J Biol Chem. 2008 Jun 27;283(26):18086-98. doi: 10.1074/jbc.M801821200. Epub 2008 Apr 29.

The human TRPV6 channel protein is associated with cyclophilin B in human placenta.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Stumpf, T., Zhang, Q., Hirnet, D., Lewandrowski, U., Sickmann, A., Wissenbach, U., Dorr, J., Lohr, C., Deitmer, J. W., Fecher-Trost, C.,
["Abteilungen Proteinfunktion/Proteomics and Allgemeine Zoologie des Fachbereichs Biologie, Technische Universitat Kaiserslautern, Kaiserslautern, Germany."]
Transcellular calcium transport in the kidney, pancreas, small intestine, and placenta is partly mediated by transient receptor potential (TRP) channels. The highly selective TRPV6 calcium channel protein is most likely important for the calcium transfer in different specialized epithelial cells. In the human placenta the protein is expressed in trophoblast tissue, where it is implicated in the transepithelial calcium transfer from mother to the fetus. We enriched the TRPV6 channel protein endogenously expressed in placenta together with annexin A2 and cyclophilin B (CypB), which is a member of the huge immunophilin family. In the human placenta TRPV6 and CypB are mainly located intracellularly in the syncytiotrophoblast layer, but a small amount of the mature glycosylated TRPV6 channel protein and CypB is also expressed in microvilli apical membranes, the fetomaternal barrier. To understand the role of CypB on the TRPV6 channel function, we evaluated the effect of CypB co-expression on TRPV6-mediated calcium uptake into Xenopus laevis oocytes expressing TRPV6. A significant increase of TRPV6-mediated calcium uptake was observed after CypB/TRPV6 co-expression. This stimulatory effect of CypB was reversed by the immunosuppressive drug cyclosporin A, which inhibits the enzymatic activity of CypB. Cyclosporin A had no significant effect on TRPV6 and CypB protein expression levels in the oocytes. In summary, our results establish CypB as a new TRPV6 accessory protein with potential involvement in TRPV6 channel activation through its peptidyl-prolyl cis/trans isomerase activity.
PMID: 18445599External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c
Screening Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Experimental screening Non-experimental screening Reference
TRP channel construct Interactor source
TRP channel Interactor Method Species Region Species Organ/tissue Sample type
TRPV5 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Inference Prediction 18445599
TRPV6 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Affinity purification-mass spectrometry Human 1-725 Human Placenta Microsomal membrane fraction 18445599
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Validation: In vivo validation Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  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
TRPV6 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Co-immunoprecipitation Human placenta 18445599
TRPV6 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Co-immunofluorescence staining Xenopus oocyte Human Full-length Human Full-length 18445599
TRPV6 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Co-immunofluorescence staining Human placenta 18445599
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Functional consequence Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
TRP channel Interactor Method Post-translational modification Subcellular trafficking Activity Reference
TRPV5 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Calcium measurement Activation 18445599
TRPV6 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Cyclophilin B Calcium measurement Activation 18445599
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

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