The function of Ensembl gene identifier ENSG00000159197 (KCNE2, potassium voltage-gated channel subfamily E regulatory subunit 2) is as follows. Ancillary protein that functions as a regulatory subunit of the voltage-gated potassium (Kv) channel complex composed of pore- forming and potassium-conducting alpha subunits and of regulatory beta subunits (PubMed:10219239, PubMed:11034315, PubMed:11101505, PubMed:12185453, PubMed:20533308). KCNE2 beta subunit modulates the gating kinetics and enhances stability of the channel complex (PubMed:10219239, PubMed:11034315, PubMed:11101505, PubMed:12185453, PubMed:20533308). Alters the gating of the delayed rectifier Kv channel containing KCNB1 alpha subunit (PubMed:11101505, PubMed:20533308). Associates with KCNH2/HERG alpha subunit Kv channel to form the rapidly activating component of the delayed rectifying potassium current (IKr) in heart (PubMed:10219239, PubMed:12185453). May associate with KCNQ2 and/or KCNQ3 alpha subunits to modulate the native M-type current (PubMed:11034315). May associate with HCN1 and HCN2 channel subunits to increase potassium current (By similarity). Forms a heterooligomer complex with KCNQ1/KVLQT1 alpha subunits which leads to currents with an apparently instantaneous activation, a rapid deactivation process and a linear current-voltage relationship and decreases the amplitude of the outward current (PubMed:11101505). KCNQ1-KCNE2 channel associates with Na(+)-coupled myo-inositol symporter in the apical membrane of choroid plexus epithelium and regulates the myo-inositol gradient between blood and cerebrospinal fluid with an impact on neuron excitability (By similarity). {ECO:0000250|UniProtKB:P63161, ECO:0000250|UniProtKB:Q9D808, ECO:0000269|PubMed:10219239, ECO:0000269|PubMed:11034315, ECO:0000269|PubMed:11101505, ECO:0000269|PubMed:12185453, ECO:0000269|PubMed:20533308}.