J Biol Chem. 2001 Jun 15;276(24):21303-10. Epub 2001 Apr 4.
Identification of common binding sites for calmodulin and inositol 1,4,5-trisphosphate receptors on the carboxyl termini of trp channels.
Tang, J., Lin, Y., Zhang, Z., Tikunova, S., Birnbaumer, L., Zhu, M. X.,
["Neurobiotechnology Center, Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, USA."]
["Neurobiotechnology Center, Department of Neuroscience, Ohio State University, Columbus, Ohio 43210, USA."]
Homologues of Drosophila Trp (transient receptor potential) form plasma membrane channels that mediate Ca(2+) entry following the activation of phospholipase C by cell surface receptors. Among the seven Trp homologous found in mammals, Trp3 has been shown to interact with and respond to IP(3) receptors (IP(3)Rs) for activation. Here we show that Trp4 and other Trp proteins also interact with IP(3)Rs. The IP(3)R-binding domain also interacts with calmodulin (CaM) in a Ca(2+)-dependent manner with affinities ranging from 10 nm for Trp2 to 290 nm for Trp6. In addition, other binding sites for CaM and IP(3)Rs are present in the alpha but not the beta isoform of Trp4. In the presence of Ca(2+), the Trp-IP(3)R interaction is inhibited by CaM. However, a synthetic peptide representing a Trp-binding domain of IP(3)Rs inhibited the binding of CaM to Trp3, -6, and -7 more effectively than that to Trp1, -2, -4, and -5. In inside-out membrane patches, Trp4 is activated strongly by calmidazolium, an antagonist of CaM, and a high (50 microm) but not a low (5 microm) concentration of the Trp-binding peptide of the IP(3)R. Our data support the view that both CaM and IP(3)Rs play important roles in controlling the gating of Trp-based channels. However, the sensitivity and responses to CaM and IP(3)Rs differ for each Trp.
PMID: 11290752

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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 | |||
TRPC2 |
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Calmodulin | Inference | Prediction | 11290752 | |||||
TRPC2 |
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IP3R3 | Inference | Prediction | 11290752 | |||||
TRPC3 |
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IP3R2 | Inference | Prediction | 11290752 | |||||
TRPC4 |
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Calmodulin | Inference | Prediction | 11290752 | |||||
TRPC4 |
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IP3R3 | Inference | Prediction | 11290752 | |||||
TRPC5 |
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Calmodulin | Inference | Prediction | 11290752 | |||||
TRPC5 |
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IP3R3 | Inference | Prediction | 11290752 | |||||
TRPC6 |
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Calmodulin | Inference | Prediction | 11290752 | |||||
TRPC7 |
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Calmodulin | Inference | Prediction | 11290752 | |||||
TRPC7 |
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IP3R3 | Inference | Prediction | 11290752 |
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)

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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 | Mouse | 688-974 | In vitro translation | Not specified | Not specified | Not specified | 11290752 |
TRPC4 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 688-974 | In vitro translation | Human | 669-698 | E. coli | 11290752 |
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)

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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 | ||||
TRPC1 |
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Calmodulin | Fusion protein-pull down assay | Human | 719-751 | Not specified | Not determined | 11290752 | ||
TRPC1 |
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Calmodulin | Fluorescence probe labeling | Human | 720-749 | Not specified | Not determined | 30 nM | 11290752 | |
TRPC1 |
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IP3R3 | Fusion protein-pull down assay | Human | 719-751 | Human | 669-698 | 11290752 | ||
TRPC2 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 901-936 | Not specified | Not determined | 11290752 | ||
TRPC2 |
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Calmodulin | Fluorescence probe labeling | Mouse | 905-934 | Not specified | Not determined | 10 nM | 11290752 | |
TRPC2 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 901-936 | Human | 669-698 | 11290752 | ||
TRPC3 |
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Calmodulin | Fusion protein-pull down assay | Human | 761-795 | Not specified | Not determined | 11290752 | ||
TRPC3 |
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Calmodulin | Fluorescence probe labeling | Human | 764-793 | Not specified | Not determined | 100 nM | 11290752 | |
TRPC3 |
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IP3R1 | Fusion protein-pull down assay | Mouse | 725-848 | Not specified | 654-688 | 11290752 | ||
TRPC3 |
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IP3R2 | Fusion protein-pull down assay | Mouse | 725-848 | Not specified | 675-695 | 11290752 | ||
TRPC3 |
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IP3R3 | Fusion protein-pull down assay | Human | 761-795 | Human | 669-698 | 11290752 | ||
TRPC3 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 725-848 | Human | 681-698 | 11290752 | ||
TRPC4 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 789-812 | Not specified | Not determined | 11290752 | ||
TRPC4 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 695-724 | Not specified | Not determined | 11290752 | ||
TRPC4 |
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Calmodulin | Fluorescence probe labeling | Mouse | 695-724 | Not specified | Not determined | 200 nM | 11290752 | |
TRPC4 |
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Calmodulin | Fluorescence probe labeling | Mouse | 787-812 | Not specified | Not determined | 600 nM | 11290752 | |
TRPC4 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 781-864 | Human | 669-698 | 11290752 | ||
TRPC4 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 695-724 | Human | 669-698 | 11290752 | ||
TRPC5 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 701-733 | Not specified | Not determined | 11290752 | ||
TRPC5 |
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Calmodulin | Fluorescence probe labeling | Mouse | 702-731 | Not specified | Not determined | 220 nM | 11290752 | |
TRPC5 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 701-733 | Human | 669-698 | 11290752 | ||
TRPC6 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 838-872 | Not specified | Not determined | 11290752 | ||
TRPC6 |
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Calmodulin | Fluorescence probe labeling | Mouse | 843-872 | Not specified | Not determined | 290 nM | 11290752 | |
TRPC6 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 838-872 | Human | 669-698 | 11290752 | ||
TRPC7 |
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Calmodulin | Fusion protein-pull down assay | Mouse | 766-798 | Not specified | Not determined | 11290752 | ||
TRPC7 |
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Calmodulin | Fluorescence probe labeling | Mouse | 769-798 | Not specified | Not determined | 19 nM | 11290752 | |
TRPC7 |
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IP3R3 | Fusion protein-pull down assay | Mouse | 766-798 | Human | 669-698 | 11290752 |
(
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click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
