The TASK (TWIK-related Acid Sensitive K+) family of K2P is comprised of three members: TASK-1 (KCNK3); TASK-3 (KCNK9) and the non-functional TASK-5. Functional diversity of this family is increased by the formation of heterodimers between TASK-1 and TASK-3 and, perhaps, with TWIK-1, and by the interaction with auxiliary subunits such as coat protein 1, 14-3-3, p11 and syntaxin-8. They are thought to contribute to the background currents in many neuronal populations throughout the central nervous system, including cerebellar granule neurons, cerebral cortex, the brainstem Pre-Botzinger and retrotrapezoid regions, hippocampal neurons, thalamocortical relay neurons, hypoglossal and spinal cord motor neurons, dorsal vagal neurons. In peripheral tissues high levels of TASK-1 expression have been found in the carotid bodies, in the atrium of the heart; in neuroepithelial bodies of the lung and in PASMCs.