Molecules and Cells Minireview Regulator of Calcineurin (RCAN): Beyond Down Syndrome Critical Region Sun-Kyung Lee1,2,* and Joohong Ahnn1,2,* 1Department of Life Science, 2Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea *Correspondence:
[email protected] (SKL);
[email protected] (JA) https://doi.org/10.14348/molcells.2020.0060 www.molcells.org The regulator of calcineurin (RCAN) was first reported as RCAN3 a novel gene called DSCR1, encoded in a region termed the Down syndrome critical region (DSCR) of human chromosome 21. Genome sequence comparisons across INTRODUCTION species using bioinformatics revealed three members of the RCAN gene family, RCAN1, RCAN2, and RCAN3, present in The regulator of calcineurin (RCAN) was first reported as a most jawed vertebrates, with one member observed in most Down syndrome critical region 1 (DSCR1), which is encoded invertebrates and fungi. RCAN is most highly expressed in in a region that at that time was thought to participate in the brain and striated muscles, but expression has been reported onset of Down syndrome (DS) (Antonarakis, 2017; Fuentes in many other tissues, as well, including the heart and et al., 1995). Soon after, evidence showed that RCAN binds kidneys. Expression levels of RCAN homologs are responsive to and regulates the Ca2+/calmodulin-dependent serine/thre- to external stressors such as reactive oxygen species, Ca2+, onine phosphatase calcineurin, whose substrates include nu- amyloid β, and hormonal changes and upregulated in clear factor of activated T cells (NFAT), the transcription factor pathological conditions, including Alzheimer’s disease, that regulates gene expression in many cell types, including cardiac hypertrophy, diabetes, and degenerative neuropathy.