J Cell Biol. 2004 Aug 16;166(4):537-48. Epub 2004 Aug 9.
Junctate is a key element in calcium entry induced by activation of InsP3 receptors and/or calcium store depletion.
Treves, S., Franzini-Armstrong, C., Moccagatta, L., Arnoult, C., Grasso, C., Schrum, A., Ducreux, S., Zhu, M. X., Mikoshiba, K., Girard, T., Smida-Rezgui, S., Ronjat, M., Zorzato, F.,
["Department of Anesthesiology, University of Basel Kantosspital, Basel, Switzerland."]
["Department of Anesthesiology, University of Basel Kantosspital, Basel, Switzerland."]
In many cell types agonist-receptor activation leads to a rapid and transient release of Ca(2+) from intracellular stores via activation of inositol 1,4,5 trisphosphate (InsP(3)) receptors (InsP(3)Rs). Stimulated cells activate store- or receptor-operated calcium channels localized in the plasma membrane, allowing entry of extracellular calcium into the cytoplasm, and thus replenishment of intracellular calcium stores. Calcium entry must be finely regulated in order to prevent an excessive intracellular calcium increase. Junctate, an integral calcium binding protein of endo(sarco)plasmic reticulum membrane, (a) induces and/or stabilizes peripheral couplings between the ER and the plasma membrane, and (b) forms a supramolecular complex with the InsP(3)R and the canonical transient receptor potential protein (TRPC) 3 calcium entry channel. The full-length protein modulates both agonist-induced and store depletion-induced calcium entry, whereas its NH(2) terminus affects receptor-activated calcium entry. RNA interference to deplete cells of endogenous junctate, knocked down both agonist-activated calcium release from intracellular stores and calcium entry via TRPC3. These results demonstrate that junctate is a new protein involved in calcium homeostasis in eukaryotic cells.
PMID: 15302852
 Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
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Screening
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| Experimental screening | Non-experimental screening | Reference | ||||||||
| TRP channel construct | Interactor source | |||||||||
| TRP channel | Interactor | Method | Species | Region | Species | Organ/tissue | Sample type | |||
| TRPC3 |
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Junctate | Inference | Prediction | 15302852 | |||||
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
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Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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| Validation: In vitro validation
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| Assay with recombinant proteins | Reference | |||||||||
| TRP channel construct | Interactor construct | |||||||||
| TRP channel | Interactor | Method | Species | Region | Expression system | Species | Region | Expression system | ||
| TRPC3 |
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Junctate | Fusion protein-pull down assay | Bovine | Full-length | HEK293 lysates | Not specified | 1-85 | Not specified | 15302852 |
(:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
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Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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top
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| Functional consequence
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| TRP channel | Interactor | Method | Post-translational modification | Subcellular trafficking | Activity | Reference | ||||||
| TRPC3 |
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Junctate | Patch clamp | Activation | 15302852 | |||||||
(:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)