Eur J Cell Biol. 2009 Mar;88(3):141-52. doi: 10.1016/j.ejcb.2008.10.002. Epub 2008 Nov 22.
Functional interaction of the cation channel transient receptor potential vanilloid 4 (TRPV4) and actin in volume regulation.
Becker, D., Bereiter-Hahn, J., Jendrach, M.,
["Institute for Cell Biology and Neuroscience, Center of Excellence Frankfurt: Macromolecular Complexes, JW Goethe University, Frankfurt/Main, Germany."]
["Institute for Cell Biology and Neuroscience, Center of Excellence Frankfurt: Macromolecular Complexes, JW Goethe University, Frankfurt/Main, Germany."]
Many vertebrate cells react to hypotonic conditions with swelling, followed by an active downregulation of the cell volume; a progress called regulatory volume decrease (RVD). While the actual process of volume decrease by loss of osmotically active molecules like K(+) and Cl(-), followed by water efflux has been extensively investigated, the signal for activation of RVD still remains obscure. Studies with different cell lines demonstrated a participation of the cation channel transient receptor potential vanilloid 4 (TRPV4) as well as the actin cytoskeleton in volume regulation. Therefore, we analyzed putative links between TRPV4 and F-actin in RVD in HaCaT keratinocytes and CHO cells. Laser scanning microscopy studies revealed a distinct colocalization of TRPV4 and actin in highly dynamic membrane structures, such as microvilli, filopodia and lamellipodia edges. After treatment of cells with the actin-destabilizing reagent latrunculin A, TRPV4 and F-actin no longer colocalized within the membrane. In accordance with these data, close interaction between TRPV4 and F-actin was revealed by FRAP and FRET studies. For functional analysis, CHO cells that endogenously do not express TRPV4, were transfected with recombinant TRPV4, which rendered them RVD-competent. Treatment with latrunculin A abolished both, RVD and the accompanying rise of [Ca(2+)](i) after hypotonic stress in TRPV4-transfected CHO cells. Taken together, our data demonstrate a functional interaction between TRPV4 and F-actin in sensing hypotonicity and the onset of RVD.
PMID: 19027987
 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 | |||
| TRPV4 |
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Ƣ-actin | Inference | Prediction | 19027987 | |||||
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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 | ||||
| TRPV4 |
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Ƣ-actin | Fluorescence resonance energy transfer | CHO | Human | Full-length | Human | Full-length | 19027987 | |
| TRPV4 |
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Ƣ-actin | Co-immunofluorescence staining | HaCaT | Human | Full-length | Not used | 19027987 | ||
(:
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)