Circ Res. 2009 Mar 13;104(5):670-8. doi: 10.1161/CIRCRESAHA.108.188748. Epub 2009 Jan 22.
TRPC1 associates with BK(Ca) channel to form a signal complex in vascular smooth muscle cells.
Kwan, H. Y., Shen, B., Ma, X., Kwok, Y. C., Huang, Y., Man, Y. B., Yu, S., Yao, X.,
["Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, The Chinese University of Hong Kong, Hong Kong, China."]
["Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, and Department of Physiology, The Chinese University of Hong Kong, Hong Kong, China."]
TRPC1 (transient receptor potential canonical 1) is a Ca(2+)-permeable cation channel involved in diverse physiological function. TRPC1 may associate with other proteins to form a signaling complex, which is crucial for channel function. In the present study, we investigated the interaction between TRPC1 and large conductance Ca(2+)-sensitive K(+) channel (BK(Ca)). With the use of potentiometric fluorescence dye DiBAC(4)(3), we found that store-operated Ca(2+) influx resulted in membrane hyperpolarization of vascular smooth muscle cells (VSMCs). The hyperpolarization was inhibited by an anti-TRPC1 blocking antibody T1E3 and 2 BK(Ca) channel blockers, charybdotoxin and iberiotoxin. These data were confirmed by sharp microelectrode measurement of membrane potential in VSMCs of intact arteries. Furthermore, T1E3 treatment markedly enhanced the membrane depolarization and contraction of VSMCs in response to several contractile agonists including phenylephrine, endothelin-1, and U-46619. In coimmunoprecipitation experiments, an antibody against BK(Ca) alpha-subunit [BK(Ca)(alpha)] could pull down TRPC1, and moreover an anti-TRPC1 antibody could reciprocally pull down BK(Ca)(alpha). Double-labeling immunocytochemistry showed that TRPC1 and BK(Ca) were colocalized in the same subcellular regions, mainly on the plasma membrane, in VSMCs. These data suggest that, TRPC1 physically associates with BK(Ca) in VSMCs and that Ca(2+) influx through TRPC1 activates BK(Ca) to induce membrane hyperpolarization. The hyperpolarizing effect of TRPC1-BK(Ca) coupling could serve to reduce agonist-induced membrane depolarization, thereby preventing excessive contraction of VSMCs to contractile agonists.
PMID: 19168436
 Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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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 | |||
| TRPC1 |
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BKca | Inference | Prediction | 19168436 | |||||
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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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| 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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BKca | Co-immunofluorescence staining | Rat aortic vascular smooth muscle cell | 19168436 | |||||
| TRPC1 |
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BKca | Co-immunoprecipitation | HEK293 | Human | Full-length | Human | Full-length | 19168436 | |
| TRPC1 |
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BKca | Co-immunoprecipitation | Rat vascular smooth muscle cell | 19168436 | |||||
(:
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)