Regulatory subunit of Kv4/D (Shal)-type voltage-gated rapidly inactivating A-type potassium channels. Modulates KCND2 channel density, inactivation kinetics and rate of recovery from inactivation in a calcium-dependent and isoform-specific manner (PubMed:11847232, PubMed:18957440, PubMed:23576435). Modulates KCND3/Kv4.3 currents (PubMed:23576435). Isoform 4 does not increase KCND2 expression at the cell membrane (PubMed:18957440). Isoform 4 retains KCND3 in the endoplasmic reticulum and negatively regulates its expression at the cell membrane. Component of heteromultimeric potassium channels (PubMed:23576435). Identified in potassium channel complexes containing KCND1, KCND2, KCND3, KCNIP1, KCNIP2, KCNIP3, KCNIP4, DPP6 and DPP10 (By similarity). Interacts with KCND2 (PubMed:11847232, PubMed:18957440). Interacts with KCND3 (By similarity). Interacts with the C-terminus of PSEN2 and probably PSEN1 (PubMed:11847232). Predominantly expressed in brain. The KIS (K-channel inactivation suppressor) domain is required for converting A-type Kv4 current to a slowly inactivating delayed rectifier potassium current. Belongs to the recoverin family.