K_V4.1 is a voltage-dependent K⁺ channel that belongs to the Shal channel subfamily and includes two other members: K_V4.2 and K_V4.3.

K_V4.1 possesses the signature structure of the voltage-dependent K⁺ channels: six membrane-spanning domains with intracellular N- and C-termini. As with other members of the voltage-gated K⁺ channel superfamily, the functional channel is a tetramer that can be composed of more than one member of the Shal subfamily, i.e. heterotetramers of K_V4.1 and K_V4.2.

The K_V4 channels are characterized by activation at subthreshold membrane potentials, inactivate rapidly and recover from inactivation quickly compared with other voltage-dependent K⁺ channels. This type of current is known as transient A-type K⁺ currents. For example, depolarization-activated K⁺ currents in rat neostriatal cholinergic interneurons are predominantly of the A-type and attributable to coexpression of K_V4.1 and K_V4.2 subunits. The biophysical properties of the K_V4.1 subunit can be modified by its association with auxiliary b subunits such as KChIP1 that increase K_V4.1 current densities and accelerates both the inactivation and the recovery time.

K_V4.1 is highly expressed in the brain but is also expressed in peripheral tissues such as the colon, heart and lung.

The pharmacology of K_V4.1 has been less well studied than that of the other K_V4 members. K_V4.1 is sensitive to the classical K⁺ channel blockers, 4-aminopyridine and tetraethylammonium. Recently, HmTx1, a peptide blocker derived from the venom of the African tarantula Heteroscodra maculata, has been shown to be a potent K_V4.1 inhibitor.