STAT3 and pulmonary arterial hypertension: Studies also revealed the regulating role of STAT3/NFAT/Ca2+‐K+channels in PAH development.34 NFAT (nuclear factor of activated T cells) and Ca(2+)/calcineurin‐sensitive transcription factor, were shown to down‐regulate the K+ channels, leading to cell depolarization, increased calcium levels and cell proliferation.