Regulatory subunit of the voltage-gated potassium (Kv) channel which, when coassembled with KCNB1, modulates the kinetics parameters of the heterotetrameric channel namely the time course of activation, deactivation and inactivation and on the voltage-dependence of activation (PubMed:12060745, PubMed:19074135). Potassium channel subunit that does not form functional channels by itself (Probable) (PubMed:12060745). Reduces the deactivation rate (PubMed:12060745, PubMed:19074135). Modulates the threshold for activation by shifting by approximately 20 mV in hyperpolarizing direction (PubMed:12060745). Markedly changes the inactivation by shifting the voltage dependence of inactivation by approximately 40 mV in hyperpolarizing direction (PubMed:12060745). Acceleratee activation and enhances the time course of activation (PubMed:12060745). {ECO:0000269|PubMed:12060745, ECO:0000269|PubMed:19074135, ECO:0000305|PubMed:19074135}. This is the function of Ensembl gene identifier ENSG00000168418 (KCNG4, potassium voltage-gated channel modifier subfamily G member 4).