MAPK-dependent actin cytoskeletal reorganization underlies BK channel activation by insulin

Dervla O'Malley, Jenni Harvey

    Research output: Contribution to journalArticle

    29 Citations (Scopus)

    Abstract

    Numerous brain regions are enriched with insulin and insulin receptors, and several lines of evidence indicate that insulin is an important modulator of neuronal function. Indeed, recent studies have demonstrated that insulin inhibits hippocampal epileptiform-like activity, in part by activating large-conductance Ca2+-activated potassium (BK) channels. Moreover, the mitogen-activated protein kinase (MAPK) signalling cascade has been found to couple insulin to BK channel activation. However, the cellular events downstream of MAPK that underlie this action of insulin are unknown. Here we demonstrate that in hippocampal neurons, BK channel activation by insulin is blocked by actin filament stabilization, suggesting that this process is dependent on the actin cytoskeleton. Stabilizing actin filaments also markedly attenuated the ability of insulin to inhibit the aberrant hippocampal synaptic activity evoked following Mg2+ removal. Insulin also promoted rapid reorganization of fluorescently labelled polymerized actin filaments; an action that was prevented by inhibitors of MAPK activation. Moreover, in parallel studies, insulin increased the level of phospho-MAPK immunostaining in hippocampal neurons. These data are consistent with BK channel activation by insulin involving MAPK-dependent alterations in actin dynamics. This process may have important implications for the role of insulin in regulating hippocampal excitability.
    Original languageEnglish
    Pages (from-to)673-682
    Number of pages10
    JournalEuropean Journal of Neuroscience
    Volume25
    Issue number3
    DOIs
    Publication statusPublished - 2007

    Fingerprint

    Large-Conductance Calcium-Activated Potassium Channels
    Mitogen-Activated Protein Kinases
    Actins
    Insulin
    Actin Cytoskeleton
    Neurons
    Potassium Channels
    Insulin Receptor

    Keywords

    • Actin Cytoskeleton
    • Animals
    • Antineoplastic Agents
    • Cells, Cultured
    • Depsipeptides
    • Electrophysiology
    • Epilepsy
    • Hippocampus
    • Hypoglycemic Agents
    • Insulin
    • Large-Conductance Calcium-Activated Potassium Channels
    • MAP Kinase Signaling System
    • Membrane Potentials
    • Neurons
    • Phosphorylation
    • Rats

    Cite this

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    abstract = "Numerous brain regions are enriched with insulin and insulin receptors, and several lines of evidence indicate that insulin is an important modulator of neuronal function. Indeed, recent studies have demonstrated that insulin inhibits hippocampal epileptiform-like activity, in part by activating large-conductance Ca2+-activated potassium (BK) channels. Moreover, the mitogen-activated protein kinase (MAPK) signalling cascade has been found to couple insulin to BK channel activation. However, the cellular events downstream of MAPK that underlie this action of insulin are unknown. Here we demonstrate that in hippocampal neurons, BK channel activation by insulin is blocked by actin filament stabilization, suggesting that this process is dependent on the actin cytoskeleton. Stabilizing actin filaments also markedly attenuated the ability of insulin to inhibit the aberrant hippocampal synaptic activity evoked following Mg2+ removal. Insulin also promoted rapid reorganization of fluorescently labelled polymerized actin filaments; an action that was prevented by inhibitors of MAPK activation. Moreover, in parallel studies, insulin increased the level of phospho-MAPK immunostaining in hippocampal neurons. These data are consistent with BK channel activation by insulin involving MAPK-dependent alterations in actin dynamics. This process may have important implications for the role of insulin in regulating hippocampal excitability.",
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    language = "English",
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    MAPK-dependent actin cytoskeletal reorganization underlies BK channel activation by insulin. / O'Malley, Dervla; Harvey, Jenni.

    In: European Journal of Neuroscience, Vol. 25, No. 3, 2007, p. 673-682.

    Research output: Contribution to journalArticle

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    AU - Harvey, Jenni

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    AB - Numerous brain regions are enriched with insulin and insulin receptors, and several lines of evidence indicate that insulin is an important modulator of neuronal function. Indeed, recent studies have demonstrated that insulin inhibits hippocampal epileptiform-like activity, in part by activating large-conductance Ca2+-activated potassium (BK) channels. Moreover, the mitogen-activated protein kinase (MAPK) signalling cascade has been found to couple insulin to BK channel activation. However, the cellular events downstream of MAPK that underlie this action of insulin are unknown. Here we demonstrate that in hippocampal neurons, BK channel activation by insulin is blocked by actin filament stabilization, suggesting that this process is dependent on the actin cytoskeleton. Stabilizing actin filaments also markedly attenuated the ability of insulin to inhibit the aberrant hippocampal synaptic activity evoked following Mg2+ removal. Insulin also promoted rapid reorganization of fluorescently labelled polymerized actin filaments; an action that was prevented by inhibitors of MAPK activation. Moreover, in parallel studies, insulin increased the level of phospho-MAPK immunostaining in hippocampal neurons. These data are consistent with BK channel activation by insulin involving MAPK-dependent alterations in actin dynamics. This process may have important implications for the role of insulin in regulating hippocampal excitability.

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