KCNK17 is a K+ channel that conducts voltage-dependent outward rectifying currents upon membrane depolarisation. Its voltage sensing is coupled to the K+ electrochemical gradient in an "ion flux gating" mode, in which outward but not inward ion flow opens the gate. The channel is an open rectifier that primarily passes outward current under physiological K+ concentrations. It is also permeable to other monovalent cations such as Rb+ and Cs+, and the KCNK17 gene is activated at alkaline pH.

The KCNK17 protein belongs to the two pore domain potassium channel family (TC 1.A.1.8), whose members contain two pore-forming P domains. It homodimerises and heterodimerises to form functional channels with distinct regulatory and gating properties, so the subunit composition of a channel influences how it behaves. The protein is found at the cell membrane. Alternatively spliced transcript variants encoding different isoforms have been reported for the gene.

KCNK17 is present in the cardiac conduction system, where it may regulate the action potential duration and beating frequency of cardiac myocytes. The gene sits in the HGNC group of potassium two pore domain channel subfamily K members. It has been called TALK-2 and TASK-4 in the literature, and earlier HGNC names were potassium channel, subfamily K, member 17 and potassium channel, two pore domain subfamily K, member 17.