Calcium ions are important secondary messengers inside the cell that control various cellular processes, one of them being the activation of the NFAT transcription factor. The influx of calcium ions into the cell is, among other things, regulated by the transmembrane ion channels from the TRP family, many of which are sensitive to mechanical stimulation. The coupling of the calcium signal pathways with transgenes and molecules that detect external stimuli enables control over cellular functions. One of the possible means of control is ultrasound, which facilitates noninvasive and highly specific cell stimulation. We set out to determine the activity of ion channels TRPA1, TRPC1, TRPC3, TRPV1 and TRPV4, onto which we bound proteins eGFP, BFP or BFP-gs10-P4. The reporter system included firefly luciferase with ten binding sites for NFAT (10AB Pmin fluc) and the artificial transcription factor NFAT (mNFAT:TALE:VP16:KRφ). We showed that overexpression of ion channels can affect the influx of calcium ions into the cytosol of unstimulated cells and consequently, the transcription of the reporter gene. Good self-regulation was shown by the ion channels TRPV4, TRPC1 along with its constructs, and TRPA1 constructs. The mechanical sensitivity of the channels was determined by ultrasound stimulation. Cells with overexpressed channels TRPC1 and TRPV4 showed only slightly better response to the ultrasound, while the responses of TRPC3 and TRPV1 were more prominent. Because activity in non-induced cells is not desirable, it is important for further research that we use the appropriate quantity of the ion channels or its constructs e.g. TRPC1.
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