title: The over-expression of TRPC6 channels in HEK-293 cells favours the intracellular accumulation of zinc.
abstract: TRPC6 are plasma membrane cation channels. By means of live-cell imaging and spectroscopic methods, we found that HEK cells expressing TRPC6 channels (HEK-TRPC6) are enriched in zinc and sulphur and have a reduced copper content when compared to HEK cells and HEK cells expressing TRPC3 channels (HEK-TRPC3). Hence, HEK-TRPC6 cells have larger pools of mobilizable Zn2+ and are more sensitive to an oxidative stress. Synchrotron X-ray fluorescence experiments showed a higher zinc content in the nuclear region indicating that the intracellular distribution of this metal was influenced by the over-expression of TRPC6 channels. Their properties were investigated with the diacylglycerol analogue SAG and the plant extract hyperforin. Electrophysiological recordings and imaging experiments with the fluorescent Zn2+ probe FluoZin-3 demonstrated that TRPC6 channels form Zn2+-conducting channels. In cortical neurons, hyperforin-sensitive channels co-exist with voltage-gated channels, AMPA and NMDA receptors, which are known to transport Zn2+. The ability of these channels to regulate the size of the mobilizable pools of Zn2+ was compared. The data collected indicate that the entry of Zn2+ through TRPC6 channels can up-regulate the size of the DTDP-sensitive pool of Zn2+. By showing that TRPC6 channels constitute a Zn2+ entry pathway, our study suggests that they could play a role in zinc homeostasis.
authors.affiliation: UMR CNRS 5249, CEA, DSV, IRTSV, Inserm U 836, Université Joseph Fourier, Grenoble, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Gibon
authors.forename: Peng
authors.initials: P
authors.lastname: Tu
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bohic
authors.forename: Pierre
authors.initials: P
authors.lastname: Richaud
authors.forename: Josiane
authors.initials: J
authors.lastname: Arnaud
authors.forename: Mike
authors.initials: M
authors.lastname: Zhu
authors.forename: Guylain
authors.initials: G
authors.lastname: Boulay
authors.forename: Alexandre
authors.initials: A
authors.lastname: Bouron
mesh_terms: D002460:Cell Line; D003124:Colorimetry; D005456:Fluorescent Dyes / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D050052:TRPC Cation Channels / Q000378:metabolism*; D000074287:TRPC6 Cation Channel; D015032:Zinc / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D015032:Zinc