Biochem J. 2001 May 1;355(Pt 3):663-70.
The transient receptor potential, TRP4, cation channel is a novel member of the family of calmodulin binding proteins.
Trost, C., Bergs, C., Himmerkus, N., Flockerzi, V.,
["Institut fur Pharmakologie und Toxikologie der Universitat des Saarlandes, D-66421 Homburg, Germany. claudia.trost@med-rz.uni-sb.de"]
["Institut fur Pharmakologie und Toxikologie der Universitat des Saarlandes, D-66421 Homburg, Germany. claudia.trost@med-rz.uni-sb.de"]
The mammalian gene products, transient receptor potential (trp)1 to trp7, are related to the Drosophila TRP and TRP-like ion channels, and are candidate proteins underlying agonist-activated Ca(2+)-permeable ion channels. Recently, the TRP4 protein has been shown to be part of native store-operated Ca(2+)-permeable channels. These channels, most likely, are composed of other proteins in addition to TRP4. In the present paper we report the direct interaction of TRP4 and calmodulin (CaM) by: (1) retention of in vitro translated TRP4 and of TRP4 protein solubilized from bovine adrenal cortex by CaM-Sepharose in the presence of Ca(2+), and (2) TRP4-glutathione S-transferase pull-down experiments. Two domains of TRP4, amino acid residues 688-759 and 786-848, were identified as being able to interact with CaM. The binding of CaM to both domains occurred only in the presence of Ca(2+) concentrations above 10 microM, with half maximal binding occurring at 16.6 microM (domain 1) and 27.9 microM Ca(2+) (domain 2). Synthetic peptides, encompassing the two putative CaM binding sites within these domains and covering amino acid residues 694-728 and 829-853, interacted directly with dansyl-CaM with apparent K(d) values of 94-189 nM. These results indicate that TRP4/Ca(2+)-CaM are parts of a signalling complex involved in agonist-induced Ca(2+) entry.
PMID: 11311128
 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 | ||
| TRPC4 |
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Calmodulin | Fusion protein-pull down assay | Not used | Bovine adrenal cortex lysates | Xenopus | Full-length | In vitro translation | 11311128 | |
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
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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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top
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| Characterization
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| Binding region mapping | Stoichiometry | Affinity (Kd) | Reference | |||||||
| TRP channel | Interactor | |||||||||
| TRP channel | Interactor | Method | Species | Region | Species | Region | ||||
| TRPC4 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 786-848 | Not specified | Not determined | 11311128 | ||
| TRPC4 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 688-759 | Not specified | Not determined | 11311128 | ||
| TRPC4 |
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Calmodulin | Fluorescence probe labeling | Mouse | 694-718 | Bovine | Not determined | 94 nM | 11311128 | |
| TRPC4 |
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Calmodulin | Fluorescence probe labeling | Mouse | 829-853 | Bovine | Not determined | 138 nM | 11311128 | |
| TRPC4 |
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Calmodulin | Fluorescence probe labeling | Mouse | 708-728 | Bovine | Not determined | 189 nM | 11311128 | |
(:
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)