PLoS One. 2013 Aug 16;8(8):e73424. doi: 10.1371/journal.pone.0073424. eCollection 2013.
TRPP2 and TRPV4 form an EGF-activated calcium permeable channel at the apical membrane of renal collecting duct cells.
Zhang, Z. R., Chu, W. F., Song, B., Gooz, M., Zhang, J. N., Yu, C. J., Jiang, S., Baldys, A., Gooz, P., Steele, S., Owsianik, G., Nilius, B., Komlosi, P., Bell, P. D.,
["Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America."]
["Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America."]
OBJECTIVE: Regulation of apical calcium entry is important for the function of principal cells of the collecting duct. However, the molecular identity and the regulators of the transporter/channel, which is responsible for apical calcium entry and what factors regulate the calcium conduction remain unclear. METHODS AND RESULTS: We report that endogenous TRPP2 and TRPV4 assemble to form a 23-pS divalent cation-permeable non-selective ion channel at the apical membrane of renal principal cells of the collecting duct. TRPP2\TRPV4 channel complex was identified by patch-clamp, immunofluorescence and co-immunprecipitation studies in both principal cells that either possess normal cilia (cilia (+)) or in which cilia are absent (cilia (-)). This channel has distinct biophysical and pharmacological and regulatory profiles compared to either TRPP2 or TRPV4 channels. The rate of occurrence detected by patch clamp was higher in cilia (-) compared to cilia (+) cells. In addition, shRNA knockdown of TRPP2 increased the prevalence of TRPV4 channel activity while knockdown of TRPV4 resulted in TRPP2 activity and knockdown of both proteins vastly decreased the 23-pS channel activity. Epidermal growth factor (EGF) stimulated TRPP2\TRPV4 channel through the EGF receptor (EGFR) tyrosine kinase-dependent signaling. With loss of cilia, apical EGF treatment resulted in 64-fold increase in channel activity in cilia (-) but not cilia (+) cells. In addition EGF increased cell proliferation in cilia (-) cell that was dependent upon TRPP2\TRPV4 channel mediated increase in intracellular calcium. CONCLUSION: We conclude that in the absence of cilia, an EGF activated TRPP2\TRPV4 channel may play an important role in increased cell proliferation and cystogenesis.
PMID: 23977387
 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 | ||||
| TRPP1 |
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TRPV4 | Co-immunofluorescence staining | Mouse orpk collecting duct cell line | 23977387 | |||||
| TRPP1 |
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TRPV4 | Co-immunoprecipitation | Mouse inner medullary collecting duct cell | 23977387 | |||||
| TRPP1 |
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TRPV4 | Co-immunoprecipitation | Mouse orpk collecting duct cell line | 23977387 | |||||
| TRPV4 |
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TRPP1 | Co-immunofluorescence staining | Mouse orpk collecting duct cell line | 23977387 | |||||
| TRPV4 |
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TRPP1 | Co-immunoprecipitation | Mouse inner medullary collecting duct cell | 23977387 | |||||
| TRPV4 |
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TRPP1 | Co-immunoprecipitation | Mouse orpk collecting duct cell line | 23977387 | |||||
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:
click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)