RyR1/SERCA1 cross-talk regulation of calcium transport in heavy sarcoplasmic reticulum vesicles

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dc.contributor.authorGilchrist, JSC
dc.contributor.authorPalahniuk, C
dc.contributor.authorAbrenica, B
dc.contributor.authorRampersad, P
dc.contributor.authorMutawe, M
dc.contributor.authorCook, T
dc.date.accessioned2007-10-09T18:29:21Z
dc.date.available2007-10-09T18:29:21Z
dc.date.issued2003-03-31
dc.description.abstractWe investigated the functional interdependence of sarco-endoplasmic reticulum Ca2+ ATPase isoform 1 and ryanodine receptor isoform 1 in heavy sarcoplasmic reticulum membranes by synchronous fluorescence determination of extravesicular Ca2+ transients and catalytic activity. Under conditions of dynamic Ca2+ exchange ATPase catalytic activity was well coordinated to ryanodine receptor activation/inactivation states. Ryanodine-induced activation of Ca2+ release channel leaks also produced marked ATPase activation in the absence of measurable increases in bulk free extravesicular Ca2+. This suggested that Ca2+ pumps are highly sensitive to Ca2+ release channel leak status and potently buffer Ca2+ ions exiting cytoplasmic openings of ryanodine receptors. Conversely, ryanodine receptor activation was dependent on Ca2+-ATPase pump activity. Ryanodine receptor activation by cytosolic Ca2+ was (i) inversely proportional to luminal Ca2+ load and (ii) dependent upon the rate of presentation of cytosolic Ca2+. Progressive Ca2+ filling coincided with progressive loss of Ca2+ sequestration rates and at a threshold loading, ryanodine-induced Ca2+ release produced small transient reversals of catalytic activity. These data indicate that attainment of threshold luminal Ca2+ loads coordinates sensitization of Ca2+ release channels with autogenic inhibition of Ca2+ pumping. This suggests that Ca2+-dependent control of Ca2+ release in intact heavy sarcoplasmic reticulum membranes involves a Ca2+-mediated "cross-talk" between sarco-endoplasmic reticulum Ca2+ ATPase isoform 1 and ryanodine receptor isoform 1.en
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dc.format.mimetypeapplication/pdf
dc.identifier.citation0008-4212; CAN J PHYSIOL PHARMACOL, MAR 2003, vol. 81, no. 3, p.301 to 310.en
dc.identifier.doihttp://dx.doi.org/10.1139/y03-035
dc.identifier.urihttp://hdl.handle.net/1993/2914
dc.language.isoengen_US
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dc.rightsopen accessen_US
dc.statusPeer revieweden
dc.subjectCa2+en
dc.subjectRyRen
dc.subjectSERCAen
dc.subjectcell nucleusen
dc.subjectFK506en
dc.subjectthapsigarginen
dc.subjectryanodineen
dc.subjectINOSITOL 1,4,5-TRISPHOSPHATE RECEPTORen
dc.subjectRYANODINE RECEPTORen
dc.subjectCA2+ CHANNELSen
dc.subjectSARCOPLASMIC-RETICULUMen
dc.subjectENDOPLASMIC-RETICULUMen
dc.subjectNUCLEAR CA2+en
dc.subjectFK506-BINDING PROTEINen
dc.subjectSKELETAL-MUSCLEen
dc.subjectRELEASE CHANNELen
dc.subjectCYTOSOLIC CA2+en
dc.titleRyR1/SERCA1 cross-talk regulation of calcium transport in heavy sarcoplasmic reticulum vesiclesen
dc.typejournal articleen_US
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