Three groups of K+ channels have been identified: voltage-gated, inwardly rectifying, and weakly rectifying. The weakly rectifying K+ channels, which are open at rest and exhibit little time- or voltage-dependence, comprise dimers of subunits, each of which
contains four transmembrane domains and two pore domains. Within this family of weakly rectifying channels, the TASK channels
are known to be sensitive to acidic pH, hypoxia, temperature changes, and volatile anesthetics. Evidence suggests that the
subunits TASK-1 and TASK-3 might form heterodimers, in addition to homodimers, allowing for channels with intermediate properties.
What tasks, ahem, these channels participate in are discussed.