Voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. Forms tetrameric potassium- selective channels through which potassium ions pass in accordance with their electrochemical gradient. The channel alternates between opened and closed conformations in response to the voltage difference across the membrane. Can form functional homotetrameric channels and heterotetrameric channels that contain variable proportions of KCNA1, KCNA2, KCNA4, KCNA5, and possibly other family members as well; channel properties depend on the type of alpha subunits that are part of the channel (PubMed:12130714). Channel properties are modulated by cytoplasmic beta subunits that regulate the subcellular location of the alpha subunits and promote rapid inactivation (PubMed:12130714). Homotetrameric channels display rapid activation and slow inactivation (PubMed:12130714, PubMed:8505626). Required for normal electrical conduction including formation of the infranodal ventricular conduction system and normal action potential configuration, as a result of its interaction with XIRP2 (By similarity). May play a role in regulating the secretion of insulin in normal pancreatic islets. {ECO:0000250|UniProtKB:Q61762, ECO:0000269|PubMed:12130714, ECO:0000269|PubMed:17267549, ECO:0000269|PubMed:20018952, ECO:0000269|PubMed:36917789, ECO:0000269|PubMed:8505626}. [Isoform 2]: Exhibits a faster depolarization rate, reduced voltage-dependent recovery from inactivation and an excessive cumulative inactivation. . This is the function of KCNA5 (potassium voltage-gated channel subfamily A member 5, Ensembl gene identifier ENSG00000130037).