Separation and characterization of the activated pool of colony-stimulating factor 1 receptor forming distinct multimeric complexes with signalling molecules in macrophages.
Colony-stimulating factor 1 (CSF-1) triggers the activation of intracellular proteins in macrophages through selective assembly of signalling complexes. The separation of multimeric complexes of the CSF-1 receptor (CSF-1R) by anion-exchange chromatography enabled the enrichment of low-stoichiometry complexes. A significant proportion of the receptor in CSF-1-stimulated cells that neither possessed detectable ... tyrosine kinase activity nor formed complexes was separated from the receptor pool displaying autokinase activity that formed chromatographically distinct multimeric complexes. A small pool of CSF-1R formed a multimeric complex with phosphatidylinositol-3 kinase (PI-3 kinase), SHP-1, Grb2, Shc, c-Src, Cbl, and a significant number of tyrosine-phosphorylated proteins in CSF-1-stimulated cells. The complex showed a considerable amount of CSF-1R complex-associated kinase activity. A detectable level of the complex was also present in untreated cells. PI-3 kinase in the multimeric complex displayed low lipid kinase activity despite the association with several proteins. The major pool of activated CSF-1R formed transient multimeric complexes with distinctly different tyrosine-phosphorylated proteins, which included STAT3 but also PI-3 kinase, Shc, SHP-1, and Grb2. A significant level of lipid kinase activity was detected in PI-3 kinase in the latter complexes. The different specific enzyme activities of PI-3 kinase in these complexes support the notion that the activity of PI-3 kinase is modulated by its association with CSF-1R and other associated cellular proteins. Specific structural proteins associated with the separate CSF-1R multimeric complexes upon CSF-1 stimulation and the presence of the distinct pools of the CSF-1R were dependent on the integrity of the microtubular network.
Mesh Terms:
Animals, Cell Line, Chromatography, Ion Exchange, Cytochalasin D, Indoleacetic Acids, Intracellular Signaling Peptides and Proteins, Macrophages, Mice, Models, Biological, Nocodazole, Phosphatidylinositol 3-Kinases, Phosphorylation, Phosphotransferases, Precipitin Tests, Protein Conformation, Protein Tyrosine Phosphatase, Non-Receptor Type 11, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Protein Tyrosine Phosphatases, Receptors, Colony-Stimulating Factor, Signal Transduction, Subcellular Fractions, Time Factors, Tyrosine
Animals, Cell Line, Chromatography, Ion Exchange, Cytochalasin D, Indoleacetic Acids, Intracellular Signaling Peptides and Proteins, Macrophages, Mice, Models, Biological, Nocodazole, Phosphatidylinositol 3-Kinases, Phosphorylation, Phosphotransferases, Precipitin Tests, Protein Conformation, Protein Tyrosine Phosphatase, Non-Receptor Type 11, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Protein Tyrosine Phosphatases, Receptors, Colony-Stimulating Factor, Signal Transduction, Subcellular Fractions, Time Factors, Tyrosine
Mol. Cell. Biol.
Date: Jun. 01, 1999
PubMed ID: 10330148
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