Deleting the accessory subunit KChIP2 results in loss of Ito,f and increased IK,slow that maintains normal action potential configuration

KChIP2 deficiency eliminated HpTx-2-sensitive Ito,f, but had little impact on total APD, secondary to upregulation of 4-AP-sensitive IK,slow in association with increased KV1.5 expression. There is increased sensitivity to 4-AP-mediated APD prolongation in KChIP2−/−. Thus, KChIP2 seems important for murine repolarization in circumstances of reduced repolarization reserve.