Calcium-dependent gene expression is regulated with the NFAT transcription factor, which is activated with an increased concentration of free calcium ions in the cytosol. Transcriptional activation occurs upon NFAT dephosphorylation and conformational change, which enables its localization to the nucleus of the cell. However, several research groups have shown partial nuclear localization of NFAT even in the absence of calcium stimulation, which can cause unwanted transcriptional activation of target genes when NFAT is overexpressed. In this MSc thesis we fused cationic peptides to NFAT to enable its anchoring to the plasma membrane in the absence of stimulation, while the protein was released from the membrane only upon addition of calcium. In this way, we have shown decreased transcriptional activity of the reporter gene in the absence of calcium and maintained high levels of transcriptional activity upon stimulation. Cationic anchoring peptides represent an excellent tool for precise and efficient modulation of calcium-dependent transcriptional control.
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