Abstract
Modulation of voltage-gated Ca(2+) channels controls activities of excitable cells. We show that high-voltage activated Ca(2+) channels are regulated by membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) with different sensitivities. Plasma membrane PIP(2) depletion by rapamycin-induced translocation of an inositol lipid 5-phosphatase or by a voltage-sensitive 5-phosphatase (VSP) suppresses Ca(V)1.2 and Ca(V)1.3 channel currents by approximately 35% and Ca(V)2.1 and Ca(V)2.2 currents by 29% and 55%, respectively. Other Ca(V) channels are less sensitive. Inhibition is not relieved by strong depolarizing prepulses. It changes the voltage dependence of channel gating little. Recovery of currents from inhibition needs intracellular hydrolysable ATP, presumably for PIP(2) resynthesis. When PIP(2) is increased by overexpressing PIP 5-kinase, activation and inactivation of Ca(V)2.2 current slow and voltage-dependent gating shifts to slightly higher voltages. Thus, endogenous membrane PIP(2) supports high-voltage activated L-, N-, and P/Q-type Ca(2+) channels, and stimuli that activate phospholipase C deplete PIP(2) and reduce those Ca(2+) channel currents.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adenosine Triphosphate / analogs & derivatives
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Adenosine Triphosphate / metabolism
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Adenosine Triphosphate / pharmacology
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Barium / pharmacology
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Biophysics
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Calcium / metabolism
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Calcium Channels, L-Type / genetics
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Calcium Channels, L-Type / physiology*
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Cell Line, Transformed
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Chelating Agents / pharmacology
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Egtazic Acid / analogs & derivatives
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Egtazic Acid / pharmacology
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Electric Stimulation / methods
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Fluorescence Resonance Energy Transfer / methods
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Green Fluorescent Proteins / genetics
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Humans
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Immunosuppressive Agents / pharmacology
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Ion Channel Gating / drug effects
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Ion Channel Gating / genetics
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Ion Channel Gating / physiology*
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Membrane Potentials / drug effects
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Membrane Potentials / genetics
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Muscarinic Agonists / pharmacology
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Oxotremorine / pharmacology
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Patch-Clamp Techniques / methods
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Phosphatidylinositol 4,5-Diphosphate / metabolism*
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Phosphoric Monoester Hydrolases / genetics
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Phosphoric Monoester Hydrolases / pharmacology
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Sirolimus / pharmacology
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Time Factors
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Transfection
Substances
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CACNA1D protein, human
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Calcium Channels, L-Type
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Chelating Agents
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Immunosuppressive Agents
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L-type calcium channel alpha(1C)
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Muscarinic Agonists
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Phosphatidylinositol 4,5-Diphosphate
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Green Fluorescent Proteins
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Barium
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5'-adenylyl (beta,gamma-methylene)diphosphonate
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Egtazic Acid
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Oxotremorine
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Adenosine Triphosphate
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voltage-sensor-containing phosphatase, Ciona intestinalis
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Phosphoric Monoester Hydrolases
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1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
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Calcium
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Sirolimus