Document Detail

Cytosolic [Ca2+] regulation of InsP3-evoked puffs.
MedLine Citation:
PMID:  23035871     Owner:  NLM     Status:  MEDLINE    
InsP3-mediated puffs are fundamental building blocks of cellular Ca2+ signalling, and arise through the concerted opening of clustered InsP3Rs (InsP3 receptors) co-ordinated via Ca2+-induced Ca2+ release. Although the Ca2+ dependency of InsP3Rs has been extensively studied at the single channel level, little is known as to how changes in basal cytosolic [Ca2+] would alter the dynamics of InsP3-evoked Ca2+ signals in intact cells. To explore this question, we expressed Ca2+-permeable channels (nicotinic acetylcholine receptors) in the plasma membrane of voltage-clamped Xenopus oocytes to regulate cytosolic [Ca2+] by changing the electrochemical gradient for extracellular Ca2+ entry, and imaged Ca2+ liberation evoked by photolysis of caged InsP3. Elevation of basal cytosolic [Ca2+] strongly increased the amplitude and shortened the latency of global Ca2+ waves. In oocytes loaded with EGTA to localize Ca2+ signals, the number of sites at which puffs were observed and the frequency and latency of puffs were strongly dependent on cytosolic [Ca2+], whereas puff amplitudes were only weakly affected. The results of the present study indicate that basal cytosolic [Ca2+] strongly affects the triggering of puffs, but has less of an effect on puffs once they have been initiated.
Michiko Yamasaki-Mann; Angelo Demuro; Ian Parker
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  The Biochemical journal     Volume:  449     ISSN:  1470-8728     ISO Abbreviation:  Biochem. J.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2012-12-10     Completed Date:  2013-02-08     Revised Date:  2014-01-09    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  England    
Other Details:
Languages:  eng     Pagination:  167-73     Citation Subset:  IM    
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MeSH Terms
Calcium / physiology*
Calcium Signaling / physiology*
Cell Membrane / physiology
Cytosol / physiology*
Inositol 1,4,5-Trisphosphate Receptors / physiology*
Xenopus laevis
Grant Support
Reg. No./Substance:
0/Inositol 1,4,5-Trisphosphate Receptors; SY7Q814VUP/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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