On the endothelial cell I(SOC).
Ca2+ store depletion activates both Ca2+ selective and non-selective currents in endothelial cells. Recently, considerable progress has been made in understanding the molecular make-up and regulation of an endothelial cell thapsigargin-activated Ca2+ selective current, I(SOC). Indeed, I(SOC) is a relatively small inward Ca2+ current that exhibits an approximate +40mV reversal potential and is strongly inwardly rectifying. This current is sensitive to organization of the actin-based cytoskeleton. Transient receptor potential (TRP) proteins 1 and 4 (TRPC1 and TRPC4, respectively) each contribute to the molecular basis of I(SOC), although it is TRPC4 that appears to be tethered to the cytoskeleton through a dynamic interaction with protein 4.1. Activation of I(SOC) requires association between protein 4.1 and the actin-based cytoskeleton (mediated through spectrin), suggesting protein 4.1 mediates the physical communication between Ca2+ store depletion and channel activation. Thus, at present findings indicate a TRPC4-protein 4.1 physical linkage regulates I(SOC) activation following Ca2+ store depletion.
Cioffi
Donna L
DL
Department of Pharmacology, Center for Lung Biology, University of South Alabama College of Medicine, Mobile, AL 36688, USA.
Wu
Songwei
S
Stevens
Troy
T
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D020013:Calcium Signaling; D004594:Electrophysiology; D004730:Endothelium, Vascular / Q000166:cytology*; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013049:Spectrin / Q000378:metabolism / Q000494:pharmacology
D015220:Calcium Channels; D013049:Spectrin; D002118:Calcium