Abstract
We investigated subcellular distribution of ERK2 in osteoblast-like UMR-106 cell and explored to determine if its activities are regulated by insulin. 23%, 34% and 43% of total ERK2 were distributed in membrane, cytosol and nucleus, respectively. Insulin caused 40% increase of ERK2 content in membrane in 10 min whereas it induced approximately 50% decrease of ERK2 in cytosol in 10 min. In terms of kinase activity, insulin stimulated phosphorylation of the membrane-associated ERK2 by 2-fold and 1.8-fold in 1 min and 10 min and cytosolic ERK2 by 2.7-fold and 2.3-fold in 1 min and 10 min, respectively. In contrast, the phosphorylation of nuclear ERK2 was stimulated by insulin in time-dependent manner with maximal (3-fold) activity observed at 30 min. Insulin also increased the content of MEK2 in membrane by 2.2- to 2.6-fold in 10 min. MEK2 translocated into membrane in response to insulin may play a role in the activation of the membrane-associated ERK2 via phosphorylation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Calcium-Calmodulin-Dependent Protein Kinases / drug effects*
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism
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Cell Membrane / drug effects
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Cell Membrane / enzymology
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Cell Nucleus / drug effects
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Cell Nucleus / enzymology
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Cytosol / drug effects
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Cytosol / enzymology
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Insulin / pharmacology*
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MAP Kinase Kinase 2
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase Kinases*
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Osteoblasts / drug effects*
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Osteoblasts / enzymology*
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Phosphorylation / drug effects
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Protein Serine-Threonine Kinases / drug effects
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Protein Serine-Threonine Kinases / metabolism
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Protein-Tyrosine Kinases / drug effects
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Protein-Tyrosine Kinases / metabolism
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Rats
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Subcellular Fractions / drug effects
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Subcellular Fractions / enzymology
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Tumor Cells, Cultured
Substances
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Insulin
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Protein-Tyrosine Kinases
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Protein Serine-Threonine Kinases
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Calcium-Calmodulin-Dependent Protein Kinases
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Mitogen-Activated Protein Kinase 1
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MAP Kinase Kinase 2
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Mitogen-Activated Protein Kinase Kinases