Biochim Biophys Acta. 2011 Dec;1808(12):2789-97. doi: 10.1016/j.bbamem.2011.07.049. Epub 2011 Aug 18.
Electrophysiological properties of heteromeric TRPV4-C1 channels.
Ma, X., Nilius, B., Wong, J. W., Huang, Y., Yao, X.,
["Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China."]
["Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China."]
We previously reported that TRPV4 and TRPC1 can co-assemble to form heteromeric TRPV4-C1 channels [12]. In the present study, we characterized some basic electrophysiological properties of heteromeric TRPV4-C1 channels. 4alpha-Phorbol 12,13-didecanoate (4alpha-PDD, a TRPV4 agonist) activated a single channel current in HEK293 cells co-expressing TRPV4 and TRPC1. The activity of the channels was abrogated by a TRPC1-targeting blocking antibody T1E3. Conductance of the channels was ~95pS for outward currents and ~83pS for inward currents. The channels with similar conductance were also recorded in cells expressing TRPV4-C1 concatamers, in which assembled channels were expected to be mostly 2V4:2C1. Fluorescence Resonance Energy Transfer (FRET) experiments confirmed the formation of a protein complex with 2V4:2C1 stoichiometry while suggesting an unlikeliness of 3V4:1C1 or 1V4:3C1 stoichiometry. Monovalent cation permeability profiles were compared between heteromeric TRPV4-C1 and homomeric TRPV4 channels. For heteromeric TRPV4-C1 channels, their permeation profile was found to fit to Eisenman sequence VI, indicative of a strong field strength cation binding site, whereas for homomeric TRPV4 channels, their permeation profile corresponded to Eisenman sequence IV for a weak field strength binding site. Compared to homomeric TRPV4 channels, heteromeric TRPV4-C1 channels were slightly more permeable to Ca2+ and had a reduced sensitivity to extracellular Ca2+ inhibition. In summary, we found that, when TRPV4 and TRPC1 were co-expressed in HEK293 cells, the predominate assembly type was 2V4:2C1. The heteromeric TRPV4-C1 channels display distinct electrophysiological properties different from those of homomeric TRPV4 channels.
PMID: 21871867
 Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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Validation: In vivo validation
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| Assay with endogenous proteins | Assay with overexpressed proteins | Reference | ||||||||
| Cell or tissue | Cell or tissue | TRP channel construct | Interactor construct | |||||||
| TRP channel | Interactor | Method | Species | Region | Species | Region | ||||
| TRPC1 |
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TRPV4 | Fluorescence resonance energy transfer | HEK293 | Human | Full-length | Mouse | Full-length | 21871867 | |
| TRPV4 |
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TRPC1 | Fluorescence resonance energy transfer | HEK293 | Mouse | Full-length | Human | Full-length | 21871867 | |
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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 | ||||
| TRPC1 |
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TRPV4 | Fluorescence resonance energy transfer | 2:2 | 21871867 | |||||
| TRPV4 |
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TRPC1 | Fluorescence resonance energy transfer | 2:2 | 21871867 | |||||
(:
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)