KCNK1 and idiopathic pulmonary arterial hypertension: In the present study, KCNK3/TASK1 (29.8 and 30.2% homology with KCNK1 and KCNK2, respectively) and KCNK6/TWIK2 (46.9 and 33.1%) channel expression at the protein level was slightly down-regulated by 18% and 21%, respectively, in PASMCs from IPAH patients.