cell-free system

Vignais, M. L., Gilman, M. (May 1999) Distinct mechanisms of activation of Stat1 and Stat3 by platelet-derived growth factor receptor in a cell-free system. Molecular and Cellular Biology, 19 (5). pp. 3727-35. ISSN 0270-7306 (Print)

URL: http://www.ncbi.nlm.nih.gov/pubmed/10207096

Abstract

Ligand-dependent activation of the platelet-derived growth factor receptor (PDGFR) in fibroblasts in culture leads to the activation of the JAK family of protein-tyrosine kinases and of the transcription factors Stat1 and Stat3. To determine the biochemical mechanism of STAT activation by PDGFR, we devised a cell-free system composed of a membrane fraction from cells overexpressing PDGFR. When supplemented with crude cytosol, the membrane fraction supported PDGF- and ATP-dependent activation of both Stat1 and Stat3. However, the extent of Stat3 activation differed depending on the source of the cytosolic fraction. Using purified recombinant STAT proteins produced in Escherichia coli, we found that Stat1 could be activated by immunopurified PDGFR and showed no additional requirement for membrane- or cytosol-derived proteins. In contrast, activation of Stat3 exhibited a strong requirement for the cytosolic fraction. The activity present in the cytosolic fraction could be depleted with antibodies to JAK proteins. We conclude that the mechanisms of activation of Stat1 and Stat3 by PDGFR are distinct. Stat1 activation appears to result from a direct interaction with the receptor, whereas Stat3 activation additionally requires JAK proteins.

Item Type: Paper
Uncontrolled Keywords: Cell Membrane/metabolism Cytosol/metabolism DNA-Binding Proteins/analysis/ metabolism Humans Phosphorylation Phosphotyrosine/analysis Precipitin Tests Protein-Tyrosine Kinase/metabolism Receptors, Platelet-Derived Growth Factor/ metabolism Recombinant Proteins/metabolism Research Support, U.S. Gov't, P.H.S. STAT1 Transcription Factor STAT3 Transcription Factor Trans-Activators/ metabolism Tumor Cells, Cultured
Subjects: bioinformatics > genomics and proteomics > small molecules > ATP
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > genes: types
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > kinase > Protein kinase C
organs, tissues, organelles, cell types and functions > tissues types and functions > transport > trans-membrane transport
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > transcription factor
CSHL Authors:
Communities: CSHL labs
Depositing User: Kathleen Darby
Date: May 1999
Date Deposited: 28 Apr 2014 15:32
Last Modified: 08 May 2014 19:03
PMCID: PMC84192
Related URLs:
URI: http://repository.cshl.edu/id/eprint/29811

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