Potassium Channel Subfamily K, Member 9 (KCNK9)

KCNK9 contains structural features characteristic of the 2-pore channel family, including the canonical GYG/GFG sequences within the 2 channel pore regions, and a C terminus with 3 protein kinase C sites and a protein kinase A site. mRNA dot-blot analysis indicated expression mainly in neuronal tissue, particularly in cerebellum. KCNK9 exhibited a time-independent, noninactivating K(+)-selective current when expressed in COS-7 cells. The KCNK9 current was highly sensitive to changes in extracellular pH, a hallmark of the TASK family of K+ channels.KCNK9 was blocked by barium, quinidine, and lidocaine. Although the KCNK9 protein has multiple potential phosphorylation sites for protein kinases A and C, it is not regulated via phosphorylation by either kinase.