To address this, we employed a Sugen/hypoxia (Su/H) mouse model of PAH and conducted in vitro studies using human PASMCs to determine the effects of MELK inhibition with OTS167 and MELK overexpression on vascular remodeling, PASMC behavior, and Hippo–YAP/TAZ signaling. This evidence concerns the gene YAP1 and pulmonary arterial hypertension.