Abstract
We have demonstrated previously that class I(A) phosphoinositide 3-kinases play a major role in regulation of interleukin-3 (IL)-3-dependent proliferation. Investigations into the downstream targets involved have identified the MAPK cascade as a target. Expression of Deltap85 and incubation with LY294002 both inhibited IL-3-induced activation of Mek, Erk1, and Erk2. This was most pronounced during the initial phase of Erk activation. The Mek inhibitor, PD98059, blocked IL-3-driven proliferation, an effect enhanced by Deltap85 expression, suggesting that inhibition of Mek and Erks by Deltap85 contributes to the decrease in IL-3-induced proliferation in these cells but that additional pathways may also be involved. To investigate the mechanism leading to decreased activation of Erks, we investigated effects on SHP2 and Gab2, both implicated in IL-3 regulation of Erk activation. Expression of Deltap85 led to a reduction in SHP2 tyrosine phosphorylation and its ability to interact with Grb2 and Gab2 but increased overall tyrosine phosphorylation of Gab2. LY294002 did not perturb SHP2 interactions, potentially related to differences in the effects of these inhibitors on levels of phosphoinositides. These results imply that the regulation of Erks by class I(A) phosphoinositide 3-kinase may contribute to IL-3-driven proliferation and that both SHP2 and Gab2 are possibly involved in this regulation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Animals
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Blood Cells / cytology
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Blood Cells / metabolism
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Cell Division / drug effects
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Cell Line
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Cell Nucleus / metabolism
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Chromones / pharmacology
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Enzyme Inhibitors / pharmacology
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Flavonoids / pharmacology
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GRB2 Adaptor Protein
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Interleukin-3 / pharmacology*
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Intracellular Signaling Peptides and Proteins
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MAP Kinase Kinase 1
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MAP Kinase Kinase 2
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Mice
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Mitogen-Activated Protein Kinase 1 / antagonists & inhibitors
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Mitogen-Activated Protein Kinase 1 / physiology*
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinase Kinases / metabolism
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Mitogen-Activated Protein Kinases / antagonists & inhibitors
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Mitogen-Activated Protein Kinases / physiology*
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Morpholines / pharmacology
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Phosphatidylinositol 3-Kinases / genetics
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Phosphatidylinositol 3-Kinases / physiology*
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Phosphoinositide-3 Kinase Inhibitors
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Phosphoproteins / physiology*
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Phosphorylation
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Protein Serine-Threonine Kinases / metabolism
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases / physiology*
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Protein-Tyrosine Kinases / metabolism
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Proteins / metabolism
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Sequence Deletion
Substances
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Adaptor Proteins, Signal Transducing
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Chromones
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Enzyme Inhibitors
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Flavonoids
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GRB2 Adaptor Protein
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Gab2 protein, mouse
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Grb2 protein, mouse
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Interleukin-3
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Intracellular Signaling Peptides and Proteins
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Morpholines
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Phosphoinositide-3 Kinase Inhibitors
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Phosphoproteins
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Proteins
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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MAP2K2 protein, human
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Protein-Tyrosine Kinases
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Protein Serine-Threonine Kinases
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 1
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MAP Kinase Kinase 2
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MAP2K1 protein, human
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Map2k1 protein, mouse
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Mitogen-Activated Protein Kinase Kinases
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PTPN6 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases
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Ptpn6 protein, mouse
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one