Abstract
The elusive coupling between endoplasmic reticulum (ER) Ca2+ stores and plasma membrane (PM) "store-operated" Ca2+ entry channels was probed through a novel combination of cytoskeletal modifications. Whereas coupling was unaffected by disassembly of the actin cytoskeleton, in situ redistribution of F-actin into a tight cortical layer subjacent to the PM displaced cortical ER and prevented coupling between ER and PM Ca2+ entry channels, while not affecting inositol 1,4,5-trisphosphate-mediated store release. Importantly, disassembly of the induced cortical actin layer allowed ER to regain access to the PM and reestablish coupling of Ca2+ entry channels to Ca2+ store depletion. Coupling is concluded to be mediated by a physical "secretion-like" mechanism involving close but reversible interactions between the ER and the PM.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Actins / physiology
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Animals
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Calcium / metabolism*
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Calcium Channels / metabolism*
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Calcium Signaling / physiology*
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Cell Line, Transformed
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Cell Membrane / metabolism*
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Cell Membrane / ultrastructure
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Cells, Cultured
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Cytochalasin D / pharmacology
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Cytoskeleton / drug effects
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Cytoskeleton / physiology
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Cytoskeleton / ultrastructure
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Endoplasmic Reticulum / metabolism*
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Inositol 1,4,5-Trisphosphate / metabolism
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Ion Channel Gating / physiology*
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Ion Transport
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Marine Toxins
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Microscopy, Fluorescence
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Muscle, Smooth, Vascular / drug effects
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Muscle, Smooth, Vascular / metabolism
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Muscle, Smooth, Vascular / ultrastructure
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Okadaic Acid / pharmacology
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Oxazoles / pharmacology
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Phosphoprotein Phosphatases / antagonists & inhibitors
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Phosphoprotein Phosphatases / physiology
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Rats
Substances
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Actins
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Calcium Channels
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Marine Toxins
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Oxazoles
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Okadaic Acid
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Cytochalasin D
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calyculin A
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Inositol 1,4,5-Trisphosphate
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Phosphoprotein Phosphatases
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Calcium