Regulation of CacyBP/SIP expression by NFAT1 transcription factor

- Overexpression of NFAT1 increases the level of CacyBP/SIP protein and mRNA.
- Inhibition or activation of NFATs influences CacyBP/SIP expression.
- NFAT1 binds to its cognate binding sites within the CacyBP/SIP gene.
- Up-regulation of CacyBP/SIP by NFAT1 points to its role in the immune system.

In this work we have shown that NFAT1 transcription factor is involved in the regulation of CacyBP/SIP expression. We have demonstrated, by applying Western blot, RT-PCR and luciferase assay that the level of CacyBP/SIP increases upon NFAT1 overexpression. Moreover, inhibition or stimulation of NFAT transcriptional activity exerts a corresponding effect on the expression of CacyBP/SIP gene. Furthermore, EMSA and chromatin immunoprecipitation (ChIP) assay have shown that NFAT1 binds to its specific binding sites within the CacyBP/SIP gene. In conclusion, our data have shown for the first time the regulation of CacyBP/SIP gene expression by NFAT1. Since NFAT transcription factors are involved in processes related to immune response, these results indicate potential involvement of CacyBP/SIP in the immune system.