Regulatory subunit of Kv4/D (Shal)-type voltage-gated rapidly inactivating A-type potassium channels. Regulates channel density, inactivation kinetics and rate of recovery from inactivation in a calcium-dependent and isoform-specific manner. In vitro, modulates KCND1/Kv4.1 and KCND2/Kv4.2 currents. Increases the presence of KCND2 at the cell surface. Component of heteromultimeric potassium channels. Identified in potassium channel complexes containing KCND1, KCND2, KCND3, KCNIP1, KCNIP2, KCNIP3, KCNIP4, DPP6 and DPP10 (By similarity). Part of a heterooctamer composed of the tetrameric channel and four KCNIP1 chains. Interacts with KCND3 and the N-terminal domain of KCND2. Probably part of a complex consisting of KCNIP1, KCNIP2 isoform 3 and KCND2. Self-associates to form homodimers and homotetramers. Interacts with KCNIP2 isoform 3 in a calcium-dependent manner. Interacts with Naja atra venom CTX3. Isoform 1 and isoform 2 are expressed in brain and kidney. Isoform 1 is also expressed in liver, pancreas, skeletal muscle, small intestine and testis. Isoform 2 is also expressed in lung, pancreas, leukocytes, prostate and thymus. Belongs to the recoverin family.