Mediates the voltage-dependent potassium ion permeability of excitable membranes. Has an important role in repolarization and in regulating the pattern of action potential firing. Isoform a expresses currents in a more depolarized voltage range than isoform d. Expressed in a variety of interneurons and sensory neurons, as well as body wall muscle. Delayed spike repolarization. Belongs to the potassium channel family. A (Shaker) (TC 1.A.1.2) subfamily. Shaker sub-subfamily.