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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1999-1-28
|
| pubmed:abstractText |
Calreticulin is a Ca2+ binding protein located primarily in the endoplasmic reticulum (ER) lumen of non-excitable cells, where it is considered to be involved mainly in Ca2+ storage and buffering. However, there is increasing evidence to implicate the protein in other facets of Ca2+ signalling. In this study, we sought to establish more clearly the role of the protein in the regulation of intracellular Ca2+ signalling. Generating HeLa cells stably transfected with GFP-tagged calreticulin (GFPCRT) allowed to us to select cells by FACS in which calreticulin was expressed at ten times its endogenous levels. Using transiently expressed aequorin as a Ca2+ indicator in these cells, we investigated the role of calreticulin in intracellular Ca2+ storage, IP3-mediated Ca2+ release, and capacitative Ca2+ entry. The data showed that the capacity of the ionomycin-sensitive Ca2+ store was doubled in over-expressing cells, indicating that although calreticulin has a role in Ca2+ storage within the lumen, other lumenal proteins are also likely to be involved. No difference was observed in the release of Ca2+ from the IP3-sensitive store in response to prolonged single stimulation with histamine in the absence of extracellular Ca2+, but use of short, sequential pulses of histamine and ATP revealed that calreticulin may exert an effect upon IP3-mediated Ca2+ release. Two different experimental approaches indicated that calreticulin participates in the regulation of capacitative Ca2+ entry. In the presence of extracellular Ca2+, the histamine-generated cytosolic Ca2+ signal was significantly lower in GFPCRT cells than those in control cells. Induction of capacitative Ca2+ entry by complete emptying of the store using the SERCA pump inhibitor, cyclopiazonic acid also showed that the influx component was significantly reduced in the GFPCRT cells. Use of ER-targeted apoaequorin acting as a luciferase demonstrated that the resting ER free [Ca2+] in the GFPCRT cells was lower than that in control cells. These data implicate calreticulin in the control of IP3-mediated Ca2+ release and capacitative Ca2+ entry, which may involve direct interaction with Ca2+ signalling components or control of ER free [Ca2+].
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Aequorin,
http://linkedlifedata.com/resource/pubmed/chemical/Apoproteins,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium-Binding Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Calreticulin,
http://linkedlifedata.com/resource/pubmed/chemical/Green Fluorescent Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Histamine,
http://linkedlifedata.com/resource/pubmed/chemical/Inositol 1,4,5-Trisphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Ionomycin,
http://linkedlifedata.com/resource/pubmed/chemical/Luminescent Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Fusion Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Ribonucleoproteins,
http://linkedlifedata.com/resource/pubmed/chemical/apoaequorin
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Oct
|
| pubmed:issn |
0143-4160
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
24
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
253-62
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:9883279-Adenosine Triphosphate,
pubmed-meshheading:9883279-Aequorin,
pubmed-meshheading:9883279-Apoproteins,
pubmed-meshheading:9883279-Calcium,
pubmed-meshheading:9883279-Calcium Signaling,
pubmed-meshheading:9883279-Calcium-Binding Proteins,
pubmed-meshheading:9883279-Calreticulin,
pubmed-meshheading:9883279-Endoplasmic Reticulum,
pubmed-meshheading:9883279-Flow Cytometry,
pubmed-meshheading:9883279-Green Fluorescent Proteins,
pubmed-meshheading:9883279-HeLa Cells,
pubmed-meshheading:9883279-Histamine,
pubmed-meshheading:9883279-Humans,
pubmed-meshheading:9883279-Inositol 1,4,5-Trisphosphate,
pubmed-meshheading:9883279-Ionomycin,
pubmed-meshheading:9883279-Luminescent Proteins,
pubmed-meshheading:9883279-Recombinant Fusion Proteins,
pubmed-meshheading:9883279-Recombinant Proteins,
pubmed-meshheading:9883279-Ribonucleoproteins,
pubmed-meshheading:9883279-Transfection
|
| pubmed:year |
1998
|
| pubmed:articleTitle |
Role of calreticulin in regulating intracellular Ca2+ storage and capacitative Ca2+ entry in HeLa cells.
|
| pubmed:affiliation |
Department of Medical Biochemistry, University of Wales College of Medicine, Cardiff, UK.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|