rdf:type |
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lifeskim:mentions |
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pubmed:issue |
4
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pubmed:dateCreated |
2008-4-1
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pubmed:abstractText |
The luminal Ca2+ regulation of cardiac ryanodine receptor (RyR2) was explored at the single channel level. The luminal Ca2+ and Mg2+ sensitivity of single CSQ2-stripped and CSQ2-associated RyR2 channels was defined. Action of wild-type CSQ2 and of two mutant CSQ2s (R33Q and L167H) was also compared. Two luminal Ca2+ regulatory mechanism(s) were identified. One is a RyR2-resident mechanism that is CSQ2 independent and does not distinguish between luminal Ca2+ and Mg2+. This mechanism modulates the maximal efficacy of cytosolic Ca2+ activation. The second luminal Ca2+ regulatory mechanism is CSQ2 dependent and distinguishes between luminal Ca2+ and Mg2+. It does not depend on CSQ2 oligomerization or CSQ2 monomer Ca2+ binding affinity. The key Ca2+-sensitive step in this mechanism may be the Ca2+-dependent CSQ2 interaction with triadin. The CSQ2-dependent mechanism alters the cytosolic Ca2+ sensitivity of the channel. The R33Q CSQ2 mutant can participate in luminal RyR2 Ca2+ regulation but less effectively than wild-type (WT) CSQ2. CSQ2-L167H does not participate in luminal RyR2 Ca2+ regulation. The disparate actions of these two catecholaminergic polymorphic ventricular tachycardia (CPVT)-linked mutants implies that either alteration or elimination of CSQ2-dependent luminal RyR2 regulation can generate the CPVT phenotype. We propose that the RyR2-resident, CSQ2-independent luminal Ca2+ mechanism may assure that all channels respond robustly to large (>5 muM) local cytosolic Ca2+ stimuli, whereas the CSQ2-dependent mechanism may help close RyR2 channels after luminal Ca2+ falls below approximately 0.5 mM.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-10620297,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-10748065,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-10926870,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-11463625,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-11704930,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-11751318,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-12215490,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-12270947,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-12594204,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-12975450,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-1375450,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-14907713,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-15041652,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-15276012,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-15289928,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-15545399,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-15731387,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-15913575,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-16239337,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-16601229,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-16852978,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-16908766,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-17569730,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-17627988,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-17881003,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-1830516,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-2227093,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-2321095,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-3335548,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-3379055,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-3427023,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-3469659,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-5432063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-6147356,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-6736018,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-7473684,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-7816057,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-7867192,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-8035165,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-8550602,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-8744299,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-8781199,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-9788925,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-9826602,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18347081-9925817
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
1540-7748
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pubmed:author |
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pubmed:issnType |
Electronic
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pubmed:volume |
131
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
325-34
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:18347081-Animals,
pubmed-meshheading:18347081-Calcium,
pubmed-meshheading:18347081-Magnesium,
pubmed-meshheading:18347081-Rats,
pubmed-meshheading:18347081-Tachycardia, Ventricular,
pubmed-meshheading:18347081-Microsomes,
pubmed-meshheading:18347081-Electric Conductivity,
pubmed-meshheading:18347081-Patch-Clamp Techniques,
pubmed-meshheading:18347081-Cytosol,
pubmed-meshheading:18347081-Dimerization,
pubmed-meshheading:18347081-Sarcoplasmic Reticulum,
pubmed-meshheading:18347081-Structure-Activity Relationship,
pubmed-meshheading:18347081-Myocytes, Cardiac,
pubmed-meshheading:18347081-Lipid Bilayers,
pubmed-meshheading:18347081-Calcium Signaling
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