Store-operated Ca2+ entry: evidence for a secretion-like coupling model.
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.
Patterson
R L
RL
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore 21201, USA.
van Rossum
D B
DB
Gill
D L
DL
D000199:Actins / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002461:Cell Line, Transformed; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D015640:Ion Channel Gating / Q000502:physiology*; D017136:Ion Transport; D008387:Marine Toxins; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D019319:Okadaic Acid / Q000494:pharmacology; D010080:Oxazoles / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000502:physiology; D051381:Rats
D000199:Actins; D015220:Calcium Channels; D008387:Marine Toxins; D010080:Oxazoles; D019319:Okadaic Acid; D015638:Cytochalasin D; C059041:calyculin A; D015544:Inositol 1,4,5-Trisphosphate; D010749:Phosphoprotein Phosphatases; D002118:Calcium